Two copper(II) complexes, [Cu2L2(μ1,1-N3)2]·2CH2Cl2 (1) and [CuL(μ1,5-dca)]n (dca = dicyanamide) (2) have been synthesized using a tridentate Schiff base ligand, 1-[(3-methylamino-propylimino)-methyl]-naphthalen-2-ol (HL) and azide or dicyanamide as co-ligand. Both complexes are characterized by elemental analysis, IR and UV-Vis spectroscopy and single crystal X-ray diffraction studies. The coordination geometry around the copper center in complex 1 is as an elongated (4 + 1) square pyramid and that in complex 2 is square planar with the tridentate Schiff base ligand in the basal plane. Complex 1 is a centrosymmetric dimer in which metal centers are connected by the double μ-1,1-azido bridges. On the other hand, complex 2 is a 1D zigzag chain in which metal centers are connected by μ1,5-N(CN)2 ligands. The catecholase like activity for both complexes have been studied by using 3,5-di-tert-butylcatechol (3,5-DTBC) as the substrate. Complex 1 shows higher activity (kcat = 40.8 h-1) than that of complex 2 (27.6 h-1) towards such oxidation reaction. © 2015 Elsevier B.V. All rights reserved.

ASHUTOSH GHOSH

Chemistry

P BHOWMIK

L K DAS

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.

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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

Inorganica Chimica Acta

Three new copper(II) complexes, [Cu2L2Cl2(4,4′-bpy)]·2.7H2O (1), [CuL(4,4′-bpy)(H2O)]NO3 (2) and [CuL(4,4′-bpy)(H2O)]ClO4 (3), where HL = 1-[1-(2-Dimethylamino-ethylimino)-ethyl]-naphthalen-2-ol, have been synthesized and characterized by elemental analysis, IR, UV-Vis spectroscopy and single crystal X-ray diffraction studies. Complex 1 is a centrosymmetric dinuclear species in which 4,4′-bipyridine acts as bridging bidentate linker between the two copper(II) ions whereas, complexes 2-3 are rare mononuclear complexes in which the 4,4′-bpy ligand shows monodentate coordination mode stabilized by H-bonding interactions through its electronegative non-coordinated N-atom. These interactions involve imine and methylene hydrogen atoms of the Schiff-base ligand for 2, whereas a single H-bond with one of the hydrogen atoms of the coordinated water is established in 3. In addition, several non-covalent interactions like hydrogen bonding and π-based interactions (C-H/π, anion-π and π-π stacking) are also observed in crystal packing of all three complexes. These interactions have been investigated by means of DFT calculations and assigned with discrete interaction energies. The strong influence of the coordination of the 4,4′-bpy ligand to the copper(II) centers upon the binding strength of the π-based interactions has also been demonstrated. © 2016 Elsevier B.V. All rights reserved.

Anion dependent supramolecular architectures in Cu(II) complexes containing N2O-donor Schiff-base and 4,4â€²-bipyridine ligands: Structural analyses and theoretical studies

Three novel μ2-aqua bridged dinuclear Ni(II) complexes, [Ni2(HL1)4(H2O)] (1), [Ni 2(HL2)4(H2O)] (2) and [Ni 2(HL3)4(H2O)] (3) have been synthesized using Schiff base ligands derived from 5-amino-1-pentanol and salicylaldehyde (H2L1), 5-bromo salicylaldehyde (H 2L2) and 3-methoxy salicylaldehyde (H2L 3), respectively. They are characterized by a variety of physical techniques including elemental analysis, infrared and UV-Vis spectroscopy, NMR, cyclic voltammetry, variable temperature magnetic measurements and single crystal X-ray diffraction. X-ray crystallographic analysis reveals that all the three complexes possess distorted octahedral environment with a bridging aqua ligand. Complexes 1 and 3 exhibit 3D supramolecular architecture whereas 2 demonstrates a 2D netlike arrangement along ab plane. Catecholase activity of the dinuclear Ni(II) systems are investigated using 3,5-di-tert-butylcatechol as the substrate. The complexes are efficient catalysts with turnover numbers 1.87 × 104, 1.79 × 104 and 1.38 × 10 4 h-1 for 1, 2 and 3, respectively. The probable structures of the intermediates formed during the process are proposed on the basis of kinetic and spectral analyses. The magnetic data disclose that weak ferromagnetic couplings are transmitted between the metal centers and the magnetic properties are correlated with the structural features around the Ni(II) centers. © 2014 Elsevier B.V. All rights reserved.

