Chromium-(II) and -(III) Complexes containing Hydrazines or Hydrazinecarboxylates as Ligands

DOI: 10.1039/DT9920001761

Source and publish data:

Journal of the Chemical Society, Dalton Transactions p. 1761 - 1768 (1992)

Update date:2022-08-05

Topics:

Authors:

Edwards, Dennis A.

Thompsett, David

Bellerby, John M.

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Article abstract of DOI:10.1039/DT9920001761

The complexes <> (X = Cl, R1 = H, Me or Ph, R2 = H; R1 = R2 = Me; X = r, R1 = H or Ph, R2 = H) have been prepared and spectroscopic data acquired which suggest that the monomethylhydrazine complex is analogous to the well known hydrazine complexes with bridging NH2NHR (R = H or Me) ligands and terminal halide ligands, whereas the N,N-dimethyl- and phenylhydrazine complexes involve unidentate hydrazine and bridging halide ligands.The quadrupole metal-metal bonded complexes <n> (R1 = H or Me, R2 = H; R1 = R2 = Me) containing bridging NH2NR1R2 ligands and containing unidentate NH2NHPh ligands have also been prepared and characterised.Chromium(II) hydrazinecarboxylate, <n> has been prepared by either cleavage of the metal-metal bonds of (L = H2O or 0.5 N2H4) or ligand-displacement reactions of mononuclear chromium(II) complexes.Its infrared spectrum and that of the fully deuteriated analogue have been recorded and vibrational assignments proposed.Oxidation of <n> or other chromium(II) species in aqueous leads to the chromium(III) *2H2O.The substituted hydrazinecarboxylates 3>*H2O and have also been isolated., the latter probably containing -O,O' groups bridging a metal-metal bonded Cr2 unit in the manner well established for other carboxylate anions.