1:1 Adducts of Copper(I) and Silver(I) Halides with the Olefinic Phosphane Tri(1‐cyclohepta‐2, 4, 6‐trienyl)phosphane. Molecular Structures of CuX[P(C7H7)3] (X = Cl,Br), AgCl[P(C7H7)3] and {Cu(μ3‐I)[P(C7H7)3]}4

A suspension of CuX (X = Cl, Br) or AgCl in organic solvents (such as CH₂Cl₂) reacts with P(C₇H₇)₃ ( 1 ) in a molar ratio 1:1 to give the mononuclear adducts CuX[P(C₇H₇)₃] (X = Cl ( 2a ), Br ( 2b )) and AgCl[P(C₇H₇)₃] ( 3a ) which crystallize as isotypic compounds in the orthorhombic space group Pnma (Z = 4). In the crystal, two (of the three) cyclohepta‐2, 4, 6‐trienyl substituents are present in the boat conformation, thus establishing a loose long‐distance interaction between the central double bond and the metal atom. A distorted pseudo‐tetrahedral coordination sphere is assumed to exist around the metal atom, with large P‐M‐X angles of 165.49(8)° ( 2a ), 162.07(7)° ( 2b ) and 168.54(3)° ( 3a ), respectively. The tetrameric 1:1 adduct {Cu(μ₃‐I)[P(C₇H₇)₃]}₄( 2c ) which was obtained from CuI and 1 in boiling ethanol, has also been characterized by X‐ray crystallography (monoclinic space group P2(1)/n, Z = 4); it contains all 12 cyclohepta‐2, 4, 6‐trienyl substituents in the chair conformation. The NMR spectra (¹H, ¹³C, ³¹P) of the new complexes 2a‐c and 3a indicate non‐rigid structures in solution. At room temperature, the ³¹P NMR signal of 3a appears as a doublet with an averaged coupling constant, ¹J(Ag, P), of 700.1 Hz, whereas at —45 °C the two expected doublets are clearly discernible with coupling constants ¹J(¹⁰⁷Ag, ³¹P) = 671.0 Hz and ¹J(¹⁰⁹Ag, ³¹P) = 774.4 Hz, respectively.