bluuebunny/crossref_metadata_2025 huggingface dataset:
Retracted: Sphingosine kinase 1 regulates pro‐inflammatory responses triggered by TNFα in primary human monocytes
Authors: Zhi Liang , Leung Bernard P. , Melendez Alirio J.
Published: March 2006

Monocytes play an important role in inflammation, angiogenesis, and atherosclerosis. During these processes monocytes release pre‐formed proinflammatory mediators from granules, and synthesize de novo cytokines and chemokines important in the amplification of the inflammatory response. One of the most prominent triggers of inflammatory responses is the cytokine TNFα. However, the intracellular signaling cascades triggered by TNFα are not fully understood. In this study we investigated the roles of SPHK on the TNFα‐triggered responses on human primary monocytes. We show that TNFα rapidly triggers S1P generation and activation of SPHK. Moreover, our data shows that SPHK1 is the isoform activated by TNFα, and plays an essential role on the TNFα‐triggered intracellular Ca2+ signals, degranulation, cytokine production, and activation of NFκB, thus suggesting a pivotal role for SPHK1 on the proinflammatory responses triggered by TNFα. J. Cell. Physiol. © 2006 Wiley‐Liss, Inc.
Increased mobilization of c‐kit+ Sca‐1+ Lin− (KSL) cells and colony‐forming units in spleen (CFU‐S) following de novo formation of a stem cell niche depends on dynamic, but not stable, membranous ossification
Authors: Nagayoshi Kazunari , Ohkawa Hiroyuki , Yorozu Keigo , Higuchi Masato , Higashi Sayumi , Kubota Naoki , Fukui Hiroyasu , Imai Nobuo , Gojo Satoshi , Hata Jun‐ichi , Kobayashi Yoshiro , Umezawa Akihiro
Published: March 2006

Stem cells are thought to inhabit in a unique microenvironment, known as “niche,” in which they undergo asymmetric cell divisions that results in reproducing both stem cells and progenies to maintain various tissues throughout life. The cells of osteoblastic lineage have been identified as a key participant in regulating the number of hematopoietic stem cells (HSCs). HSCs receive their regulatory messages from the microenvironment in the bone marrow. This would account for a reason why the localization of hematopoiesis is usually restricted in the bone marrow. To clarify the above possibility we employed a cell implantation‐based strategy with a unique osteoblast cell line (KUSA‐A1) derived from a C3H/He mouse. The implantation of KUSA‐A 1 cells resulted in the generation of ectopic bones in the subcutaneous tissues of the athymic BALB/c nu/nu mice. Subsequently the mice obtained a greater amount of the bone marrow than normal mice, and they showed an increased number of HSCs. These results indicate that the newly generated osteoblasts‐derived ectopic bones are responsible for the increase in the number of the HSC population. Furthermore, the increased number of HSCs directly correlates with both the magnitude of dynamic osteogenic process and the size of the newly generated bone or “niche.” J. Cell. Physiol. © 2006 Wiley‐Liss, Inc.
Wnt induction of chondrocyte hypertrophy through the Runx2 transcription factor
Authors: Dong Yu‐Feng , Soung Do Y. , Schwarz Edward M. , O'Keefe Regis J. , Drissi Hicham
Published: March 2006

We investigated the molecular mechanisms underlying canonical Wnt‐mediated regulation of chondrocyte hypertrophy using chick upper sternal chondrocytes. Replication competent avian sarcoma (RCAS) viral over‐expression of Wnt8c and Wnt9a, upregulated type X collagen (col10a1) and Runx2 mRNA expression thereby inducing chondrocyte hypertrophy. Wnt8c and Wnt9a strongly inhibited mRNA levels of Sox9 and type II collagen (col2a1). Wnt8c further enhanced canonical bone morphogenetic proteins (BMP‐2)‐induced expression of Runx2 and col10a1 while Wnt8c and Wnt9a inhibited TGF‐β‐induced expression of Sox9 and col2a1. Over‐expression of β‐catenin mimics the effect of Wnt8c and Wnt9a by upregulating Runx2, col10a1, and alkaline phosphatase (AP) mRNA levels while it inhibits col2a1 transcription. Western blot analysis shows that Wnt8c and β‐catenin also induces Runx2 protein levels in chondrocytes. Thus, our results indicate that activation of the canonical β‐catenin Wnt signaling pathway induces chondrocyte hypertrophy and maturation. We further investigated the effects of β‐catenin‐TCF/Lef on Runx2 promoter. Co‐transfection of lymphoid enhancer factor (Lef1) and β‐catenin in chicken upper sternal chondrocytes together with deletion constructs of the Runx2 promoter shows that the proximal region spanning the first 128 base pairs of this promoter is responsible for the Wnt‐mediated induction of Runx2. Mutation of the TCF/Lef binding site in the −128 fragment of the Runx2 promoter resulted in loss of its responsiveness to β‐catenin. Additionally, gel‐shift assay analyses determined the DNA/protein interaction of the TCF/Lef binding sites on the Runx2 promoter. Finally, our site‐directed mutagenesis data demonstrated that the Runx2 site on type X collagen promoter is required for canonical Wnt induction of col10a1. Altogether we demonstrate that Wnt/β‐catenin signaling is regulated by TGF‐β and BMP‐2 in chick upper sternal chondrocytes, and mediates chondrocyte hypertrophy at least partly through activation of Runx2 which in turn may induce col10a1 expression. J. Cell. Physiol. © 2006 Wiley‐Liss, Inc.
p16 inhibits matrix metalloproteinase‐2 expression via suppression of Sp1‐mediated gene transcription
Authors: Wang Chie‐Hong , Chang Hui‐Chiu , Hung Wen‐Chun
Published: March 2006

Previous studies demonstrate that p16, a cyclin‐dependent kinase inhibitor and a tumor suppressor, may inhibit matrix metalloproteinase‐2 (MMP‐2) expression in human cancer cells to suppress tumor invasion and metastasis. However, the detailed mechanism is still unclear. Our results show that p16 inhibits MMP‐2 expression via transcriptional repression. Promoter deletion and mutation analysis indicates that p16 acts through the Sp1 transcription factor‐binding site located between −72 and −64 bp region from the transcriptional start site of the human MMP‐2 promoter to repress gene expression. DNA affinity precipitation assay (DAPA) and chromatin immuno‐precipitation (CHIP) assay demonstrate that Sp1 proteins constitutively bind to this consensus sequence in vitro and in vivo. p16 attenuates Sp1 binding to the MMP‐2 promoter to suppress gene transcription and overexpression of Sp1 may counteract p16‐induced downregulation of MMP‐2. CyclinA/CDK complex may directly phosphorylate Sp1 and enhance its DNA‐binding activity. Thus, we investigated the effect of p16 on the interaction between cyclin A and Sp1. Our results indicate that p16 induces downregulation of cyclin A and CDK2, reduces the interaction between cyclin A and Sp1, and attenuates phosphorylation of Sp1. Ectoexpression of cyclin A counteracts p16‐mdeiated inhibition of DNA binding of Sp1 and activates MMP‐2 promoter activity and mRNA expression. Collectively, our results suggest that p16 suppresses MMP‐2 by blocking Sp1‐mediated gene transcription. J. Cell. Physiol. © 2006 Wiley‐Liss, Inc.
Investigation of the electrochemical oxidation products of zotepine and their fragmentation using on‐line electrochemistry/electrospray ionization mass spectrometry
Authors: Nozaki Kazuyoshi , Kitagawa Hiroshi , Kimura Sumihisa , Kagayama Akira , Arakawa Ryuichi
Published: March 2006

