Crystal structures of six complexes of phosphane chalcogenides R (1) R (2) R (3)PE (R = tert-butyl or isopropyl, E = S or Se) with the metal halides MX (2) (M = Pd or Pt, X = Cl or Br), two halochalcogenyl-phospho-nium derivatives ( (t) Bu(2) (i)PrPEBr)(2)[Pd(2)Br(6)] and one hydrolysis product.

The L (2) MX (2) complexes 1-5 (1: L = (t) Bu(i)Pr(2)PSe, M = Pd, X = Cl; 2: L = (t) Bu(2) (i)PrPSe, M = Pd, X = Cl; 3: L = (t) Bu(2) (i)PrPSe, M = Pd, X = Br; 4: L = (t) Bu(2) (i)PrPS, M = Pd, X = Br; 5: L = (t) Bu(2) (i)PrPS, M = Pt, X = Cl) {systematic names: (tert-butyl-diiso-propyl-phosphine selenide-κSe)di-chlorido-palladium(II), [PdCl(2)(C(10)H(23)PSe)(2)] (1), (di-tert-butyl-iso-propyl-phosphine selenide-κSe)di-chloridopalladium(II), [PdCl(2)(C(11)H(25)PSe)(2)] (2), di-bromido-(di-tert-butyl-iso-propyl-phosphine selenide-κSe)palladium(II), [PdBr(2)(C(11)H(25)PSe)(2)] (3), di-bromido-(di-tert-butyl-iso-propyl-phosphine sulfide-κS)palladium(II), [PdBr(2)(C(11)H(25)PS)(2)] (4), di-chlorido-(di-tert-butyl-iso-propyl-phosphine sulfide-κS)palladium(II), [PdCl(2)(C(11)H(25)PS)(2)] (5)} all display a trans configuration with square-planar geometry at the metal atom. Compounds 2 and 3 are isotypic. The mol-ecules of 1 and 4 display crystallographic inversion symmetry; compound 5 involves two independent mol-ecules, each with inversion symmetry but with differing orientations of the tri-alkyl-phosphane groups. Chemically equivalent bond lengths all lie in narrow ranges, whereby the values for palladium and platinum compounds scarcely differ. Compound 6, ( (t) Bu(i)Pr(2)PS)(2)Pd(2)Cl(4) {systematic name: di-μ-chlorido-bis-[(tert-butyldiiso-propyl-phosphine sulfide-κS)chlorido-palladium(II)], [PdCl(2)(C(10)H(23)PS)(2)]}, is dinuclear with a central Pd(2)Cl(2) ring, and displays crystallographic inversion symmetry. The bonds to the bridging are longer than those to the terminal chlorine atoms; the Pd-S bond is shorter than the M-S bonds in 4 and 5, reflecting the weaker trans influence of (bridging) chlorine compared to sulfur. Compounds 7 and 8, 2( (t) Bu(2) (i)PrPEBr)(+) [Pd(2)Br(6)](2-) with E = S for 7 and Se for 8 {systematic names: (bromo-sulfan-yl)di-tert-butyl-iso-propyl-phosphanium di-μ-bromido-bis-[di-bromido-palladium(II)], (C(11)H(25)BrPS)(2)[Pd(2)Br(6)] (7) and (bromo-selan-yl)di-tert-butyl-iso-propyl-phosphanium di-μ-bromido-bis-[di-bromido-palladium(II)], (C(11)H(25)BrPS(2))(2)[Pd(2)Br(6)], (8)}, were obtained by oxidizing the appropriate Pd(II) precursors with elemental bromine; they are not isotypic. The ions are connected by very short halogen bonds Br⋯Br. For both compounds, two E⋯Br contacts further link the cations and anions to form ribbons. Compound 9 {systematic name: bis-[dimeth-yl(sulfanyl-idene)phosphin-ito-κSe]bis-(hy-droxy-diiso-propyl-phosphine selenide-κSe)palladium(II), [Pd(C(6)H(14)OP)(2)(C(6)H(15)OP)(2)], {((i)Pr(2)PSeO)(2)H}(2)Pd, is a hydrolysis product with inversion symmetry and contains an intra-molecular P-O⋯H-O-P group with a disordered hydrogen atom. Compounds 1-6 and 9 show few, if any, short inter-molecular contacts, although some H⋯M contacts are observed. A problem with atom-type assignment for structure refinement is discussed.