Dimeric dithiophosphate

The tin(II) derivative Sn[S2P(OPh)2]2 is a dimeric supermolecule formed through intermolecular Sn- S secondary bonds and Sn-7i-aryl interactions.57 Lead(II) dithiophosphates, Pb[S2P(OR)2]2, e.g. R = Me,58 Pr" and Cy,59 all form supramolecular chain-like arrays. The ligands are unsymmetrically bridging and form Pb- S secondary bonds. 

A next step in the assignment of the excited states responsible for emissions in gold-dithiophosphate dimers is the contribution of Eisemberg et al. [37]. They analyzed the optical properties of the complexes [Au2 S2P(OR)2 2] (R = Me, Et, n-Pr, n-Bu), for which the crystal structure determinations of the complexes with R = Me and R = Et revealed that these are extended linear chain polymers formed by gold interactions between dinuclear units of about 3 A, of the same type as those described previously. 

Among CT band promoted electron transfers, some cases are known for anionic donors as for example when mixtures of methyl viologen (as its tetrafluoroborate) and dithiophosphate anions are irradiated by visible light in acetonitrile [202]. In this system, the dark back electron transfer is prevented by the dimerization of the obtained thio radicals. 

The formation of desaurins from ketones, carbon disulfide, and base 1275,1281,1282,1285-1290 believed to involve nucleophilic attack on a thioketene by the dianion of a 1,1-dimercaptoalkene, as shown for the synthesis of 572. Related syntheses involve the use of thiophosgene instead of carbon disulfide and the use of diazoalkanes or phosphonium and sulfonium ylides instead of a ketone and base. Treatment of perfluoroiso-butylene with fluoride ion and elemental sulfur in a dipolar, aprotic solvent ° °° or with sources of anionic sulfur (potassium sulfide, sodium hydrosulfide,potassium thiocyanate,sodium thiosulfate, dithiocarbamate salts, dithiophosphate salts ) give the dimer (573) of bis(trifIuoromethyl)-thioketene. Similarly, other 2,4-bis(methylene)-l,4-dithietanes are obtained by treating 2,2-dichlorovinyl ketones with anionic sulfur re-... 

Dithiophosphate groups in PhAs[S2P(OPr )j]2 chelate in an asymmetric fashion with As—S distances of 2.310/2.317 and 3.135/3.187 A to give a square-pyramidal arrangement about arsenic , and when bis(dimethylarsino)sulphide, (Me2As)2S, coordinates to dimeric trimethylplatinum bromide it does so via the arsenic atoms and bridges between the two Pt atoms The arsenic-sulphur distances are normal with an As—S—As angle... 

Of the three structurally characterized dithiophosphates with simple R groups, [Bi S2P(OEt)2 3] is six-coordinate (distorted octahedral), but [Bi S2P(OR)2 3] (R = Ph or Me) are dimeric with distorted pentagonal bipyramidal bismuth. " " " Similarly, in the dithiophosphinate series [Bi(S2PR2)3] R = Et is distorted octahedral, whereas R = Me or Ph are dimeric (Figure 74). " " " One curious observation is that in [Bi(S2PEt2)3] (Figure 75) the Bi—bonds within the chelate rings are very similar (2.794(5), 2.782(5) A) which contrasts with the anisobidentate coordination... 

An unexpected self-assembly, 149, with dimer formation, was observed in phen-oxarsine dithiophosphinates, 0(C6H4)2AsS2PR2- With R = Ph [377] and R = Et [378] dimers, 149, are formed by secondary As- - -S bonding (primary As-S 2.315 A, intermolecular secondary As---S 3.402 A, intramolecular secondary As- - -S 3.402 A when R = Ph primary As-S 2.318 A, intermolecular secondary As- - -S 3.440 A and intramolecular secondary As- - -S 3.505 A when R — Et). The methyl derivative (R = Me) is, however, an rmassociated monomer. The secondary As- - - S bonds observed in these compounds are longer (weaker) than the intramolecular secondary bonds measured in a phenylarsenic dithiophosphate, PhAs[S2P(OPr )2]2, investigated earlier (primary As-S 2.310 and 2.317 A intramolecular secondary As---S 3.135 and 3.187 A) [379]. 

---