Syntheses, characterization and non-linear optical properties of nickel complexes of multi-sulfur 1,2-dithioiene with strong near-IR absorption

Abstract

A series of new nickel complexes with multi-sulfur 1,2-dithiolene ligands have been synthesized and characterized by electrochemical measurements, EPR, IR and UV–VIS spectroscopies. One of the typical structures for the neutral complex of [Ni(phdt)₂]2(phdt = 5,6-dihydro-5-phenyl-l,4-dithiin-2,3-dithiolate) was obtained by X-ray structure determination. Electrical conductivities measured for compacted pellets range from 1.4 × 10^–8 to 1.4 × 10^–5 S cm^–1. These complexes show intense absorptions in the near-IR region. The third-order non-linear optical susceptibilities, χ⁽³⁾, for three of the complexes have been determined to be of the order of 10^–11 esu.