The mononuclear copper(II) complexes, [CuL1](ClO4) (1), and [CuL2](ClO4) (2) with unsymmetrical quadridentate Schiff base ligands derived from the 1:1:1 condensation of 2,4-pentanedione, pyridine-2-carboxaldehyde and 1,2-ethanediamine (HL1) or 1,3-propanediamine (HL2) have been prepared and characterised. Complex 2 undergoes Cu(II)/H+ catalysed rearrangement to [CuL3](ClO4)2 (3) where L3 is a symmetrical tetradentate Schiff base involving 1,3-propanediamine and pyridine-2-carboxaldehyde. Structures of all the three compounds have been verified by single crystal X-ray analysis. The geometry around Cu(II) is square-planar in I and 2 whereas that in 3 is distorted octahedral with two axially coordinated perchlorate ions. © 2003 Elsevier Science B.V. All rights reserved.

ASHUTOSH GHOSH

Chemistry

M S RAY

R BHATTACHARYA

S CHAUDHURI

L RIGHI

G BOCELLI

G MUKHOPADHYAY

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Synthesis, characterisation and X-ray crystal structure of copper(II) complexes with unsymmetrical tetradentate schiff base ligands: First evidence of Cu(II) catalysed rearrangement of unsymmetrical to symmetrical complex

Polyhedron

Three copper(II) complexes [CuL(PhCOOH)(ClO4)] (1), [Cu 2L2(PhCOO)](ClO4) (2) and [Cu3L 2{(o-NO2)PhCOO}2](ClO4) (3), where HL = 2-[1-(2-dimethylamino-ethylimino)-ethyl]-phenol, a well known Schiff base ligand, have been prepared and characterized by elemental analysis, IR and UV-Vis spectroscopy and single crystal X-ray diffraction studies. Complex 1 crystallizes in triclinic space group P - 1, complex 2 in monoclinic C 2 and complex 3 in monoclinic P21/c. The co-ordination polyhedron around each copper atom is best described as an elongated (4 + 1) square pyramid. Complex 1 is mononuclear with a terminal benzoate, complex 2 is dinuclear containing a μ1,3 benzoate whereas complex 3 is trinuclear having a rare μ1,1,3 benzoate binding three copper centers simultaneously. © 2012 Elsevier B.V. All rights reserved.

Inorganica Chimica Acta

Synthesis and structure of mono-, di- and tri-nuclear copper(II) benzoate complexes with a tridentate N2O donor Schiff base ligand

Two new nickel(II) complexes, [NiL(H 2O) 2Cl] (1) and [{NiLL′(H 2O)} 2(μ-H)]NO 3·H 2O (2), have been synthesized using a tridentate Schiff base ligand, HL, 2-[(2-dimethylamino-ethylimino)-methyl]-phenol, along with Cl - or NO 3 - as an anionic co-ligand or counter anion (where L′H = salicylaldehyde). Both complexes have been characterized by X-ray crystallography. The structural analyses reveal that complex 1 is mononuclear whereas 2 is a hydrogen-bridged dinuclear complex. The Ni(II) ions possess a distorted octahedral geometry in both structures. Both complexes show negative solvatochromic behaviour with increasing donor number (DN) of the solvent. In more coordinating solvents, like DMSO or methanol, the colour of the solutions is green, whereas in less coordinating solvents, like dichloromethane (DCM) or acetonitrile, it is red. © 2011 Elsevier Ltd. All rights reserved.

