bluuebunny/crossref_metadata_2025 huggingface dataset:
Dendritic morphology, local circuitry, and intrinsic electrophysiology of principal neurons in the entorhinal cortex of macaque monkeys
Authors: Buckmaster Paul S. , Alonso Angel , Canfield Don R. , Amaral David G.
Published: January 2004

Little is known about the neuroanatomical or electrophysiological properties of individual neurons in the primate entorhinal cortex. We have used intracellular recording and biocytin‐labeling techniques in the entorhinal slice preparation from macaque monkeys to investigate the morphology and intrinsic electrophysiology of principal neurons. These neurons have previously been studied most extensively in rats. In monkeys, layer II neurons are usually stellate cells, as in rats, but they occasionally have a pyramidal shape. They tend to discharge trains, not bursts, of action potentials, and some display subthreshold membrane potential oscillations. Layer III neurons are pyramidal, and they do not appear to display membrane potential oscillations. The distribution of dendrites and of axon collaterals suggests that neurons in layers II and III are interconnected by a network of associational fibers. Layer V and VI neurons are pyramidal and tend to discharge trains of action potentials. The distribution of dendrites and axon collaterals suggests that there is an associative network of principal neurons in layers V and VI, and they also project axon collaterals toward superficial layers. Importantly, entorhinal cortical neurons in monkeys appear to exhibit significant differences from those in rats. Morphologically, neurons in monkey entorhinal layers II and III have more primary dendrites, more dendritic branches, and greater total dendritic length than in rats. Electrophysiologically, layer II neurons in monkeys exhibit less sag, and subthreshold oscillations are less robust and slower. Some monkey layer III neurons discharge bursts of action potentials that are not found in rats. The interspecies differences revealed by this study may influence information processing and pathophysiological processes in the primate entorhinal cortex. J. Comp. Neurol. 470:317–329, 2004. © 2004 Wiley‐Liss, Inc.
Distinct muscle targets do not vary in the developmental regulation of brain‐derived neurotrophic factor
Authors: Vernon Elizabeth Marie , Oppenheim Ronald W. , Johnson James E.
Published: January 2004

Developing neurons depend on many target‐derived signals. One of these signals is the neurotrophin brain‐derived neurotrophic factor (BDNF). Exogenous application of BDNF in vitro and in vivo rescues a population of lumbar motoneurons from programmed cell death. Given that BDNF does not rescue all motoneurons and that motoneurons differ in trophic factor receptor expression, subpopulations of motoneurons may have different sensitivities to the factor. These differences may be reflected in distinct target muscles specialized to produce different protein concentrations, or muscles may contain equal amounts of the factor and receptor expression determines motoneuron responsiveness. By using a sensitive electrochemiluminescent immunoassay (ECLIA), we measured normal developmental changes in BDNF protein concentration in anatomically and functionally distinct chick embryonic thigh muscles from E6 to E18. We found that there were no significant differences in BDNF protein concentration between muscles classified according to function (fast vs. slow) or anatomical position (flexor vs. extensor) and that the quantity of BDNF in the target did not appear to be activity dependent. These results suggest that, during development, the differences in the response of motoneurons to BDNF are not due to the anatomical or functional diversity of muscle targets. J. Comp. Neurol. 470:330–337, 2004. © 2004 Wiley‐Liss, Inc.
FocalPoint slide classification algorithms show robust performance in classification of high‐grade lesions on SurePath liquid‐based cervical cytology slides
Authors: Parker Elizabeth M. , Foti Joseph A. , Wilbur David C.
Published: January 2004

The FocalPoint Primary Screening System (FPPS) operates by assigning scores to each slide relative to the probability that an abnormality is present. This information ranks each slide within five “quintiles” (1 = highest risk, 5 = lowest risk) of the “review” population, allowing examining cytologists to understand the risk inherent in each slide. Such information helps to make the primary and quality control rescreening processes most efficient. This study examines the efficiency of AutoPap scoring and, thus, stratification of high‐grade cases within a clinical trial setting. A total of 1,275 SurePath (TriPath, Burlington, NC) slides were screened on the FPPS. There were 124 high‐grade cases in the set (32 HSIL, 5 AIS, and 87 cancers) as determined by cytologic truth adjudication. The efficiency of FPPS ranking was determined by analysis of the numbers of high‐grade cases ranked into quintiles 1 (top 20%) and 1+2 (top 40%). FPPS places cases scored as “unsatisfactory” (HSIL, 3; Cancer, 18) into quintile 5 to ensure a manual review. These cases were excluded from the analysis. Overall, 58% of high‐grade slides were classified as Q1 and 83% were classified as Q1+Q2. For HSIL, 66% were classified as Q1 and 90% as Q1+Q2. For Cancer, 59% were classified as Q1 and 84% as Q1+Q2. No high‐grade slides were ranked in the lower “no review” population (slides that would receive no manual examination). The results confirm the robust performance of the FPPS classification algorithm. Far more high‐grade slides are classified into the top two quintiles than would be expected by random chance alone (20% and 40%, respectively). These results validate the safety and effectiveness of this device on SurePath liquid‐based slides. Diagn. Cytopathol. 2004;30:107–110. © 2004 Wiley‐Liss, Inc.
Gliosarcoma: Cytopathologic characteristics on fine‐needle aspiration (FNA) and intraoperative touch imprint
Authors: Parwani Anil V. , Berman David , Burger Peter C. , Ali Syed Z.
Published: January 2004

