The molecular structures of the bifunctional ligand, (C6H5)2P(O)CH2S(O)2N(CH3)2 (1), and its coordination complex, UO2(NO3)2 [(C6H5)2P(O)CH2- S(O)2N(CH3)2]2 (2), were determined by single crystal X-ray diffraction techniques, and the structural influences on the ligand due to coordination were examined. The ligand 1 crystallizes in the monoclinic space group Cc, with a = 15.982(3), b = 10.003(2), c = 10.245(3) Å, β = 99.47(2)°, Z = 4 and V = 1615.5 Å3, RF = 2.8% on 1158 unique reflections (I ≥ 2σ(I)). Complex 2 is found in the monoclinic space group P21/c, with a = 12.680(3), b = 16.149(5), c = 20.204(6) Å, β = 107.17(2), Z = 4 and V = 3952.7 Å3, RF = 5.2% on 5060 unique reflections (I ≥ 2σ(I)). The complex contains two phosphine oxide ligands bonded to the uranium atom through the phosphoryl oxygen atoms in a trans orientation with UO(P) 2.35(1) Å. The molecular structure for the sulfinylmethylphosphonate complex, UO2(NO3)2 [(i-C3H7O)2 P(O)CH2 S(O)(p-CH3C6H4)] (3), was also determined by single crystal X-ray diffraction techniques, and it crystallized in the monoclinic space group P21/c, with a = 10.759- (8), b = 13.811(3), c = 17.823(5) Å, β = 105.83(3)°, Z = 4 and V = 2548 Å3, RF = 10.9% on 1908 unique reflections (I ≥ 2σ(I)). The complex shows a single ligand bonded in a bidentate mode to the uranium atom with UO(P) 2.37(2) Å and UO(S) 2.36(2) Å. © 1990.
