The comparative investigation on redox property and second-order nonlinear response of Keggin-type α-[PM12O39NPh]3- (M = W and Mo) and Mo6NPh

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2009,（2）
• 页码范围: 203-211
• 页数: 9页
• 语种: 英文
• DOI: 10.1007/s11434-008-0500-5

摘要

Keggin-type phenylimido-polyoxometalates a-[PM12O39NPh]3- (M = W and Mo) have been systematically investigated on the electronic structures, redox as well as nonlinear optical (NLO) properties by density functional theory (DFT). The strong M=N bond confirmed by natural bond orbital (NBO) analysis com-prises one a bond and two rr bonds, the same as Mo≡N in [Mo6O18NPh]2-. Furthermore, phenylimido segment effectively modifies the electronic properties of α-[PM12O39NPh]3-. On one hand, when enlarging the inorganic cluster from {MO6O18} to {PMo12O39}, the energy gap between HOMO and LUMO in α-[PMo12O39NPh]3- decreased, resulting in enormously anodic shift for the reduction potential, while the excitation energy is less and the total second-order polarizability/30 is up to 438.3x10-30 esu, which is nearly 10 times larger than that of [Mo6O16NPh]2-. On the other hand, when metal W in α-[PM12O39NPh]3-is substituted by Mo, the interaction between Mo and N is enhanced and the redox ability becomesstronger. The/βo value for α-[PMo12O39NPh]3- is more than 5 times higher than that of α-[PW12O39NPh]3-. It indicates that changing appropriate metal or enlarging the inorganic cluster will improve the redox properties and second-order nonlinear response. Moreover, the electron transition for three com-pounds mentioned above occurred mainly from organoimido segment (as the electron donor) to poly-anion cluster (as the acceptor). As a result, α-[PMo12O39NPh]3- may be a promising candidate for oxi-dant and nonlinear optical material.