Hh. Alkam et al., INFLUENCE OF SUBSTITUENTS WITHIN BIDENTATE NITROGENOUS BASES ON THE SPECTRA OF MIXED-LIGAND (1,1-DITHIOLATO) COPPER(II) AND NICKEL(II) CHELATES, Inorganica Chimica Acta, 256(1), 1997, pp. 41-50
A series of mixed-ligand copper(II) and Nickel(II) chelates, [M(enR)(i
-MNT)], containing the dianion of 1,1-dicyano-2,2-ethlenedithiole, (i-
MNT)(2-), and an N-alkyl substituted 1,2-diaminoethane, enR, were prep
ared and characterised. From the IR spectra of [M(enR)(i-MNT)] it tran
spires that the influence of the groups attached to the diamine on gro
up vibrations is not as important as that of substituents linked to th
e >C=C< entity. It is established that the frequency of a strong band
in the 1340 to 1550 cm(-1) region is inversely proportional to the int
eratomic distance of the >C=C< entity. The magnetic behaviour and the
electronic excitation and ESR spectra indicated a square-planar struct
ure. The existence of metal(II) in a square-planar environment was con
firmed by the X-ray diffraction of [Ni(Et(2)en)(i-MNT)] determined fro
m a single microcrystal (monoclinic, space group P2(1)/n, a=7.277(2),
b=8.793(3), c=21.557(3) angstrom, beta=95.07(1)(0), Z=4, R=0.0491, R-w
=0.0551)