Gliosarcoma (GS) is a rare subtype of glioblastoma multiforme (GBM), which shows a dimorphic population of glial and mesenchymal elements. The cytopathology of GS to our knowledge has not been previously described. Although prognostically insignificant within the group of GBM, an accurate recognition of this subtype may help to rule out other morphologically similar primary and metastatic central nervous system (CNS) neoplasms. Thirteen cases of histologically confirmed GS with concomitant touch imprints (TI) or prior fine‐needle aspiration (FNA) were retrieved from the files of The Johns Hopkins Hospital (1985–2002). A comprehensive review of the clinico‐radiologic, cytologic, and histologic material was undertaken to define the morphologic characteristics of GS. Material was obtained via computerized tomography (CT)‐guided needle biopsy. Slides were stained with DiffQuik® and/or hematoxylin and eosin (H&E) stains. Smears were highly cellular and showed a high‐grade neoplasm with glial and mesenchymal elements. The latter component, however, predominated and showed a variety of phenotypic patterns, which included fibrosarcoma‐like, rhabdoid type, osteoclastic giant cell type, undifferentiated type, and tumor with heterologous components (such as chondroid or osteoid tissue). A rich arborizing capillary network was evident, as were a high mitosis/karyorrhexis index and foci of necrosis. The glial component consisted of pleomorphic round to oval nuclei and numerous gemistocytes embedded in a fibrillary stroma. Diagn. Cytopathol. 2004;30:77–81. © 2004 Wiley‐Liss, Inc.
Aspiration cytology of focal xanthogranulomatous pyelonephritis: A diagnostic challenge
Authors: Kumar Neeta , Jain Shyama
Published: January 2004

A case of focal xanthogranulomatous pyelonephritis presenting as a circumscribed mass in a functioning kidney of a young male is described. Clinical, radiological, and cytological features closely mimicked renal cell carcinoma leading to radical nephrectomy. Peroperative findings and gross pathological features also corroborated preoperative diagnosis. The final diagnosis was a histologic surprise. It is an uncommon entity with cortical location, no pelvic communication, and progressively destroying the kidney. It should be considered in the differential diagnosis of any mass lesion at any age during preoperative clinicoradiological and cytological evaluation. A correct preoperative diagnosis can save unnecessary nephrectomy. Diagn. Cytopathol. 2004;30:111–114. © 2004 Wiley‐Liss, Inc.
Fine‐needle aspiration of an adenoid cystic carcinoma of the larynx mimicking a thyroid mass
Authors: Natarajan Sathima , Greaves Timothy S. , Raza Anwar S. , Cobb Camilla J.
Published: January 2004

Adenoid cystic carcinoma (ACC) is most often primary in the major and minor salivary glands but can also arise from the submucosal seromucinous glands of the larynx and trachea. We report a case of adenoid cystic carcinoma of the larynx that presented as a diffuse swelling in the thyroid area. Fine‐needle aspiration (FNA) was consistent with a neoplastic process, which was difficult to classify further but was felt to be of thyroid origin. Subsequent gross and histopathologic examination showed the lesion to represent an ACC arising from the larynx. This case highlights the need to be aware of unusual lesions that may arise in the region of the thyroid. Knowledge of these non‐thyroidal lesions that can clinically mimic a thyroid mass will help in making the correct cytologic diagnosis when these lesions are sampled by FNA. Diagn. Cytopathol. 2004;30:115–118. © 2004 Wiley‐Liss, Inc.
Extrapulmonary tuberculosis as a mimicker of neoplasia
Authors: Hwang S. , Simsir A. , Waisman J. , Moreira A. L.
Published: January 2004

Despite the efforts for control and eradication of tuberculosis, new cases of the disease are diagnosed daily. The diagnosis of tuberculosis is easily made when the classical features of pulmonary necrotizing granulomatous inflammation are seen. However, extrapulmonary lesions may clinically and radiographically mimic a neoplastic process, and this may lead to misdiagnosis and delay in treatment. We studied 6 patients by aspiration biopsy, all recent immigrants and immunocompetent, who presented with weight loss and fatigue. Of these, 5 patients had a mass. One patient presented with a lytic lesion of bone. In all cases the clinical diagnosis was neoplasia. In all aspirates, the smears showed necrotic debris with neutrophils. No neoplastic cells or granulomas were seen. All cases were signed out descriptively with no specific diagnosis. A search for acid‐fast organisms leading to the correct diagnosis of tuberculosis was prompted by clinical investigations that revealed pulmonary lesions, or by repeat aspiration biopsy, which showed granulomatous inflammation. Tuberculosis when present in atypical forms is still a challenging diagnosis. The finding of necrotic debris in a needle biopsy without the clinical signs of an abscess should prompt a search for acid‐fast bacilli, since the correct diagnosis will eliminate a needless surgical procedure and will lead to timely and appropriate therapy. Diagn. Cytopathol. 2004;30:82–87. © 2004 Wiley‐Liss, Inc.
Fine‐needle aspiration biopsy diagnosis of intrathoracic extramedullary hematopoiesis presenting as a posterior mediastinal tumor in a patient with sickle‐cell disease: Case report
Authors: Al‐Marzooq Yusef M. , Al‐Bahrani Ahmed T. , Chopra Rajan , Al‐Momatten Mohmmed I.
Published: January 2004

Extramedullary hematopoiesis (EMH) is a rare cause of an intrathoracic mass. Fine‐needle aspiration biopsy (FNAB) has been only occasionally documented as a useful tool in diagnosing EMH tumor. We report a case of posterior mediastinal extramedullary hematopoietic mass in an 80‐yr‐old man with sickle‐cell anemia. The mass was revealed incidentally on chest X‐ray. The definitive diagnosis of this mass lesion was achieved by FNAB. The cytologic smears showed hematopoietic elements with erythroid hyperplasia. A correct cytologic diagnosis can thus help to avoid unnecessary surgical intervention, particularly in an asymptomatic patient. Diagn. Cytopathol. 2004;30:119–121. © 2004 Wiley‐Liss, Inc.
Differentiating nonhigh‐grade duct carcinoma in situ from benign breast lesions
Authors: Kumarasinghe Marian Priyanthi , Poh Wee Teng
Published: January 2004

