Three copper(II) complexes, [Cu2L2(μ 1,1-NCO)(NCO)] (1), [Cu2L2(μ1,3- NCS)(NCS)] (2) and [CuL(μ1,5-dca)]n- ·nH 2O (3), where HL = 2-[1-(2-dimethylamino-ethylimino)-ethyl]-phenol, have been prepared and characterized by elemental analysis, IR and UV-Vis spectroscopy, single crystal X-ray diffraction studies and by cyclic voltammetry. Complexes 1 and 3 crystallize in monoclinic space group P2 1/n and complex 2 in monoclinic P21/c. In complex 1, OCN- shows μ1,1 bridging mode; in complex 2, SCN - shows μ1,3 bridging mode whereas in complex 3, N(CN)-2 shows μ1,5 bridging mode. The tridentate Schiff base ligand reacts with copper(II) to occupy its three equatorial positions. The coordination polyhedra around one of the copper center in compounds 1 and 2 are best described as an elongated (4 + 1) square pyramid, whereas the coordination polyhedra around other copper center is square planer. The copper atom in compound 3 has a slightly distorted square pyramidal environment. Significant C-H/π interactions are observed in both complexes 1 and 2. Complex 3 is an example of MOFs containing penta-cordinated Cu(II) ions linked together by N(CN)-2 to yield 1D infinite P and M-helical chains. © 2012 Elsevier B.V. All rights reserved.

ASHUTOSH GHOSH

Chemistry

P BHOWMIK

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

Four new tri-nuclear hetero-metallic copper(II)-cadmium(II) complexes [(CuL)2CdCl2] (1), [(CuL)2CdBr2] (2), [(CuL)2CdI2] (3) and [(CuL)2Cd(NO3)2] (4) have been synthesized using [CuL] as ‘‘ligand complex’’ (where H2L = N,N′-bis(2-hydroxynaphthyl-methylidene)-1,3-propanediamine) and characterized by elemental analysis, IR, UV–Vis spectroscopy and single crystal X-ray diffraction studies. Crystal structure analyses reveal that all four complexes consist of a tri-nuclear moiety in which two square-pyramidal [CuL] units are bonded to a central Cd(II) ion through double phenoxido bridges. The Cd(II) is in a six-coordinate octahedral environment being bonded additionally to two mutually trans chloride (in 1), bromide (in 2), iodide (in 3) and oxygen atoms of nitrate (in 4) ions. Presence of several non-covalent interactions (i.e. π···π, C[sbnd]H···O and Cu···Cu interactions) has been observed in the crystal packing of all the four molecules that assist the formation of 1D supramolecular assemblies in the solid state. The interactions were investigated by means of high level DFT calculations (PBE0-D3/def2-TZVP) with the help of TURBOMOLE 7.0 program, characterized using Bader's theory of “atoms-in-molecules” (AIM) and rationalized using molecular electrostatic potential (MEP) surface calculations. © 2019 Elsevier B.V.

Tri-nuclear copper-cadmium complexes of a N2O2-donor ligand with the variation of counter anions: Structural elucidation and theoretical study on inter-molecular interactions

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 new Mn(II) coordination compounds {[Mn(NCNCN) 2(azpy)] •0.5azpy} n (1), {[Mn(NCS) 2(azpy)(CH 3OH) 2]•azpy} n (2), and [Mn(azpy) 2(H 2O) 4][Mn(azpy)(H 2O) 5]•4PF 6•H 2O•5.5azpy (3) (where azpy = 4,4′-azobis(pyridine)) have been synthesized by self-assembly of the primary ligands, dicyanamide, thiocyanate, and hexafluorophosphate, respectively, together with azpy as the secondary spacer. All three complexes were characterized by elemental analyses, IR spectroscopy, thermal analyses, and single crystal X-ray crystallography. The structural analyses reveal that complex 1 forms a two-dimensional (2D) grid sheet motif. These sheets assemble to form a microporous framework that incorporates coordination-free azpy by host-guest π•••π and C-H•••N hydrogen bonding interactions. Complex 2 features azpy bridged one-dimensional (1D) chains of centrosymmetric [Mn(NCS) 2(CH 3OH) 2] units which form a 2D porous sheet via a CH 3•••π supramolecular interaction. A guest azpy molecule is incorporated within the pores by strong H-bonding interactions. Complex 3 affords a 0-D motif with two monomeric Mn(II) units in the asymmetric unit. There exist π•• •π, anion•••π, and strong hydrogen bonding interactions between the azpy, water, and the anions. Density functional theory (DFT) calculations, at the M06/6-31+G* level of theory, are used to characterize a great variety of interactions that explicitly show the importance of host-guest supramolecular interactions for the stabilization of coordination compounds and creation of the fascinating three-dimensional (3D) architecture of the title compounds. © 2012 American Chemical Society.