When zotepine, an antipsychotic drug, was electrochemically oxidized using electrospray ionization mass spectrometry (ESI‐MS) coupled with a microflow electrolytic cell, [M + 16 + H]+ (m/z 348), [M—H]+ (m/z 330) and [M—14 + H]+ (m/z 318) were observed as electrochemical oxidation product ions (M represents the zotepine molecule). Although a major fragment ion that was derived from the dimethyl aminoethyl moiety was observed only at m/z 72 in the collision‐induced dissociation (CID) spectrum of zotepine, new fragments such as m/z 315 and 286 ions could be generated in the CID spectrum by combining electrochemical oxidation and CID. Since these fragments were relatively specific with high ion strength, it was thought that they would be useful for developing a sensitive LC‐MS/MS assay. The S‐oxide and N‐demethylated products were detected by electrolysis assuring that a portion of P450 metabolites of zotepine could be mimicked by the electrochemistry/electrospray ionization mass spectrometry (EC/ESI‐MS) system. Copyright © 2006 John Wiley & Sons, Ltd.
Blue natural organic dyestuffs—from textile dyeing to mural painting. Separation and characterization of coloring matters present in elderberry, logwood and indigo
Authors: Pawlak Katarzyna , Puchalska Maria , Miszczak Agata , Rosłoniec Elżbieta , Jarosz Maciej
Published: March 2006

Natural dyestuffs used for painting or dyeing of textiles are complex mixtures of compounds of various chemical properties. Proper identification of the dye used by a painter and, even better, its origin is possible only when its compositional ‘fingerprint’ can be evaluated. For this reason gradient program for liquid chromatographic separation of 16 color compounds—components of natural blue dyes: elderberry, logwood and indigo—has been developed. Two detector systems were used simultaneously: UV‐Vis spectrophotometry (at 280, 445, 520 and 600 nm) and ESI mass spectrometry (positive and negative SIM mode). It was found that fragmentation observed in ESI‐MS is affected not only by ion source parameters, but also by chromatographic conditions, especially in case of the less stable substances: cyanidin glucosides, tannic acid, rutin and hematoxylin. Examination of characteristic dissociation pathways of the compounds under investigation after direct admission into ion source or after chromatographic separation allowed to select proper ions for SIM detection and to develop novel and efficient reversed phase high performance liquid chromatographic (RP‐HPLC)—UV‐Vis/ESI‐MS method for the analysis of natural blue dyes. The procedure was successfully applied for identification of indigotin and carminic acid—main colorants extracted from a fiber taken from the blue–red ‘Italian’ tapestry (the collection of the National Museum in Warsaw, Poland). Copyright © 2006 John Wiley & Sons, Ltd.
A justification for using NMR model‐free methods when investigating the solution structures of rhombic paramagnetic lanthanide complexes
Authors: Terazzi Emmanuel , Rivera Jean‐Pierre , Ouali Nadjet , Piguet Claude
Published: March 2006

The detailed analysis of the 1H NMR hyperfine shifts according to the model‐free methods shows that the semi‐rigid monometallic complexes [Ln(L)(NO3)3] (Ln = Eu–Yb) are isostructural in solution. The associated separation of contact and pseudo‐contact contributions to the hyperfine NMR shifts in each rhombic lanthanide complex at room temperature provides paramagnetic susceptibility tensors whose principal magnetic axes match the expected symmetry requirements. Moreover, both axial (Δχax) and rhombic (Δχrh) paramagnetic anisotropies display satisfactory linear dependence on Bleaney's factors, a correlation predicted by the approximate high‐temperature expansion of the magnetic susceptibility limited to T−2. Consequently, the simple, and chemically attracting NMR model‐free methods are not limited to axial systems, and can be safely used for the investigation of the solution structures of any lanthanide complexes. Molecular‐based structural criteria for the reliable estimation of paramagnetic susceptibility tensors by NMR are discussed, together with the assignment of the labels of the crystal‐field and magnetic axes within Bleaney's approach. Copyright © 2006 John Wiley & Sons, Ltd.
Production of cloned goats by nuclear transfer of cumulus cells and long‐term cultured fetal fibroblast cells into abattoir‐derived oocytes
Authors: Lan Guo‐Cheng , Chang Zhong‐Le , Luo Ming‐Jiu , Jiang Yun‐Liang , Han Dong , Wu Yan‐Guang , Han Zheng‐Bin , Ma Suo‐Feng , Tan Jing‐He
Published: March 2006

Dairy goats are ideal for the transgenic production of therapeutic recombinant proteins. The use of recombinant somatic cell lines for nuclear transfer (NT) allows the introduction of genes by transfection, increases the efficiency of transgenic animal production to 100%, and overcomes the problem of founder mosaicism. Although viable animals have been cloned via NT from somatic cells of 11 species, the efficiency has been extremely low. Both blastomere and somatic cell NT increased fetal loss and perinatal morbidity/mortality in cattle and sheep, but fetal loss and perinatal mortality appear to be relatively low in goats. In this study, we produced cloned goats by NT from cumulus cells and long‐term cultured fetal fibroblast cells (FFCs) to abattoir‐derived oocytes. NT embryos were constructed from electrofusion of cumulus cells (CCs), FFCs, or skin fibroblast cells (SFCs) with cytoplasts prepared from abattoir‐derived ovaries. The NT embryos were activated with an optimized activating protocol (1 min exposure to 2.5 µM ionomycin followed by 2 hr incubation in 2mM 6‐DMAP). Two viable cloned kids from CCs and one from long‐term cultured FFCs (at passage 20–25) were born. Microsatellite analysis of 10 markers confirmed that all cloned offspring were derived from corresponding donor cells. To our knowledge, the production of cloned goat offspring using abattoir‐derived oocytes receiving nuclei from CCs and long‐term cultured FFCs has not been reported. The production of viable cloned animals after activation with reduced intensity of ionomycin and 6‐DMAP treatment has also not been reported. Loss of cloned embryos was obvious after 45 and 90 days of pregnancy, and a lack of cotyledons, heart defects, and improperly closed abdominal wall were observed in the aborted fetuses and one cloned kid. The fusibility and in vitro developmental potential of embryos reconstructed from FFCs at passage 20–25 were significantly lower than those of embryos reconstructed from FFCs at passage 3–5, and the cloning efficiency of the long‐term cultured cells was low (0.5%). Mol. Reprod. Dev. © 2006 Wiley‐Liss, Inc.
Pseudospectral method for MHD pipe flow
Authors: Carabineanu Adrian , Lungu Emil
Published: March 2006

