CRYSTAL AND MOLECULAR-STRUCTURE OF N-PHENYL SUBSTITUTED 1,2-NAPHTHALIMIDE, 2,3-NAPHTHALIMIDE AND 1,8-NAPHTHALIMIDE

The three structures were solved by direct methods and refined by full -matrix least-squares procedure. 2-phenyl-1 H-benz[f]isoindole-1,3(2 H )-dione, (compound 1): orthorhombic, space group Pcab, a = 7.618(1) An gstrom, b = 11.717(2) Angstrom, c = 28.540(4) Angstrom, V = 2547.4(7) Angstrom(3), Z = 8 and d = 1.425 Mg m(-3), R = 0.038 (Rw = 0.038) for 190 parameters and 820 observations with I > 2.5 sigma(I). 2-phenyl-1 H-benz[e]isoindole-1,3 (2 H)-dione (compound 2): orthorhombic, space g roup Pc2(1)b, a = 6.7042(9) Angstrom, b = 7.4589(9) Angstrom, c = 26.4 41(7) Angstrom, V = 1322.4(4) Angstrom(3), Z = 4 and d = 1.373 Mg m(-3 ), R = 0.037 (Rw = 0.032) for 190 parameters and 1186 observations wit h I > 3 sigma(I). 2-phenyl-1 H-benz[de]isoquinoline-1,3(2 H)-dione (co mpound 3): monoclinic, space group C2/c, a = 13.501(3) Angstrom, b = 1 3.212(4) Angstrom, c = 8.305(2) Angstrom, beta = 116.24(2 degrees, V = 1329(9) Angstrom(3), Z = 4, and d = 1.366 Mg m(-3), R = 0.038 (Rw = 0 .033) for 71 parameters and 754 observations with I > 3 sigma(I). The plane of the N-phenyl substituent has an axis which lies in the plane of the naphthalimide part and passes by the carbon atom bound to the n itrogen atom and by the carbon in para position. It makes a dihedral a ngle with the plane of the naphthalimide moiety of 59.2 degrees, 46.5 degrees and 69.4 degrees for the compounds 1, 2 and 3 respectively. Th is difference in geometry between the three molecules brings new insig hts into their spectroscopic properties.