This study was undertaken to determine the discriminating cytological features between nonhigh‐grade duct carcinoma in situ (NHGDCIS) and benign breast lesions and to determine any histological characteristics which would influence the cytological categorization. Smears of 12 each of histologically confirmed NHGDCIS and benign breast lesions were reviewed with regard to cellularity, cell discohesion, nuclear atypia, crowding of cells, tubule formation, necrosis, and presence of bare atypical nuclei and regular bare bipolar nuclei, and statistically analyzed. Architectural pattern, presence of necrosis, and the size of the lesion assessed at histological examination were compared with the initial cytological categorization. NHGDCIS lesions showed more cell discohesion (P = 0.04), bare atypical nuclei (P = 0.05), necrosis (P = 0.03), and sparse bare bipolar nuclei (P = 0.02) than benign lesions. These differences were statistically significant. Cellularity (P = 0.8), nuclear atypia (P = 0.06), crowding of cells (P = 0.1), and tubule formation did not show a significant difference. Six (out of six lesions) with a solid architectural pattern and six (of seven) with necrosis could be cytologically categorized as suspicious or malignant. Size of the lesion did not influence this. We conclude that cell discohesion, bare atypical and bare bipolar nuclei, and necrosis are discriminating features between NHGDCIS and benign breast lesions and NHGDCIS lesions with a solid architectural pattern and necrosis are more likely to be satisfactorily categorized cytologically. Diagn. Cytopathol. 2004;30:98–102. © 2004 Wiley‐Liss, Inc.
Analysis of routine cytopathologic reports in 1,598 histologically verified benign breast lesions
Authors: Pogačnik A. , Us‐Krašovec M.
Published: January 2004

This retrospective study was designed to evaluate the accuracy of cytopathologic diagnosis and of correct classification of benign breast diseases. A total of 1,598 FNABs were identified to have met the study criteria; of these, 1,258 (78.7%) cases were cytologically benign, 88 (5.5%) suspicious, 3 (0.18%) false‐positive, and in 249 (15.6%) cases an inadequate sample was obtained. A specific diagnosis was made in 847/1,258 (67.3%) cases; the other 411 were diagnosed as benign NOS. Out of 847 specific FNABs diagnoses, 451 were fibroadenomas, 27 phyllodes tumors, 289 fibrocystic diseases, 4 proliferative fibrocystic diseases, 38 papillomas, 22 fat necrosis, 9 mastitis, 1 pseudolymphoma, 2 lipomas, 2 duct ecstasies, and 2 atheromas. In our study group the cytopathologic diagnosis of benign breast diseases excluding unsatisfactory aspirates was correct in 93%. Specific diagnosis was correct on average in 50% of cases, only in FA was its accuracy over 60%; in adequately sampled tumor, the predictive value of FA was 86.2%. Diagn. Cytopathol. 2004;30:125–130. © 2004 Wiley‐Liss, Inc.
Mixed follicular‐medullary thyroid carcinoma: A case report
Authors: Luboshitzky Rafael , Dharan Muralee
Published: January 2004

We report on a 35‐yr‐old woman presenting with a single thyroid nodule. Fine‐needle aspiration (FNA) of the nodule was reported to contain both follicular and parafollicular cells. The biphasic nature of the tumor was highlighted on immunohistochemical investigation of the cellblock. Positive staining for thyroglobulin was limited to the follicular structures and the dense areas stained positive for calcitonin. The serum calcitonin level was highly elevated. Surgery was recommended because of suspected malignancy. The patient underwent total thyroidectomy. The diagnosis of mixed medullary and follicular carcinoma of the thyroid was established by histological investigation using immunohistochemical staining for thyroglobulin, chromogranin, and calcitonin. The patient was well 1 yr after the operation. Repeated measurements of serum calcitonin levels were normal. Total body scan revealed no radioactive iodine uptake in the thyroid bed, bones, or lungs. Diagn. Cytopathol. 2004;30:122–124. © 2004 Wiley‐Liss, Inc.
P*,N‐Bidentate Amino Phosphoramidites: New Highly Effective Ligands for Pd‐Catalysed Asymmetric Allylic Substitution
Authors: Gavrilov Konstantin N. , Tsarev Vasily N. , Shiryaev Alexei A. , Bondarev Oleg G. , Lyubimov Sergey E. , Benetsky Eduard B. , Korlyukov Alexander A. , Antipin Mikhail Yu. , Davankov Vadim A. , Gais Hans‐Joachim
Published: January 2004

New chiral P*,N‐hybrid amino phosphoramidites have been obtained by one‐step phosphorylation of amino alcohols. Complexation of the new ligands with [Rh(CO)2Cl]2 and [Pd(allyl)Cl]2 gave the corresponding chelate complexes [Rh(CO)Cl(η2‐P,N)] and [Pd(allyl)(η2‐P,N)]+BF4−, which subsequently afforded up to 90% ee in the asymmetric Pd‐catalysed sulfonylation of 1,3‐diphenyl‐2‐propenyl acetate with sodium p‐toluenesulfinate. In the enantioselective alkylation of 1,3‐diphenyl‐2‐propenyl acetate with dimethyl malonate, up to 98% enantioselectivity was achieved with [Pd(allyl)(η2‐P,N)]+BF4− complexes as chiral catalysts. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Electrochemical Behaviour of First Row Transition Metal Substituted Polyoxotungstates: A Comparative Study in Acetonitrile
Authors: Balula Maria Salete , Gamelas José A. , Carapuça Helena M. , Cavaleiro Ana M. V. , Schlindwein Walkiria
Published: January 2004

A comparative study of the electrochemical behaviour of several transition metal substituted polyoxotungstates in acetonitrile solution with tetra‐n‐butylammonium perchlorate as a supporting electrolyte is presented. Tetra‐n‐butylammonium salts of Keggin‐type polyoxoanions, α‐[(C4H9)4N]4Hx[XW11M(H2O)O39]·nH2O, X = P, Si; MII = Co, Ni, MIII = Fe, Mn, x = 0−2, n = 0−2, and sandwich‐type polyoxoanions, α‐B‐[(C4H9)4N]7H3[M4(H2O)2(PW9O34)2], MII = Co, Mn, have been studied by cyclic voltammetry and spectroelectrochemistry. Under the conditions used, the tungsten‐oxo framework of the metal substituted Keggin anions could accept up to three electrons in quasi‐reversible one‐electron consecutive processes. Comparison with the corresponding lacunary anions is presented. Redox processes at the metal centre have been detected for all metals M except Ni. For the anions α‐[XW11M(H2O)O39]m−, the co‐existence of species with a different degree of protonation was deduced from cyclic voltammetry results whenever protons were included in the molecular formula. The influence of the solids’ composition on the electrochemical results is stressed. For the sandwich anions, cyclic voltammetry revealed redox processes occurring on the W atoms and also on the metallic belt. Two metal atoms in the belt of the α‐B‐[CoII4(H2O)2(PW9O34)2]10− anion could be electrochemically oxidised to CoIII in two separate steps. A similar result was observed for the MnII analogue, but the corresponding first step was not as well defined. Re‐oxidation was only detected for the Co anion. This work is the first comparative study of the electrochemical behaviour of such transition metal substituted polyoxotungstates in an organic medium. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Flexidentate Behaviour of 2‐Pyridylsulfonamides − Direct Electrochemical Synthesis and Spectroscopic and X‐ray Characterisation of Neutral Copper(II) Complexes of N‐(2‐Pyridyl)sulfonamides
Authors: Beloso Inmaculada , Borrás Joaquín , Castro Jesús , García‐Vázquez José A. , Pérez‐Lourido Paulo , Romero Jaime , Sousa Antonio
Published: January 2004