The paper deals with MHD flow in pipes with arbitrary wall conductivity under the influence of a transverse magnetic field. We employ the pseudospectral collocation method for obtaining a numerical solution of the problem. The numerical results are compared with analytical ones in the case of pipe with insulating walls. We notice that the magnetic field is slowing the motion. Copyright © 2006 John Wiley & Sons, Ltd.
Continuum‐based design sensitivity analysis and optimization of nonlinear shell structures using meshfree method
Authors: Yi Kiyoung , Choi K. K. , Kim Nam H. , Botkin Mark E.
Published: March 2006

A continuum‐based shape and configuration design sensitivity analysis (DSA) method for a finite deformation elastoplastic shell structure has been developed. Shell elastoplasticity is treated using the projection method that performs the return mapping on the subspace defined by the zero‐normal stress condition. An incrementally objective integration scheme is used in the context of finite deformation shell analysis, wherein the stress objectivity is preserved for finite rotation increments. The material derivative concept is used to develop a continuum‐based shape and configuration DSA method. Significant computational efficiency is obtained by solving the design sensitivity equation without iteration at each converged load step using the same consistent tangent stiffness matrix. Numerical implementation of the proposed shape and configuration DSA is carried out using the meshfree method. The accuracy and efficiency of the proposed method is illustrated using numerical examples. Copyright © 2006 John Wiley & Sons, Ltd.
Design and testing of a virtual environment to train stroke patients with unilateral spatial neglect to cross a street safely
Authors: Weiss Patrice L. (Tamar) , Naveh Yuval , Katz Noomi
Published: March 2006

Virtual reality (VR) entails the use of advanced technologies, including computers and various multimedia peripherals, to produce a simulated (that is, virtual) environment that users perceive as comparable to real world objects and events. In recent years, virtual reality technologies have begun to be used as an assessment and treatment tool in occupational therapy, in part because of the ability to create environments that provide patients with opportunities to engage in meaningful, purposeful tasks that are related to real‐life interests and activities. The objective of this study was to determine the suitability and feasibility of using a PC‐based, nonimmersive, VR system (that is, a system in which the user has a reduced sense of actual presence in and control over the simulated environment) for training individuals with unilateral spatial neglect to cross streets in a safe and vigilant manner. A virtual environment, consisting of a typical city street, was programmed using Superscape's™TM 3D‐Webmaster, a 3D web‐authoring tool. Twelve subjects, aged 55 to 75 years, participated in the initial feasibility study and, to date, a further eight subjects have participated in the intervention study. Six of the initial subjects and all eight of the intervention subjects had sustained a right hemispheric stroke at least 6 weeks prior to the study. The remaining subjects were healthy age‐matched adults who were independently mobile and had no difficulty in crossing streets. The results show that this virtual environment was suitable in both its cognitive and motor demands for the targeted population and indicate that the virtual reality training is likely to prove beneficial to people who have difficulty with crossing streets. The generalizability of these results, and recommendations regarding the use of virtual reality as an occupational therapy intervention, must be substantiated by further studies using a range of VR platforms with people with different cognitive and motor disabilities. Copyright © 2003 Whurr Publishers Ltd.
Intelligent transport systems and occupational therapy practice
Authors: Stefano Marilyn Di , Macdonald Wendy
Published: March 2006

This paper explores some of the most widely available in‐vehicle information technology systems (intelligent transport systems, or ITSs) and discusses their implications for occupational therapy practice. Therapists often evaluate the impact of functional impairment on driving ability and, with an ageing population, the need for such assessments is increasing. Concurrently, ITSs are becoming increasingly common and it is important that their potential effects on both driving task demand and crash risk are considered by therapists when assessing drivers. Interactions between drivers and ITSs are analysed in an information processing framework, highlighting the importance of drivers' cognitive functioning. It is evident that the ability to use an ITS while driving is influenced by a driver's sensory, perceptual, cognitive and motor capacities and skills, all of which are likely to vary with age, disability and/or driving experience. The compatibility of ITS interface design with drivers' capacities and needs is crucial in determining how effectively, and safely, a particular system will be used. Therapists need to analyse interface demands in relation to the ability of individual drivers to cope with or benefit from an ITS, and to consider the potential for calibrating particular products to the specific requirements of individual drivers. It is concluded that many ITSs are at an early stage of development and should not be recommended without critical evaluation of their utility, usability and safety for the intended users. Therapists face the challenge of understanding the parameters and implications of ITSs so that they can assist their clients to optimize their occupational performance despite functional limitations, while also protecting the safety of other road users. Standards related to interface design are still undergoing development, and there is an urgent need for further research to evaluate the impact of vehicle technologies on human behaviour and road safety. Copyright © 2003 Whurr Publishers Ltd.
Acoustical force nanolithography of thin polymer films
Authors: Rubio‐Sierra F. J. , Yurtsever A. , Hennemeyer M. , Heckl W. M. , Stark R. W.
Published: March 2006

Nanomachining of thin polymer resist films with an atomic force microscope (AFM) is a promising route for the fabrication of nanoscale devices. In order to enhance the controllability of the nanomachining process an in‐plane acoustic wave is coupled to the sample support. This enhances the intermittent force exerted by the AFM tip. The lateral resolution reached by this method is only limited by the physical size of the AFM tip to dimensions far below the light diffraction limit. The main process parameters are the frequency and magnitude of the acoustic wave, and the preloading force. In this work, the feasibility of acoustical force lithography and the influence of the relevant parameters are investigated. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Detection of 28 neurotransmitters and related compounds in biological fluids by liquid chromatography/tandem mass spectrometry
Authors: Bourcier Sophie , Benoist Jean‐François , Clerc Frédéric , Rigal Odile , Taghi Méryam , Hoppilliard Yannik
Published: March 2006

