Thermal ellipsoid drawing of 9a. Ellipsoids are displayed at 50% probability level. Hydrogen atoms are omitted. Selected distances (Å) and angles (deg): W(1)-N(1) = 1.7617(18) Å, W(1)-N(2) = 2.0536(16) Å, W(1)-O(1) = 1.9713(13) Å, W(1)-C(81) = 2.0697(19) Å, W(1)-C(82) = 2.353(2) Å, W(1)-C(83) = 2.0428(19) Å, W(1)-N(1)-C(51) = 176.83(16)°, W(1)-O(1)-C(1) = 160.80(13)°, N(1)-W(1)-C(81) = 91.28(8)°, N(1)-W(1)-C(83) = 94.32(8)°, C(81)-W(1)-C(83) = 83.91(8)°.