Crystal and molecular structure of 2,3-dicyanonaphthalene: a naphthalocyanine precursor

The crystals of 2,3-dicyanonaphthalene (2,3-DCN) have been obtained by a su blimation method. 2,3-DCN crystallizes in the acentric space group of the t riclinic system with two independent molecules in the unit cell. The bond d istances in both the independent 2,3-DCN molecules between the naphthalene nucleus fall into two groups and indicate that in the fused ring the pi-ele ctrons are not fully delocalized over all the nuclei of the naphthalene rin g. A similar pattern of long and short bonds in the 2,3-DCN ring is also ob served in the ab initio full optimized molecule. The differences in C-C bon d lengths and angles in the naphthalene ring were interpreted and analyzed in terms of the distribution of the charge density. A substitution effect o f both the C=N groups on the distribution of the charge density and locatio n of the bond critical points (3, -1) is discussed. (C) 2000 Elsevier Scien ce B.V. All rights reserved.