bluuebunny/crossref_metadata_2025_split huggingface dataset:
Frontline: Induction of apoptosis and modulation of c‐FLIPL and p53 in immature dendritic cells infected with herpes simplex virus
Authors: Müller Dagmar B. , Raftery Martin J. , Kather Angela , Giese Thomas , Schönrich Günther 
Published: March 2004

AbstractHerpes simplex virus (HSV) can perturb the function of dendritic cells (DC). The underlying mechanisms are not defined. In the present study we demonstrate that HSV induces a substantial number of immature DC to undergo apoptosis by a mechanism involving caspase‐8. We found strongly enhanced expression of TNF‐α and TRAIL but not CD95 ligand after HSV infection. Blocking experiments suggested that these classical death ligands contribute to HSV‐induced cell death of immature DC. Because uninfected DC are resistant to the apoptosis‐inducing effect of death ligands we searched fora viral "competence‐to‐die" signal. Further analysis revealed that HSV‐infected immature DC down‐regulate long cellular FLICE‐inhibitory protein (c‐FLIPL) and up‐regulate p53 whereas otherapoptosis‐regulating proteins (e.g. Bcl‐2, RIP, FADD) were not affected. Down‐regulation of c‐FLIPL was not due to diminished gene transcription or reduced mRNA stability because the level of c‐FLIPL mRNA was rather increased. Moreover, down‐regulation of c–FLIPL could not be blocked by the anti‐herpetic drug acyclovir. Finally, the underlying mechanism was also operative in human umbilical vein endothelial cells, which show a similar susceptibility to HSV infection and strength of c‐FLIPL expression. These results suggest that HSV targets c‐FLIPL protein in immature DC and other infectable cells to disrupt their function.
Increased islet antigen presentation leads to type‐1 diabetes in mice with autoimmune susceptibility
Authors: Judkowski Valeria , Krakowski Michelle , Rodriguez Enrique , Mocnick Lorraine , Santamaria Pere , Sarvetnick Nora 
Published: March 2004

AbstractGranulocyte‐macrophage colony‐stimulating factor (GM‐CSF) is frequently used in preclinical and clinical protocols to modulate autoimmune responses, bone marrow transplants, and recovery from immune ablative therapies. The immunological outcome of such therapies is not fully understood. We tested the hypothesis that GM‐CSF would enhance the maturation of antigen‐presenting cells, facilitating presentation of β‐cell autoantigens to autoreactive T cells. We found that islet expression of GM‐CSF greatly enhanced disease in male mice. Islet‐derived APC but not splenic APC showed markedly enhanced capacity to stimulate in vitro proliferative responses of islet‐antigen‐specific autoreactive T cells. In vivo transfer of CD8+ and CD4+ T cells demonstrate that autoreactive T cells undergo extensive division in pancreatic lymph nodes of GM‐CSF‐transgenic mice compared with wild‐type NOD male mice. Together, the results presented here demonstrate that expression of GM‐CSF in the pancreas can enhance autoimmunity in disease‐susceptible mice.
CD4+ effector T cell distribution in vivo: TGF‐β1/TGF‐β receptor II interaction during activation mediates accumulation in the target tissue by preferential proliferation
Authors: Bode Ulrike , Tiedemann Kerstin , Westermann Jürgen 
Published: March 2004

AbstractCD4+ effector T cells generated in mesenteric lymph nodes (mLN) leave into the blood. Although they enter many tissues, mLN effector T cells are later found preferentially in the gut,the drainage area of mLN. We show in the rat that this is not an intrinsic property of mLN T cells. Instead, within the mLN milieu T cells are instructed by cytokines such as transforming growth factor β1 (TGF‐β1) to up‐regulate TGF‐β receptor II (TGF‐βRII) during activation. This enables effector T cells to continue proliferation upon subsequent contact with TGF‐β1 in mLNand gut, and to accumulate in the lymph node draining area, the most likely site of pathogen invasion.
Comparative analysis of human NK cell activation induced by NKG2D and natural cytotoxicity receptors
Authors: André Pascale , Castriconi Roberta , Espéli Marion , Anfossi Nicolas , Juarez Tiffany , Hue Sophie , Conway Holli , Romagné François , Dondero Alessandra , Nanni Marina , Caillat‐Zucman Sophie , Raulet David H. , Bottino Cristina , Vivier Eric , Moretta Alessandro , Paul Pascale 
Published: March 2004

