Hydrotris methane complexes

The tris(N-(3-ter(-butyl)pyrazolyl)methane ligand, with an extremely bulky 3-substituent, favors the formation of tetrahedral complexes in much the same way as observed in the chemistry of the hydrotris(3-tert-butyl-pyrazolyl)borate ligand. ... 

Organonickel derivatives also offer cases of the -coordination of the substituted hydrotris(pyrazol-l-yl)borate ligand. For the palladium and platinum complexes, the M(II) M(IV) (M = Pd, Pt) transformation is facile. Organopalla-dium chemistry offers a new type of agostic interactions, C—H Pd, where the C—H bond belongs to one of the pyrazolate rings. Cyclopalladation of various pyrazol-l-ylborates and -methanes does not modify their structure. 

Casarin M, Pandolfo L, Vittadini A. Carbonyl copper(I) complexes with hydrotris(l,2,4-triazolyl)borate, hydrotris(pyrazolyl)borate, and tris(pyrazolyl)methane Hgands. A DFT smdy. Phys Chem Chem Phys. 2009 11 94-96. 

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