Crystal structures of six miscellaneous products arising from the oxidation of precursors R1R2R3PEAuX (R = tert-butyl or isopropyl; E = S or Se; X = Cl, Br or I)

Abstract

Various compounds involving phosphane chalcogenides (or their derivatives) and gold have been characterized; their packing is analysed in terms of weak hydrogen bonds and halogen⋯chalcogen contacts.

Compound 1, (disulfane-1,2-di­yl)bis­(tert-butyl­diiso­propyl­phospho­nium) bis­[tetra­chlorido­aurate(III)], (^tBuⁱPr₂P)₂S₂·[AuCl₄]₂, contains the first structurally characterized dication of the form {(R₃P)₂E}₂²⁺. The ions are linked by S⋯Cl contacts and C—H_methine⋯Cl hydrogen bonds to form ribbons of residues parallel to the a axis. Compound 2 is bis­(di-tert-butyl­iso­propyl­phosphine sulfide-κS)gold(I) triiodide/di­iodido­aurate(I)(0.905/0.095), [Au(C₁₁H₂₅PS)₂][AuI₂]_0.095(I₃)_0.905, or [(^tBu₂ⁱPrPS)₂Au]I₃ with 9.5% of the triiodide replaced by di­iodido­aurate(I). Chains of alternating anions and cations parallel to [110] are formed by two S⋯I contacts. Compound 3 is bis­(tert-butyl­diiso­propyl­phosphine sulfide-κS)gold(I) triiodide/di­iodido­aurate(I)(0.875/0.125), [Au(C₁₀H₂₃PS)₂][AuI₂]_0.125(I₃)_0.875 or [(^tBuⁱPr₂PS)₂Au]I₃ with 12.5% of the triiodide replaced by di­iodo­aurate(I). Chains parallel to [101] are formed by two S⋯I contacts. Compound 4, bis­(di-tert-butyl­iso­propyl­phosphine sulfide-κS)gold(I) hepta­iodide, [Au(C₁₁H₂₅PS)₂]I₇ or [(^tBu₂ⁱPrPS)₂Au]I₃·2I₂, is formally the bis-diiodine adduct of 3, uncontaminated by di­iodido­aurate(I). The cations and anions display crystallographic twofold symmetry. The unbranched I₇⁻ groups, I—I⋯I—I—I⋯I—I, are bent at the third and fifth atoms. The anions are linked by two S⋯I contacts to form a layer structure parallel to the bc plane. In all three structures 2–4, there are also weak C—H_methine⋯I contacts. Compound 5, di­bromido­(di-tert-butyl­dithio­phosphato-κ²S,S′)gold(III), [AuBr₂(C₈H₁₈PS₂)] or [AuBr₂(^tBu₂PS₂)], contains a four-membered chelate ring. It crystallizes with imposed mirror symmetry. An S⋯Br contact links the mol­ecules to form corrugated layers parallel to the bc plane. In compound 6, di-tert-but­yl{[di-tert-but­yl(hy­droxy)phosphan­yl]diselan­yl}phosphine oxide tetra­bromido­aurate(III), (C₁₆H₃₇O₂P₂Se₂)[AuBr₄] or [(^tBu₂OPSe)₂H][AuBr₄], the cation has a central diselenide unit, and also displays an intra­cationic hydrogen bond O—H⋯O. Two Se⋯Br contacts link the residues to form zigzag chains parallel to [201]. The problem of determining whether an E⋯X contact (E = chalcogen, X = halogen) represents a halogen bond or a chalcogen bond is discussed.