Syntheses, crystallographic characterization, catecholase activity and magnetic properties of three novel aqua bridged dinuclear nickel(II) complexes

This paper presents the synthesis, crystal structure, catechol oxidase activity and electrospray ionization mass spectra (ESI-MS positive) of a mixed-valence CoIIICoII compound [CoIIICo IIL(N3)3]· 0.5CH3CN·0. 27H2O (1) derived from the Robson type tetraiminodiphenolate macrocyclic ligand H2L, which is the [2 + 2] condensation product of 2,6-diformyl-4-methylphenol and 2,2-dimethyl-1,3-diaminopropane. Compound 1 crystallizes in the monoclinic P21/n space group. The structure consists of two independent units of diphenoxo-bridged CoIIICo II moieties where the CoIII center is hexacoordinated (distorted octahedral) having O(phenoxo)2N(imine)2N(azide) 2 environment, while CoII center is pentacoordinated (distorted square pyramidal) having O(phenoxo)2N(imine) 2N(azide) environment. Catechol oxidase activity of 1 has been investigated using 3,5-di-tert-butylcatechol (3,5-DTBCH2) as the substrate, revealing that it is an active catalyst with Kcat value 114.24 h-1. Electrospray ionization mass spectra (ESI-MS positive) of 1 and 1 + 3,5-DTBCH2 in acetonitrile have been recorded. No complex⋯substrate aggregate in the spectrum of 1 + 3,5-DTBCH 2 has been identified. However, interestingly, two hydrogen bonded metal complex⋯solvent aggregates [{CoII(LH2)(N 3)}⋯(CH3CN)]+ and [{Co III(LH2)(N3)2}⋯(CH 3CN)]+ have been identified in the spectrum of 1. Catecholase activity has also been studied with pyrocatechol and tetrachlorocatechol (TCCH2) as substrates. While no activity has been found with TCCH2, weak activity has been observed with pyrocatechol. © 2013 Elsevier B.V. All rights reserved.

Crystal structure, catecholase activity and ESI-MS of a mixed valence cobalt(III)-cobalt(II) complex derived from a macrocyclic ligand: Identification/proposition of hydrogen bonded metal complexâ‹¯solvent aggregates in ESI-MS

Two new alternating μ 1,1 - and μ 1,3 -azido bridged chains, [Cu(N 3 ) 2 (mtn)] n (1) and [Ni(N 3 ) 2 (mtn)] n (2) where mtn = N-methyl-1,3-propanediamine, have been synthesized and characterized by single crystal X-ray diffraction. In both complexes, each metal atom is coordinated to six nitrogen atoms from four azide anions and one N-methyl-1,3-propanediamine molecule in a distorted octahedral geometry. In 1, the basal-apical double μ 1,1 -azido bridged Cu(ii)-dimers are connected through two asymmetric μ 1,3 -N 3 bridges to form a 1D chain in which one of the azide acts as a μ 1,1,3 bridge while the other one is terminal. The structure of 2 is very similar but one of the azide ions acts as μ 1,1 and the other as μ 1,3 to form an alternating chain. Magnetic data of both compounds were fitted to an alternating ferro/antiferromagnetic chain model (g = 2.120, J F = +15.6 cm -1 , J AF = -2.6 cm -1 and a paramagnetic impurity of ca. 0.4% for 1 and g = 2.180, J F = +23 cm -1 and J AF = -33 cm -1 for 2). © 2014 the Partner Organisations.

