A new mononuclear Cu(II) complex, [CuL(ClO4)2] (1) has been derived from symmetrical tetradentate di-Schiff base, N,N′-bis-(1-pyridin-2-yl-ethylidene)-propane-1,3-diamine (L) and characterized by X-ray crystallography.The copper atom assumes a tetragonally distorted octahedral geometry with two perchlorate oxygens coordinated very weakly in the axial positions.Reactions of 1 with sodium azide, ammonium thiocyanate or sodium nitrite solution yielded compounds [CuL(N3)]ClO4 (2), [CuL(SCN)]ClO4 (3) or [CuL(NO2)]ClO4 (4), respectively, all of which have been characterized by X-ray analysis.The geometries of the penta-coordinated copper(II) in complexes 2-4 are intermediate between square pyramid and trigonal bipyramid (tbp) having the Addition parameters (τ) 0.47, 0.45 and 0.58, respectively.In complex 4, the nitrite ion is coordinated as a chelating ligand and essentially both the O atoms of the nitrite occupy one axial site.Complex 1 shows distinct preference for the anion in the orderSCN- &gt; N3- &gt; NO2- in forming the complexes 2-4 when treated with a SCN- / N3- / NO2- mixture. Electrochemical electron transfer study reveals CuIICuI reduction in acetonitrile solution. © 2006 Elsevier B.V. All rights reserved.

ASHUTOSH GHOSH

Chemistry

S CHATTOPADHYAY

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.

&nbsp;

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.

&nbsp;

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

Inorganica Chimica Acta

The 1:1 condensation of N-methyl-1,3-diaminopropane and N,N-diethyl-1,2-diminoethane with 2-acetylpyridine, respectively at high dilution gives the tridentate mono-condensed Schiff bases N-methyl-N′-(1- pyridin-2-yl-ethylidene)-propane-1,3-diamine (L1) and N,N-diethyl-N′-(1-pyridin-2-yl-ethylidene)-ethane-1,2-diamine (L 2). The tridentate ligands were allowed to react with methanol solutions of nickel(II) thiocyanate to prepare the complexes [Ni(L 1)(SCN)2(OH2) (1) and [{Ni(L 2)(SCN)}2] (2). Single crystal X-ray diffraction was used to confirm the structures of the complexes. The nickel(II) in complex 1 is bonded to three nitrogen donor atoms of the ligand L1 in a mer orientation, together with two thiocyanates bonded through nitrogen and a water molecule, and it is the first Schiff base complex of nickel(II) containing both thiocyanate and coordinated water. The coordinated water initiates a hydrogen bonded 2D network. In complex 2, the nickel ion occupies a slightly distorted octahedral coordination sphere, being bonded to three nitrogen atoms from the ligand L2, also in a mer orientation, and two thiocyanate anions through nitrogen. In contrast to 1, the sixth coordination site is occupied by a sulfur atom from a thiocyanate anion in an adjacent molecule, thus creating a centrosymmetric dimer. A variable temperature magnetic study of complex 2 indicates the simultaneous presence of zero-field splitting, weak intramolecular ferromagnetic coupling and intermolecular antiferromagnetic interactions between the nickel(II) centers. © 2010 Elsevier Ltd. All rights reserved.

Polyhedron

Synthesis, structure and magnetic properties of mono- and di-nuclear nickel(II) thiocyanate complexes with tridentate N3 donor Schiff bases

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.

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

The brown nitro isomer, trans-[NiL 1 (L\ N,N@-dipropyl-1,2-diaminoethane), was synthesized by adding 2 (NO2 ) 2 ], L to a suspension of in methanol. Complex K 1 is metastable at ca. 298 K and transforms slowly 4 [Ni(NO2 ) 6 ] É H2 O to the greenish blue nitrito(O,O) isomer, cis-[NiL 2. This transformation is accelerated with 2 (O2 N)](NO2 ), increasing temperature and slowed down on lowering the temperature (\283 K). Complex 2 shows a reversible phase transition, 2% 3 (cooling : *H\ 8.150^ 0.004 kJ mol~1 ; 266È255 K ; heating : *H\ [7.960^ 0.003 kJ mol~1 ; 257È268 K), whereas complex 1 does not exhibit any such transition. The structures of 1, 2 and 3 have been characterized by X-ray single crystal structure analyses, which reveal that 1 and 2/3 are nitro and nitrito(O,O) linkage isomers, respectively. Complexes 2 and 3 have essentially similar structures and their reversible transformation is supposed to be due to the change in thermal motion of the side chains on variation of temperature

New Journal of Chemistry

First report on thermally induced nitro→nitrito(O,O) linkage isomerization in diamine complexes of nickel(II) in the solid state: X-ray single crystal structural analyses of nitro and nitrito isomers

The complexes [NiL3](NO2)2P2H2O (violet, 1) and cis-[NiL2(NO2)2]P0.5H2O (pink, 1b) (Ls1,2-diamino-2-methylpropane) have been synthesized from solution. The X-ray single crystal structure analysis of compound 1b has been carried out, but the presence of a water molecule cannot be detected. Upon heating, complex 1b undergoes dehydration followed by an endothermic phase transition to produce trans- [NiL2(NO2)2] (1d). The violet species (1) also undergoes dehydration upon heating with deamination resulting (1d). q2000 Elsevier Science Ltd All rights reserved.

Cis–trans isomerism in nickel(II)–diamine nitrite: synthesis and single crystal structure of an unusual cis-dinitronickel(II) complex, [NiL2(NO2)2] (L=1,2-diamino-2-methylpropane)

The linkage isomers trans-bis[1-(2-aminoethyl)piperidine]dinitronickel() (brown) 1 and trans-bis[1-(2-aminoethyl)- piperidine]dinitritonickel() (blue) 2 have been synthesized and characterised by X-ray single crystal structure analysis.

Journal of the Chemical Society, Dalton Transactions

First structural characterisation of nitro–nitrito linkage isomers of nickel(II): synthesis and single crystal structures of [NiL2(NO2)2] and [NiL2(ONO)2] [L = 1-(2-aminoethyl)piperidine]

Journal	Data powered by TypesetInorganica Chimica Acta
Publisher	Data powered by TypesetELSEVIER SCIENCE SA
ISSN	0020-1693
Open Access	No