X-Ray crystal structure of {7,8,15,17,18,20-hexahydrodibenzo[e,m]pyrazino[2,3-b][1,4,8,11]tetra-azacyclotetradecinato(2-)}nickel(II) and of {7,8,15,16,17,18-hexahydrodibenzo[e,m][1,4,8,11]tetra-azacyclotetradecinato(2-)}nickel(II)

Abstract

The crystal structures of the title compounds [(I) and the related non-pyrazino-compound (II)] have been determined by Patterson and Fourier methods from single-crystal X-ray diffractometer data, and refined by least-squares methods to R 0·058 [(I) 1272] and 0·048 [(II) 995 reflections].

Crystals of (I) are triclinic, space group P, a= 12·134(1), b= 9·132(1), c= 8·1994(9)Å, α= 69·10(1), β= 96·58(1), γ= 92·11 (1)°, Z= 2; crystals of (II) are orthorhombic, space group Pbca, a= 26·775(4), b= 18·980(2), c= 6·0675(7)Å, Z= 8.

Within the NiN₄ molecular core, Ni–N distances are in both cases as expected [means: (I) 1·857(6), (II) 1·847(6)Å]; both environments have a small distortion from planarity.