Facile Synthesis and Nonlinear Optical Properties of Push-Pull 5,15-Diphenylporphyrins.
A series of 5,15-diphenylporphyrinatonickel(II) derivatives containing electron-releasing (Me(2)NC(6)H(4)C&tbd1;C-) and -withdrawing groups [-CHO, -CH=C(CN)(2), -CH=C(CO(2)Et)(2), -CH=CHCHO] in opposite meso positions has been synthesized through the classical formylation, halogenation, Knoevenagel condensation, and palladium-catalyzed cross-coupling reaction of porphyrins. The molecular first hyperpolarizabilities (beta) of two of these push-pull porphyrins, namely 5-(2',2'-dicyanoethenyl)-15-[[4"-(N,N-dimethylamino)phenyl]ethynyl]-10,20-diphenylporphyrinatonickel(II) (7) and 5-formyl-15-[[4'-(N,N-dimethylamino)phenyl]ethynyl]-10,20-diphenylporphyrinatonickel(II) (8) have been determined experimentally by electric-field-induced second-harmonic generation (EFISH) at 1907 nm and computationally by semiempirical methods (ZINDO sum-over-states). The values of beta(&mgr;) (124 and 66 x 10(-)(30) cm(5) esu(-)(1), for 7 and 8, respectively) are moderate because the acceptor group is significantly tilted with respect to the porphyrin core in these complexes, which decreases the electronic coupling across the system. This nonplanar geometry has been confirmed by X-ray structure analyses and molecular modeling studies.
Yeung
Ming
M
Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, Department of Chemistry, University of Reading, Reading RG2 6AD, U.K., Molecular Simulations Inc., 9685 Scranton Road, San Diego, California 92121-2777, and Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706-1396.
Ng
Anthony C. H.
AC
Drew
Michael G. B.
MG
Vorpagel
Erich
E
Breitung
Eric M.
EM
McMahon
Robert J.
RJ
Ng
Dennis K. P.
DK