M. Ravi et al., MOLECULAR AND CRYSTAL-STRUCTURES OF A CLASS OF PUSH-PULL QUINONOID COMPOUNDS WITH POTENTIAL NONLINEAR-OPTICAL APPLICATIONS, Structural chemistry, 7(3), 1996, pp. 225-232
Molecular and crystal structures of three compounds with electron dono
r-conjugation unit-electron acceptor framework are reported where the
conjugation unit is formally a quinonoid ring. Semiempirical quantum c
hemical calculations indicate large hyperpolarizabilities in these pus
h-pull molecules. Since all the crystal structures are found to belong
to centrosymmetric space groups, modifications are necessary for quad
ratic nonlinear optical applications.