Nitrogen xanthate structures

Metal complexes of ligands containing a sulfur donor in conjunction with nitrogen, oxygen or a second sulfur have been reviewed in the past [11-13]. For example, reviews of the coordination compounds of dithiophosphates [14], dithiocarbamates [15, 16], dithiolates [17], dithiodiketonates [18], and xanthates [16] have appeared. The analytical aspects [19] and the spectral and structural information of transition metal complexes of thiosemicarbazones [20, 21] have been reviewed previously. Recent developments in the structural nature of metal complexes of 2-heterocyclic thiosemicarbazones and S-alkyldithiocarbazates, depicted below, are correlated to their biological activities. 

There are two closely related structures, that is, [Zn (2-Me-5-Ph-pyr-azole)3BH (S2COMe)] (172) and [Zn (2-Me-5-(4-/-Pr-Ph)-pyrazole)3BH (S2. COEt)] (173), in which the putative Zn- -O secondary bond interactions alluded to above attain a higher level of significance. The molecular structure of the former molecule is shown in Fig. 94 from which it can be seen that three coordination sites about the zinc center are occupied by nitrogen atoms derived from the substituted pyrazole ligand. The xanthate ligand coordinates via the SI... 

The Pb- -S mediated chains observed in the structure of polymeric Pb(S2COEt)2 are disrupted upon the addition of base. The immediate coordination geometry about the lead atom in the adduct Pb(S2CO—i-Pr)2(py) (231) is shown in Fig. 145(a). The lead atom is coordinated by the pyridine nitrogen atom and two xanthate ligands, one that forms asymmetric Pb—SI and Pb—S2 distances of 2.72(2) and 3.06(2) A, and one that forms symmetric bonds of... 

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