The structure of binuclear molybdenum(VI) oxocomplexes with dianionic tridentate Schiff bases

Summary The new Mo^VI complex Mo(O) (-O) (SAE)]₂ was prepared and characterized by means of spectroscopic (i.r.,¹Hn.m.r.) and crystallographic measurements. Crystals of the Mo(C₉H₈NO₂)(H₂O)]₂, M=582.3, orthorhombic, space group Pbca,a=13.108(4),b=8.982(2),c=16.842(4) Å, v=1982.9 ų, z=4, D_m=1.93(2), D_c=1.95 g cm^–3, MoK =0.71069 Å, =1.3 mm^–1, F(000)=1152, T=295K, R=0.035 for 2413 reflections.The crystal structure consists of Mo(O)(-O)(L)]₂, in dimeric units. The coordination geometry around each molybdenum atom is distorted octahedral with Mo–O (terminal) and Mo–O (bridge) distances of 1.694(3) and 1.760(3) Å, respectively, and with the angle O(1)–Mo–O(2) of 105.6(1)^o, typical for manycis-dioxocomplexes of Mo^VI. The asymmetric bridge is characterized by the following parameters: Mo–O(2)ⁱ and Mo–Moⁱ distances equal 2.408(3) and 3.319(3) Å, respectively, and the Mo–O(2)–Moⁱ and O(2)–Mo–O(2)ⁱ angles equal 104.5(1)^o and 75.5(1)^o, respectively.The i. r. and Raman spectra of molybdenum complexes with an asymmetric double oxygen bridge display a strong absorption the 800–850 cm^–1 range.