This work presents two liquid chromatography/tandem mass spectrometry (LC/MS/MS) acquisition modes: multiple reaction monitoring (MRM) and neutral loss scan (NL), for the analysis of 28 compounds in a mixture. This mixture includes 21 compounds related to the metabolism of three amino acids: tyrosine, tryptophan and glutamic acid, two pterins and five deuterated compounds used as internal standards. The identification of compounds is achieved using the retention times (RT) and the characteristic fragmentations of ionized compounds. The acquisition modes used for the detection of characteristic ions turned out to be complementary: the identification of expected compounds only is feasible by MRM while expected and unexpected compounds are detected by NL. In the first part of this work, the fragmentations characterizing each molecule of interest are described. These fragmentations are used in the second part for the detection by MRM and NL of selected compounds in mixture with and without biological fluids. Any preliminary extraction precedes the analysis of compounds in biological fluids. Copyright © 2006 John Wiley & Sons, Ltd.
The nature of being: a thomistic perspective related to health and healing
Authors: Leathard Helen L.
Published: March 2006

This study explores the coherence between postmodern perspectives on holistic health and healing and Thomas Aquinas' theory of the nature of being. It elucidates Aquinas' account of the nature of being as encompassing the being of God as act (willing), as goodness and as love; the being of creatures as created, loved and destined for eternal life united with God; and, finally, being as relationality. This concept of the nature of being is then explicated, using quotations from contemporary sources, as providing an explanatory epistemology of postmodern healthcare professionals' rediscovery that ‘being with’ patients and clients is commonly much more conducive to their healing than ‘doing for’ them. Copyright © 2004 Whurr Publishers Ltd.
God sends us nothing but angels
Authors: Landman Angus
Published: March 2006

God sends us nothing but angels represents the core vision of a radical psychospiritual perspective, wherein all symptoms are understood as symptomatic of the fundamental human wound of forgetfulness, arising in the form of mistaken identity. We are not who we think we are and the reality we perceive is no more than a perception based on this mistaken identity. We think we are awake but in reality we are only dreaming. To awaken we need something that breaks through the dream to remind us of who we really are when Awakened. That ‘something’ is something which to the dreamer appears unbidden and unwanted, but to the Awakened One, angelic. That something is the perceived experience of death in all its different forms. Death heralding life heralding death. Copyright © 2004 Whurr Publishers Ltd.
Icarus versus King David: two sides of the evolution toward the self
Authors: Javanbakht Arash
Published: March 2006

According to psychoanalysis and analytical psychology schools, myth and religious stories are believed to be the representatives of the intrapsychic life. They symbolize the evolution, interactions of elements, fears, hopes, failures and growth of the human psyche that is reflected in the language of symbolic stories. An archetype is a universal form or predisposition to characterize thoughts or feelings–an unlearned tendency to experience things in a certain way that can evoke powerful emotions in the reader or the audience because it awakens a primordial image of the unconscious memory. Myths, legends and religious stories are full of archetypes, which enhances their power to affect us at an unconscious level as well as at a conscious one. Through these legends, myths and religious stories, analytical psychologists seek the traces of human psychic nature and unconscious life. These legends and stories can also be of diagnostic and therapeutic help because they can be guidelines to the steps of psychic evolution and its challenges. They may also be used for helping people to know where they are in their journey toward the so‐called process of individuation. In this report the symbolism of two spontaneous pictures of Icarus and King David that recurrently entered the consciousness of a well‐socialized young man are discussed and compared. Copyright © 2004 Whurr Publishers Ltd.
Using song as a means of connecting with truth: an experiential approach involving the whole person
Authors: Rakusen Jill
Published: March 2006

Following a session held at the 2003 International Spirituality and Health Conference, a self‐help, inclusive approach to the use of song is explored, called Giving Voice. Examples are given of how a wide variety of individuals, including the author, have harnessed it during sessions or courses and also in daily life. Anecdotal evidence of its effects is presented, with particular reference to the experience of connecting with truth and the internal sacred space. The process and mechanisms through which these effects occur are considered, in particular the roles of choice, willingness and responsibility. The relationship of this approach to religious beliefs (including absence or distrust thereof) is examined, and conclusions are drawn in relation to the awesome potential that lies at the heart of song. Copyright © 2004 Whurr Publishers Ltd.
A free convection crop dryer fired with kerosene
Authors: Williams JO , Babarinsa FA
Published: March 2006

The hot air dryer comprises a firing compartment, heat exchanger and drying chamber. It was evaluated by drying cassava chips at 50–57°C and compared with traditional sun drying at 21–28°C. Drying times were reduced by 67% and the product was of higher quality in terms of colour and appearance. Copyright © 2003 Whurr Publishers Ltd
Effect of harvest age on the storability of four sweetpotato varieties in an indoor barn
Authors: Okwuowulu PA
Published: March 2006

The rate of sprouting decreased as the duration of storage increased from 1 to 3 months and differed significantly among four sweetpotato varieties. TIS 8441 sprouted most and TIS 2534 least. Weight loss and rotting also differed significantly, with varieties, TIS 8441 suffering most and TIS 87/0087 or TIS 2534 least. Age at harvest significantly affected storability. Roots harvested 3 months after planting deteriorated most as a result of sprouting and weight loss but rotted least. Roots harvested 5 months after planting were most prone to rotting during storage. Application of potassium fertilizer did not significantly affect sprouting, weight loss and rotting. Copyright © 2003 Whurr Publishers Ltd
Effect of plant height at cutting and fertilizer on growth of Napier grass (Pennisetum purpureum)
Authors: Zewdu Tessema , Baars RMT , Yami Alemu
Published: March 2006

The dry matter yield (DMY) of Napier grass was significantly affected by plant height at cutting, fertilizer application and their interaction. The highest yield, 12.34 t/ha, was from cutting at 1.0 m with 92 kg N kg/ha. Plant height at cutting had a significant positive effect on number of leaves per tiller and per plant. The internodes and internode length per tiller, the number of tillers per plant and basal circumference were positively affected by both plant height at cutting and fertilizer application, but the effect of leaf:stem ratio on DMY was negative. Copyright © 2003 Whurr Publishers Ltd
Synthesis, Characterization of a Novel 1,2,4‐Thiotriazine Derivative (CAMTTO), and Copper(I) and Silver(I) Complexes thereof (CAMTTO = {(4‐[(4‐Chlorobenzylidene)‐amino]‐6‐methyl‐3‐thioxo‐[1,2,4]‐triazin‐3,4‐dihydro(2H)‐5‐one)}
Authors: Ghassemzadeh Mitra , Tabatabaee Masoomeh , Pooramini Mostafa M. , Heravi Majid M. , Eslami Abbas , Neumüller Bernhard
Published: March 2006

