Cation–anion interactions in triphenyl telluronium salts. The crystal structures of (Ph3Te)2[MCl6] (M=Pt, Ir), (Ph3Te)[AuCl4], and (Ph3Te)(NO3)·HNO3

Triphenyltelluronium hexachloroplatinate (1), hexachloroiridate (2), tetrachloroaurate (3), and tetrachloroplatinate (4) were prepared from Ph3TeCl and potassium salts of the corresponding anions. Upon recrystallization of 4 from concentrated nitric acid, K2[PtCl6] and (Ph3Te)(NO3)·HNO3 (5) were obtained. The crystal structures of 1–3 and 5 are reported. Compounds 1 and 2 are isostructural. They are triclinic, P1̄, Z=2 (the asymmetric unit contains two formula units). Compound 1: a=10.7535(2), b=17.2060(1), c=21.4700(3) Å, α=78.9731(7), β=77.8650(4), γ=78.8369(4)°. Compound 2: a=10.7484(2), b=17.1955(2), c=21.4744(2) Å, α=78.834(1), β=77.649(1), γ=78.781(1)°. Compound 3 is monoclinic, P21/c, Z=4, a=8.432(2), b=14.037(3), c=17.306(3) Å, β=93.70(3)°. Compound 5 is monoclinic. P21/n, Z=4, a=9.572(2), b=14.050(3), c=13.556(3) Å, β=90.76(3)°. The primary bonding in the Ph3Te+ cation in each salt is a trigonal AX3E pyramid with TeC bond lengths in the range 2.095(8)–2.14(2) Å and the bond angles 94.1(6)–100.9(5)°. The weak Te⋯Cl (1–3) and Te⋯O (5) secondary interactions expand the coordination sphere. In 1 and 2 the cation shows a trigonal bipyramidal AX3YE coordination with one primary TeC bond and the shortest secondary Te⋯Cl contact in axial positions and the two other TeC bonds and the lone-pair in equatorial positions. The cation in 3 shows a distorted octahedral AX3Y3E environment and that in 5 is a more complex AX3Y3Y′2 arrangement. In both latter salts the structure is a complicated three-dimensional network of cations and anions.