Kishalay Bhar

Crystallographic Evidence for Reversible Symmetry Breaking in a Spin‐Crossover d7 Cobalt(II) Coordination Polymer

This work was supported by the DST and CSIR, India. J.S.C. thanks the Spanish MICINN through CTQ2009-06959 for the research fellowship “Juan de la Cierva” (18-08-463B-750). J.R. also thanks the Spanish MICINN through CTQ2009-07264.

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 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

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

-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.

Syntheses, structures and magnetic properties of μ1,5 dicyanamide bridged coordination polymers of copper(II) and nickel(II) containing a tetradentate N-donor Schiff base

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.

Synthesis, molecular and crystalline architectures, and properties of novel bis(bidentate) and bis(tridentate) Schiff base bridged dinuclear mercury(II)pseudohalides: Control of coordination numbers by varying denticities

AbstractA dinuclear compound [Mn2(L)2(μ-tp)](PF6)2⋅3.57H2O (1) [L = N,N′-(bis(pyridin-2-yl)benzy-lidene)-1,3-propanediamine and tp = terephthalate dianion] has been isolated and characterized on the basis of microanalytical, spectroscopic and other physicochemical properties. X-ray structural study showed interesting bis(bidentate) bridging motif of tp in the dicationic dinuclear unit [Mn2(μ-tp)]2+. Each manganese(II) centre adopts a rare distorted trigonal prismatic geometry with an MnN4O2 chromophore. Chelation of the tetradentate Schiff base (L) along with bis(bidentate) bridging of two O atoms of tp complete hexacoordination around each manganese(II) centre. The dinuclear units of 1 are associated through cooperative C-H⋯F hydrogen bonds and π⋯π, C-H⋯π and rare anion⋯π interactions to promote the dimensionality in a graded manner. Variable temperature magnetic susceptibility measurement of 1 in the 2–300 K temperature range revealed weak anti-ferromagnetic interaction presumably due to long bridging arm of tp. Graphical AbstractSynthesis, crystal structure and magnetic behavior of a dinuclear manganese(II) terephthalate complex with tetradentate N-donor Schiff base has been described. Interesting trigonal prismatic geometry around metal ion was observed in the complex. The dinuclear units of 1 are the source of rare anion⋯π interactions to promote the dimensionality of compound.