Prototypical Phosphine Complexes of Antimony(III)

Complexes of the generic formula [Cl_n(PR₃)_mSb]^(3–n)+ (n = 1, 2, 3, or 4 and m = 1 or 2) have been prepared featuring [ClSb]²⁺, [Cl₂Sb]¹⁺, Cl₃Sb, or [Cl₄Sb]¹⁻ as acceptors with one or two phosphine ligands {PMe₃, PPh₃, PCy₃ (Cy = C₆H₁₁)}. The solid-state structures of the complexes reveal foundational features that define the coordination chemistry of a lone pair bearing stibine acceptor site. The experimental observations are interpreted with dispersion-corrected density functional theory calculations to develop an understanding of the bonding and structural diversity.