168000-59-7Relevant academic research and scientific papers
Solution-state interactions of Bis(pentamethylcyclopentadienyl)ytterbium, Cp2Yb, with trialkylphosphines and R3PX complexes (X = O, NR′, CHR″)
Schwartz,Andersen
, p. 4308 - 4318 (1995)
The interactions formed between Cp*2Yb (1) and phosphines and R3PX derivatives (X = O, NR', CHR″) in solution have been investigated using multinuclear (1H, 13C, 31P, 171Yb) and variable-temperature NMR spectroscopy. Adducts of 1 with Me3PO and Et3PNH undergo slow intermolecular exchange in solution at 25°C (NMR time scale); both 1:1 adducts (Cp*2Yb(OPMe3), 7; Cp*2Yb(HNPEt3), 9 and 1:2 adducts (Cp*2Yb(OPMe3)2, 8; Cp*2Yb(HNPEt3)2, 10 have been isolated. The spectroscopic properties of two ylide adducts, Cp*2Yb(Me2PhPCHSiMe3) (12) and Cp*2Yb(Me2PhPCH2) (13), have also been investigated. Intermolecular exchange can be slowed at low temperature in both cases; in the former complex a second process, resulting in inequivalent Cp* rings and inequivalent P-bound methyl groups, can also be slowed at lower temperatures. The nature of this process is discussed in detail. The solid-state structure of 12 has been determined. The NMR values for all of the complexes are discussed in detail. In addition, the '171Yb chemical shifts for 6, 7, and 12 have been measured, via 1H/171Yb indirect detection utilizing long-range JYbH coupling, and are discussed.