AbstractNKG2D and natural cytotoxicity receptors (NCR) are essential recognition structures that mediate NK cell activation. NKG2D and NCR signaling is achieved through membrane association with signaling adaptors. The adaptors that associate with NCR — such as CD3ζ, FcRγ and KARAP/DAP12 — bear intracytoplasmic immunoreceptor tyrosine‐based activation motifs that activate Syk protein tyrosine kinases. Human NKG2D associates with the DAP10 transmembrane adaptor, which bears a YxxM motif and activates the phosphatidylinositol 3‐kinase pathway. In the mouse, a short NKG2D‐S isoform, generated by Nkg2d alternative splicing, can associate with either DAP10 or KARAP/DAP12. Here, we report that neither short human NKG2D alternative transcripts nor NKG2D association with KARAP/DAP12 was detected in activated human NK cells. Despite these results, NK cell triggering by both recombinant soluble NKG2D ligands (MICA and ULBP‐1) and anti‐NCR cross‐linking antibodies inducedsimilar CD25 expression, NK cell proliferation and cytokine production. In contrast, NKG2D triggering by anti‐NKG2D antibodies did not lead to any detectable activation signals. These data thus show that target recognition via NKG2D or NCR triggers all aspects of NK activation, and pave the way for further dissection of the signaling pathways induced by NK cell recognition of ULBP‐1 and MICA.
Systemic administration of antigen‐loaded CD40‐deficient dendritic cells mimics soluble antigen administration
Authors: Hochweller Kristin , Anderton Stephen M. 
Published: March 2004

AbstractThe decision to mount a T cell response to antigen (Ag) is dependent on the cellular context in which the Ag is presented. Activated dendritic cells (DC) are potent stimulators of immune responses, an ability which is linked to their high expression of several costimulatory molecules. In contrast, resting DC have been implicated in the generation of self tolerance, presumably due to their reduced costimulatory capacity. However, the precise molecular basis for the choice between Ag‐induced immunity and unresponsiveness remains unclear. We show here that CD40 plays an important rolein this decision. Systemic administration of Ag‐loaded, CD40‐deficient DC failed to induce a productive primary T cell expansion and rendered mice relatively unresponsive to subsequent immunizationwith Ag in adjuvant. Using a TCR‐transgenic T cell transfer system, we found that CD40–/– DC triggered an initial T cell activation that could not be sustained, resulting in loss of Ag‐reactive T cells and reduced cytokine production by those T cells that did persist. Furthermore, administration of CD40–/– DC that had been loaded with a central nervous system autoantigen was found to protect mice from autoimmune pathology. These data implicate the CD40:CD40L interaction as a key checkpoint in the development of T cell immunity rather than tolerance.
Involvement of NKR‐P2/NKG2D in DC‐mediated killing of tumor targets: indicative of a common, innate, target‐recognition paradigm?
Authors: Alli Rajshekhar , Savithri Balasubramanian , Das Suvendu , Varalakshmi Chavvakula , Rangaraj Nandini , Khar Ashok 
Published: March 2004

