Abstract
Synthetic complexes containing a cis-[MoO(2)](2+) core are well-established models for the molybdenum co-factor (Moco). Here we report the crystal structure of such a model complex bearing a tetra-dentate amine bis-(phenolate) ligand with fluorine substituents on the phenolate rings, namely, [2,2'-({[2-(di-methyl-amino)-eth-yl]aza-nedi-yl}bis-(methyl-ene))bis-(4,6-di-fluoro-phenolato)]dioxidomolybden-um(VI)), [Mo(C(18)H(18)F(4)N(2)O(2))O(2)]. Distortion from idealized octa-hedral symmetry about the Mo center is evident in the large O=Mo=O angle [108.54 (4)°] and the small N-Mo-O(phenolate) angles [79.79 (4), 81.21 (3), 77.83 (3), and 84.59 (3)°]. The dihedral angle between the phenolate rings is 60.06 (4)°, and π-π stacking is observed between aromatic rings related by inversion (1 - x, 1 - y, 1 - z). The lower data-collection temperature of 150 K vs room-temperature data collection reported previously [KOWXIF; Cao et al. (2014 ▸). Transit. Met. Chem. 39, 933-937] and larger 2θ range for data collection (5.8-66.6° versus 6-54.96°) led to a structure with lower R (1) and ωR (2) values (0.019 and 0.049 vs 0.0310 and 0.0566 for KOWXIF). Comparison of the metrical parameters with KOWXIF suggests that this dataset offers a more realistic depiction of bonding within the Mo(VI)=O moiety.