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Synthesis and Characterization of Cobalt(II), Nickel(II), and Zinc(II) Complexes with N,N ′-bis( Trans- Cinnamaldehyde)-1,2-Diiminoethane Ligand, (ca 2 en): Crystal and Molecular Structures of Co(ca 2 en)Cl 2 , Co(ca 2 en)Br 2 and Ni(ca 2 en)Br 2
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2003
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Inorganic ChemistryChemical EngineeringSchiff BaseBr 2EngineeringCoordination ComplexX-ray DiffractionMolecular ComplexCl 2ChemistryTrans- CinnamaldehydeInorganic SynthesisNew ComplexesInorganic Compound
A series of new complexes of the Schiff base obtained from trans- cinnamaldehyde and 1,2-diaminoethane (en) with the general formula of M(ca 2 en)X 2 (M = Co(II), Ni(II), Zn(II); X = Cl, Br, I, NCS, N 3 ; (ca 2 en) = N,N '-bis( trans- cinnamaldehyde)-1,2-diiminoethane) have been synthesized and characterized. The crystal structures of three pseudo -tetrahedral complexes, Co(ca 2 en)Cl 2 ( 1 ), Co(ca 2 en)Br 2 ( 2 ), and Ni(ca 2 en)Br 2 ( 5 ), were determined by X-ray diffraction. Crystal data for 1 , Co(ca 2 en)Cl 2 : monoclinic; space group P 2 1 / c ; a = 7.1925(14) Å, b = 20.327(4) Å, c = 14.029(3) Å; g =95.06(3)°; V = 2043.1(7) Å 3 ; Z = 4; and final R 1 = 0.0381 ( wR 2 = 0.0718) for 4653 independent reflections with I > 2 σ ( I ) and 226 parameters; 2 , Co(ca 2 en)Br 2 ; monoclinic, space group P 2 1 / c ; a = 7.3780(6) Å, b = 20.4372(17) Å, c = 14.1649(12) Å; g = 94.902(2)°; V = 2128.1(3) Å 3 ; Z = 4; and final R 1 = 0.0491 ( wR 2 = 0.1052) for 5858 independent reflections with I > 2 σ ( I ) and 227 parameters; 5 , Ni(ca 2 en)Br 2 : monoclinic, space group P 2 1 / c ; a = 7.2388(6) Å, b = 20.4651(16) Å, c = 14.2782(12) Å; g = 94.160(2)°; V = 2109.6(3) Å 3 ; Z = 4; R 1 = 0.0481 ( wR 2 = 0.0907) for 5914 independent reflections with I > 2 σ ( I ) and 227 parameters. The structures consist of discrete molecules in which the coordination polyhedra about the central metal ion are highly distorted tetrahedra with Cl(1)-Co-Cl(2), 115.51(3)°; N(1)-Co-N(2), 83.71(7)°; Br(1)-Co-Br(2), 114.58(4)°; N(1)-Co-N(2), 84.92(19)°; and Br(1)-Ni-Br(2), 125.23(3)°; N(1)-Ni-N(2), 85.11(15)° in 1 , 2 , and 5 , respectively. The stiryl groups are cis -endo with respect to the metal atom and the chelate ring is puckered. Utilization is made of electronic and vibrational spectra in structural diagnosis of other complexes.