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

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—Hmethine...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—Hmethine...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.

Keywords

• crystal structure
• gold
• phosphane chalcogenides
• secondary interactions