AbstractDC are the most efficient antigen‐presenting cells that regulate the immune response. Here, we demonstrate the expression of NK cell receptor protein‐2 (NKR‐P2) on rat and mouse DC, and we show that NKR‐P2 gets reorganized upon antigen contact. DC activated with anti‐NKR‐P2 mAb exhibit enhanced apoptotic killing of tumor targets, whereas blocking the interaction between NKR‐P2 and its ligand with rNKR‐P2 abrogated apoptotic killing, suggesting NKR‐P2 to function as an activating molecule on DC. In vivo injection of anti‐NKR‐P2 mAb augmented DC activity and delayed tumor progression. NKR‐P2 signaling involved Ca2+ influx, culminating in the expression of the apoptosis‐inducing molecule, TNF‐α. Taken together, these observations suggest that NKR‐P2 (the rat orthologue of human NKG2D) acts as a target‐recognition molecule on DC.
Frontline: Optimal T cell activation requires the engagement of CD6 and CD166
Authors: Hassan Namir J. , Barclay A. Neil , Brown Marion H. 
Published: March 2004

AbstractThe T cell surface glycoprotein, CD6 binds CD166 in the first example of an interaction between a scavenger receptor cysteine‐rich domain and an immunoglobulin‐like domain. We report that in human these proteins interact with a KD =0.4–1.0 μM and Koff ≥0.4–0.63 s–1, typical of many leukocyte membrane protein interactions. CD166 also interacts in a homophilic manner but with around 100‐fold lower affinity (KD =29–48 μM and Koff ≥ 5.3 s–1). At concentrations, that will block the CD6/CD166 interaction, soluble monomeric CD6 and CD166 inhibit antigen‐specific human T cell responses. This is consistent with extracellular engagement between CD6 and CD166 being required for an optimal immune response.
Complement activation by both classical and alternative pathways is critical for the effector phase of arthritis
Authors: Hietala Max Albert , Nandakumar Kutty S , Persson Linda , Fahlén Susann , Holmdahl Rikard , Pekna Marcela 
Published: March 2004

AbstractTo analyze the role of the classical and alternative pathways of complement activation in the effector phase of arthritis, we have induced arthritis in C3‐ and factor B (FB)‐deficient (C3–/– and FB–/–) DBA/1J mice using well‐defined monoclonal IgG2b and IgG2a antibodies to type II collagen. In control DBA/1J mice, severe swelling of the joints, destruction of cartilage and erosion of bone developed very rapidly with a 100% incidence and a peak on days 7–10. Although 75% of C3–/– mice developed arthritis, the clinical severity was very mild and the onset was delayed. Severity of arthritis in FB–/– mice ranked intermediate in comparison with C3–/– and control mice with an incidence of 100%. Immunohistochemical analysis of the inflamed joints demonstrated substantial reduction in macrophage and neutrophilic leukocyte infiltration in both C3–/– and FB–/– mice, thereby confirming the clinical findings. We conclude that both the classical and the alternative pathways of complement activation are involved in the effector phase of arthritis.
Maintenance of memory CTL responses by T helper cells and CD40‐CD40 ligand: antibodies provide the key
Authors: Bachmann M. F. , Hunziker Lukas , Zinkernagel R. M. , Storni T. , Kopf M. 
Published: March 2004

AbstractVol. 34(2) 2004, pp 317–326, DOI 10.1002/eji.200324717The authors would like to add the following information regarding the viral doses used in the experiments:All experiments with recombinant vaccinia virus were performed with a standard dose of 2×106 pfu. All experiments with LCMV WE were performed with a standard dose of 200 pfu. The intravenous route of infection was used for both viruses.See original article http://dx.doi.org/10.1002/eji.200324717
Hydrothermal Syntheses, Crystal Structures, Magnetism and Fluorescence Quenching of Oxamidato‐Bridged Pentanuclear CuII4LnIII Complexes Containing Macrocyclic Ligands (Ln = Eu, Tb) and the Crystal Structure of a Hexanuclear NiII5SmIII Complex
Authors: Sun Ya‐Qiu , Liang Mao , Dong Wen , Yang Guang‐Ming , Liao Dai‐Zheng , Jiang Zong‐Hui , Yan Shi‐Ping , Cheng Peng 
Published: March 2004

