Preparation of tetraalkyl phosphine complexes of the f-block metals. Crystal structure of Th(CH2Ph)4(Me2PCH2CH 2PMe2) and U(CH2Ph)3Me(Me2PCH2CH 2PMe2)

Article abstract of DOI:10.1021/om00080a023

Reaction of 4 molar equiv of PhCH₂Li with MCl₄(Me₂PCH₂CH₂PMe₂) ₂ gives M(CH₂Ph)₄-(Me₂PCH₂CH ₂PMe₂), where M is Th or U. Reaction of a mixture of 3 molar equiv of PhCH₂Li and 1 molar equiv of MeLi with MCl₄(Me₂PCH₂CH₂PMe₂) ₂ gives the unsymmetrical alkyls M(CH₂Ph)₃Me-(Me₂PCH₂CH ₂PMe₂), where M is Th or U. The molecular structure of Th(CH₂C₆H₅)₄(Me₂PCH ₂CH₂PMe₂) and U(CH₂C₆H₅)₃Me(Me₂PCH ₂CH₂PMe₂) were determined by single-crystal X-ray diffraction methods. Crystals of Th(CH₂Ph)₄(Me₂PCH₂CH ₂PMe₂) are triclinic of space group P1 with cell dimensions a = 111.463 (2) ?, b = 16.151 (3) ?, c = 21.527 (3) ?, α = 106.28 (2)°, β = 95.85 (2)°, and γ = 107.78 (2)°; there are four molecules in the unit cell. Crystals of U(CH₂Ph)₃Me(Me₂PCH₂CH ₂PMe₂) are monoclinic of space group P2₁/c with cell dimensions a = 13.035 (2) ?, b = 15.381 (2) ?, c = 14.540 (2) ?, β = 98.06 (2)°; there are four molecules in the unit cell. In the Th complex there are two independent molecules in the unit cell. The Th atoms are each bonded to four benzyl groups and to two phosphorus atoms from the bis(dimethylphosphino)ethane ligand; the average Th-C distance is 2.55 (2) ?, and the average Th-P distance is 3.17 (3) ?. In the U complex the uranium atom is bonded to a methyl group, three benzyl groups, and the two phosphorus atoms of the bis(dimethylphosphino)ethane ligand. The U-C(methyl) distance is 2.41 (1) ?; the average U-C(benzyl) distance is 2.50 (4) ?.