Diphosphine and Diarsine Complexes of Chromium(III). Crystal and Molecular Structure of n4>

DOI: 10.1039/DT9830002573

Source and publish data:

Journal of the Chemical Society, Dalton Transactions p. 2573 - 2580 (1983)

Update date:2022-08-03

Topics:

Authors:

Gray, Leslie R.

Hale, Annette L.

Levason, William

McCullough, Francis P.

Webster, Michael

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Article abstract of DOI:10.1039/DT9830002573

cis-^- ions (X=Cl, Br, or I; L-L=diphosphine or diarsine) have been isolated as tetra-alkylammonium salts by reaction of X, (thf=tetrahydrofuran) , and L-L.The reaction of with L-L' in CH2Cl2 gave Cr(L-L')1.5X3 , which are formulated as trans-cis-.In the case of o-C6H4(PMe2)2 only, it is possible to isolate both Cr1.5X3 and 2X2>X depending upon the Cr:L-L ratio.The ligand Me2As(CH2)3AsMe2 gave Cr(L-L)1.5X3 (X=Cl or Br) complexes for which a ligand-bridged structure is proposed .Weaker donors (Ph2PCH2CH2PPh2, cis-Ph2PCHCHPPh2, or Ph2AsCH2CH2AsPh2) react with to give which contain one uni- and one bi-dentate diphosphine or diarsine, and in the presence of moisture can be isolated.The complexes Y - or PF6^-; L-L=o-C6H4(AsMe2)2 or o-C6H4(PMe2)2> have also been obtained.The complexes have been characterised by analysis, conductance, i.r. and electronic spectroscopy, and the electronic spectra analysed (d³) to produce Dq, B', and β₃₅.The title complex is triclinic, a=17.534(3), b=11.930(2), c=11.108(3) Angstroem, α=116.30(2), β=75.12(2), γ=110.61(1) deg, and Z=2; space group P1 (no. 2). 1757 Reflections were refined to R=0.0656 (R'=0.0658).The structure consist of tetrahedral NPrⁿ4⁺ cations, and pseudo-octahedral ^- anions.In the anion Cr-P=2.485(4) and 2.511(4) Angstroem; Cr-Cl=2.2331(4), 2.319(4), 2.318(4), and 2.316(4) Angstroem; P-Cr-P=81.2 deg.The diphosphine does not exert any trans influence, consistent with weak binding to the hard Cr^III ion.