DINITROSYLMOLYBDENUM(0) COMPLEXES OF CATALYTIC AND ENVIRONMENTAL RELEVANCE: A NOVEL SINGLE-STEP SYNTHESIS OF DINITROSYLMOLYBDENUM(0) COMPLEXES OF {Mo(NO)₂}⁶ ELECTRON CONFIGURATION INVOLVING CHELATING LIGANDS DIRECTLY FROM MOLYBDATE(VI) AND THEIR CHARACTERIZATION

ABSTRACT

This paper reports the synthesis of a new series of novel hexa-coordinated, mixed-ligand dinitrosyl complexes of molybdenum(0) of the compositions [Mo(NO)₂(L′)₂]·H₂O {where HL′=4-butyryl-3-methyl-1-phenyl-2-pyrazoline-5-one (HL¹), N-(4′-butyrylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-o-phenitidine (HL²) or N-(4′-butyrylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-p-anisidine (HL³)}, [Mo(NO)₂(L⁴)]·H₂O {where H₂L⁴=N,N-(4′-butyrylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-o-phenylenediamine} and [{Mo(NO)₂}₂ (L⁵)₂]·H₂O (where H₂L⁵=N,N-(4′-butyrylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-m-phenylenediamine) in a single step directly from molybdate(VI). The resulting chelates, which have been characterized by elemental analyses, molar conductance, decomposition temperature, magnetic measurements, ¹H NMR, IR, and electronic spectral studies, and were found to contain low-spin Mo(0).

ACKNOWLEDGMENTS

The authors are thankful to Shri Arun Gurtoo, Vice-chancellor of this University, for encouragement, and Professor K. K. Mishra, Head, Department of Chemistry, for laboratory facilities and helpful discussions. Analytical facilities provided by the Central Drug Research Institute, Lucknow, India, and the Regional Sophisticated Instrumentation Centre, Indian Institute of Technology, Chennai, India, are gratefully acknowledged.

Notes

Enemark and Feltham have proposed circumventing the problem of the nature of the nitrosyl ligand by considering metal nitrosyls as containing an {M(NO)_x}ⁿ group, where n is the number of electrons of M, plus the number of electrons in the π*-orbital of NO (or more conveniently, n is the number of d-electrons if nitrosyl is regarded as being coordinated as NO⁺) (Enemark, J. H.; Feltham, R. D. Principles of Structures, Bonding, and Reactivity for Metal Nitrosyl Complexes. Coord. Chem. Rev. 1974, 13, 339).