Synthesis and the third-order optical nonlinearities of two novel charge-transfer complexes of a heteropoly blue type (C_9H_7NO)_4 H_7PMo_(12)O_(40) centre dot 3H_2O (C_9H_7NO = quinolin-8-ol) and (phen)_3 H_7PMo_(12)O_(40) centre dot CH_3CN centre d

摘要

The title compounds (C_9H_7NO)_4H_7PMo_(12)O_(40) centre dot 3H_2O (I) and (phen)_3H_7PMo_(12)O_(40) centre dot CH_3CN centre dot H_2O (II) were synthesized by reactions of C_9H_7NO and phen with the four-electron-reduced heteropoly blue H_7[PMo_8~(VI)Mo_4~VO_(40) centre dot 12H_2O, respectively, and characterized by elemental analysis, TG/DTA, IR and ~(31)P NMR. Spectroscopic data support the view that the heteropoly blue anion in the product molecules still retain the Keggin structure, and both C_9H_7NO and phen are functioning as bases, i.e. they are protonated by the heteropoly blue acid, Nonlinear optical (NLO) properties of the charge-transfer complexes were studied with a 200 ps pulsed laser at 532 nm with I_o = 5.6 * 10~(13) W/m~2. Complexes (I) and (II) exhibit mainly optical self-defocusing with negligibly very small nonlinear absorption. The third-order NLO susceptibilities x~(3) of the two complexes are 9.6 * 10~(-11) esu as measured with an 1.34 * 10~(-10) mol dm~(-3) DMSO solution for (I) and 1.48 * 10~(-12) esu as measured with an 8.4 * 10~(-4) mol dm~(-3) DMSO solution for (II), respectively. These nonlinear optical properties of the complexes were compared with those of complexes prepared by reacting C_9N_7NO and phen with H_3[PMo_(12)~(VI)O_(40)] centre dot nH_2O, respectively. It reveals a qualitative structure/NLO property correlation.