Dithiosquarate ligands

The longest average M—S bond lengths for structures based on a particular element occur with the dithiosquarate ligand, S2C402 (Table IIC, Entry 52 ... 

There are 35 Au dithiolene units with formal metal oxidation states mostly as Au(III) and some as Au(IV) . The complexes are often considered alongside isoelectronic Pt bis(dithiolene) examples. Coordination geometries for all the Au structures are square planar as is the case for the Auidmit) 1 example shown in Fig. 8. Average Au—S bond distances range from 2.263-2.344 A (Fig. 5) and the longest Au—S bonds are observed with the dithiosquarate ligand (Table IIC, Entry 52). 

The syntheses of the metal-benzenethiolate complexes are accomplished by a ligand substitution reaction between the appropriate O-ethyl dithiocarbonate complexes and potassium benzenethiolate, KSPh. In the original report on the syntheses of the [M(SPh)4]2 complexes,1 the bis(3,4-dimercapto-cyclobutane-1,2-dione) [dithiosquaric acid] metal complexes were used in the ligand substitution reactions. The rather involved synthesis of the dithiosquarate ligand,2 using expensive starting materials, prompted us to develop new synthetic procedures which utilize the readily available, inexpensive O-ethyl dithiocarbonate complexes.3... 

Homoleptic gold(III) complexes with other related dithiolate ligands, as dmit (317),1855-1864 dddt,1865,1866 l,3,5-trithiepin-6,7-dithiolate,1867 dithiosquarate (318),1868,1869 6,7-dihydro-6-methy-lene-5H-l,4-dithiepine-2,3-dithiolate,1870 3,4-thiophenedithiolate (319),1637 quinoxaline-3,3-dithiolate (320),1871 2,2-diacetylethylene-1,1-dithiolate,1872 or o-carborane-1,2-dithiolate have been... 

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