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 L_P is triphenylphosphine or a fluorinated phosphine [PPh_F = P(C₆H₅)₂(C₆F₅) 1, P(C₆H₅)(C₆F₅)₂ 2 and P(C₆F₅)₃ 3] and X is chloride or a fluorinated thiolate [SR_F = 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 ^–SR_F ligand decreases the stability of the compound. Furthermore, this substitution shifts the ³¹P-NMR signals to low field, which indicates differences in the electronegativity of the phosphorus due to the distinct trans influences of the Cl^– and ^–SR_F 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.