The reaction of 4‐amino‐6‐methyl‐1,2,4‐triazin‐thione‐5‐one (H2AMTTO, 1) with 4‐chlorobenzaldhyde led to the corresponding iminic compound {(4‐[(4‐chloro‐benzylidene)‐amino]‐6‐methyl‐3‐thioxo[1,2,4]‐triazin‐3,4‐dihydro(2H)‐5‐one), CAMTTO (2). Treatment of 2 with copper(I) chloride in chloroform gave the dimeric complex [{(CAMTTO)2CuCl}2]·2CHCl3 (3). Treatment of 2 with copper(I) chloride and silver(I) nitrate in the presence of the co‐ligand triphenylphophane gave the complexes [(CAMTTO)CuCl(PPh3)2] (4) and [(CAMTTO)Ag(PPh3)2]NO3·2CHCl3 (5). All compounds have been characterized by elemental analyses, 1H NMR spectroscopy, IR spectroscopy, and partly by mass spectrometry and X‐ray diffraction studies. In addition 4 and 5 have been characterized by 31P{1H} NMR spectroscopy. Crystal data for 2 at −80 °C: monoclinic, space group P21/c, a = 1370.3(1), b = 767.8(1), c = 1268.7(1) pm, β = 107.12(1)°, Z = 4, R1 = 0.0379; for 3 at −80 °C: monoclinic, space group P21/c, a = 1442.6(2), b = 878.8(1), c = 2558.7(3) pm, β = 95.31(1)°, Z = 2, R1 = 0.0746; for 4 at −80 °C: triclinic, space group ${\rm P}{\bar 1}$, a = 1287.9(1), b = 1291.7(1), c = 1359.5(1) pm, α = 90.44(1)°, β = 94.81(1)°, γ = 107.54(1)°, Z = 2, R1 = 0.0359 and for 5 at −80 °C: triclinic, space group ${\rm P}{\bar 1}$, a = 1060.5(1), b = 1578.2(2), c = 1689.6(2) pm, α = 87.70(1)°, β = 86.66(1)°, γ = 76.84(1)°, Z = 2, R1 = 0.0487.
Copper(I) and Gold(I) Complexes with N,N′‐Bis(diphenylphosphino)‐2,6‐diaminopyridine as Ligand: Synthesis and Molecular Structures
Authors: Pan Zhida , Gamer Michael T. , Roesky Peter W.
Published: March 2006

Reaction of CuI with 1 or 2 equivalent(s) N,N′‐Bis(diphenylphosphino)‐2,6‐diaminopyridine (BDDP) gives two different complexes, [Cu(I)μ‐(BDDP‐κP,Npy)]2 (1) and [Cu(BDDP‐κP,Npy)2]I (2), in high yields. The determination of the molecular structure show that both CuI atoms are tetrahedrally coordinated, rather than a square‐planar geometry reported for Cr0, NiII‐BDDP complexes before, which contains a planar tridentate chelate ring system. The introduction of AuCl(tht) (tht = tetrahydrothiophene) into [Cu(BDDP‐κP,Npy)2]I leads unexpectedly to the formation of a digold complex 2,6‐[(ClAuPh2P)HN]2C5H3N and dimeric [Cu(I)μ‐(BDDP‐κP,Npy)]2.
Preparation and Characterization of Dinuclear Chromium(III) Complexes of a Hexadentate Tetraaza‐Dithiophenolate Ligand
Authors: Siedle Gabriel , Kersting Berthold
Published: March 2006

The ability of the tetraaza‐dithiophenolate ligand H2L2 (H2L2 = N,N′‐Bis‐[2‐thio‐3‐aminomethyl‐5‐tert‐butyl‐benzyl]propane‐1,3‐diamine) to form dinuclear chromium(III) complexes has been examined. Reaction of CrIICl2 with H2L2 in methanol in the presence of base followed by air‐oxidation afforded cis,cis‐[(L2)CrIII2(μ‐OH)(Cl)2]+ (1a) and trans,trans‐[(L2)CrIII2(μ‐OH)(Cl)2]+ (1b). Both compounds contain a confacial bioctahedral N2ClCrIII(μ‐SR)2(μ‐OH)CrIIIClN2 core. The isomers differ in the mutual orientation of the coligands and the conformation of the supporting ligand. In 1a both Cl− ligands are cis to the bridging OH function. In 1b they are in trans‐positions. Reaction of the hydroxo‐bridged complexes with HCl yielded the chloro‐bridged cations cis,cis‐[(L2)CrIII2(μ‐Cl)(Cl)2]+ (2a) and trans,trans‐[(L2)CrIII2(μ‐Cl)(Cl)2]Cl (2b), respectively. These bridge substitutions proceed with retention of the structures of the parent complexes 1a and 1b.
Synthese, Kristallstruktur und spektroskopische Charakterisierung von [Au12(PPh)2(P2Ph2)2(dppm)4Cl2]Cl2
Authors: Sevillano Paloma , Fuhr Olaf , Matern Eberhard , Fenske Dieter
Published: March 2006

Synthesis, Crystal Structure and Spectroscopic Characterization of [Au12(PPh)2(P2Ph2)2(dppm)4Cl2]Cl2

The reaction of [(AuCl)2dppm] (dppm = Ph2PCH2PPh2) with P(Ph)(SiMe3)2 in CHCl3 results in the formation of [Au12(PPh)2(P2Ph2)2(dppm)4Cl2]Cl2 (1), the crystal structure of which was determined by single crystal X‐ray analysis (space group P21/c, a = 1425.3(3) pm, b = 2803.7(6) pm, c = 2255.0(5) pm, β = 95.00(3)°, V = 8977(3)·106 pm3, Z = 2). The dication in 1 consists of two Au6P3 units built by highly distorted Au3P and Au2P2 heterotetrahedra, connected via four bidentate phosphine ligands. Additionally, the compound was characterized by IR‐, UV‐ and NMR spectroscopy. The 31P{1H} NMR spectrum is discussed in detail.
Die Reaktion des Digalliumsubiodids R(I)Ga‐Ga(I)R [R = C(SiMe3)3] mit Lithium‐diphenylphosphanid – radikalische Öffnung der Ga‐Ga‐Bindung
Authors: Uhl Werner , El‐Hamdan Abdel Hakim
Published: March 2006

The Reaction of the Digallium Subiodide R(I)Ga‐Ga(I)R [R = C(SiMe3)3] with Lithium Diphenylphosphanide – Radical Cleavage of the Ga‐Ga Bond

