Transient Ni(dtc)(2)(dtc(center dot)) complex in photochemistry of thiuramdisulfide and dithiocarbamate Ni(II) complex solutions

The optical and ESR spectra of the radical complex Ni(dtc)(2)(dtc(.)) (wher e Ni(dtc), is a flat dithiocarbamate Ni(II) complex), have been recorded in frozen matrices. The dtc(.) radicals (R2NCS2.)were produced by photodissoc iation of thiuram disulfide molecules (tds = R2NC(S)S-S(S)CNR2 where R is a n alkyl group) at a low temperature close to the melting point of the solve nt. Coordination of radicals gives rise to both the optical spectrum with i ntense absorption bands in the range 200-800 nm and the ESR spectrum with a nisotropic g-factor(g(xx) = 2.154, g(yy) = 2.136, and g(zz) = 2.040). For s ome solvents, forming a polycrystalline matrix upon freezing, the ESR spect rum of the Ni(dtc) (2) (dtc(.)) complex transforms into a wide singlet line due to the increased local concentration. (C) 1999 Published by Elsevier S cience B.V. All rights reserved.