Platinum-dithiolene

In chloroform solvent, the platinum dithiolene complexes Pt(S2C2R2)2 are photooxidized between 300 and 350 nm, providing the complexes used are those for which the R groups result in redox potentials in the 0.1 to 0.5 V (vs SCE) range. The results are consistent with the reaction shown in equation (534).1849 Further work on this system identifies the fact that several excited states are probably photoreactive in this process,1850 and no definitive answer on the excited state reactivities is yet available. Very recently, however, highly structured solid-state emissions have been observed for Pt S2C2(CN)2 P(OR)3 2, and this data may help resolve some of these questions.1851... 

In 1977, Giroud and Mueller-Westerhoff [11] reported some mesomorphic nickel and platinum dithiolenes, 3. This work is widely accepted as being the beginning of systematic research into metallomesogens. Since then, many laboratories have entered the field and many new types of metallo-mesogen have been synthesized. 

In a subsequent study by Robertson, Murphy, and coworkers, polymer 23 was synthesized by anodie polymerization on platinum electrodes and eompared to polymer 19 in order to determine the effect of the position of the linkage of the dithiolene to thiophene moieties. In this study, the researchers used the salts [Bu4N][ll] and [Bu4N][16] in MeCN to prepare the respective polymers 19 and 23. Surprisingly, the polymerization of the anion 11 resulted in films exhibiting different electroehemieal response than that observed for 19... 

Table 10 Half-wave Potentials for Bis-1,2-dithiolene Complexes of Platinum in MeCN with a Calomel Scale...

Another patent describes an advantage for a light-absorbing layer that contains a platinum complex of an alkene-l,2-dithiolate (1,2-dithiolene) such as (124) because of an inherently greater volatility.257... 

Dithiolene complex 138 (having a 1 1 ratio) was also formed in the reaction of 3,4-di(l-adamantyl)-l,2-dithiete 135 or its valence tautomer 136 with ethylenebis(triphenylphosphine)platinum(0) 137 (Scheme 16) <2003JA12114>. 

Very few dithiolene platinum complex-based compounds have been reported and most of them exhibit poor electrical conductivity (9, 122, 123). The complex (Me4N)[Pt(dmit)2]2 does show metal-like behavior (RT conductivity = 10 S cm 1) but only >220 K (123). Another exception is (NHMe3)[Pt(dmit)2]3. This compound, which has the unusual 1 3 stoichiometry, behaves as a metal down to 180 K, with a room temperature conductivity of 140 S cm-1 (91). The Pt(dmit)2 units form pairs with an eclipsed overlap mode. Unlike the analogue Ni derivatives (see above) substituting one hydrogen atom for one methyl group in the (Me4N)+ cation leads to an improvement in the electrical properties. 

A number of platinum diimine-dithiolene complexes display long-lived solution and solid-state luminescence in ambient conditions and in frozen solvent glasses. A linear correlation has been found between emission energies and the difference in the ground-state redox potentials. These results provide the tools for tuning and systematically controlling... 

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