Complexes of NiX 2 (X = Cl - and NO 3 - ) with a NNO donor Schiff base: Anion dependent structural variations and spectroscopic behaviour

A mononuclear octahedral nickel(II) complex [Ni(HL1) 2](SCN)2 (1) and an unusual penta-nuclear complex [{(NiL2)(μ-SCN)}4Ni(NCS)2]·2CH 3CN (2) where HL1 = 3-(2-aminoethylimino)butan-2-one oxime and HL2 = 3-(hydroxyimino)butan-2-ylidene)amino)propylimino)butan-2- one oxime have been prepared and characterized by X-ray crystallography. The mono-condensed ligand, HL1, was prepared by the 1:1 condensation of the 1,2-diaminoethane with diacetylmonoxime in methanol under high dilution. Complex 1 is found to be a mer isomer and the amine hydrogen atoms are involved in extensive hydrogen bonding with the thiocyanate anions. The dicondensed ligand, HL2, was prepared by the 1:2 condensation of the 1,3-diaminopropane with diacetylmonoxime in methanol. The central nickel(II) in 2 is coordinated by six nitrogen atoms of six thiocyanate groups, four of which utilize their sulphur atoms to connect four NiL2 moieties to form a penta-nuclear complex and it is unique in the sense that this is the first thiocyanato bridged penta-nuclear nickel(II) compound with Schiff base ligands. © 2010 Elsevier B.V. All rights reserved.

Syntheses, characterization and X-ray crystal structures of a mono-and a penta-nuclear nickel(II) complex with oximato Schiff base ligands

Two octahedral complexes [Ni(HL1)2](ClO4)2 (1) and [Ni(HL2)2](ClO4)2 (2) and a square planar complex [Ni(HL3)]ClO4 (3) have been prepared, where [HL1 = 3-(2-amino-ethylimino)-butan-2-one oxime, HL2 = 3-(2-amino-propylimino)butan-2-one oxime] and H2L3 = 3-[2-(3-hydroxy-1-methyl-but-2-enylideneamino)-1-methyl-ethylimino]-buta n-2-one oxime. All the complexes have been characterized by elemental analyses, spectral studies and room temperature magnetic moment measurements. The molecular structures of all three compounds were elucidated on the basis of X-ray crystallography; complexes 1 and 2 are seen to be the mer isomers. © 2008 Elsevier Ltd. All rights reserved.

Syntheses, characterization and X-ray crystal structures of Ni(II) complexes of tridentate monocondensed and tetradentate dicondensed Schiff bases

Two linear, trinuclear mixed-valence complexes, [CoII{(μ- L1)-(μ-OAc)CoIII(OAc)}2] (1) and [Co II{(μ-L2)(μ-OAc)CoIII(OAc)}2] (2) and two mononuclear CoIII complexes [CoIII{L 3}(OAc)] (3), and [CoIII{L4}(OAc)] (4) were prepared and the molecular structures of 1, 2 and 4 elucidated on the basis of X-ray crystallography [OAc = Acetate ion, H2L1 = H 2Salen = 1,6-bis(2-hydroxyphenyl)-2,5-diazahexa-1,5-diene, H 2L2 = H2Me2-Salen = 2,7-bis(2-hydroxyphenyl)-2,6-diazaocta-2,6-diene, H2L3 = H2Salpn = 1,7-bis(2-hydroxyphenyl)-2,6-diazahepta-1,6-diene, H 2L4 = H2Me2Salpn = 2,8-bis(2-hydroxyphenyl)-3,7-diazanona-2,7-diene]. In complexes 1 and 2, the acetate groups show both monodentate and bridging bidentate coordination modes, whereas chelating bidentate acetate is present in 4. The terminal Co IIIN2O4 centres in 1 and 2 exhibit uniform facial arrangements of both non-bridged N2O and bridging O 3 donor sets and the CoII centre is coordinated to six (four phenoxo and two acetato) oxygen atoms of the bridging ligands. The effective magnetic moment at room temperature corresponds to the presence of high-spin CoII in both 1 and 2. The complexes 1 and 2 are thus CoIII(S = 0)-CoII(S = 3/2)-CoIII(S = 0) trimers. Complexes 3 and 4 are monomeric and diamagnetic containing low-spin CoIII(S = 0) with chelating tetradentate Schiff base and bidentate acetate. Calculations based on DFT rationalise the formation of trinuclear or mononuclear complexes. © Wiley-VCH Verlag GmbH &amp; Co. KGaA, 2008.

Journal	Data powered by TypesetPolyhedron
Publisher	Data powered by TypesetElsevier Ltd
ISSN	0277-5387
Open Access	No