AbstractThree novel oxamidato‐bridged complexes incorporating a macrocyclic oxamide of formula [(CuL)3{CuL(C2H5OH)}Eu(H2O)](ClO4)3·1.5H2O (1), [(CuL)3{CuL(C2H5OH)}Tb(H2O)](ClO4)3·2H2O (2) and [(NiL)5Sm](ClO4)3·2H2O (3) (CuL and NiL, H2L = 2,3‐dioxo‐5,6,14,15‐dibenzo‐1,4,8,12‐tetraazacyclopentadeca‐7,13‐dien), have been hydrothermally synthesized and structurally characterized. In these complexes, the central LnIII and external copper (or nickel) ions are bridged by macrocyclic oxamide groups. The EuIII (or TbIII) ion of 1 (or 2) resides in a distorted tricapped trigonal prismatic environment surrounded by eight oxygen atoms from four oxamide groups and one oxygen atom from a water molecule, whereas the SmIII ion of 3 resides in a distorted bicapped square antiprismatic environment surrounded by ten oxygen atoms from five oxamide groups. Furthermore, there are hydrogen bonding interactions in 1 and 2 between perchlorate, ethanol and water moieties. Especially for 1 and 2, O−H···O and weak coordination of ClO4− groups link the pentanuclear fragments and perchlorate ions to form a 1‐D supramolecular architecture. The fluorescence of EuIII and TbIII are almost completely quenched in 1 and 2. The magnetic properties of 1 and 2 have been characterized. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Macrocyclic and Open‐Chain CuII‐4f (4f = GdIII, CeIII) Complexes with Planar Diamino Chains: Structures and Magnetic Properties
Authors: Costes Jean‐Pierre , Dahan Françoise , Novitchi Ghenadie , Arion Vladimir , Shova Sergiu , Lipkowski Janusz 
Published: March 2004

AbstractUntil now, the known structures of heterodinuclear Cu−Ln complexes involve compartmental Schiff‐base ligands with saturated diamino chains. We report here two Cu−Ln complexes (Ln = Gd or Ce) which are the first structurally characterized Cu−Ln entities involving S‐methylisothiosemicarbazide as the diamino bridge, with open chain and macrocyclic ligands. The macrocyclic Cu−Gd entity is a well isolated dinuclear complex whereas two hydrogen bonds join together a pair of binuclear Cu−Ce complexes to give tetranuclear {Cu−Ce···Ce−Cu} entities. The Cu−Gd complexes [H = ‐J(SCuSGd)] exhibit ferromagnetic interactions between 5 and 5.5 cm−1. Since the Cu−Ce complexes do not follow the Curie law due to the presence of orbital degeneracy, an analysis based on a simple spin‐only Hamiltonian is not possible. Nevertheless, the EPR spectra of the Cu−Ce complexes do confirm the existence of magnetic interactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Hydrolytic Cleavage of DNA by Ternary Amino Acid Schiff Base Copper(II) Complexes Having Planar Heterocyclic Ligands
Authors: Reddy Pattubala A. N. , Nethaji Munirathinam , Chakravarty Akhil R. 
Published: March 2004