The easily available organoelement digallium(II) subiodide R(I)Ga‐Ga(I)R (1) [R = C(SiMe3)3] reacted with two equivalents of lithium diphenylphosphanide in toluene by the replacement of both iodine atoms by two phosphanido groups. The product, [R(H)Ga‐P(C6H5)2]2 (2), contains a four‐membered Ga2P2 heterocycle without direct Ga‐Ga bonding interactions and the gallium atoms exclusively in an oxidation state of +III. They are attached to hydrogen atoms, which may result from a reaction of a reactive intermediate with the solvent.
Synthese, Struktur und Eigenschaften der Komplexe [(H2O)Cl4Os≡N‐IrCl(C5Me5)(AsPh3)], [(Ph3Sb)Cl4Os≡N‐IrCl(C5Me5)(SbPh3)], [(Ph3Sb)2Cl3Os≡N‐IrCl(COD)] und [{(Me2PhP)2(CO)Cl2Re≡N}2ReNCl2(PMe2Ph)]
Authors: Morrogh Daniel , Schwarz Simon , Maichle‐Mössmer Cäcilia , Strähle Joachim
Published: March 2006

Synthesis, Crystal Structure, and Properties of the Complexes [(H2O)Cl4Os≡N‐IrCl(C5Me5)(AsPh3)], [(Ph3Sb)Cl4Os≡N‐IrCl(C5Me5)(SbPh3)], [(Ph3Sb)2Cl3Os≡N‐IrCl(COD)] and [{(Me2PhP)2(CO)Cl2Re≡N}2ReNCl2(PMe2Ph)]

The dinuclear complexes [(H2O)Cl4Os≡N‐IrCl(C5Me5)(AsPh3)]·H2O (1·H2O), [(Ph3Sb)Cl4Os≡N‐IrCl(C5Me5)(SbPh3)] (2), and [(Ph3Sb)2Cl3Os≡N‐IrCl(COD)] (3) result from the reaction of the nitrido complexes [(Ph3As)2OsNCl3] and [(Ph3Sb)2OsNCl3] with the iridium compounds [IrCl2(C5Me5)]2 and [IrCl(COD)]2 in dichloromethane. 1 crystallizes as 1·H2O in form of green platelets in the monoclinic space group Cm and a = 1105.53(6); b = 1486.76(9); c = 2024.88(10) pm, β = 97.191(4)°, Z = 4. The formation of 1 in air involves a ligand exchange, and the coordination of a water molecule in trans position to the Os‐N triple bond. The resulting complex fragments [(H2O)Cl4Os≡N] and [IrCl(C5Me5)(AsPh3)] are connected by an asymmetric nitrido bridge Os≡N‐Ir. The nitrido bridge is characterised by an Os‐N‐Ir bond angle of 173.7(7)°, and distances Os‐N = 168(1) pm and Ir‐N = 191(1) pm. 2 crystallizes in clumped together brown platelets with the space group ${\rm P}{\bar 1}$ and a = 1023.3(3), b = 1476.2(3), c = 1872.5(6) pm, α = 74.60(2), β = 73.84(2), γ = 76.19(2)°, Z = 2. In 2 the asymmetric nitrido bridge Os≡N‐Ir joins the two complex fragments [(Ph3Sb)Cl4Os≡N] and [IrCl(C5Me5)(SbPh3)], which are formed by a ligand exchange reaction. 3 forms dark green crystals with the triclinic space group ${\rm P}{\bar 1}$ and a = 1079.4(1), b = 1172.3(1), c = 1696.7(2) pm, α = 101.192(9),β = 92.70(1), γ = 92.61(1)°, Z = 2. The distances in the almost linear nitrido bridge (Os≡N‐Ir = 175.3(7)°) are Os‐N = 171(1) pm and Ir‐N = 183(1) pm. The reaction of [ReNCl2(PMe2Ph)3] with [Mo(CO)3(NCMe)3] unexpectedly affords the trinuclear complex [{(Me2PhP)2(OC)Cl2Re≡N}2ReNCl2(PMe2Ph)] (4) as the main product. It forms triclinic brown crystals with the composition 4·2THF and the space group ${\rm P}{\bar 1}$ (a = 1382.70(7), b = 1498.58(7), c = 1760.4(1) pm, α = 99.780(7), β = 99.920(7), γ = 114.064(6)°, Z = 2). In the trinuclear complex, the central fragment, [ReNCl2(PMe2Ph)] is joined in trans position to two nitrido complexes [(Me2PhP)2(CO)Cl2Re≡N], giving an almost linear Re≡N‐Re‐N≡Re arrangement. The bond angles and distances in the nitrido bridges are Re‐N‐Re = 167.8(3)°, Re‐N = 171.1(8) pm and 204.2(8) pm; and Re‐N‐Re = 168.1(4)°, Re‐N = 170.9(9) and 203.5(9) pm respectively. As expected, the Re‐N bond length to the terminal nitrido ligand on the central Re atom is much shorter at 161.2(9) pm than the triple bonds of the asymmetric bridges.
A Diazabutadiene stabilized Nickel(0) Cyclooctadiene Complex: Synthesis, Characterization and the Reaction with Diphenylacetylene
Authors: Schaub Thomas , Radius Udo
Published: March 2006

The reaction of [Ni(COD)2] with one equivalent of DABMes (DABMes = (2,4,6‐Me3C6H2)N=C(Me)‐C(Me)=N(2,4,6‐Me3C6H2)) affords a mixture of the compound [Ni(DABMes)2] (2) and starting material [Ni(COD)2]. The crystallographically characterized, diamagnetic complex 2 can be obtained in a stoichiometric reaction of [Ni(COD)2] and two equivalents of DABMes. This reaction can be accelerated by addition of 1‐chloro‐fluorobenzene or methyl iodide. In the presence of 1‐chloro‐fluorobenzene, [Ni(DABMes)(COD)] (3) is available via reaction of [Ni(COD)2] and one equivalent of DABMes. The crystallographically characterized complex 3 reacts with diphenylacetylene to afford [Ni(DABMes)(Ph‐C≡C‐Ph)] (4). A long‐wavelength absorption band in the UV‐Vis spectrum of this compound has to be assigned to a mixed MLCT/LL′CT transition, as quantum chemical calculations reveal.
Theoretical Studies of Inorganic Compounds. 361) Structures and Bonding Analyses of Beryllium Chloro Complexes with Nitrogen Donors
Authors: Metz Sebastian , Holthausen Max C. , Frenking Gernot
Published: March 2006

