{sup 113}Cd shielding tensors of monomeric cadmium compounds containing nitrogen donor atoms. 3. CP/MAS studies on five-coordinate cadmium complexes having N{sub 3}X{sub 2} (X = H, N, O, and S) donor atoms
- Pacific Northwest National Lab., Richland, WA (United States)
- Univ. of South Carolina, Columbia, SC (United States); and others
The principal elements of the {sup 113}Cd shielding tensor for a set of five- coordinate compounds having mixed donor atoms coordinating to the cadmium were determined via CP/MAS NMR experiments. The first complex, [HB-(3,5-Me{sub 2}pz){sub 3}]CdBH{sub 4} (where pz = pyrazolyl), has a CdN{sub 3}H{sub 2} inner coordination sphere. The isotropic chemical shift in the solid state is 355.1 ppm, and its chemical shift anisotropy (CSA, {Delta}{sigma}) is -596 ppm with an asymmetry parameter ({eta}) of 0.64. The second complex, [HB(3,5-Me{sub 2}pz){sub 3}]Cd[H{sub 2}B(pz){sub 2}], has five nitrogen donor atoms bonded to the cadmium. This N{sub 5} or N{sub 3}N{sub 2} compound was the only material of this study to manifest dipolar splitting of the cadmium resonance from the quadrupolar {sup 14}N. The isotropic chemical shift, CSA, and the value of {eta} for this material were therefore determined at higher field where the dipolar splitting was less than the linewidth, yielding values of 226.6 ppm, -247 ppm, and 0.32, respectively. A second N{sub 5} material, [HB(3-Phpz){sub 3}]Cd[H{sub 2}B(3,5-Me{sub 2}-pz){sub 2}], was also investigated and has an isotropic shift of 190.2 ppm, a CSA of 254 ppm, and an {eta} of 0.86. Also studied was [HB(3-Phpz){sub 3}]Cd[(Bu{sup t}CO){sub 2}CH], which has an CdN{sub 3}O{sub 2} inner core. The isotropic chemical shift of this complex is 173.6 ppm, and the values of {Delta}{sigma} and {eta} were determined to be -258 ppm and 0.38, respectively. The final compound, [HB(3,5-Me{sub 2}pz){sub 3}]Cd[S{sub 2}CNEt{sub 2}], with N{sub 3}S{sub 2} donor atoms, has an isotropic shift of 275.8 ppm, an {eta} of 0.51, and a CSA of +375 ppm. Utilizing previous assignments, the most shielded tensor information is used to speculate on the coordination geometry of the CdN{sub 3}O{sub 2} inner core complex.
- DOE Contract Number:
- FG06-89ER75522; AC06-76RL01830
- OSTI ID:
- 530812
- Journal Information:
- Inorganic Chemistry, Vol. 35, Issue 24; Other Information: PBD: 20 Nov 1996
- Country of Publication:
- United States
- Language:
- English
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