Inorganic Chemistry

Host-guest supramolecular interactions in the coordination compounds of 4,4â€²-Azobis(pyridine) with MnX 2 (X = NCS -, NCNCN -, and PF 6 -): Structural analyses and theoretical study

One new complex of Cu(II), [(CuL)2Cu3(N 3)6]n (1) has been synthesized by reacting the "ligand complex", [CuL] with copper acetate and sodium azide (NaN 3) in methanol-water where the di-Schiff base ligand H2L = N,N′-bis(α-methylsalicylidene)-1,3-propanediamine. The X-ray single crystal structural analysis shows that complex 1 consists of an incomplete face-sharing double cube of four Cu(II) ions with the formula of [(CuL) 2Cu2(N3)2]2+ which are connected by [Cu(N3)4]2- unit to form a novel 1D chain. © 2012 Elsevier B.V. All rights reserved.

Journal of Molecular Structure

A novel 1D chain of azido bridged copper(II) with a salen-type di-Schiff base ligand

Two new polynuclear complexes of Cu(II), [(CuL 1 )Cu(N 3 C 2 ) 2 ] n (1) and [(CuL 2 ) 2 Cu(N 3 C 2 ) 2 ] ·H 2 O (2), have been synthesized by reacting the "ligand complexes", [CuL 1 ] and [CuL 2 ] respectively with copper perchlorate and sodium dicyanamide (NaN 3 C 2 ) in ethanol-water, where the di-Schiff base ligands H 2 L 1 = N,N′-bis(salicylidene)-1,3-propanediamine and H 2 L 2 = N,N′-bis(α-methylsalicylidene)-1,3-propanediamine. Structural analysis shows that complex 1 is a 2D polymer formed by linking the dinuclear units through a μ 1,5 -dicyanamido bridge. It contains alternating helical chains of P and M types. Complex 2 is a discrete bent trinuclear species where phenoxido groups of two terminal "ligand complexes" coordinate to a central Cu(II) along with terminally coordinated dicyanamido anions. Both complexes exhibit irreversible reductive Cu(II)/Cu(I) and quasi-reversible oxidative Cu(II)/Cu(III) responses in cyclic voltammetry. The electrochemically generated Cu(I) species for both complexes are unstable and undergo disproportionation to Cu 0 and Cu 2+ . © 2012 Elsevier Ltd. All rights reserved.

Polyhedron

Structural variations in polynuclear copper(II) complexes based on salicylaldimine type ligands along with dicyanamido co-ligand

A tetra-nuclear, heterometallic copper(II)-cadmium(II) complex, [{CuL(H 2 O)} 2 (CuL)Cd](ClO 4 ) 2 · H 2 O (1) has been synthesized by reacting the "ligand complex" [CuL] with Cd(ClO 4 ) 2 where H 2 L is the tetradentate di-Schiff base derived from 1,3-propanediamine and 2-hydroxyacetophenone. Complex 1 transforms into a trinuclear species, [(CuL) 2 Cd(NCS) 2 ] (2) on treatment with an ammonium thiocyanate solution. Both complexes have been characterized by X-ray single crystal structure analyses. In both structures, the central Cd(II) ion has a six-coordinate distorted octahedral environment being bonded to six oxygen atoms from three Cu(II) units in 1 and to four oxygen atoms from two [CuL] units along with a couple of thiocyanate nitrogen atoms in complex 2. Complex (1) exhibits reversible reductive (Cu(II)/Cu(I); Epc,-1.03 V) and oxidative (Cu(II)/Cu(III); Epa, +1.04 V, respectively) responses in cyclic voltammetry. The generated Cu(I) species for both the complexes are unstable and undergo disproportionation. © 2010 Elsevier Ltd. All rights reserved.

Synthesis and crystal structure of a heterometallic tetra-nuclear copper(II)-cadmium(II) complex and its anion modulated conversion into a trinuclear species

Three Cu(II)-azido complexes of formula [Cu 2 L 2 (N 3 ) 2 ] (1), [Cu 2 L 2 (N 3 ) 2 ]·H 2 O (2) and [CuL(N 3 )] n (3) have been synthesized using the same tridentate Schiff base ligand HL (2-[(3-methylaminopropylimino)-methyl]-phenol), the condensation product of N-methyl-1,3-propanediamine and salicyldehyde). Compounds 1 and 2 are basal-apical μ-1,1 double azido bridged dimers. The dimeric structure of 1 is centrosymmetric but that of 2 is non-centrommetric. Compound 3 is a μ-1,1 single azido bridged 1D chain. The three complexes interconvert in solution and can be obtained in pure form by carefully controlling the synthetic conditions. Compound 2 undergoes an irreversible transformation to 1 upon dehydration in the solid state. The magnetic properties of compounds 1 and 2 show the presence of weak antiferromagnetic exchange interactions mediated by the double 1,1-N 3 azido bridges (J = -2.59(4) and -0.10(1) cm- 1 , respectively). The single 1,1-N 3 bridge in compound 3 mediates a negligible exchange interaction. © 2011 Elsevier B.V. All rights reserved.

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