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Coordination Ligands (coordination + ligand)
Selected AbstractsTransition Metal-Assisted Hydrolysis of Pyrazole-Appended Organooxotin Carboxylates Accompanied by Ligand TransferEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2007Vadapalli Chandrasekhar Abstract The reaction of the potentially multi-site coordination ligands [{nBu2SnO2CL}2O]2 (1), [{nBu2SnO2CL,}2O]2 (2), [nBuSn(O)O2CL]6 (3), and [nBuSn(O)O2CL,]6 (4), (L = (Pz)2CH-); L, = (3,5-Me2Pz)2CH-; Pz = pyrazolyl) with hydrated metal salts leads to the hydrolysis of the organotin carboxylates accompanied by the formation of insoluble organotinoxide/hydroxides and metal complexes. The in situ generated LCOO and L,COO ligands bind to the metal ions. The complexes [Cu(LCOO)2(NO3)2(nBu2Sn((H2O)2)]n[Cu(LCOO)2] (5), [Mg(L,COO)2] (6), [Cu(LCOO)2] (7), and [{(Cu(L,COO)2(Cu(MeOH))3}{ClO4}2]n (8) were isolated and structurally characterized. The solid-state structure of 5 reveals that two discrete molecules are present in the same asymmetric unit; a heterobimetallic coordination polymer, [Cu(LCOO)2(NO3)2(nBu2Sn((H2O)2)]n and a discrete coordination complex, [Cu(LCOO)2]. The cationic portion of the heterobimetallic compound contains alternate six-coordinate SnIV and CuII centers bridged by the carboxylate oxygen atoms of the LCOO ligand.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] The role of Bi3+ -complex ion as the stabilizer in electroless nickel plating processAICHE JOURNAL, Issue 4 2009K. Wang Abstract Bi3+ -complex ion is presented here as a less toxic stabilizer for use in electroless nickel plating (ENP) to replace the existing Pb2+ ion stabilizer. The asymmetric derivatives of EDTA are identified to be a type of coordination ligands that can combine with Bi3+ ions to form soluble complexes in the acidic ENP solution. In the ENP system studied the Bi3+ -complex ion displays a critical stabilizer concentration of about 10,5 mol/L, that is, the percolation concentration over which the ENP rate drops sharply. Besides the experimental measurement, deposition rates of both Ni and P are also simulated by using a kinetic model that has been derived from the double electric layer theory. The Bi3+ -complex ion, behaving like conventional Pb2+ ion, stabilizes ENP bath through the chemical replacement reaction at the surface of Ni deposition layer and results in a passive plating surface. This investigation also verifies the properties of the EN deposit, which are insignificantly affected by the length of service time of the plating solution by employing Bi3+ -complex ion stabilizer. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Synthesis, structure and ethylene polymerization of group 4 complexes with phosphinoamide ligandsAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 2 2006Changhe Qi Abstract Group 4 complexes containing diphosphinoamide ligands [Ph2PNR]2MCl2 (3: R = tBu, M = Ti; 4: R = tBu, M = Zr; 5: R = Ph, M = Ti; 6: R = Ph, M = Zr) were prepared by the reaction of MCl4 (M = Ti; Zr) with the corresponding lithium phosphinoamides in ether or THF. The structure of [Ph2PNtBu]2TiCl2 (3) was determined by X-ray crystallography. The phosphinoamides functioned as ,2 -coordination ligands in the solid state and the TiN bond length suggests it is a simple single bond. In the presence of modified methylaluminoxane or i -Bu3Al/Ph3BC(C6F5)4, catalytic activity of up to 59.5 kg PE/mol cat h bar was observed. Copyright © 2005 John Wiley & Sons, Ltd. [source] Theoretical Investigation on the Absorption and Emission Properties of the Three Isomers of Bis(thiocyanato)(2,2,-bipyridyl)platinum(II)CHINESE JOURNAL OF CHEMISTRY, Issue 9 2007Xiao-Ying Hu Abstract This paper presents a Density Functional or Time Dependent Density Functional (DFT/TDDFT) study of the molecular and electronic structures, optical absorption and emission spectra of three linkage isomers:bis(isothiocyanato-S)(2,2,-bipyridyl) platinum(II) ([Pt(SCN)2(bpy)]), (isothiocyanato-S)(thiocyanato-N)-(2,2,-bipy- ridyl) platinum(II) ([Pt(SCN)(NCS)(bpy)]), and bis(thiocyanato-N)(2,2,)-bipyridyl)platinum(II) ([Pt(NCS)2(bpy)]), in which different coordination ligands based on the N- and S-coordination of the thiocyanato ligands control the luminescent color. The electronic structures were studied using the B3LYP functional. Optimized geometries were compared to the experimentally observed structures. TDDFT calculation was carried out to investigate the excited singlet and triplet states. Calculations have been performed both in vacuo and in solvents, using a polarized continuum model (PCM) to account for solute-solvent interactions. Inclusion of the solvent led to a significant energy change, and as a consequence, the computed spectrum calculated in the presence of the solvent was in good agreement with the experimental determinations. The first two absorptions were found to originate from mixed platinum-SCN (or NSC) to bipyridyl-,* transitions rather than pure metal-to-ligand-charge-transfer (MLCT) transitions, whereas the higher-energy bands arose from intraligand ,,,* transitions. The stretching frequencies of C,N have been calculated both in the ground and excited states, which are relative to the charge transition during the excitation. In addition, different sizes of basis sets were also discussed in this paper. [source] | ||||||||||