Formation and crystal and molecular structures of dioxouranium(VI) complexes containing bidentate carbamoylmethylphosphinate and phosphine oxide ligands

Abstract

The ligands (C 6H 5)(C 2H 5O)P(O)CH 2C(O)N(C 2H 5) 2 ( 1) and (C 6H 5) 2P(O)CH 2C(O)N(C 2H 5) 2 ( 2) have been prepared and characterized by spectroscopic methods, and the coordination complexes, UO 2(NO 3) 2[(C 6H 5)(C 2H 5O)P(O)CH 2C(O)N(C 2H 5) 2] ( 3) and UO 2(NO 3) 2[(C 6H 5) 2P(O)CH 2C(O)N(C 2H 5) 2] ( 4), have been isolated and characterized by elemental analyses and spectroscopic methods. A single crystal X-ray diffraction analysis of 3 has been completed at 20 °C, and the complex crystallizes in the monoclinic space group P2 1/ n with a= 13.141(3) Å, b= 13.281(2) Å, c= 13.918(3) », β= 116.79(2)°, Z= 4, V= 2168.5(8) Å 3, and ϱ calcd = 2.07 g×cm −3. The structure was solved by heavy-atom methods and blocked least-squares refinement converged with R F = 0.048 and R wF = 0.046. Single crystal X-ray diffraction analysis of 4 has been performed at 26 °C and the complex crystallizes in the monoclinic space group P2 1/ n with a = 11.155(3) Å, b = 11.265(2) Å, c = 20.317(5) Å, β = 107.44(2)°, Z = 4, V = 2435.5(8) Å 3 and ϱ calcd = 1.93 g×cm −3. The structure was solved by heavy atom methods and blocked least-squares refinement converged with R F , = 0.035 and R wF = 0.029. The molecular structures contain linear UO2 2+ ions bonded to two bidentate nitrate ions and one bidentate carbamoylmethylphosphinate or phosphine oxide ligand. The structures of these complexes are compared with the structure of UO 2(NO 3) 2[(i-C 3H 7O) 2P(O)CH 2C(O)N(C 2H 5) 2].