Inorganic Chemistry, Vol.33, No.7, 1502-1505, 1994
Destructive or Cooperative Attack of Iodide Anions on Alkyltriiodophosphonium Cations - Elimination of Iodine in Solution and Layer Structures in the Solid-State
Solid-state and solution P-31 NMR shifts of t-BuPI4 and crystal structure determinations of t-BuPI4, i-PrPI4, and MePI4 reveal that alkyltetraiodophosphorus compounds RPI4 (R = t-Bu (I), i-Pr (2), Me3SiCH2 (3), Me (4)) in the solid state involve mu3-bridging I...I interactions between RPI3+ cations and I-anions (leading to the formation of layer structures (2,4) or a 3-dimensional network (1)) whereas, in CS2/CD2Cl2 solutions, deiodination by nucleophilic I- anions causes all RPI4 compounds and PI5 to decompose into the iodophosphanes RPI2 or PI3 and molecular iodine. 1 crystallizes in the cubic space group I2(1)3, with a = 13.613(2) angstrom, V = 2522.7(6) angstrom3, and Z = 8. 2 crystallizes in the monoclinic space group P2(1)/c, with a = 6.686(2) angstrom, b = 19.918(5) angstrom, c = 8.961(3) angstrom, beta = 97.41(2)degrees, V = 1183.4(6) angstrom3, and Z = 4. 4 crystallizes in the orthorhombic space group Pbcm, with a = 6.031(2) angstrom, b = 18.426(7) angstrom, c = 8.741(3) angstrom, V = 971.4(3) angstrom3, and Z = 4. Cation-anion I...I interactions of solid RPI4 are stronger than molecule-ion interactions within the related anion network of solid PhCH2NMe3+HCI4-(5), which crystallizes in the monoclinic space group P2(1)/c, with a = 8.200(1) angstrom, b = 13.723(1) angstrom, c = 16.216(1) angstrom, beta = 91.32(2)degrees, V = 1824.3(3) angstrom3, and Z = 4.