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)

Compound 1, (disulfane-1,2-di-yl)bis-(tert-butyl-diiso-propyl-phospho-nium) bis-[tetra-chlorido-aurate(III)], ( ^t Bu ⁱ Pr₂P)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-butyl-iso-propyl-phosphine sulfide-κS)gold(I) triiodide/di-iodido-aurate(I)(0.905/0.095), [Au(C₁₁H₂₅PS)₂][AuI₂]_0.095(I₃)_0.905, or [( ^t Bu₂ⁱ PrPS)₂Au]I₃ with 9.5% of the triiodide replaced by di-iodido-aurate(I). Chains of alternating anions and cations parallel to [110] are formed by two S⋯I contacts. Compound 3 is bis-(tert-butyl-diiso-propyl-phosphine sulfide-κS)gold(I) triiodide/di-iodido-aurate(I)(0.875/0.125), [Au(C₁₀H₂₃PS)₂][AuI₂]_0.125(I₃)_0.875 or [( ^t Bu ⁱ Pr₂PS)₂Au]I₃ with 12.5% of the triiodide replaced by di-iodo-aurate(I). Chains parallel to [101] are formed by two S⋯I contacts. Compound 4, bis-(di-tert-butyl-iso-propyl-phosphine sulfide-κS)gold(I) hepta-iodide, [Au(C₁₁H₂₅PS)₂]I₇ or [( ^t Bu₂ⁱ PrPS)₂Au]I₃·2I₂, is formally the bis-diiodine adduct of 3, uncontaminated by di-iodido-aurate(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, di-bromido-(di-tert-butyl-dithio-phosphato-κ²S,S')gold(III), [AuBr₂(C₈H₁₈PS₂)] or [AuBr₂( ^t Bu₂PS₂)], contains a four-membered chelate ring. It crystallizes with imposed mirror symmetry. An S⋯Br contact links the mol-ecules to form corrugated layers parallel to the bc plane. In compound 6, di-tert-but-yl{[di-tert-but-yl(hy-droxy)phosphan-yl]diselan-yl}phosphine oxide tetra-bromido-aurate(III), (C₁₆H₃₇O₂P₂Se₂)[AuBr₄] or [( ^t Bu₂OPSe)₂H][AuBr₄], the cation has a central diselenide unit, and also displays an intra-cationic 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.