Quantum chemical calculations at various levels of theory (BP86, B3LYP, MP2, CCSD(T), CBS‐QB3) of the beryllium complexes [BeCl2(NHPH3)], [BeCl2(NHPH3)2], [BeCl3(py)]−, [BeCl2(NH3)], [BeCl2(NH3)2], [BeCl3(py)]− and [BeCl3(NH3)]− as well as the boron compounds [BCl3(py)] and [BCl3(NH3)] show that BeCl2 is a very strong Lewis acid. The theoretically predicted bond dissociation energy at CBS‐QB3 of Cl2Be‐NH3 (De = 32.5 kcal/mol)is even higher than that of Cl3B‐NH3 (De = 28.6 kcal/mol). Even the second ammonia molecule in [BeCl2(NH3)2] still has a strong bond with De = 24.2 kcal/mol. The theoretically predicted bond strengths for the phosphaneimine ligands in [BeCl2(NHPH3)2] are De = 46.7 kcal/mol for the first ligand and De = 29.8 kcal/mol for the second. The anion BeCl3− is a moderately strong Lewis acid which has bond energies of De = 14.1 kcal/mol in [BeCl3(py)]− and De = 14.2 kcal/mol in [BeCl3(NH3)]−. The higher bond energy of [BeCl2(NH3)] compared with [BCl3(NH3)] comes from less deformation energy for BeCl2 than for BCl3. The intrinsic attraction between BeCl2 and NH3 calculated with frozen geometries of the complex geometry is ∼5 kcal/mol less than the attraction between BCl3 and NH3. The bonding analysis with the EDA method shows that the attractive energy of the beryllium complexes comes manly from electrostatic attraction. The larger contribution of the electrostatic term is the most significant difference between the nature of the donor‐acceptor bonds of the beryllium and boron complexes.
Influence of the Counterions on the Structures of Ternary Zn/Sn/Se Anions: Synthesis and Properties of [Rb10(H2O)14.5][Zn4(μ4‐Se)2(SnSe4)4] and [Ba5(H2O)32][Zn5Sn(μ3‐Se)4(SnSe4)4]
Authors: Ruzin Eugen , Dehnen Stefanie
Published: March 2006

Reactions of rubidium or barium salts of the ortho‐selenostannate anion, [Rb4(H2O)4][SnSe4] (1) or [Ba2(H2O)5][SnSe4] (2) with Zn(OAc)2 or ZnCl2 in aqueous solution yielded two novel compounds with different ternary Zn/Sn/Se anions, [Rb10(H2O)14.5][Zn4(μ4‐Se)2(SnSe4)4] (3) and [Ba5(H2O)32][Zn5Sn(μ3‐Se)4(SnSe4)4] (4). 1 – 4 have been determined by means of single crystal X‐ray diffraction: 1: triclinic space group $P{\bar 1}$ lattice dimensions at 203 K: a = 8.2582(17) Å, b = 10.634(2) Å, c = 10.922(2) Å, α = 110.16(3)°, β = 91.74(3)°, γ = 97.86(3)°, V = 888.8(3) Å3; R1 [I > 2σ(I)] = 0.0669; wR2 = 0.1619; 2: orthorhombic space group Pnma; lattice dimensions at 203 K: a = 17.828(4) Å, b = 11.101(2) Å, c = 6.7784(14) Å, V = 1341.5(5) Å3; R1 [I > 2σ(I)] = 0.0561; wR2 = 0.1523; 3: triclinic space group $P{\bar 1}$; lattice dimension at 203 K: a = 17.431(4) Å, b = 17.459(4) Å, c = 22.730(5) Å, α = 105.82(3)°, β = 99.17(3)°, γ = 90.06(3)°, V = 6563.1(2) Å3; R1 [I > 2σ(I)] = 0.0822; wR2 = 0.1782; 4: monoclinic space group P21/c; lattice dimensions at 203 K: a = 25.231(5) Å, b = 24.776(5) Å, c = 25.396(5) Å, β = 106.59(3)°, V = 15215.0(5) Å3; R1 [I > 2σ(I)] = 0.0767; wR2 = 0.1734. The results serve to underline the crucial role of the counterion for the type of ternary anion to be observed in the crystal. Whereas Rb+(aq) stabilizes a P1‐type Zn/Sn/Se supertetrahedron in 3 like K+, the Ba2+(aq) ions better fit to an anionic T3‐type Zn/Sn/Se cluster arrangement as do Na+ ions. It is possible to estimate a radius:charge ratio for the stabilization of the two structural motifs.
Selten‐Erd‐Metall‐Koordinationspolymere: Synthese und Kristallstrukturen von fünf neuen Adipinaten, [M2(Adi)3(H2O)4](AdiH2)(H2O)4 (M = La, Nd), [Er(Adi)(H2O)5]Cl(H2O) und [M(Adi)(H2O)5](NO3)(H2O) (M = Gd, Er)
Authors: Bromant Claudia , Flemig Holger , Nika Wassiliki , Pantenburg Ingo , Meyer Gerd
Published: March 2006

Rare‐Earth‐Metal Coordination Polymers: Synthesis and Crystal Structures of Five New Adipinates, [M2(Adi)3(H2O)4](AdiH2)(H2O)4 (M = La, Nd), [Er(Adi)(H2O)5]Cl(H2O) and [M(Adi)(H2O)5](NO3)(H2O) (M = Gd, Er)

The new rare‐earth compounds [M2(Adi)3(H2O)4](AdiH2)(H2O)4 (M = La (1), Nd (2)), [Er(Adi)(H2O)5]Cl(H2O) (3) and [M(Adi)(H2O)5](NO3)(H2O) (M = Gd (4), Er (5)) were obtained from the reaction of adipinic acid with La(OH)3·xH2O, Nd2O3, ErCl3·6H2O, Gd(NO)3·xH2O and Er2O3, respectively. Their crystal structures were determined by single‐crystal X‐ray diffraction. The coordination polymers [M2(Adi)3(H2O)4](AdiH2)(H2O)4 crystallize in the triclinic space group ${\rm P}{\bar 1}$ (no. 2) with a = 875.4(1), b = 1000.4(2), c = 1179.0(2) pm, α = 74.70(1), β = 69.85(1), γ = 86.18(2)° and Z = 1 (crystal data for M = La, (1)). The quasi‐isostructural compounds [Er(Adi)(H2O)5]Cl(H2O) (3) and [M(Adi)(H2O)5](NO3)(H2O) (M = Gd (4), Er (5)) crystallize with monoclinic symmetry, space group C2/c (no. 15) with lattice parameters of a = 1231.5(1), b = 1532.6(1), c = 895.4(1) pm, β = 123.44(1)° and Z = 4 (crystal data for (3)). The rare‐earth cations have the coordination numbers 10 (1, 2) and 9 (3, 4 and 5), respectively. The compounds [M2(Adi)3(H2O)4](AdiH2)(H2O)4 are constructed of infinite chains of edge‐sharig [MO8(H2O)2] polyhedra that are cross‐linked by adipinic acid molecules to form framework structures. In [Er(Adi)(H2O)5]Cl(H2O) (3) and [M(Adi)(H2O)5](NO3)(H2O) (M = Gd (4), Er (5)) the central cations are bridged by adipinic acid molecules in a bidentate‐chelating manner to positively charged zigzag chains. Between these the counter ions and crystal water molecules are incorporated.
Di‐Benzo‐18‐Crown‐6 and its Derivatives as Ligands in the Search for Ion Channels
Authors: Fromm Katharina M. , Bergougnant Rémi D. , Robin Adeline Y.
Published: March 2006