Dalton Transactions

Synthesis, crystal structure and magnetic properties of two alternating double Î¼ 1,1 and Î¼ 1,3 azido bridged Cu(ii) and Ni(ii) chains

Four new hetero-metallic copper(ii)-cadmium(ii) complexes [{(CuL) 2Cd}2(μ1,5-N(CN)2) 2](ClO4)2·(H2O)2 (1), {[{(CuL)2Cd}2(μ1,3,5-N(CN) 2)2](ClO4)2}n (2), {[(CuL)2Cd(μ1,5-N(CN)2)](ClO 4)}n (3) and [(CuL)2Cd(μ1,5-N(CN) 2)2]n (4) have been synthesized using a trinuclear hetero-metallic node, [(CuL)2Cd]2+ (where H2L = N,N′-bis(salicylidene)-1,3-propanediamine) and a dicyanamido spacer by varying the ratios of the reactants and temperature. The hetero-trinuclear node is formed in situ by the reaction of the "metalloligand" [CuL], cadmium perchlorate and sodium dicyanamide. All the complexes are structurally characterized. Complex 1 is a discrete hexanuclear cluster where two trinuclear nodes are connected through the Cd centres by convergent double μ1,5-dicyanamido spacers. Complex 2 is a 1D stair coordination polymer, in which the hexanuclear units are joined by the coordination of the central nitrogen atom of a μ1,3,5- dicyanamido ligand to the Cu atom of another unit. In contrast, complex 3 is a 1D zigzag chain, formed by connecting the Cd centre of trinuclear nodes via divergent μ-l,5-dicyanamido spacers. These three complexes contain a common [(CuL)2Cd(N(CN)2)]ClO4 trinuclear unit as the molecular building block. They represent an example of "supramolecular isomerism" of 0D/1D coordination polymers. On the other hand, replacement of the perchlorate ions from this trinuclear unit by another dicyanamido spacer results in complex 4, which is a 3D network, constructed by joining the trinuclear nodes through both Cd and Cu centers with the help of divergent dicyanamido spacers in the μ-l,5 mode. © 2013 The Royal Society of Chemistry.

CrystEngComm

Structural diversity in the complexes based on a hetero-trimetallic Cu 2Cd node and dicyanamide spacer: A hexanuclear cluster, a 1D stair polymer and a 1D zigzag chain as supramolecular isomers, and a 3D network

Two phenoxido bridged dinuclear Cu(II) complexes, [Cu2(L 1)2(NCO)2] (1), and [Cu2(L 2)2(NCO)2]·2CH3OH (2), have been synthesized using the tridentate reduced Schiff-base ligands 2-[(2-dimethylamino-ethylamino)-methyl]-phenol (HL1) and 2-[(2-diethylamino-ethylamino)-methyl]-phenol (HL2) respectively. Re-crystallization of compound 2 from dichloromethane produced desolvated complex [Cu2(L2)2(NCO)2] (3). The compounds 2 and 3 are pseudopolymorphs or solvomorphs which differ in the crystal system (orthorhombic, Pbca for 2 and monoclinic, P21/n for 3). The complexes have been characterized by X-ray structural analyses and spectroscopic methods. In all three complexes Cu(II) is penta-coordinated having the geometry intermediate between distorted square pyramid and trigonal bipyramid with Addison parameter (τ) = 0.33, 0.48 and 0.53 for 1, 2 and 3 respectively. Using 3,5-di-tert-butylcatechol (3,5-DTBC) as the substrate, the catecholase activity of complexes 1 and 2 has been studied in methanol solution; compound 2 shows slightly higher catecholase activity (kcat = 98.4h 1) than compound 1 (kcat = 64.2 h 1). © 2013 Elsevier Ltd. All rights reserved.

Polyhedron

Solvomorphism and catecholase activities of bis(Î¼-phenoxido) dicopper(II) complexes

A dinuclear and a 1D zigzag chain of copper(II) complexes with N2O donor Schiff base ligand and psuedohalides (azide and dicyanamide): Studies on catecholase-like activity

Journal	Data powered by TypesetInorganica Chimica Acta
Publisher	Data powered by TypesetElsevier S.A.
ISSN	0020-1693
Open Access	No