Somnath Choubey

First examples of two ferromagnetic end-to-end cyanate bridged 1D linear coordination polymers of nickel(II) containing an unsymmetrical diamine

Two new end-to-end (EE) cyanate bridged 1D coordination polymers of Ni(II) are isolated which contain linear (180°) Ni-N-C and Ni-O-C angles in Ni-NCO-Ni bridges and show ferromagnetic (F) coupling in agreement with the reported theoretical model for linear EE bridges.

Syntheses, molecular and crystalline architectures, and luminescence behaviour of terephthalate bridged heptacoordinated dinuclear lead(II) complexes containing a pentadentate N-donor Schiff base

AbstractOne-pot synthesis using a 2:2:1:2 molar ratio of Pb(OAc)2·3H2O, L, piperidinum terephthalate (ptp) and NaClO4/NH4PF6 at room temperature affords two dinuclear compounds of the type [Pb2(L)

Syntheses, structures and luminescence behaviour of some zinc(II) complexes containing acetate and tetradentate Schiff bases

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Syntheses, structures and properties of two dinuclear mercury(II) iodide compounds containing tetradentate tripodal amine/pentadentate N-donor Schiff base: Control of molecular and crystalline architectures by varying ligand matrices

-tp)](ClO4/PF6)2 (1/2) [L=N,N′-(bis-(pyridin-2-yl)benzylidene)diethylenetriamine and tp = terephthalate dianion]. The compounds are characterized by microanalytical, spectroscopic, thermal and other physicochemical results. X-ray structural analyses of 1 and 2 reveal that each heptacoordinated lead(II) centre with a PbN5O2 chromophore are bound by five N atoms of L and connected through O atoms of a bis(bidentate) tp bridge. The arrangements of L and tp suggest a gap around the metal centre due to occupation of a stereo-active lone pair of electrons reflecting a hemidirected coordination around the metal centre. The complexes exhibit reasonable thermal stabilities with the tolerate temperatures ca. 255°C for 1 and 263°C for 2. The complexes display intraligand (π-π*) fluorescence in the solid state and in DMF solutions at room temperature. Graphical AbstractTwo dinuclear lead(II) compounds are isolated and X-ray crystallographically characterized. Each heptacoordinated metal(II) center adopts a hemidirected environment and connected through bis(bidentate) terephthalate bridge. The complexes exhibit intraligand 1(π-π*) fluorescence in the solid state and in DMF solutions at room temperature.

An anti-ferromagnetic terephthalate-bridged trigonal prismatic dinuclear manganese(II) complex: Synthon of rare anion⋯π interaction promoting dimensionality

AbstractTwo mononuclear compounds of the types pentacoordinated [Zn(L1)(OAc)]PF6⋅H2O (1) and hexacoordinated [Zn(L2)(OAc)]PF6 (2) [L1 = N,N′

Synthesis, structures, luminescence and magnetic properties of two dinuclear μ1,5 dicyanamide bridged copper(II) complexes containing a tetradentate N-donor Schiff base

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Syntheses, structures, and magnetic properties of terephthalato bridged dinuclear copper(II) and manganese(II) complexes with a tetradentate N-donor Schiff base

-(bis(pyridin-2-yl)formylidene)-1,3-propanediamine; L2 = N,N′

Synthesis, structure and magnetic property of an asymmetric chlorido bridged dinuclear copper(II) complex containing a didentate Schiff base

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Varied dicarboxylate bridges in dinuclear trigonal prismatic manganese(II) and octahedral nickel(II) compounds containing tetradentate N-donor Schiff bases: Syntheses, structures and magnetic behaviors

-(bis(pyridin-2-yl)benzylidene)-1,4-butanediamine] have been synthesized using one-pot reactions of a 1:1:1 molar ratio of Zn(OAc)2.2H2O, L1/L2, ammonium hexafluorophosphate in MeOH at room temperature. Compounds 1 and 2 are characterized on the basis of microanalytical, spectroscopic, thermal and other physicochemical results. Single crystal X-ray structural study reveals that the zinc(II) centre in 1 is coordinated by four N atoms of the Schiff base L1 and one O atom of terminal acetate with a ZnN4O chromophore, whereas in 2, the zinc(II) centre is bound by four N atoms of the tailored Schiff base L2 and two O atoms of the chelated acetate. In the crystalline state, mononuclear units in 1 are engaged in weak cooperative intermolecular O-H ⋯O and C-H ⋯F hydrogen bonds affording a 1D chain. The individual units of 2 are packed by π⋯π and anion ⋯π interactions to form a 2D sheet structure. The complexes show reasonable thermal stabilities and display intraligand π→π∗ fluorescence in solid state at room temperature. Graphical AbstractTwo mononuclear zinc(II) compounds are isolated and X-ray crystallographically characterized. A subtle change in coordination geometry from square pyramid to octahedral in going from 1 to 2 is observed with change of the end-capping ligands. The complexes show reasonable thermal stabilities and exhibit intraligand (π-π*) fluorescence in the solid state at room temperature.

A set of new coordination compounds of cadmium(II)/mercury(II) halides/pseudohalides containing polyamines: Syntheses involving in situ metal–ligand reactions, crystal structures and molecular properties

AbstractTwo dinuclear mercury(II) iodide complexes of the types [(L1)Hg(μ-I)HgI3] (1) and [Hg2(L2)(I)4] ⋅H2O (2) [L1 =tris(2-aminoethyl)amine and L2 = N,N′-(bis-(pyridin-2-yl)benzylidene)diethylenetriamine] have been synthesized and characterized using microanalytical, spectroscopic, thermal and other physicochemical results. Structures of both the compounds are solved by X-ray diffraction measurements. Structural analyses show that one mercury (II) centre in 1 adopts a distorted tetrahedral geometry with an HgI4 chromophore surrounded by four iodides, while the other has a distorted trigonal bipyramidal environment with an HgN4I chromophore bound by four N atoms of L1 and one bridging iodide. Pentadentate Schiff base (L2) in 2 shows unusual binucleating bis(bidentate) behaviour to bind two different mercury(II) centres—Hg1 with an HgN3I2 chromophore in a distorted square pyramidal geometry and Hg2 with an HgN2I2 chromophore in a tetrahedral environment. Weak intermolecular N–H ⋅⋅⋅I hydrogen bonds in 1 and cooperative C–H ⋅⋅⋅π and π⋅⋅⋅π interactions in 2 promote dimensionalities. The Schiff base complex, 2, shows intraligand (π– π*) fluorescence in DMF solution at room temperature, whereas compound 1 containing tripodal amine is fluorescent-inactive. Graphical AbstractTwo new dinuclear lead(II) compounds were isolated and X-ray crystallographically characterized. Each heptacoordinated metal(II) center adopts a hemidirected environment and connected through bis(bidentate) terephthalate bridge. The complexes exhibit intraligand 1(π–π∗) fluorescence in the solid state and in DMF solutions at room temperature.