Two phenoxo bridged dinuclear Cu(II) complexes, [Cu2L 2(NO2)2] (1) and [Cu2L 2(NO3)2] (2) have been synthesized using the tridentate reduced Schiff-base ligand 2-[(2-dimethylamino-ethylamino)-methyl]- phenol (HL). The complexes have been characterized by X-ray structural analyses and variable-temperature magnetic susceptibility measurements. The structures of the two compounds are very similar having the same tridentate chelating ligand (L) and mono-dentate anionic ligand nitrite for 1 and nitrate for 2. In both complexes Cu(II) is penta-coordinated but the square pyramidal geometry of the copper ions is severely distorted (Addison parameter (τ) = 0.33) in 1 while the distortion is quite small (average τ = 0.11) in 2. These differences have marked effect on the magnetic properties of two compounds. Although both are antiferromagnetically coupled, the coupling constants (J = -140.8 and -614.7 cm-1 for 1 and 2, respectively) show that the coupling is much stronger in 2. © 2011 Elsevier B.V. All rights reserved.

ASHUTOSH GHOSH

Chemistry

A BISWAS

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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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

A diphenoxido bridged dinuclear Ni(II) complex [Ni2L2(NO2)2] (1) and a μ2and μ3-phenoxido, μ3-hydroxido, and μ2-nitrito (1κO:2κN) bridged trinuclear Ni(II) complex [Ni3L3(OH)(NO2)]·ClO4(2), have been synthesized using a tridentate reduced Schiff base ligand HL (HL = 2-[(2-dimethylamino-ethylamino)-methyl]-phenol). Both complexes were characterized by X-ray structure determination and variable-temperature magnetic susceptibility measurements. In both complexes the nickel atoms are six-coordinated with a distorted octahedral environment. The interesting feature of the trimeric complex 2 is that the three mononuclear units are assembled around a μ3-hydroxido ion in such a way that the three phenoxido groups and one nitrito group form a cyclic bridge that markedly modify the magnetic properties. Complex 1 presents a moderate antiferromagnetic Ni–Ni coupling (J = −39 cm−1) through the phenoxido bridges with a wide Ni–O–Ni bond angle of 101.77(6)° whereas the lower Ni–O–Ni bond angles, in the range 86.66(6)–96.07(7)°, lead to a moderate ferromagnetic coupling (J = +18.2 cm−1) in the trimeric complex 2 with a weak antiferromagnetic contribution (J′ = −0.51 cm−1) via the 1κO:2κN nitrito bridge. © 2016 Elsevier Ltd

Polyhedron

Formation of a dinuclear and a trinuclear Ni(II) complex on slight variation of experimental conditions: Structural analysis and magnetic properties

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.

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

The phenoxo-bridged dinuclear CuII complex [Cu2L 2(NCNCN)2] (1) and the dicyanamide-bridged molecular rectangle [Cu4L4{μ1,5-(NCNCN)2}] ·(ClO4)2(H2O)2 (2) were synthesized using the tridentate reduced Schiff-base ligand HL {2-[(2-dimethylamino-ethylamino)methyl]phenol}. The complexes were characterized by X-ray structural analyses and variable-temperature magnetic susceptibility measurements. Complex 2 was formed through the joining of the phenoxo-bridged dinuclear Cu2O2 cores of 1 via the μ1,5- bridging mode of dicyanamide. The structural properties of the Cu 2O2 cores in two complexes are significantly different. The geometry of the copper ions is distorted trigonal bipyramid in 1 but is nearly square-pyramidal in 2. These differences have a marked effect on the magnetic properties of two compounds. Although both are antiferromagnetically coupled, the coupling constants (J = -185.2 and -500.9 cm-1 for 1 and 2, respectively) differ considerably. © 2011 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

European Journal of Inorganic Chemistry

Synthesis, crystal structures and magnetic properties of a phenoxo-bridged dinuclear CuII complex and a dicyanamide bridged novel molecular rectangle based on it

Two mixed bridged one-dimensional (1D) polynuclear complexes, [Cu 3L2(μ1,1-N3)2(μ-Cl) Cl]n (1) and {[Cu3L2(μ-Cl)3Cl] 0.46CH3OH}n (2), have been synthesized using the tridentate reduced Schiff-base ligand HL (2-[(2-dimethylamino-ethylamino)- methyl]-phenol). The complexes have been characterized by X-ray structural analyses and variable-temperature magnetic susceptibility measurements. In both complexes the basic trinuclear angular units are joined together by weak chloro bridges to form a 1D chain. The trinuclear structure of 1 is composed of two terminal square planar [Cu(L)(μ1,1-N3)] units connected by a central Cu(II) atom through bridging nitrogen atoms of end-on azido ligands and the phenoxo oxygen atom of the tridentate ligand. These four coordinating atoms along with a chloride ion form a distorted trigonal bipyramidal geometry around the central Cu(II). The structure of 2 is similar; the only difference being a Cl bridge replacing the μ1,1-N 3 bridge in the trinuclear unit. The magnetic properties of both trinuclear complexes can be very well reproduced with a simple linear symmetrical trimer model (H = -JSiSi+1) with only one intracluster exchange coupling (J) including a weak intertrimer interaction (j) reproduced with the molecular field approximation. This model provides very satisfactory fits for both complexes in the whole temperature range with the following parameters: g = 2.136(3), J = -93.9(3) cm-1 and zj = -0.90(3) cm-1 (z = 2) for 1 and g = 2.073(7), J = -44.9(4) cm -1 and zJ′ = -1.26(6) cm-1 (z = 2) for 2. © 2010 American Chemical Society.

