Mononuclear Chromium Complexes of the Tripod Ligand (Tripod = 1,1,1-Tris((dimethylphosphino)methyl)ethane)

Atta M. Arif, John G. Hefner, Richard A. Jones, Bruce R. Whittlesey

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

Tripod (tripod = 1,1,1-tris((dimethylphosphino)methyl)ethane) reacts with anhydrous CrCl3 or CrCl3(THF)3 in THF or CH2Cl2 to give CrCl3(tripod), which may be crystallized from CH2Cl2 as a dichloromethane solvate,fac-CrCl3(tripod)·CH2Cl2(1), in high yield (>95%). All three phosphorus atoms are coordinated to the Cr atom. The reaction of anhydrous CrCl2 with 2 equiv of tripod in THF yields trans-CrCl2(tripod)2(2) in 96% yield. In 2, each tripod behaves as a bidentate ligand with one uncoordinated -PMe2 group. The reduction of 2 with Na/Hg in THF yields Cr(tripod)2 (3) in 70% yield. The coordination geometry about Cr in 3 is that of a trigonal antiprism. X-ray diffraction studies have been performed on fac-C-CrCl3(tripod)·CH2Cl2(1), CrCl2(tripod)2(2), and Cr(tripod)2 (3). Crystal data for 1 (CrCl5P3C12H29): Mr = 495.55, orthorhombic, Pbca (No. 61), a = 15.602 (2) Å, b = 16.718 (5) Å, c = 17.030 (2) Å, V = 4442 Å3, dcalcd = 1.482 g/cm3, Z = 8, X(Mo K a) = 0.710 73 A (graphite monochromator), μ(Mo Ka) = 13.2 cm-1, final R = 0.046 (Rw= 0.049) from 2351 observed reflections (I > 3σ(I)) of 4351 measured. Crystal data for 2 (CrCl2P6C22H54): Mr= 627.42, monoclinic, P21/c (No. 14), a = 8.305 (1) Å, b = 20.528 (3) Å, c = 10.008 (2) Å, β = 103.799 (13)°, V = 1658 Å3, dcalcd = 1.257 g/cm3, Z = 2, λ(Mo Ka) = 0.71073 A (graphite monochromator), μ(MoKa) = 8.0 cm-1, final R = 0.059 (Rw= 0.071) from 1397 observed reflections (I > 3σ(I)) of 1546 measured. Crystal data for 3 (CrP6C22H54): Mr = 556.52, orthorhombic, Pnnm (No. 58), a = 9.964 (2) Å, b = 10.709 (2) Å, c = 13.723 (3) Å, V = 1464 Å3, dcalcd= 1.262 g/cm3, Z = 2, X(Mo Ka) = 0.71073 A (graphite monochromator), μ(Mo Ka) = 7.1 cm-1, final R = 0.063 (Rw= 0.067) from 815 observed reflections (I > 3 σ(I)) of 1511 measured. Complexes 1–3 have also been characterized spectroscopically.

Original languageEnglish
Pages (from-to)1080-1084
Number of pages5
JournalInorganic Chemistry
Volume25
Issue number8
DOIs
StatePublished - 1986

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