Magnetic properties, infrared spectroscopy, thermal and theoretical studies of oxomolybdenum(V) complexes with 2,2'- Bypirimidine

DELIA B. SORIA*; MONTSERRAT BARQUÍN; MARIA J. GONZALEZ GARMENDIA; GUILLERMINA ESTIU

Journal. of Coordination Chemistry

Taylor and Francis

Lugar: Notre Dame; Año: 2008 vol. 61 p. 3815 - 3828

ABSTRACT Mono- and dinuclear complexes of oxomolybdenum(V) with 2,2L-bipyrimidine (bpym), namely  MoOCl3(bpym) (1) as two geometric isomers (violet and brown), Mo2O3Cl4(bpym)2 (2), Mo2O4Cl2(bpym)2 (3), and Mo2O2Cl6(ƒÊ-bpym) (4), have been prepared and characterized by electronic, infrarred and Raman spectroscopy, thermal analysis and theoretical calculations. Magnetic subsceptibilities in the 4.6-290 K range show different magnetic behavior for the MoO3+, Mo2O34+ and Mo2O2 (ƒÊ-bpym)6+ units. The EPR spectra have been also registered. The theoretical calculations converged to two stable isomers named cis and trans for MoOCl3(bpym), Mo2O3Cl4(bpym)2 and for Mo2O4Cl2(bpym)2 but four isomers for Mo2O2Cl6(ƒÊ-bpym). Based on the theoretical and experimental results for the violet and the brown complexes, we assumed that both isomers cis and trans are present in the solid state in different proportions. This fact could also explain the existence of two isomers in Mo2O2Cl6(ƒÊ-bpym).