AbstractThe ternary copper(II) complexes [Cu(salgly)L] (L = phen, 1; dpq, 2), [Cu(salala)L] (L = phen, 3; dpq, 4) and [Cu(salphe)L] (L = phen, 5; dpq, 6), where salgly, salala and salphe are tridentate Schiff‐base ligands derived from the condensation of salicylaldehyde with glycine, L‐alanine and L‐phenylalanine, respectively, are prepared and their nuclease activity studied (phen, 1,10‐phenanthroline; dpq, dipyridoquinoxaline). The crystal structure of 3 displays a distorted square‐pyramidal (4+1) coordination geometry in which the ONO‐donor Schiff base is bonded to the metal atom in the basal plane. The chelating phen ligand displays an axial−equatorial mode of bonding. The complexes exhibit a d−d band near 670 nm and a charge transfer band near 370 nm in methanol. The one‐electron paramagnetic complexes display axial EPR spectra in DMF glass at 77 K, indicating a {d−}1 ground state. The complexes are redox‐active and exhibit a quasi‐reversible CuII/CuI couple in DMF at approximately −0.6 V vs. SCE. They show catalytic activity in the oxidation of ascorbic acid by molecular oxygen. The ability of the complexes to bind calf thymus (CT) DNA follows the order: 2 ≈︁ 4 ≈︁ 6 > 1 ≈︁ 3 ≈︁ 5. Complexes 1−6 show oxidative DNA cleavage activity in the presence of mercaptopropionic acid as a reducing agent. All the complexes show hydrolytic cleavage activity in the absence of light or any reducing agent. The oxidative and hydrolytic DNA cleavage efficiencies follow the order: 2 ≈︁ 4 ≈︁ 6 > 1 ≈︁ 3 ≈︁ 5. The dpq complexes, which have a greater DNA binding ability, display enhanced nuclease activity than their phen analogues. The hydrolytic DNA cleavage rate of 1.8 h−1, observed for 2, is significantly high relative to most of the known copper‐based synthetic hydrolases. Mechanistic pathways involved in the nuclease activity of the complexes are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Rhodium(I), Palladium(II) and Platinum(II) Coordination Chemistry of the Short‐Bite Chiral Ligands (Sc)‐N,N‐Bis(diphenylphosphanyl)‐sec‐butylamine, (Ra,Ra)‐N,N‐Bis(binaphthylphosphonito)phenylamine and (Ra,Sc)‐N‐(Diphenylphosphanyl)‐N‐(binaphthylphosphonito)‐sec‐butylamine
Authors: Calabrò Gianpiero , Drommi Dario , Graiff Claudia , Faraone Felice , Tiripicchio Antonio 
Published: March 2004

AbstractThe new short‐bite chiral ligands (Sc)‐N,N‐bis(diphenylphosphanyl)‐sec‐butylamine [(Sc)‐1], (Ra,Ra)‐N,N‐bis(binaphthylphosphonito)phenylamine [(Ra,Ra)‐2] and (Ra,Sc)‐N‐(diphenylphosphanyl)‐N‐(binaphthylphosphonito)‐sec‐butylamine [(Ra,Sc)‐3] have been treated with rhodium(I), palladium(II) and platinum(II) substrates. The (Sc)‐1 ligand reacts with [Pd(C6H5CN)2Cl2], [Pt(COD)Cl2] and [Rh(COD)(THF)2]PF6 to afford the products [Pd(Sc‐1)Cl2] (4), [Pt(Sc‐1)Cl2] (5) and [Rh(COD)(Sc‐1)]PF6 (6), respectively, in high yields. By bubbling CO to a CH2Cl2 solution of 6, we formed the dicarbonyl species [Rh(CO)2(Sc‐1)]PF6 (7), which is stable only in solution under CO. Compounds 4 and 5 were characterized additionally by X‐ray diffraction studies. The ligand (Ra,Ra)‐2 reacts with [Pd(C6H5CN)2Cl2] and [Pt(COD)I2] to give [Pd(Ra,Ra‐2)Cl2] (8) and [Pt(Ra,Ra‐2)I2] (9), respectively; the reaction with [Rh(CO)2Cl]2 or [Rh(COD)(THF)2]PF6 affords a mixture of mono‐ and binuclear compounds, in which the ligand is oxidized to the corresponding phosphonate or is partially hydrolysed. The compounds [Pd(Ra,Sc‐3)Cl2] (10) and [Pt(Ra,Sc‐3)I2] (11) were obtained in the analogous reactions using the asymmetric (Ra,Sc)‐3 ligand. This ligand reacted with [Rh(CO)2Cl]2 in a 2:1 molar ratio in hexane to give a mixture of products in almost equal amounts. The 31P{1H} NMR spectrum recorded in CDCl3 allowed us to identify the chelate [Rh(Ra,Sc‐3)(CO)Cl] (12); the nature of the accompanying dinuclear species 13 is not clear. The catalytic systems formed by [Rh(acac)(CO)2] and the ligands (Ra,Ra)‐2 and (Ra,Sc)‐3, at ligand/metal ratios of 1:1 and 1:2, were unstable under the experimental conditions used (CO/H2 pressure of 50 atm and temperature of 40 °C) for the hydroformylation of styrene; instead, metallic rhodium was afforded together with unidentified decomposition products. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The Synthesis of Stable Intramolecularly Dialkylamino‐Coordinated Silenes and Their Methyl Iodide Induced Isomerization into Cyclic Aminosilanes
Authors: Mickoleit Martin , Schmohl Kathleen , Michalik Manfred , Oehme Hartmut 
Published: March 2004

