Crystal structures of six complexes of phosphane chalcogenides R¹R²R³PE (R = tert-butyl or isopropyl, E = S or Se) with the metal halides MX₂ (M = Pd or Pt, X = Cl or Br), two halochalcogenylphosphonium derivatives (^tBu₂ⁱPrPEBr)₂[Pd₂Br₆] and one hydrolysis product

The L₂MX₂ complexes 1–5 (1: L = ^tBuⁱPr₂PSe, M = Pd, X = Cl; 2: L = ^tBu₂ⁱPrPSe, M = Pd, X = Cl; 3: L = ^tBu₂ⁱPrPSe, M = Pd, X = Br; 4: L = ^tBu₂ⁱPrPS, M = Pd, X = Br; 5: L = ^tBu₂ⁱPrPS, M = Pt, X = Cl) {systematic names: (tert-butyl­diiso­propyl­phosphine selenide-κSe)di­chlorido­palladium(II), [PdCl₂(C₁₀H₂₃PSe)₂] (1), (di-tert-butyl­iso­propyl­phosphine selenide-κSe)di­chloridopalladium(II), [PdCl₂(C₁₁H₂₅PSe)₂] (2), di­bromido­(di-tert-butyl­iso­propyl­phosphine selenide-κSe)palladium(II), [PdBr₂(C₁₁H₂₅PSe)₂] (3), di­bromido­(di-tert-butyl­iso­propyl­phosphine sulfide-κS)palladium(II), [PdBr₂(C₁₁H₂₅PS)₂] (4), di­chlorido­(di-tert-butyl­iso­propyl­phosphine sulfide-κS)palladium(II), [PdCl₂(C₁₁H₂₅PS)₂] (5)} all display a trans configuration with square-planar geometry at the metal atom. Compounds 2 and 3 are isotypic. The mol­ecules of 1 and 4 display crystallographic inversion symmetry; compound 5 involves two independent mol­ecules, each with inversion symmetry but with differing orientations of the tri­alkyl­phosphane groups. Chemically equivalent bond lengths all lie in narrow ranges, whereby the values for palladium and platinum compounds scarcely differ. Compound 6, (^tBuⁱPr₂PS)₂Pd₂Cl₄ {systematic name: di-μ-chlorido-bis­[(tert-butyldiiso­propyl­phosphine sulfide-κS)chlorido­palladium(II)], [PdCl₂(C₁₀H₂₃PS)₂]}, is dinuclear with a central Pd₂Cl₂ 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(^tBu₂ⁱPrPEBr)⁺ [Pd₂Br₆]²⁻ with E = S for 7 and Se for 8 {systematic names: (bromo­sulfan­yl)di-tert-butyl­iso­propyl­phosphanium di-μ-bromido-bis­[di­bromido­palladium(II)], (C₁₁H₂₅BrPS)₂[Pd₂Br₆] (7) and (bromo­selan­yl)di-tert-butyl­iso­propyl­phosphanium di-μ-bromido-bis­[di­bromido­palladium(II)], (C₁₁H₂₅BrPS₂)₂[Pd₂Br₆], (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[dimeth­yl(sulfanyl­idene)phosphin­ito-κSe]bis­(hy­droxy­diiso­propyl­phosphine selenide-κSe)palladium(II), [Pd(C₆H₁₄OP)₂(C₆H₁₅OP)₂], {(ⁱPr₂PSeO)₂H}₂Pd, is a hydrolysis product with inversion symmetry and contains an intra­molecular P—O⋯H—O—P group with a disordered hydrogen atom. Compounds 1–6 and 9 show few, if any, short inter­molecular contacts, although some H⋯M contacts are observed. A problem with atom-type assignment for structure refinement is discussed.