Five-coordination in iron(II); cobalt(II) and nickel(II) complexes

[Bis(2-diphenylphosphinoethyl)phenylphosphine]iodonickel(II) tetraphenylborate, C34H33INiP3+.C24H20B−, and [bis(2-diphenylphosphinoethyl)phenylphosphine]chloronickel(II) tetraphenylborate, C34H33ClNiP3+.C24H20B−

“…Nickel(II) halides and tridentate linear ligands often form four-and five-coordinated complexes of the type [NiLX] + and NiLX2, where X is a halogen atom (Morassi, Bertini & Sacconi, 1973 (Mealli, Peruzzini & Stoppioni, 1980). The structure determinations of the title compounds…”

[1,9-Bis(diphenylphosphino)-3,7-dithianonane]monobromonickel(II) tetraphenylborate, C31H34BrNiP2S2+.C24H20B−, at 295K, and [1,9-bis(diphenylphosphino)-3,7-dithianonane]monoiodonickel(II) tetraphenylborate, C31H34INiP2S2+.C24H20B−, at 120K

“…linear open-chain ligands, like pssp, are often of square-pyramidal type (Morassi, Bertini & Sacconi, 1973). According to Orioli (1971) Fig.…”

Structures of complexes between metal halides and phosphinothioethers or related ligands. X. [1,9-Bis(diphenylphosphino)-3,7-dithianonane]monoiodonickel tetraphenylborate

“…The highest symmetry of a five-coordinated Ni ~ complex is that of a trigonal bipyramid; next highest is the square pyramid (Morassi, Bertini & Sacconi, 1973). Linear open-chain quadridentate ligands tend to form a square pyramid.…”