Stability and trans Influence in Fluorinated Gold(I) Coordination Compounds

We examined the Au-P and Au-X chemical bonding scenario throughout the series of compounds of the general formula [AuX(L-P)] wherein LP is triphenylphosphine or a fluorinated phosphine [PPhF = P(C6H5)(2)(C6F5) 1, P(C6H5)(C6F5)(2) 2 and P(C6F5)(3) 3] and X is chloride or a fluorinated thiolate [SRF = SCF3 a, SCH2CF3 b, SC6F5 c, SC6F4(CF3)-4 d]. We found that the increase of the fluorination degree or the replacement of Cl- by a -SRF ligand decreases the stability of the compound. Furthermore, this substitution shifts the P-31-NMR signals to low field, which indicates differences in the electronegativity of the phosphorus due to the distinct trans influences of the Cl- and -SRF species. These effects correlate with the charge of the gold atom coordinated to phosphorus. Our investigation shows the high potential of fluorination as a strategy for the modulation of the properties of gold compounds, for example in catalysis, and the applicability of quantum chemical topology studies in the explanation of these features.