Nickel complexes molecular parameters

The tetrahedral coordination of Ni(PF3)4 has been confirmed by two independent electron diffraction studies of the compound in the gaseous state,82,83 giving the following molecular parameters Ni—P = 210-211 pm, ZPNiP = 109° (not refined). Tetrahedral coordination around nickel(O) has also been found in tetrakis(2-thienyldifluorophosphine)nickel, Ni PF2(C4H3S) 4, in the solid state. Relevant molecular distances and angles are Ni—P 209 pin, Z.PNiP 106-1110.84 The Ni—P bond distances found in these two complexes are noticeably shorter than those found in other pseudotetrahedral complexes of nickel(O) with... 

Table 22 Molecular Parameters for some Nickel(I) Complexes with Tertiary Phosphines and Arsines...

This molecule was the first system containing a transition-metal atom to be studied with the CASSCF method . It is the simplest molecule containing a nickel atom, and is therefore a suitable prelude to studies of more complex nickel-containing systems. Some molecular parameters are also known experimentally, and can be used to judge the quality of the calculations. 

The molecular structure of a ditame complex of nickel(II), [(12)Ni(EtOH)]Br2, shows the coordination behavior of this ligand and 1 towards Ni11 to be identical, with similar structural parameters (23). The bond from the metal center to the secondary amine donor in the apical position is shorter at 2.050(5) A than the equatorial Ni-N bonds, whose average is 2.112(7) A, in the same way as in the complexes of the pyN4 ligand (44). The secondary nature of the apical donor atom in [(12)Ni(EtOH)]Br2 gives rise to crystallographic disorder, which has been resolved. 

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