Copper complexes with potentially bidentate N‐(2‐pyridyl)sulfonylamide ligands have been synthesised by the electrochemical oxidation of the metal in an acetonitrile solution of the neutral amide and additional bidentate N−N coligands. The compounds have been characterised by microanalysis and EPR, vibrational and electronic spectroscopy. In representative cases the structures were also determined by X‐ray diffraction methods. Various coordination behaviour is found for the ligands, which act in a N,N′‐bidentate or N,O‐bidentate manner, the latter giving abnormally short Cu−O bonds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Apparent Allyl Rotation in New Allylpalladium(II) Complexes with Pyrazolyl N‐Donor Ligands
Authors: Guerrero Ana , Jalón Félix A. , Manzano Blanca R. , Rodríguez Ana , Claramunt Rosa María , Cornago Pilar , Milata Viktor , Elguero José
Published: January 2004

The ligands 2,4,6‐tris(pyrazol‐1‐yl)‐1,3,5‐triazine (TPzT), 2,4,6‐tris(3,5‐dimethyl‐pyrazol‐1‐yl)‐1,3,5‐triazine (Me2‐TPzT), and 2,4,6‐tris(3,4,5‐trimethylpyrazol‐1‐yl)‐1,3,5‐triazine (Me3‐TPzT) have been synthesised and their reaction with [Pd(η3‐C4H7)(THF)2]X was explored. The reaction in a 1:3 molar ratio (ligand/solvate) leads to the new derivatives [{Pd(η3‐C4H7)}2(BPz′TO)]X (Pz′ = pyrazole, X = BF4, 2a; Pz′ = 3,5‐dimethylpyrazole, X = PF6, 2c; Pz′ = 3,4,5‐trimethylpyrazole, X = PF6, 2d) in which the N‐donor ligand has been partially hydrolysed. The complexes exist in the form of two isomers, a meso form and a d,l pair. An apparent allyl rotation process leads to a syn‐syn/anti‐anti interconversion and also to an interchange between the two isomers. The values of ΔGc‡ at the coalescence temperature have been calculated. The results, which have also been compared with those previously obtained for the complex with the 4‐methylpyrazole ligand, indicate that the activation barrier for the process is not affected by the change in the pyrazole group. Appreciable effects were not observed on changing the concentration or on the addition of water to the acetone solutions of 2c. However, the influence of the solvent (acetone versus chloroform) is worth noting. A negative activation entropy has been found and a mechanistic proposal for the process is included. The molecular structure of 2c has been determined by X‐ray diffraction. The meso isomer, in which the two C−Me axes of the allylic groups are oriented in the same direction, is found in the solid state. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Formation of Cubic GaN Nanocrystals: A Study of the Thermal Stability of GaP Nanocrystals under Nitrogen
Authors: Gao Shanmin , Zhu Liying , Xie Yi , Qian Xiaobo
Published: January 2004

Cubic GaN nanoparticles and nanorods have been successfully synthesized from the nitridation of nanocrystalline GaP at 500 °C for 30 min, by manipulating different heating rates in nitrogen. The results of the thermal stability studies of nanocrystalline GaP under N2 at different heating rates support the idea that cubic GaN can form from GaP via a N−P metathesis mechanism. The morphology of the cubic GaN can be controlled by variation of the external synthetic parameters such as the rate of heating. This work shows that it is very simple to synthesize cubic GaN nanoparticles or nanorods and opens a wide route towards detailed studies of the fundamental properties and potential applications of semiconductor nanocrystals. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Group 13 Complexes of 5‐Methyl‐1,3,5‐dithiazinane
Authors: Gálvez‐Ruiz Juan Carlos , Guadarrama‐Pérez Carlos , Nöth Heinrich , Flores‐Parra Angelina
Published: January 2004

The synthesis of mono‐N adducts of 5‐methyl‐1,3,5‐dithiazinane (1) with Al(CH3)3, Al(CH3)2Cl, AlCl3, AlBr3 (5−8), a bis‐N adduct with InCl3 (9), and the corresponding dithiazinanium salts with the anions AlBr4−, AlCl4−, GaCl4− and BCl4− (10−14) are reported. Compounds 5−7 adopt a preferred conformation in solution at room temperature and 8 at −10 °C. ΔG≠ values for the ring inversion were calculated for 5−8. Compounds 6−14 were studied by single‐crystal X‐ray diffraction. The solution and solid‐state analyses showed that the rings are present in all cases in a chair conformation. In compounds 5−8 the tetrahedral aluminum atom is found in an equatorial position. In the indium compound 9 the metal atom has a tbp geometry. For dithiazinanium rings 10−14 dipolar intra‐ and intermolecular interactions between halogen atoms and C−H and N−H are reported. Two different conformations for the N−CH3 were found in compound 14. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Multi‐Dimensional Systems Built from Dichromate Anions − Syntheses, Crystal Structures, and Magnetic Properties
Authors: Chen Xiao‐Yan , Zhao Bin , Cheng Peng , Ding Bin , Liao Dai‐Zheng , Yan Shi‐Pin , Jiang Zong‐Hui
Published: January 2004

