| Abstract
| - The syntheses of a series of well-characterized complexes of the type TpRYX2(solvent)n and the novel solvent-free bis(polypyrazolylborate) complexes [(TpR)(BpR‘)YX] are presented. The steric, dynamic, and coordination behavior of these complexes are heavily influenced by the choice of scorpionate ligand substituents, showing the versatility of this ligand system for catalyst design. The Nd analogues of these complexes have been characterized by X-ray diffraction structure determinations.
- The syntheses of a series of well-characterized complexes of the type TpRYX2(solvent)n (1 and 2, R = H, X =Br, Cl, solvent = THF, n = 2; 4, R = Me, X = Cl, solvent = THF, n = 1; 5, R = Me, X = Cl, solvent =3,5-dimethylpyrazole, n = 1; 7, R = Ph, X = Cl, solvent = THF, n = 1) and the novel solvent-free bis(poly(pyrazolylborate) complexes [(TpR)(BpR‘)YX] (8, R = R‘ =Me, X = Cl; 9, R = H, R‘ = Ph, X = Br) arepresented. The data demonstrate that the steric, dynamic, and coordination behavior of these complexes are heavilyinfluenced by the choice of scorpionate ligand substituents, showing the versatility of this ligand system forcatalyst design. The coordinated THF solvent molecules of complexes 1, 2, and 4 are seen to undergo a dynamicsolvation/desolvation equilibrium in solution that is fast on the NMR time scale. The position of this equilibriumis solvent-dependent and can be evaluated in complex 4 by observation of the line broadening of the 3-methylresonance in the 1H NMR spectra taken in different deuterated solvents. Complex 5, formed by slow hydrolysisof 4, has been characterized by an X-ray diffraction structure determination and shown to adopt a distorted octahedralgeometry that is thought to be similar to that of complex 4. The Nd analogues of these complexes (3, R = H, X= I, solvent = THF, n = 2; 6, R = Me, X = I, solvent = THF, n = 1) have been characterized by X-raydiffraction structure determinations: 3 shows a distorted capped octahedral structure, and 6 a distorted octahedralstructure similar to that of 5. The solvent-free complex 8 is shown by 1H and 13C NMR spectroscopic analysisto be nonfluxional in solution on the NMR time scale, although 9 appears able to weakly coordinate solventscontaining donor groups such as halides.
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