Alkalimetal (Na+ and K+)- mediated supramolecular assembly of oxovanadium(V) complexes: Synthesis and structural characterization

6 páginas, 5 figuras, 6 tablas.-- El pdf del artículo es la versión post-print.-- et al.The syntheses and characterization of alkalimetal complexes [{VO2L}M(H2O}n] (1 and 2) [M = Na+ (1), K+ (2)] of anionic cis-dioxovanadium(V) species (LVO2−) of the Schiff base 2-hydroxybenzoylhydrazone of 2-hydroxybenzaldehyde have been reported. The number of coordinated water molecules in [{VO2L}M(H2O}n] decreases as the charge density of the alkalimetal ion decreases (n = 5 for Na+ and 1 for K+). These compounds represented M+-mediatedsupramolecularassembly [{VO2L}M(H2O}n]∝ with an infinite polymeric structure containing an alternating array of cis-dioxo vanadium(V), [VO2L]−, units and aquated metal ion centres, as confirmed by X-ray crystallographic investigation of both. All the compounds are characterized by elemental analysis, IR, UV–Vis and NMR spectroscopy.R. D. thanks Department of Science and Technology, Govt. of India for the Funds (Grant SR/FT/CS-016/2008) as SERC Fast Track Scheme of Young Scientist.Peer reviewe

Ligational Behaviour of 3-(2-Hydrazinocarbonyl)phenylimino-2-oximobutane Towards Oxovanadium(IV)

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Synthesis and reactivity of some octacoordinated dioxouranium(VI) complexes of diacetyl bis(benzoylhydrazone) and benzil bis(benzoylhydrazone)

980-983Octacoordinated dioxouranium(VI) complexes of the tetradentate ONNO donors diacetyl bis(benzoylhydrazone) (H2L) and benzil bis(benzoylhydrazone) (H2L') are reported. At low pH (1.5-2.5) complexes of the formula [UO2(H2L/H2L')X2](X- = Cl- , Br-, NO, NCS-, ClO, OAc- or 0.5SO) containing the ke-to form of the ligands are isolated. At higher pH(6-7), the complexes [UO2(L/L/H2L2)] are obtained in which the ligand is present in its deprotonated enolate form (L2-- or L'2-). Reactions of [[UO2(H2L/H2L')X2]/ [UO2(L/L')H2O2] with neutral monodentate (B) and bidentate lewis bases (AA) lead to the formation of mixed-ligand complexes of the type [UO2(L/L')(B2)] and [UO2(L/L')(AA)] respectively. Results of elemental analyses, magnetic susceptibility and conductivity measurements, spectroscopic (IR, electronic etc.) and thermal decomposition studies have been utilised to characterise the complexes

Molybdenum Complexes of Some N - S Donors: Part I-Syntheses & Reactivity of Mo(VI) Complexes of Some Ring-substituted 4-Phenylthiosemicarbazides

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Synthesis, structure determination and reactivity of a highly stable vanadium(III) complex

The synthesis, characterization, structure determination and reactivity study of a highly stable vanadium(III) complex of picolinic acid (picH)-a monoacid bidentate chelating donor-is reported. It can be kept in open air for days and can be heated up to 180 degrees C without oxidation. The complex [V(pic)(3)]. H2O crystallizes in the monoclinic system with space group C2/c. The V-III acceptor centre is in a highly distorted octahedral donor environment. The reason for this exceptional stability of the complex towards oxidation is evident from the analysis of the structural and electrochemical data. (C) 1997 Elsevier Science Ltd

X-ray crystal structure of [VO(DPA)(H2O)(2)]center dot 2H(2)O (DPA = dipicolinate dianion)

The X-ray crystal structure of the trans-diaqua complex [VO(DPA)(H2O2)]. 2H(2)O (I) (DPA = dipicolinate dianion) has been determined. Comparison with the known structure of [VO(DPA)(o-phen)]. 3H(2)O (2), obtained from (1) by displacement of the two coordinated aqua molecules, shows that the coordination sphere around vanadium is reorganised during this reaction

Synthesis, structure, and reactivity of some new dipyridyl and diamine-bridged dinuclear oxomolybdenum(VI) complexes

8 pages, 6 tables, 4 figures.Some new diimine and diamine-bridged dinuclear Mo(VI) complexes of the general formula [(MoO2L)2(μ-N–N)] [(μ-N–N) = 4,4′-bipyridine (4,4′-bpy) (2); trans-1,2-bis(4-pyridyl) ethene (bpe) (3); trans-1,2-bis(4-pyridyl) ethane (bpa) (4) and p-phenylenediamine (ppda) (5)] along with their common mononuclear precursor [MoO2L(C2H5OH)] (1) have been synthesized, using 2-hydroxy benzoylhydrazone of 2-hydroxybenzaldehyde as tridentate ONO donor Ligand (LH2), and structurally characterized. Structures of all the three dinuclear complexes 2, 3 and 5 are centrosymmetric with both the Mo(VI) acceptor centers existing in the same coordination environment. One 2 from the four dinuclear complexes has taken part in oxo-transfer to the substrate PPh3 forming the corresponding dinuclear Mo(IV)–Mo(IV) complex [(MoOL)2(μ-N–N)] (2a).Financial support from the Spanish Ministry of Science and Technology (Grant BQU2002-00554) and the European Regional Development Fund is gratefully acknowledged by L.R.F. and M.T.Peer reviewe

Complexes of hexadentate NSO donor ligands - III. Nickel(II) complexes of 1,3-di(o-salicylaldiminophenylthio)propane and 1,2-di(o-salicylaldiminophenylthio)xylene

Nickel(II) complexes of the hexadentate N2S2O2 donor ligands, 1,3-di(o-salicylaldiminophenylthio)propane (H(2)DSALPTP) and 1,2-di(o-salicylaldiminophenylthio)xylene (H(2)DSALPTX) have been synthesised and characterised. H(2)DSALPTP reacted with NiCl2.6H(2)O or Ni(ClO4)(2).6H(2)O in presence of ammonia to give the complex [Ni(DSALPTP)] (1). H(2)DSALPTX reacted smoothly with N(ClO4)(2) to yield the corresponding complex [Ni(DSALPTX)] (2). The ligand did not react with NiCl2 in the absence of ammonia but in its presence produced the complex (2). The molecular and crystal structure;of [Ni(DSAL PTX)] exhibits a very unusual deployment of the six donor sites of the ligand. It crystallises in the orthorhombic system with space group P2(1)2(1)2(1). In dichloromethane solution both the complexes are found to exhibit Ni(II)/Ni(III) redox couples in their cyclic voltammograms at room temperature with E-1/2 values 0.87 and 0.78 V (vs. Ag/AgCl). (C) 1998 Elsevier Science Ltd. All rights reserved

Ligational Behaviour of a Tridentate NNS Donor Ligand towards Salts of Co(III), Ni(II) & Cu(II)

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