SUBSTITUENT EFFECT ON GEOMETRY OF THE PYRIDINE AND BENZENE RINGS IN SOME 4-ARYL-2,6-DIPHENYLPYRIDINES - CRYSTAL AND MOLECULAR-STRUCTURE OF METHYL AND FLUORO DERIVATIVES

Crystal and molecular structures of 4-(4-methylphenyl)-2,6-diphenylpyr idine (I) and 4-(4-fluorphenyl)-2,6-diphenylpyridine (II) have been de termined by use of X-ray diffraction technique on a KUMA-diffractomete r. Crystal data for compound (I): C24H19N, M(r)= 321.40, monoclinic, P 2(1)/c, a=5.893(1)Angstrom, b=14.399(3)Angstrom, c=20.711(3)Angstrom, beta=97.40(3)degrees, V=1742.8(6)Angstrom(3), Z=4, R=0.058 for 2824 re flections. Crystal data for compound (II): C23H16NF, M(r)=325.37, mono clinic, P2(1)/n, a=9.011(3)Angstrom, b=20.158(5)Angstrom, c=9.575(4)An gstrom, beta=105.366(3)degrees, V=1677.1(10)Angstrom(3), Z=4, R=0.079 for 2336 reflections. Molecular geometry of 4-substituted benzene ring and pyridine ring have shown high aromatic character depending on the nature of substituent. The electron donating one (OMe), increases the quinoid form contribution.