Correlation between crystal symmetry and the splitting of d orbital in the thiocyanate nickel(II) complexes

New [Ni(SCN)2(L)4/2] complexes, where L = py (1), γ-pic (2), pyCH2OH (3), py(CH2)3OH (4) were synthesized in simple reactions of NiCl2·6H2O with ammonia thiocyanate and pyridine type ligands in methanol solutions. Blue crystals of [Ni(SCN)2(py)4] (1), [Ni(SCN)2(pyCH2OH)2] (3) and [Ni(SCN)2(py(CH2)3OH)2] (4) crystallize in the monoclinic system, blue crystal of [Ni(SCN)2(γ-pic)4] (2) – in the tetragonal one, and red crystal of [Ni(SCN)2(PPh3)2] (5) – in the triclinic one. The ligands of complexes (1) and (3) were indicated as rather strong π-acceptors while that of complex (4) one has some π-donor properties. When the aliphatic chain (CH2) elongates in the sequence: (1), (3) and (4), an increase in the orbital contribution to the magnetic moment and a decrease in the 10Dq value of the d orbital splitting are related to the change of the point group symmetry from D2h, via D2v to C2h.

New [Ni(SCN)2(L)4/2] complexes, where L = py (1), γ-pic (2), pyCH2OH (3), py(CH2)3OH (4) were synthesized in simple reactions of NiCl2·6H2O with ammonia thiocyanate and pyridine type ligands in methanol solutions. Blue crystals of [Ni(SCN)2(py)4] (1), [Ni(SCN)2(pyCH2OH)2] (3) and [Ni(SCN)2(py(CH2)3OH)2] (4) crystallize in the monoclinic system, blue crystal of [Ni(SCN)2(γ-pic)4] (2) – in the tetragonal one, and red crystal of [Ni(SCN)2(PPh3)2] (5) – in the triclinic one. The ligands of complexes (1) and (3) were indicated as rather strong π-acceptors while that of complex (4) one has some π-donor properties. When the aliphatic chain (CH2) elongates in the sequence: (1), (3) and (4), an increase in the orbital contribution to the magnetic moment and a decrease in the 10Dq value of the d orbital splitting are related to the change of the point group symmetry from D2h, via D2v to C2h.Figure optionsDownload as PowerPoint slide