AbstractThe reaction of the (dichloromethyl)oligosilanes R(Me3Si)2SiCHCl2 4a−d (4a: R = Me; 4b: R = tBu; 4c: R = Ph; 4d: R = SiMe3) with 8‐(dimethylamino)‐1‐naphthyllithium leads to the intramolecularly donor‐stabilized silenes 1a−d. Whereas 1a,b, and d were isolated as thermally stable yellow crystalline compounds, 1c could not be separated in a pure form but was characterized by NMR spectroscopy and mass spectroscopy as well as by its chemical reactivity with a variety of substrates. Dynamic 1H NMR spectroscopic studies of 1a and 1d revealed coalescence of the signals of the two CSiMe3 groups. In agreement with theoretical calculations, this effect was interpreted as the result of internal rotations about the silene double bond. These findings and the known relatively long Si=C distances for 1d, 2 and 3 help establish the ylide‐like nature of the silenes prepared. Treatment of 1a−d with water produced the silanols 9a−d. Treatment of 1a,b, and d with methyl iodide caused a rearrangement of the silenes, one methyl substituent formally migrating from the coordinated dimethylamino group to the silene carbon atom producing the respective cyclic aminosilanes 11a,b, and d. As the outcome of the reaction of 1d with benzaldehyde, 2,2‐bis(trimethylsilyl)vinylbenzene (14) and a mixture of the two isomers of the cyclodisiloxane 13 were obtained. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Tetranuclear (Borole)rhodium Clusters with Hydrido and Methylthiolato Ligands − Structures of [{Rh(C4H4BMe)}4(µ3‐H)(µ3‐I)3] and of [{Rh(C4H4BPh)}2(µ‐SMe)(µ3‐SMe)]2 (2 Rh−Rh)
Authors: Herberich Gerhard E. , Eckenrath Hartmut J. , Wagner Trixie , Wang Ruimin 
Published: March 2004

AbstractThe heterocubanes [Rh(C4H4BR)(µ3‐I)]4 (1a: R = Ph; 1b: R = Me) can be hydrogenated in THF (suspension, 1 bar H2, 20 °C) to give the µ3‐hydrido clusters [{Rh(C4H4BR)}4(µ3‐H)(µ3‐I)3] (2a,b). The structure of 2b consists of a Rh4(µ3‐H)(µ3‐I)3 core with idealized C3v symmetry and four capping η5‐borole ligands. The Rh−Rh distances within the Rh3(µ3‐H) cluster unit amount to 2.9448(6), 2.9647(6), and 2.9724(6) Å; the µ3‐H ligand is 0.064(5) Å above the Rh3 plane with a mean Rh−H bond length of 1.83(5) Å. The tris(acetonitrile) salts [Rh(C4H4BR)(NCMe)3]BF4 (4a,b) react with NaSMe to give the methylthiolato complexes [Rh(C4H4BR)(SMe)]x (3a,b). In the crystal 3a possesses a centrosymmetric stepped‐ladder structure [{Rh(C4H4BPh)}2(µ‐SMe)(µ3‐SMe)]2 (2Rh−Rh) (3a‐Rh4), with a Rh−Rh bond length of 2.9233(11) Å. In solution a dissociation equilibrium is observed with a predominating dinuclear complex [Rh(C4H4BPh)(µ‐SMe)]2 (3a‐Rh2); in pyridine a closely related solvate [Rh(py)(C4H4BPh)(µ‐SMe)]2 (5) with a static Rh2(μ‐SMe)2 core is formed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The First Silver(I) Side‐On η2‐Coordination Network Formed by Self‐Assembly of Bis(pyrrol‐2‐ylmethylene)hydrazine
Authors: Yang Lanying , Shan Xufeng , Chen Qingqi , Wang Zhengping , Ma Jin Shi 
Published: March 2004

