Direct Metal−Metal Interaction Contributions to Quadratic Hyperpolarizability: A Study on Dirhenium Complexes

Abstract

We present a comparative study of the metal-metal interaction effect on the static quadratic hyperpolarizabilities of two typical dinuclear rhenium clusters. The electronic structures, excitation spectra, dipolar moments, static polarizabilities, and quadratic hyperpolarizabilities of the two complexes with direct metal-metal interactions have been computed and analyzed with the use of high-level DFT/TDDFT methods. The geometries and the first intense excitations agree with the relevant reported measurements. The orbital decomposition scheme ( J. Phys. Chem. A 2006, 110, 1014-1021) has been applied to analyze the relationship between the electronic structures and nonlinear optical (NLO) properties of these two complexes. We propose an unprecedented NLO response mechanism featuring the contribution of the direct metal-metal interaction transition process in these dinuclear rhenium complexes. This contribution positively enhances the quadratic hyperpolarizability and relates to the intensity of the metal-metal interactions of the complexes. The results are helpful to the development of NLO chromophores in polynuclear metal clusters through the molecular design technique.

DFT Calculation of Static First Hyperpolarizabilities and Linear Optical Properties of Metal Alkynyl Complexes

“…Correction for solvent effects in quantum chemical calculations can be attempted through the use of such methodologies as the polarizable continuum model (PCM), solvation models (SM), and the conductor-like screening model (COSMO); these models all seek to mimic solvation through construction of a solute-accommodating cavity within a surrounding dielectric medium. Several studies have now addressed solvent effects in the calculation of polarizabilities and hyperpolarizabilities. − ,− A study by Wu and co-workers on the W(CO) 5 DAS chromophore ((4-dimethylamino-4′-stilbazole)tungsten pentacarbonyl) has shown β to be remarkably dependent on the dielectric constant (ε), a result consistent with studies demonstrating that different solvents can yield markedly different hyperpolarizability responses for a given solute species …”

“…Alongside the laboratory and spectroscopic techniques now accepted as suitable for the characterization of novel NLO materials, computational methods (including semiempirical methods and ab initio and density functional theory, DFT) − have become an increasingly powerful and versatile tool. DFT, in particular, appears very well suited to the modeling and exploration of large TM-containing systems, while electronic excitation spectra and response properties can be assessed using time-dependent DFT (TD-DFT).…”

“…The accurate prediction of NLO properties requires large basis sets and an appropriate treatment of electron correlation, and such considerations often incur substantial computational expense (particularly if highly accurate values are sought rather than merely an indication of the trends in NLO properties as a function of some structural parameter). Studies conducted to date have included the calculation of mononuclear electron-rich organoiron complexes, , alkynylbis(diphosphine)ruthenium complexes, ferrocenyl systems coupled with metal carbonyls, and various other organometallic systems. − ,− However, there are few studies that have explored the performance of TD-DFT for larger organometallics, and some such studies have indicated problems in the application of TD-DFT to long π-conjugated molecules and extended organometallic complexes, with the computation of substantially overestimated values for the hyperpolarizability. These problems with hyperpolarizability calculations for larger organometallics are attributed to the lack of an appropriate general exchange-correlation (XC) functional, leading to the underestimation of long-range electronic excitations. − …”

Effects of the substituting groups and proton abstraction on the nonlinear optical properties of heteroleptic bis-tridentate Ru(II) complexes

“…Compared to organic molecules, organometallic and coordination complexes offer additional flexibility by varying the metal, its oxidation state, the ligand environment and the geometry [3e9]. Moreover, they exhibit large and fast nonlinearities by introducing new NLO active charge-transfer transitions between the metal and the ligand, such as metal-to-ligand charge transfer (MLCT), ligandto-metal charge transfer (LMCT) and metal-to-metal/intervalence charge transfer (MM/IVCT) [1,10,11]. These advantages of metal complexes are conducive to efficiently switching the second-order NLO responses at the molecular level, which could provide the basis for a range of molecular-scale devices.…”

The important role of the Mo–Mo quintuple bond in catalytic synthesis of benzene from alkynes. A theoretical study

“…32 Though these diatomic metal species can be isolated only in an inert matrix at a low temperature in general, 19,20 a stable chromium dinuclear complex ArCrCrAr (Ar = C 6 H 3 -2,6(C 6 H 3 -2,6-i-Pr 2 ) 2 ) with a quintuple Cr-Cr bond was reported by Power and his co-workers in 2005. 36 Soon after that, several dinuclear metal complexes with a metal-metal multiple bond have been synthesized by Theopold et al, 37 Power et al, 38 Tsai et al, [39][40][41][42][43][44][45] and Kempe et al [46][47][48] Also, these compounds have been theoretically investigated well, [8][9][10][11][12][13][14]32,36,[49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64] in which the metalmetal bonding nature and the geometrical feature have been mainly discussed.…”