Dithiophosphate crystal structures

In this and the following section the crystal structures of dithiophosphate compounds are summarized and compared to those of related compounds. As is obvious from Tables 5 and 6, dithiophosphate compounds comprise a fruitful area for structural research. Additional data for comparative purposes may be found in Corbridge s review of the structural chemistry of phosphorus compounds. 

Crystal structures of [Au2(E E)2]2+ (E = chalcogen donor atom) have been described with dithiocarbamate [265-271], xantate [272], MNT [273-275], dithiopho-sphonate [276], dithiophosphinate [277], dithiophosphate [278, 279] or trithiocarbo-nate [280] ligands. The gold-gold interaction in complexes shown in Figure 2.48 has been analyzed by ab initio Hartree-Fock calculations [281]. 

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. 

The dithiophosphate complexes react with Ph3PO to give adducts, whose crystal structures... 

Bis(dialkyldithiophosphinato)nickel(II) complexes were prepared by the direct synthesis of an alkali metal or ammonium salt of the dithiophosphinic acid and a nickel salt in aqueous solution.2039,2061"2063 Ni(S2AsR2)2 and Ni(Se2PR2)2 complexes were prepared in a similar way.2064"2066 All of these complexes are square planar like their dithiophosphate analogues. X-Ray crystal structures of the complexes Ni(S2PR2)2, with R = Me,2067 Et, Ph,1983 R2 = Me/ Et 2°w r2 = Me/2-thienyl,2069 and Ni(Se2PPh2)21984 have been reported (Table 90). 

As relatively hard acids, Ln + ions would not be expected to complex readily with soft donor atoms like sulfur. Apart from the thiolates discussed in (see Section Polypyrazolylbo-rates ), several types of complex with chelating ligands such as dithiophosphates and dithiocarbamates have been synthesized by reaction in nonpolar solvents. These fall into two main classes, Ln(S2Q)3 and [Ln(S2Q)4] (Q = R2NC (dithiocar-bamate) or R2P (dithiophosphate)). Several crystal structures... 

Dinuclear niobium sulfido and selenido dithiophosphates, Nb2Q4[S2P(OR)2]4,75,76 (Q = S, Se R = Et) (also xanthates and dithiocarbamates) have been prepared but no crystal structure was reported. Optically active chromium complexes, Cr[S2P(OR)2]3 derived from Z)-borneol and L-menthol, have been described.77... 

The complexes expected to form when lanthanide ions are extracted into an organic solvent by a dithiophosphate extractant match those in the reported crystal structures [46]. However, [P4444][La(S2P(OEt)2)2Cl3] was crystallized directly from a reaction of LaCls 7H2O with the dithiophosphate salt and can be understood as the result of substitution of coordinated water molecules by IL ions. In this sense, the crystal stmcture should bear a closer relationship to the complexes formed when LaCls is dissolved in this IL, which differ from those expected in an organic solvent. 

It is also quite common for cationic and anionic complexes of the same metal ion to crystallize as a salt. This happens especially often for metals that form stable polyatomic ions, such as tetrachlorocobaltate [65,66] or tetrachlorozincate [67,68]. Rare earths readily form both cationic and anionic complexes, and the CSD contains many examples of crystal structures showing this phenomenon in the rare earths such as the published dithiophosphate complexes discussed previously [33]. In this case the two metal ions are bridged only through outer-sphere interactions but are inseparable (without changing the speciation) since their complexes act as counterimis to each other. It would seem reasonable that charged complexes containing two different metal ions could form a salt as well, but this approach is not as well documented. This is probably because it is difficult to control whether or not the two metals separate on crystallization if there is no covalent linkage between them. 

Single crystal X-ray structural analyses of these compounds3,4 show that the tellurium atom is surrounded by four sulfur atoms from four different dithiophosphate groups in a planar arrangement. The S —P —S group is not a bidentate ligand but serves as a bridge between tellurium atoms. 

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