The synthesis, molecular and supramolecular structure, spectroscopy and electrochemistry of a dialkoxo-bridged diuranyl(VI) compound [(UO2)2(L)2(dimethylformamide)2] (1) derived from the Schiff base ligand H2L, obtained on condensation of 3-methoxysalicylaldehyde with 2-aminoethanol, have been described. The compound has been characterized by IR, UV-Vis, NMR and mass spectra, as well as by single crystal X-ray structure determination. The title compound crystallizes in the monoclinic P21/n space group with the following unit cell parameters a = 10.5713(2) Å, b = 11.9895(2) Å, c = 12.9372(2) Å, β = 102.773(3)° and Z = 2. The structure of 1 reveals that it is a dialkoxo-bridged dinuclear compound of uranium(VI) containing two deprotonated ligands, [L]2-, two dimethylformamide (dmf) molecules and two UO22+ centers. The coordination geometry around the uranium(VI) center is distorted pentagonal bipyramidal; two uranyl oxygens occupy the axial positions, while the basal pentagonal plane is defined by a phenoxo oxygen, two bridging alkoxo oxygens, one imine nitrogen, and one dmf oxygen. Three C-H⋯O type hydrogen bonds involving one uranyl oxygen, two dmf hydrogens and the imine hydrogen link the dinuclear units into a two-dimensional network. The ESI-MS spectrum of 1 in dimethylsulfoxide exhibits two peaks at m/z = 464.17 and 927.26, which are assignable to [(UO2)2L2H]+ (60%) and [(UO2)2LH]+ (100%) cations, respectively. Cyclic voltammetric measurements of 1 reveal that the uranium(VI) center is reduced quasireversibly at E1/2 = -1112 mV with ΔEP = 97 mV. © 2008 Elsevier Ltd. All rights reserved.

SASANKA MOHANTA

Chemistry

S HAZRA

S MAJUMDER

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

Polyhedron

The synthesis, structure, magnetic and electrochemical properties of the heterobridged mu-phenoxido-mu(1,1)-azide dinickel-(II) compound [Ni-2(II)(HL1)(3)(mu-(1,1)-N-3)]center dot 3H(2)O (1) derived from the tetradentate Schiff base ligand N-(2-hydroxyethyl)-3-methoxysalicylaldimine (H2L1) are described. The title compound crystallizes in the triclinic system (space group P (1) over bar). Electrochemical analyses reveal that compound 1 exhibits two-step quasireversible couples in the reduction window with E-1/2 values of -1412 and -1762 mV. The variable-temperature (2-300 K) magnetic susceptibilities at 1 T of the title compound were measured. The interaction between the metal centres is weak ferromagnetic (J = 5.0 cm(-1), g = 2.23, D-1 = 29.2 cm(-1) and D-2 = 10.7 cm(-1)). Comparison of the exchange integral of 1 with that of the only reported mu-phenoxido-mu(1,1)-azide dinickel(II) compound results in the emergence of a unique example of the dependence of strength of magnetic exchange interaction on the metal-ligand bridge distance. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

European Journal of Inorganic Chemistry

Magnetic and Electrochemical Properties of a Heterobridged mu-Phenoxido-mu(1,1)-Azide Dinickel(II) Compound: A Unique Example Demonstrating the Bridge Distance Dependency of Exchange Integral

The synthesis, structure, magnetic and electrochemical properties of the heterobridged μ-phenoxido-μ1, 1-azide dinickel(II) compound [NiII2(HL1)3(μ 1, 1-N3)]·3H2O (1) derived from the tetradentate Schiff base ligand N-(2-hydroxyethyl)-3-methoxysalicylaldimine (H2L1) are described. The title compound crystallizes in the triclinic system (space group P1̄). Electrochemical analyses reveal that compound 1 exhibits two-step quasireversible couples in the reduction window with E1/2 values of -1412 and -1762 mV. The variable-temperature (2-300 K) magnetic susceptibilities at 1 T of the title compound were measured. The interaction between the metal centres is weak ferromagnetic (J = 5.0 cm-1, g = 2.23, D1 = 29.2 cm -1 and D2 = 1.0.7 cm-1). Comparison of the exchange integral of 1 with that of the only reported μ-phenoxido-μ 1, 1-azide dinickel(II) compound results in the emergence of a unique example of the dependence of strength of magnetic exchange interaction on the metal-ligand bridge distance. © 2009 Wiley-VCH Verlag GmbH &amp; Co. KGaA.