AbstractThis paper reports the first silver(I) network polymer formed by the self‐assembly of bis(pyrrol‐2‐ylmethylene)hydrazine with silver nitrate, in which the silver centers are bonded to the C−N bonds of the pyrrole rings in an η2‐fashion. An X‐ray crystal structure analysis revealed that the self‐assembly of the bis(pyrrol‐2‐ylmethylene)hydrazine ligand with AgI gives a 2D sheet, which is further assembled to form a 3D network through weak intermolecular hydrogen bonding between the protons of the pyrrole rings and the oxygen atoms of the nitrate ions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis, Characterization and Reactivity of New (μ‐Aminocarbyne)diruthenium Complexes Containing Alkynylimino Ligands
Authors: Busetto Luigi , Marchetti Fabio , Zacchini Stefano , Zanotti Valerio 
Published: March 2004

AbstractAddition of acetylides R′C≡CLi [R′ = Tol, Ph, Me3Si, nBu, C(Me)=CH2] to the diruthenium complexes [Ru2{μ‐CN(Me)(R)}(μ‐CO)(CO)(NCCMe3)(Cp)2]+ (R = Xy, 2a; Bz, 2b; Me, 2c) results in the formation of [Ru2{μ‐CN(Me)(R)}(μ‐CO)(CO){N(H)=C(CMe3)(C≡CR′)}(Cp)2]+ (R = Xy, R′ = Tol, 3a; R = Bz, R′ = Tol, 3b; R = Me, R′ = Tol, 3c; R = Xy, R′ = Ph, 4a; R = Bz, R′ = Ph, 4b; R = Me, R′ = Ph, 4c; R = Bz R′ = H, 5; R = Xy, R′ = nBu, 6; R = Xy, R′ = [C(Me)=CH2], 7), which contain an alkynylimino ligand, formed from addition of the acetylide to the Me3CCN ligand. Structural and spectroscopic studies show that all these complexes contain the two Cp ligands in a relative cis arrangement, whereas two isomers arise from the different orientation of the substituents on the bridging aminocarbyne μ‐CN(Me)(R) when R ≠ Me. Addition of secondary amines to 3−7 results in a stereo‐ and regioselective cis amination of the C−C triple bond to give the new complexes [Ru2{μ‐CN(Me)(R)}(μ‐CO)(CO){N(H)=C(CMe3)C(H)=C(NMe2)(Tol)}(Cp)2]+ (R = Xy, 8a; Bz, 8b; Me, 8c), [Ru2{μ‐CN(Me)(Xy)}(μ‐CO)(CO){N(H)=C(CMe3)C(H)=C(NC5H10)(Tol)}(Cp)2]+(9) and [Ru2{μ‐CN(Me)(Xy)}(μCO)(CO){N(H)=C(CMe3)C(H)=C(NMe2)C(Me)=CH2)}(Cp)2]+ (10) containing the hitherto unknown new imino‐2‐en‐3‐amine ligand. The solid‐state structures of these products have been analyzed by X‐ray analysis and, in solution, by NOE spectroscopic studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)