Based on the previously reported one‐dimensional channel system [(H2O)⊂(DB18C6)(μ2‐H2O)2/2][(H3O)⊂(DB18C6)(μ2‐H2O)2/2]I3 (2), which is realized by stacking of crown ether molecules (DB18C6 = dibenzo‐18‐crown‐6), other synthetic approaches towards ionic channels and their results are presented in this paper. The “cutting out” approach using DB18C6 as scissor, applied on NaI, yields the compound [Na⊂(DB18C6)I(THF)][Na⊂(DB18C6)(H2O)2]I(THF)2(CHI3) (1), in high yield. It is based on a neutral and a cationic complex of sodium by DB18C6 linked via H‐bonding to give short chain fragments. The anion exchange approach, trying to replace I3− by Br3− leads to the intercalation of a cation into a DB18C6 chain in [(Me3NPh)(DB18C6)]Br3 (3). A similar reaction as for the synthesis of 2, but replacing iodide with bromine, yields finally a brominated DB18C6 ligand. In the presence of iron, the compound [(H5O2)⊂(Br4‐DB18C6)2][FeBr4], 4, is observed, in which a H5O2+‐cation is encapsuled by two brominated crown ether molecules. The absence of Fe and an excess of Br2 leads to the complexation of H3O+, and co‐crystallisation of bromine in [(H3O)⊂(Br4‐DB18C6)]Br3Br2 (5).
Reaction of S2CC(PPh3)2 with Silver Salts Containing Weakly Coordinating Anions; Preparation and Crystal Structures of [Ag6{S2CC(PPh3)2}4][BF4]6 · 9.75CH2CL2 and [Ag4{S2CC(PPh3)2}4][Al{OC(CF3)3}4]4 · 4.25C2H4Cl2
Authors: Petz Wolfgang , Neumüller Bernhard , Krossing Ingo
Published: March 2006

The betain‐like carbodiphosphorane CS2 adduct S2CC(PPh3)2 (1) reacts with Ag(I) salts which contain weakly coordinating anions such as [BF4]− or [Al{OC(CF3)3}4]− to produce the cluster compounds [Ag6{S2CC(PPh3)2}4][BF4]6 (2) and [Ag4{S2CC(PPh3)2}4][Al{OC(CF3)3}4]4 (3), respectively, as orange yellow crystals containing solvent molecules. In the solid state the Ag4 unit in 3 forms a tetrahedron, and in the Ag6 core of 2 two of the opposite edges of the tetrahedron are bridged by Ag+ ions. The clusters are held together by argentophilic interactions, and each sulfur atom of 1 is coordinated to four (as in 2) or three (as in 3) silver atoms. The compounds are characterized by IR and 31P NMR spectroscopic studies and by X‐ray diffraction analyses.
Tetrakis(1‐adamantylcarboxylato)dikupfer(II) Cu2(1‐Ad)4 – Synthese, Struktur und X‐/Q‐Band‐EPR‐Untersuchungen
Authors: Griebel Jan , Leistner Franziska , Krautscheid Harald , Kirmse Reinhard
Published: March 2006

Tetrakis(1‐adamantylcarboxylato)dicopper(II) Cu2(1‐Ad)4 – Synthesis, Structure and X‐/Q‐band EPR Investigations

The synthesis and the crystal structure of tetrakis(1‐adamantylcarboxylato)dicopper(II) are reported. [Cu2(1‐Ad)4·2DMF] (1, 1‐Ad = adamantylcarboxylate) crystallizes in the space group $P{\bar 1}$ (Z = 2) with two crystallographically distinguishable complexes in the unit cell. The averaged Cu‐Cu distance of 260.5 pm is smaller than that found for Cu2(ac)4·2H2O. The combination of temperature‐dependent X‐ and Q‐band powder EPR investigations in the temperature range 6 ≤ T ≤ 295 K show the presence of an antiferromagnetically coupled Cu‐Cu dimer and allow a precise determination of the spin‐Hamiltonian parameter. A comparison of those with that derived for Cu2(ac)4·2H2O indicate a higher symmetry within the Cu2O8 central unit of [Cu2(1‐Ad)4·2DMF].
Neue Kupferkomplexe mit Phosphaalkenliganden. Molekülstruktur von [Cu{P(Mes*)C(NMe2)2}2]BF4 (Mes* = 2,4,6‐tBu3C6H2)
Authors: Weber L. , Krümberg Jens , Stammler H.‐G. , Neumann B.
Published: March 2006

New Copper Complexes Containing Phosphaalkene Ligands. Molecular Structure of [Cu{P(Mes*)C(NMe2)2}2]BF4 (Mes* = 2,4,6‐tBu3C6H2)

Reaction of equimolar amounts of the inversely polarized phosphaalkene tBuP=C(NMe2)2 (1a) and copper(I) bromide or copper(I) iodide, respectively, affords complexes [Cu3X3{μ‐P(tBu)C(NMe2)2}3] (2) (X =Br) and (3) (X = I) as the formal result of the cyclotrimerization of a 1:1‐adduct. Treatment of 1a with [Cu(L)Cl] (L = PiPr3; SbiPr3) leads to the formation of compounds [CuCl(L){P(tBu)C(NMe2)2}] (4a) (L = PiPr3) and (4b) (L = SbiPr3), respectively. Reaction of [(MeCN)4Cu]BF4 with two equivalents of PhP=C(NMe2)2 (1b) yields complex [Cu{P(Ph)C(NMe2)2}2]BF4 (5b). Similarly, compounds [Cu{P(Aryl)C(NMe2)2}2]BF4 (5c (Aryl = Mes and 5d (Aryl = Mes*)) are obtained from ArylP=C(NMe2)2 (1c: Aryl = Mes; 1d: Mes*) and [(MeCN)4Cu]BF4 in the presence of SbiPr3. Complexes 2, 3, 4a, 4b, and 5b‐5d are characterized by means of elemental analyses and spectroscopy (1H‐, 13C{1H}‐, 31P{1H}‐NMR). The molecular structure of 5d is determined by X‐ray diffraction analysis.