Magnetic properties of some molybdenum(V) dimeric coordination compounds with terminal oxo-ligands and di-μ-oxo-, di-μ-sulfido- or μ-oxo-μ-sulfido-bridges

Magnetic susceptibilities and electron spin resonances of Mo(V) dimers, Cs2[Mo2O2S2(ox)2(H2O)2] · 2H2O, Ba[Mo2O4(ox)2(H2O)2] · 3H2O, (pyH)4[Mo2O2S2(NCS)6], (pyH)4[Mo2O4(NCS)6] · H2O and (pyH)4[Mo2O3S(NCS)6] were observed at temperatures from 2 K to room temperature. The paramagnetic part of the magnetic susceptibilities of these compounds was small and approached zero with decreasing temperature. Under an applied magnetic field strength of 40 kOe, the susceptibilities had temperature independent regions but the spin susceptibilities derived from the electron spin resonances, observed at a magnetic flux density of about 3000 G, showed temperature dependences like antiferromagnetic dimers. This discrepancy was explained by a quasi alternating linear chain antiferromagnetic model. The corrections of the diamagnetic susceptibilities are discussed. (author)