Inorganic Chemistry

Use of a reduced schiff-base ligand to prepare novel chloro-bridged chains of rare Cu(II) trinuclear complexes with mixed azido/oxo and chloro/oxo bridges

Two new reduced Schiff base ligands, [HL1 = 4-{2-[(pyridin-2-ylmethyl)-amino]-ethylimino}-pentan-2-one and HL2 = 4-[2-(1-pyridin-2-yl-ethylamino)-ethylimino]-pentan-2-one] have been prepared by reduction of the corresponding tetradentate unsymmetrical Schiff bases derived from 1:1: 1 condensation of 1,2-ethanediamine, acetylacetone and pyridine-2-carboxaldehyde/2-acetyl pyridine. Four complexes, [Ni(L1)]ClO4 (1), [Cu(L1)]ClO4 (2), [Ni(L2)]ClO4 (3), and [Cu(L2)]ClO4 (4) with these two reduced Schiff base ligands have been synthesized and structurally characterized by X-ray crystallography. The mono-negative ligands L1 and L2 are chelated in all four complexes through the four donor atoms to form square planar nickel(II) and copper(II) complexes. Structures of 3 and 4 reveal that enantiomeric pairs are crystallized together with opposite chirality in the nitrogen and carbon atoms. The two CuII complexes (2 and 4) exhibit both irreversible reductive (CuII/CuI; Epc, -1.00 and -1.04 V) and oxidative (CuII/CuIII; Epa, +1.22 and +1.17 V, respectively) responses in cyclic voltammetry. The electrochemically generated CuI species for both the complexes are unstable and undergo disproportionation. © 2009 Elsevier Ltd. All rights reserved.

Nickel(II) and copper(II) complexes of unsymmetrical tetradentate reduced Schiff base ligands

A linear trinuclear Ni-Schiff base complex [Ni 3 (salpen) 2(PhCH 2COO) 2(EtOH)] has been synthesized by combining Ni(ClO 4) 2 · 6H 2O, phenyl acetic acid (C 6H 5CH 2COOH), and the Schiff base ligand, N,N′-bis(salicylidene)-1,3- pentanediamine (H 2salpen). This complex is self-assembled through hydrogen bonding and C-H-π interaction in the solid state to generate a sheet-like architecture, while in organic solvent (CH 2Cl 2), it forms vesicles with a mean diameter of 290 nm and fused vesicles, depending upon the concentration of the solution. These vesicles act as an excellent carrier of dye molecules in CH 2Cl 2. The morphology of the complex has been determined by scanning electron microscopy and transmission electron microscopy experiments, and the encapsulation of dye has been examined by confocal microscopic image and electronic absorption spectra. © 2009 American Chemical Society.

Solvent-assisted formation of vesicles by a self-assembling Ni 3-schiff base complex

Three new copper(II) complexes, [CuL1(NO2)] n (1), [CuL2(NO2)] (2), and [CuL 3(NO2)] (3), with three similar tridentate Schiff base ligands [HL1 = 6-amino-3-methyl-1-phenyl-4-azahept-2-en-1-one, HL2 = 6-amino-3-methyl-1-phenyl-4-azahex-2-en-1-one, and HL 3 = 6-diethylamino-3-methyl-1-phenyl-4-azahex-2-en-1-one] have been synthesized and characterized structurally and magnetically. In all three complexes, the tridentate Schiff base ligand and one oxygen atom of the nitrite ion constitute the equatorial plane around Cu(II), whereas the second oxygen atom of the nitrite ligand coordinates to one of the axial positions. In 1, this axially coordinated oxygen atom of the nitrite ligand also coordinates weakly to the other axial position of a Cu(II) ion of another unit to form a one-dimensional chain with the μ-nitrito-1κ2O,O′: 2κO bridging mode. Complexes 2 and 3 are discrete monomers that are joined together by intermolecular H bonds and C-H ⋯ π interactions in 2 and by only C-H ⋯ π interactions in 3. A weak antiferromagnetism (J = -1.96(2) cm-1) is observed in complex 1 due to its asymmetric nitrite bridging. Complexes 2 and 3 show very weak antiferromagnetic interactions (J = -0.089 and -0.096 cm-1, respectively) attributed to the presence of intermolecular H-bonding and C-H ⋯ π interactions. The corresponding Cu(I) species produced by the electrochemical reduction of complexes 1 and 2 disproportionate to Cu0 and Cu2+, whereas the reduced Cu(I) species of complex 3 seems to be stable presumably due to a higher tetrahedral distortion of the equatorial plane in 3 compared to that in 1 and 2. © 2008 American Chemical Society.

Rare example of Î¼-nitrito-1Îº2O,Oâ€²:2ÎºO coordinating mode in copper(II) nitrite complexes with monoanionic tridentate schiff base ligands: Structure, magnetic, and electrochemical properties

Journal	Inorganica Chimica Acta
Publisher	-
ISSN	0020-1693
Open Access	No