Three novel compounds with bridging dichromate anions with the formulae [Fe(4,4′‐bpy)2Cr2O7]n (1), [Co(4,4′‐bpy)2Cr2O7]n (2), and [Ni(dpa)2Cr2O7]·H2O (3) (4,4′‐bpy = 4,4′‐bipyridine, dpa = 2,2′‐dipyridylamine) have been synthesized and characterized. The isostructural compounds 1 and 2 belong to the monoclinic space group C2/c and have been shown to be three‐dimensional polymers in which the dichromate anions connect neighboring layers formed by [M(4,4′‐bpy)2]2+ (M = Fe, Co) units. Compound 3 is a metalla‐crown type compound, crystallizing in the monoclinic space group P21/n. Two chromate anions link two NiII centers forming a dinuclear entity. The uncoordinated oxygen atom of the dichromate anion forms a hydrogen bond with the N−H unit of dpa resulting in a two‐dimensional network. Measurements of magnetic susceptibilities indicate the presence of antiferromagnetic interactions in 1 and 2 whereas the exchange coupling between the NiII ions in 3 is ferromagnetic. The IR and UV/Vis spectra of the above complexes have also been investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
New Bifunctional Contrast Agents: Bis‐Amide Derivatives of C‐Substituted Gd‐DTPA
Authors: Laurent Sophie , Botteman François , Elst Luce Vander , Muller Robert N.
Published: January 2004

In order to expand upon and confirm previous observations on the positive and adverse roles played by the functionalization and substitution of the parent MRI contrast agent Gd‐DTPA, two new bi‐functionalized contrast agents namely Gd‐(S)‐EOB‐DTPA‐BMA and Gd‐(S)‐C4Bz‐DTPA‐BMA have been synthesized, purified, and characterized by multinuclear NMR studies. Water 1H nuclear magnetic relaxation dispersion profiles were recorded at several temperatures. τR was determined by 2H NMR on the diamagnetic lanthanum complex. τM, the water residence time, was obtained by 17O NMR measurements and the stability versus transmetallation by zinc was evaluated by proton relaxometry. The residence time of water molecules in the first coordination sphere of the Gd complexes has confirmed the antagonistic effects of amide functions and C‐4 substitution on the reduction of the water residence time, a critical parameter of relaxivity. This C‐4 position is thus particularly appropriate for the substitution required by the design of new contrast agents covalently bound to macromolecules or carrying specific vectors. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Intercalation of γ‐Butyrolactone into Vanadyl Phosphate and Niobyl Arsenate
Authors: Zima Vítězslav , Melánová Klára , Beneš Ludvík , Trchová Miroslava , Dybal Jiří
Published: January 2004

Intercalation compounds of vanadyl phosphate and isostructural niobyl arsenate with γ‐butyrolactone, VOPO4·C4H6O2 and NbOAsO4·C4H6O2, respectively, were prepared from corresponding propanol intercalates by molecular exchange in a microwave field. The prepared intercalates were characterized using powder X‐ray diffraction, density measurements, and thermogravimetric analysis. Infrared and Raman spectra indicate a coordination of the carbonyl oxygen atom of the γ‐butyrolactone molecule to the vanadium or niobium atom of the host structure. Quantum mechanical calculations at the ab initio level confirm the proposed structure in which the γ‐butyrolactone guest molecules are arranged with the plane of the ring perpendicular to the host layers and are anchored to the layers through the carbonyl oxygen atom coordinated to the transition metal atom of the host. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Glycosyl‐Curcuminoids as Potential New Chelating Agents in Iron Overload Chelation Therapy
Authors: Arezzini Beatrice , Ferrali Marco , Ferrari Erika , Grandi Romano , Monti Stefano , Saladini Monica
Published: January 2004

The iron(III) chelating ability of some glycosyl derivatives of curcuminoids is tested by means of UV, potentiometric and NMR studies. The pKa of the ligands and the stability constants of their Fe3+ and Ga3+ complexes are evaluated by UV spectroscopy. The only metal binding site of the ligand is the β‐dioxo moiety; the glycosyl moiety does not interact with the metal ion at acidic pH values but it helps to stabilise metal/ligand (1:2) complexes by means of hydrophilic interactions. By comparing the pFe3+ of our ligands with those reported for other chelating agents we suggest using these molecules as pro‐drugs in iron overload treatment. Some of the more water‐soluble derivatives are also tested for their antioxidant properties “in vitro” in biological systems and proved to act as free‐radical scavengers inhibiting the iron redox cycle. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
A Series of Vinylidene‐, Vinyl‐, Carbene‐ and Carbyneruthenium(II) Complexes with [Ru(PCy3)2] and [Ru(PiPr3)2] as Molecular Building Blocks
Authors: Jung Stefan , Ilg Kerstin , Brandt Carsten D. , Wolf Justin , Werner Helmut
Published: January 2004

The hydrido(vinylidene) complexes [RuHCl(=C=CHR)(L)2] (R = H, tBu, Ph; L = PCy3, PiPr3) undergo metathesis reactions in the presence of KX (X = I, NCO, OPh, CH3CO2, CF3CO2) to give the substitution products [RuHX(=C=CHR)(L)2] (6−15) in good to excellent yields. Treatment of [RuHX(=C=CHR)(L)2] with HBF4 in diethyl ether affords the cationic carbyneruthenium(II) derivatives [RuHX(≡CCH2R)(OEt2)(L)2]BF4 (17, 18, 20, 21) and [RuH(κ2‐O2CCH3)(≡CCH2R)(L)2]BF4 (19, 22). The reactions of [RuHCl(=C=CHR)(L)2] with MX [X = BF4, PF6, BPh4, B(Arf)4] in acetonitrile lead to the formation of cationic five‐ and six‐coordinate vinylruthenium(II) compounds 26a−d and 27a−d of which [Ru(CH=CH2)(CH3CN)2(PCy3)2]BPh4 (26c) has been characterized by X‐ray crystallography. The starting material [RuHCl(=C=CHPh)(PiPr3)2] reacts with CO to give [RuCl(CH=CHPh)(CO)2(PiPr3)2] (28) and with N2 to produce [RuCl(CH=CHPh)(N2)(PiPr3)2] (29). The molecular structure of 29 has been determined. Protonation of [Ru(CH=CH2)(CH3CN)2(PCy3)2]X and [Ru(CH=CHPh)(CH3CN)3(PiPr3)2]X with HBF4 and HB(Arf)4 yields the dicationic carbeneruthenium(II) complexes [Ru(=CHCH3)(CH3CN)2(PCy3)2]X2 (30a,b) and [Ru(=CHCH2Ph)(CH3CN)3(PiPr3)2][B(Arf)4]2 (31), the latter of which eliminates styrene to give [Ru(CH3CN)3(PiPr3)2][B(Arf)4]2 (32). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Electrochemical and Spectroelectrochemical Investigations of Mono‐ and Binuclear Cobalt(II) Complexes of “Figure‐Eight” Octapyrrolic Macrocycles
Authors: Bley‐Escrich Jordi , Gisselbrecht Jean‐Paul , Michels Martin , Zander Lars , Vogel Emanuel , Gross Maurice
Published: January 2004

