Crystal and molecular structure of the complex isothiocyanato-{NN-bis-[2-(diethylamino)ethyl]-2-(diphenylarsino)ethylamine-NNN}-nickel(II) tetraphenylborate and study of the conformational energy of the tetraphenylborate ion

Abstract

The structure of the title compound has been determined by Patterson and Fourier methods from photographic X-ray data, and refined by least-squares techniques to R 0·080 for 4097 observations. Crystals are triclinic, space group P, and Z= 2 in a unit cell of dimensions: a= 12·529(1), b= 13·589(1), c= 14·120(1)Å, α= 95·12(1), β= 103·68(1), γ= 99·38(1)°. The co-ordination about nickel is square planar and Ni–N bond lengths are compared with those in a related five-co-ordinate complex. Non-bonding to the metal by the arsenic atom is discussed in terms of simple MO models. Calculation of the conformational energy of the isolated tetraphenylborate ion, as a function of independent rotations of the four phenyl groups, indicates that the bulky counterion does not possess a considerable degree of flexibility.