Synthesis And Properties Of Nickel Dithiolene Complexes

As a class of important near-infrared(NIR) absorbing dyes, dithiolene metal complexes have been found to exhibit intense near-infrared absorption, high photochemical stabilities and excellent electrical or magnetic properties. They have raised a continuously increasing interest, due to their potential application in the fields spanning from material chemistry to biochemistry.Three kinds of dithiolene metal complexes with substitute groups of -H, -OCH₃, -C(CH₃)₃ respectively were synthesized by Schrauzer method, which showed strong maximum absorbance at ca. 855nm,926nm,885nm. Thereinto, the compound with tert-butyl was obtained for the first time. The melting-point, element composition, IR spectrum and MS spectrum were characterized. In this thesis, some complexes were prepared and used in near-infrared filters, for the night vision image system compatible lighting technology (NVIS-CLT).Diarylhydroketone intermediates played an important role in the synthesis of dithiolene metal complexes. The influencing factors on the synthesis of the intermediate substituted with tert-butyl were studied and the optimal reaction conditions were obtained. Then the effects of substituents and solvents on NIR absorption and solubility of dithiolene metal complexes were studied further, along with the photostabilities of single dithiolene and its combination with cyanine. The results showed that substituents with powerful electron-offering groups and solvents with high polarity caused a bathochromic shift of the absorption band. It was also found that dithiolene metal complexes exhibited high photostability, which could improve the photostability of cyanine effectively.In order to extend the application of dithiolene metal complexes, the complexes were applied to prepare near-infrared filters. Two kinds of filters were prepared, one composed of single complex, the other composed of both the complex substituted with hydrogen and cyanine. NIR spectrum property, photostsbility and radiance of these filters were studied to discuss whether these complexes could be used in the near-infrared filters. The results showed that dithiolene metal complexes kept good near-infrared absorption, exhibited better photostability than that in solution state. It was discovered as well that dithiolene metal complexes incorporated with cyanine could satisfy the needs of NVIS-CLT.