In this paper, electrochemical investigations of a set of three cyclooctaphyrin complexes containing divalent cobalt are reported. These complexes are the homodinuclear cobalt‐cobalt complex Co2L1 with the ligand H4L1, the mononuclear cobalt complex CoH2L2 and the heterodinuclear copper(II)‐cobalt complex CoCuL2 with the ligand H4L2. All of these species undergo two reduction and three oxidation processes, all of which are reversible one‐electron transfers. The two reduction and first two oxidation steps are ligand‐centered, as confirmed by spectroelectrochemical investigations. In contrast, the third oxidation corresponds to a metal‐centered reversible one‐electron transfer. The metal‐centered oxidation steps occur at lower potentials than the third oxidation steps of the free bases. UV/Visible spectral changes observed during oxidation confirm a metal‐centered oxidation generating a cobalt(III) cation, which is rather unusual when compared with cobalt porphyrin complexes, in which the oxidation of the metal usually occurs before the oxidation of the ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Comparative Electrochemical Study of Unsubstituted and Substituted Bis(phthalocyaninato) Rare Earth(III) Complexes
Authors: Zhu Peihua , Lu Fanli , Pan Na , Arnold Dennis P. , Zhang Shuyong , Jiang Jianzhuang
Published: January 2004

The electrochemistry of homoleptic substituted phthalocyaninato rare earth double‐decker complexes M(TBPc)2and M(OOPc)2[M = Y, La...Lu except Pm; H2TBPc = 3(4),12(13),21(22),30(31)‐tetra‐tert‐butylphthalocyanine, H2OOPc = 3,4,12,13,21,22,30,31‐octakis(octyloxy)phthalocyanine] has been comparatively studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in CH2Cl2containing 0.1Mtetra‐n‐butylammonium perchlorate (TBAP). Two quasi‐reversible one‐electron oxidations and three or four quasi‐reversible one‐electron reductions have been revealed for these neutral double‐deckers of two series of substituted complexes, respectively. For comparison, unsubstituted bis(phthalocyaninato) rare earth analogues M(Pc)2(M = Y, La...Lu except Pm; H2Pc = phthalocyanine) have also been electrochemically investigated. Two quasi‐reversible one‐electron oxidations and up to five quasi‐reversible one‐electron reductions have been revealed for these neutral double‐decker compounds. The three bis(phthalocyaninato)cerium compounds display one cerium‐centered redox wave between the first ligand‐based oxidation and reduction. The half‐wave potentials of the first and second oxidations and first reduction for double‐deckers of the tervalent rare earths depend on the size of the metal center. The difference between the redox potentials of the second and third reductions for MIII(Pc)2, which represents the potential difference between the first oxidation and first reduction of [MIII(Pc)2]−, lies in the range 1.08−1.37 V and also gradually diminishes along with the lanthanide contraction, indicating enhanced π−π interactions in the double‐deckers connected by the smaller, lanthanides. This corresponds well with the red‐shift of the lowest energy band observed in the electronic absorption spectra of reduced double‐decker [MIII(Pc′)2]−(Pc′ = Pc, TBPc, OOPc). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Electrochemistry of Heteroleptic Tris(phthalocyaninato) Rare Earth(III) Complexes
Authors: Zhu Peihua , Pan Na , Ma Changqin , Sun Xuan , Arnold Dennis P. , Jiang Jianzhuang
Published: January 2004

The electrochemical characteristics of a series of heteroleptic tris(phthalocyaninato) complexes with identical rare earths or mixed rare earths (Pc)M(OOPc)M(OOPc) [M = Eu...Lu, Y; H2Pc = unsubstituted phthalocyanine, H2(OOPc) = 3,4,12,13,21,22,30,31‐octakis(octyloxy)phthalocyanine] and (Pc)Eu(OOPc)Er(OOPc) have been recorded and studied comparatively by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in CH2Cl2 containing 0.1 M tetrabutylammonium perchlorate (TBAP). Up to five quasi‐reversible one‐electron oxidations and four one‐electron reductions have been revealed. The half‐wave potentials of the first, second and fifth oxidations depend on the size of the metal center, but the fifth changes in the opposite direction to that of the first two. Moreover, the difference in redox potentials of the first oxidation and first reduction for (Pc)M(OOPc)M(OOPc), 0.85−0.98 V, also decreases linearly along with decreasing rare earth ion radius, clearly showing the rare earth ion size effect and indicating enhanced π−π interactions in the triple‐deckers connected by smaller lanthanides. This order follows the red‐shift seen in the lowest energy band of triple‐decker compounds. The electronic differences between the lanthanides and yttrium are more apparent for triple‐decker sandwich complexes than for the analogous double‐deckers. By comparing triple‐decker, double‐decker and mononuclear [ZnII] complexes containing the OOPc ligand, the HOMO−LUMO gap has been shown to contract approximately linearly with the number of stacked phthalocyanine ligands. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Cyclopentadienyl RuII Complexes as Highly Efficient Catalysts for the N‐Methylation of Alkylamines by Methanol
Authors: Del Zotto Alessandro , Baratta Walter , Sandri Mauro , Verardo Giancarlo , Rigo Pierluigi
Published: January 2004

