Year 2005, Month 1 (Section Full Articles, Page 173)
Synthesis and physicochemical study of NiII complexes
with tetradentate acyclic and macrocyclic
N2S2 ligands as thiosalen analogs
K. P. Butin,(a)* A. A. Moiseeva,(a) E. K. Beloglazkina,(a) Yu. B. Chudinov,(a) A. A. Chizhevskii,(a) A. V. Mironov,(a)
B. N. Tarasevich,(a) A. V. Lalov,(b) and N. V. Zyk(a)
N,N´-Polymethylenebis(thiosalicylidene)iminate and macrocyclic dithiadiazadibenzocycloalkadiene complexes of nickel(II) were synthesized and their electrochemical and spectroscopic properties were studied. Dithiadiazadibenzocycloalkadiene complexes containing
two DMSO molecules coordinated to Ni2+ and two outer-sphere ClO4
– anions were synthe-
sized by the reaction of the corresponding macrocyclic ligands with Ni(ClO4)2•6H2O. The
structure of 3,6-dithia-10,14-diazadibenzo[a,g]cyclopentadeca-9,14-dienylnickel(II)[bis(dimethyl sulfoxide) bis-perchlorate] was established by X-ray diffraction. The UV-Vis spectroscopic data are consistent with octahedral structures of diiminobis(sulfide) complexes, a squareplanar structure of the thiosalen complex, and distorted tetrahedral structures of other
diiminodithiolate complexes. The reaction of S-tert-butylthiosalicylaldehyde with hydrazine
hydrate afforded di(ortho-tert-butylthiobenzal)azine. The reaction of the latter with anhydrous
NiCl2 produced a colored complex with the simplest molecular formula Ni(C16H12N2S2) in
15% yield. Semiempirical PM3(tm) calculations and the results of UV-Vis, ESR, and 1H NMR
spectroscopy demonstrate that this complex has most probably a dimeric structure, in which
two Ni centers adopt a nearly square-planar configuration. The complexes are clearly divided
into two types according to their electrochemical behavior in DMF solutions. The type 1 is
characterized by reversibility of the first reduction steps. The type 2 is characterized by irreversible two-electron reduction as the first step accompanied by deposition of Ni metal on the
electrode surface. Rapid electrochemically initiated alkylation occurs in the presence of various alkylating agents (BunI, BunBr, (DmgH)2CoCH3) in a solution of complex 1 in DMF..
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