Magnetic and electrochemical properties of a heterobridged Î¼-phenoxido-Î¼1, 1- azide dinickel(II) compound: A unique example demonstrating the bridge distance dependency of exchange integral

Syntheses, structures and magnetic properties of a heterobridged -phenoxido-1,1-NCO dinickel(II) compound [NiII 2(HL)3(-NCO)].2H2O (1) and a heterobridged bis(3-phenoxido)bis(3-alkoxido)tetranickel(II) system, [NiII4(L)2(HL)2(SeCN) 2(H2O)2].C3H7NO.4H 2O (2), containing a cubanetype NiII4O 4 core, derived from the totradontate Schiff base compartmental ligand N-(2-hydroxyolhyl)-3-methoxysalicylaldimine (H2L) were described. Compounds 1 and 2 crystallize in triclinic P1 and monoclinic P2 1/c systems, respectively. Compound 2, in which the Ni 4O4 cubane core is composed of two 3-phenoxido and two 3-alkoxido moieties, represents the sole example of this type. The variable-temperature (2-300 K) magnetic susceptibilities and magnetizations of these two compounds were measured. The interaction between the metal centres in dinuclear compound 1 is weak ferromagnetic, resulting in an ST = 2 ground state at 2 K. The overall interaction observed in 2 is weak ferromagnetic, leading to an unusual ST = 3 ground state. © 2009 Wiley-VCH Verlag GmbH &amp; Co. KGaA.

Syntheses, structures and magnetic properties of heterobridged dinuclear and cubane-type tetranuclear complexes of nickel(II) derived from a schiff base ligand

Syntheses, structures, and electrochemistry of a dialkoxo-bridged diuranyl(VI) compound. [(UO2)2(L1) 2(dimethylformamide)2] (1) and a mononuclear-mononuclear cocrystalline compound [(UO2)(L2)(H2O) ⊂(H2O)]·[(UO2)(L2)(H2O)] (2) derived from Schiff base ligands are reported (H2L1 = Schiff base ligand obtained on condensation of 3-ethoxysalicylaldehyde with 2-aminoethanol; H2L2 = N,N′-o-phenylenebis(3- ethoxysalicylaldimine)). The compounds 1 and 2 crystallize in the space groups P21/c and P1̄, respectively. Compound 1 is a dialkoxo-bridged dinuclear compound of uranium(VI) containing two deprotonated ligands, [L] 2-, two dimethylformamide (dmf) molecules and two UO2 22+ centers. Three C-H⋯O type hydrogen bonds involving one uranyl oxygen, two dmf hydrogens, and the imine hydrogen link the dinuclear units into a two-dimensional network. Compound 2 is a cocrystal of two mononuclear units, [(UO2)(L2)(H2O)⊂(H 2O)] (unit 1) and [(UO2)(L2)(H2O)] (unit 2). In unit 1, the non-coordinated water molecule forms hydrogen bonds with oxygens of phenoxo, ethoxy, and coordinated water molecules resulting in the formation of an inclusion product. The overall supramolecular structure of compound 2 is one-dimensional and consists of interlinked self-assembled dimeric unit of unit 1 and unit 2. Cyclic voltammetric measurements reveal that the uranium(VI) center in [(UO2)2(L1) 2(dimethylformamide)2] (1) is reduced quasireversibly at E1/2 = -773 mV with ΔEp = 121 mV, while the metal center in [(UO2)(L2)(H2O)⊂(H 2O)]·[(UO2)(L2)(H2O)] (2) is reduced reversibly with E1/2 = -765 mV with ΔEp = 68 mV. © 2008 WILEY-VCH Verlag GmbH &amp; Co. KGaA.

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ISSN	0277-5387
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