The ruthenium(II) half‐sandwich complex [RuCl(η5‐C5H5)(PPh3)2] (1) catalyses the reaction between methanol and alkylamines RNH2 or R1R2NH to afford RN(CH3)2 and R1R2NCH3 products, respectively. The reaction is quantitative and generally fast, at the methanol reflux temperature, for a wide spectrum of substrates. Starting from primary amines, the stepwise formation of RN=CH2, RNHCH3, and RN(CH3)2 has been observed. Both PPh3 and Cl− dissociation from 1 are key‐steps in forming the effective catalytic species. The catalytic activity of several half‐sandwich neutral or cationic complexes (2−15) related to 1 is also discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
New Pentadentate Carboxylate‐Derivatized Sulfur Ligands Affording Water Soluble Iron Complexes with [Fe(NS4)] Cores that Bind Small Molecules (CO, NO, PMe3) as Co‐Ligands
Authors: Sellmann Dieter , Peters Kai P. , Heinemann Frank W.
Published: January 2004

In the search for polydentate sulfur ligands that are able to form water‐soluble iron complexes which can bind nitrogenase relevant molecules, the new pentadentate ligands pyCO2MeS4−H2 [2,6‐bis[2‐mercapto‐3‐(methoxycarbonyl)phenylthio]dimethylpyridine] (1) and pyCO2HS4−H2 [2,6‐bis(2‐mercapto‐3‐carboxyphenylthio)dimethylpyridine] (2) having NS4 donor atom sets and terminal thiolate donors have been synthesized. The starting material was CO2MeS2−H2 (2,3‐dimercapto benzoic acid methyl ester) which was alkylated with 2,6‐bis[(tosyloxy)methyl]pyridine. The problem of specifically achieving regioselective mono‐alkylation of this 1,2‐benzene‐dithiol derivative was solved by carrying out the alkylation of CO2MeS2−H2 at −78 °C in the presence of stoichiometric amounts of a base. Saponification of 1 afforded the carboxylic acid derivative. Coordination of pyCO2MeS42− to FeII in the presence of co‐ligands (L = CO, PMe3) yielded the complexes [Fe(L)(pyCO2MeS4)] where L = CO (5) or PMe3 (4). Upon treatment with NOBF4, complex 5 afforded [Fe(NO)(pyCO2MeS4)]BF4 (7) which could be subsequently converted to the isolable 19 valence electron species [Fe(NO)(pyCO2MeS4)] (8) upon reduction with N2H4. In the absence of potential co‐ligands, coordination of pyCO2MeS42− to FeII afforded the dinuclear complex [Fe(pyCO2MeS4)]2 (6) whilst coordination to NiII gave [Ni(pyCO2MeS4)]x (3). Solubility of these complexes in water could be achieved by replacing the CO2Me groups with CO2H substituents. The ligand pyCO2HS42− afforded the iron complexes [Fe(L)(pyCO2HS4)] [L = CO (10) and PMe3 (12)] and [Fe(NO)(pyCO2HS4)]BF4 (11). Both 10 and 12 could be reversibly deprotonated to give the corresponding water‐soluble salts (NMe4)2[Fe(L)(pyCO2S4)] with L = CO {(NMe4)2 [9]} and PMe3 {(NMe4)2 [13]}. The complexes were characterized by elemental analysis, spectroscopic methods and X‐ray structural determinations. The molecular structure of [Fe(PMe3)(pyCO2HS4)] (12) was found to exhibit inter‐ and intramolecular O−H···O and O−H···S hydrogen bonds which serve as models for proton transfer steps from external sources to the active sites of metal sulfur enzymes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
On the Reactivity of the Iminodiphosphane C6H4(o‐CN)N=PPh2−PPh2: Fragmentation Versus Isomerisation
Authors: Fei Zhaofu , Scopelliti Rosario , Dyson Paul J.
Published: January 2004

The reactivity of the iminodiphosphane C6H4(o‐CN)N=PPh2−PPh2, which contains an N=P−P unit, has been investigated. Reaction with small molecules, [viz. H2O/O2, H2O2, CH3OH, C6H4(o‐CN)NH2] and elemental sulfur result in cleavage of the P−P bond to give aminophosphane‐derivatised compounds. The products from these reactions have been characterized spectroscopically, including two by single‐crystal X‐ray diffraction. The reactivity of the iminodiphosphane towards the transition metal complexes [M(cod)Cl2] (M = Pd or Pt) has also been investigated. In the reactions, the iminodiphosphane rearranges to form the more common diphosphonylamine (P−N−P) unit which chelates to the metal centres. Three different compounds were isolated from these reactions and they have all been fully characterised by spectroscopy and single‐crystal X‐ray diffraction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Mono‐ and Dinuclear Rhodium and Iridium Complexes with Chiral Phospholanes as Ligands
Authors: Krüger Peter , Werner Helmut
Published: January 2004

The dinuclear complexes [RhCl(L)2]2 (1, 2) with L = 1‐isopropyl‐(2S,5S)‐2,5‐dimethylphospholane (Isophos) and (2S,5S)‐2,5‐dimethyl‐1‐phenylphospholane (Phephos), respectively, prepared from [RhCl(C8H14)2]2 and four equivalents of L, react with Lewis bases such as L, CO, ethene and diphenylacetylene by cleavage of the chloride bridges. Mononuclear compounds of the general composition [RhCl(L)3] (3, 4) and trans‐[RhCl(L′)(L)2] (5−9; L′ = CO, C2H4, C2Ph2) were obtained, of which 4 (L = Phephos) and 8 (L′ = C2H4; L = Phephos) are in equilibrium with the precursors. Oxidative addition of H2 to 1 (L = Isophos) and [RhCl(PiPr2Ph)2]2 (10) affords the mononuclear dihydrido complexes [RhH2Cl(L)2] (13) and [RhH2Cl(PiPr2Ph)2] (14), respectively, via the unsymmetrical compounds [RhH2(L)2(μ‐Cl)2Rh(L)2] (11) and [RhH2(PiPr2Ph)2(μ‐Cl)2Rh(PiPr2Ph)2] (12) as intermediates. These intermediates can be isolated by treatment of 13 and 14 with one half equivalent of 1 or 10, respectively. The hydrogenation of the η3‐allyl and η3‐benzyl complexes [(η3‐2‐RC3H4)Rh(L)2] (16−18) and [(η3‐CH2Ph)Rh(L)2] (19, 20), which were prepared from 1 or 2 and the corresponding Grignard reagent, leads to the dinuclear RhIIIRhI products [RhH2(L)2(μ‐H)2Rh(L)2] (21, 22), which are structurally related to the dichloro(dihydrido) derivatives 11 and 12. Compound 21 (L = Isophos) reacts with CO to give trans‐[RhH(CO)(L)2] (23). While treatment of 1 with phenylacetylene yields the vinylidene complex trans‐[RhCl(=C=CHPh)(Isophos)2] (26), via η2‐alkyne and alkynyl(hydrido) intermediates, the reaction of 2 with PhC≡CH affords the labile enyne compound trans‐[RhCl{η2‐(E)‐PhC≡CCH=CHPh}(Phephos)2] (27). Reaction of 27 with CO gives 6 and the free enyne. The carbene complexes trans‐[RhCl(=CPh2)(L)2] (30, 31), obtained from trans‐[RhCl(=CPh2)(SbiPr3)2] (29) and L, react with ethene not by olefin metathesis but by formation of the isomeric olefins Ph2C=CHCH3 (32) and CH2=CHCHPh2 (33) in different ratios. With iridium as the metal center, carbonyl, dihydrido, and dihydrido(carbonyl) compounds with [IrCl(Isophos)2] as the building block have been prepared. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Syntheses, Crystal Structures and Magnetic Properties of Four CuII‐HgII Mixed‐Metal Halide Oligomers
Authors: Song Jun‐Ling , Mao Jiang‐Gao , Zeng Hui‐Yi , Dong Zhen‐Chao
Published: January 2004

