Syntheses and characterization of diamine complexes of nickel (II) trifluoroacetate : thermochromism and X-ray single crystal structure analyses of [Ni (pren) 2 (CF3CO2) 2] and [Ni (ipren) 2 (CF3CO2) 2] (pren = N-propylethane-1,2-diamine and ipren = N-isopropylethane-1,2-diamine)
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説明
Abstract The complexes, [NiL2 (CF3CO2) 2] [L = N-methylethane-1,2-diamine (meen) , N-ethylethane-1,2-diamine (eten) , N-propylethane-1,2-diamine (pren) and N-isopropylethane-1,2-diamine (ipren) ] have been prepared and X-ray single crystal structures of [Ni (pren) 2 (CF3CO2) 2] 3 and [Ni (ipren) 2 (CF3CO2) 2] 4 are determined. Both 3 and 4 have slightly distorted trans-octahedral geometry with N4O2-chromophore around nickel (II) . The crystals are stabilized by H-bonds and this interaction is higher in 4 due to close proximity of methyl H-atoms of isopropyl group with oxygen atoms of trifluoroacetate groups. The complexes 3 and 4 exhibit blue to light-violet, irreversible discontinuous thermochromism. [Ni (meen) 2 (CF3CO2) 2] 1 also shows thermochromism, blue-violet to blue but reverts on keeping in humid atmosphere. On the other hand, [Ni (eten) 2 (CF3CO2) 2] 2 undergoes decomposition without showing any phase transition. However, thermochromism here is considered to be due to a decreased in-plane ligand field strength resulting from the conformational changes in diamine chelate rings.
収録刊行物
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- Polyhedron
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Polyhedron 17 2567-2574, 1998-07-01
Elsevier BV
