The syntheses and X-ray analyses of triphenylmethyl (trityl=Tr) phosphorus compounds are reported and the structural similarities, differences and 31 P chemical shifts compared. A series of seven trityl-substituted phosphorus-containing compounds have been characterized by single crystal X-ray diffraction. Ph3CPPh2, 1, a bulky P(III) compound crystallizes in the triclinic space group P (1) over bar, a = 7.5624(6) angstrom, b = 9.5470(8) angstrom, c = 16.9722(14) angstrom, alpha = 83.4720(10)degrees, beta = 80.541(2)degrees, gamma = 68.1580(10)degrees, the borane complex of 1, 2, Ph3CPPh2(BH3) crystallizes as monoclinic colorless crystals, P2(1)/c, a = 10.0972(12) angstrom, b = 9.6955(12) angstrom, c = 25.197(3) angstrom, beta = 90.258(2)degrees. The analogous methyl substituted, 3, Ph3CPMe2(BH3) is monoclinic, C-2/c, a = 15.628(3) angstrom, b = 12.770(3) angstrom, c = 18.406(4) angstrom, beta = 103.968(3)degrees. Compounds 4-7 are trityl substituted P(V) compounds: Ph3CP(Ph)(O)(OH), 4, crystallizes in the triclinic space group P (1) over bar, a = 8.9847(18) angstrom, b = 9.7443(19) angstrom, c = 12.786(3) angstrom, alpha = 72.045(3)degrees, beta = 72.031(3)degrees, gamma = 78.769(3)degrees. Esterification of 4 affords TrCP(O)(Ph)OBn 5, space group, P2(1)/c, a = 7.9196(5) angstrom, b = 31.701(2) A, c = 19.8062(13) angstrom, b = 99.7750(10)degrees. A phosphonate diester was also characterized, Ph3CP(O)(OEt) 2, 6, triclinic, P (1) over bar, a = 7.9521(17) angstrom, b = 9.2205(19) angstrom, c = 14.471(3) angstrom, alpha = 85.906(4)degrees, beta = 83.031(4)degrees, gamma = 68.283(4)degrees. Treatment of the trityl H-phosphinic acid, Ph3CPO2H2, with elemental selenium yields yellow crystals of 7, [Ph3CP(O)(OH)Se](2), P2(1)/c, a = 9.0603(4) angstrom, b = 22.3652(11) angstrom, c = 16.9134(7) angstrom, beta = 107.035(2)degrees. In our efforts to isolate a nickel-phosphine complex, two Ni(II) complexes were crystallographically analyzed, [Ni(OP(H)Ph-2)(6)](2)BF(4)(-)8 and 9. Complex 8 with an uncoordinatedBF(4)(-) ion crystallizes as yellow orthorhombic crystals, Pbca, a = 18.8247(12) angstrom, b = 18.5518(12) angstrom, c = 21.0976(14) A, while crystals of 9 are trigonal, R (3) over barc, a = b = 13.1545(12) angstrom, c = 68.461(9) angstrom.