Four heteronuclear CuII−HgII halides containing 2,2‐bipyridine (bipy) ligands have been synthesized and structurally characterised by single‐crystal X‐ray diffraction studies. The dinuclear complex [Cu(bipy)2HgCl2Br2] (1) contains a five‐coordinate copper(II) ion and a four‐coordinate HgII ion, in which the two different types of metal ions are bridged by a pair of chloride anions. [Cu2(bipy)4HgBr4][Hg2Br6] (2) contains a trinuclear [Cu2(bipy)4HgBr4]2+ cation in which the two copper(II) ions are bridged by an [HgBr4]2− tetrahedron via two Cu−Br bonds, and an edge‐sharing tetrahedral [Hg2Br6]2− anion. The structure of [Cu2(bipy)4Hg2Br6][Hg4Br10] (3) features a 1‐D chain along the diagonal of the a and c axes constructed from tetranuclear [Cu2(bipy)4Hg2Br6]2+ cations interconnected by [Hg4Br10]2− tetramers via elongated Hg−Br contacts (3.185 Å). Within the tetranuclear cationic unit, two [Cu(bipy)2]2+ units are bridged by an edge‐sharing dimeric tetrahedral [Hg2Br6]2− anion. In the trinuclear complex [Cu(bipy)2Hg2Cl6] (4), each [Hg2Cl6]2− dimer bridges with a [Cu(bipy)2]2+ ion to form a trinuclear [Cu(bipy)2Hg2Cl6] unit, and each pair of such units is bridged by a pair of elongated Hg−Cl bonds [3.043(5) Å] to form a dimeric unit. The magnetic properties of 1, 2, and 4 have also been investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Unusual CuII and MnII Complexes of Phenol‐Based Ligands Containing Amine, Pyridine and Formyl Functions: Unexpected Structural Features and Solution Studies
Authors: Koval Iryna A. , Huisman Mieke , Stassen Arno F. , Gamez Patrick , Lutz Martin , Spek Anthony L. , Reedijk Jan
Published: January 2004

The phenol‐based ligand Hpy2ald containing formyl, amine and pyridine functions reacts with copper(II) nitrate, copper(II) bromide and manganese(II) chloride to yield complexes with unexpected structures. In contrast to previously reported coordination compounds with similar ligands, the carbonyl group of the ligand in all complexes does not coordinate to the metal ions. The metal‐to‐ligand ratio is 2:1 in the case of the copper(II) nitrate complex and 1:1 in the case of the copper(II) bromide and manganese(II) chloride complexes. The copper(II) nitrate complex exhibits both donor‐atom and coordination number asymmetry, as one copper ion is pentacoordinate with an N3O2 donor set, and the other one is hexacoordinate with an O6 donor set. In the latter two complexes, the phenol group of the ligand remains protonated and fails to bridge the two metal ions; instead it is semi‐coordinated to only one metal ion. This results in the formation of mononuclear complexes in which copper(II) or manganese(II) ions have a distorted square‐pyramidal surrounding. All complexes were structurally, spectroscopically and magnetically investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Novel Thiotetraazapentalene Complexes from the Reaction of a Ruthenium Azide Complex with Alkyl Isothiocyanates
Authors: Hsu Sheng‐Chin , Lin Ying‐Chih , Huang Shou‐Ling , Liu Yi‐Hung , Wang Yu , Liu Hwang
Published: January 2004

Reactions of the ruthenium azide complex 1 with alkyl isothiocyanates give novel ruthenium thiotetraazapentalenedithione complexes 3a−c containing a hypervalent sulfur atom. The ligand, bound through one sulfur atom, is derived from three isothiocyanate molecules and one nitrogen atom from an azide ion. The synthesis and structural determination of 3a−c, as well as a possible mechanism for their formation is described. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Design and Structural Analysis of Metallamacrocycles Based on a Combination of Ethylene Glycol Bearing Pyridine Units with Zinc, Cobalt and Mercury
Authors: Grosshans Philippe , Jouaiti Abdelaziz , Bulach Véronique , Planeix Jean‐Marc , Hosseini Mir Wais , Kyritsakas Nathalie
Published: January 2004

In the presence of MX2 salts, ligand 1 (in a M/L ratio of 2:2, M = Zn, Hg, Co, X = Cl or I), based on the ethylene glycol fragment bearing two pyridine units as monodentate coordination sites, leads to isostructural square‐shaped neutral metallamacrocycles as demonstrated by X‐ray diffraction on single crystals. For all dinuclear complexes generated, the dicationic metal centre adopts a distorted tetrahedral coordination geometry and its coordination sphere is composed of the X2N2 set of coordinating atoms. For all complexes, the parallel packing of the cyclic structures generates channels which are occupied by solvent molecules. The solvent molecules, which behave as substrates, are positioned within the cavity of the metallamacrocycles. Control of the dimension of the macrocycles, by varying the size of the connecting metal centre, has also been demonstrated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)