Virtual Eyes Designed for Quantitative Spectroscopy of Inorganic Complexes: Vibronic Signatures in the Phosphorescence Spectra of Terpyridine Derivatives

Abstract

Herein we report phosphorescence computations on several ruthenium terpyridine derivatives including all of the contributions modulating vibronic transitions at the harmonic level by means of an extension of our virtual multifrequency spectrometer from organic molecules to organometallic compounds. It turns out that the computed emission (phosphorescence) spectra are in very good agreement with the observed ones, leading to quantitative agreement for both the band positions and the overall shape of the whole spectrum. Together with the intrinsic interest of the studied molecules, this work paves the route toward integrated experimental and computational studies of inorganic complexes that couple reliability, generality, and also feasibility for nonspecialists.

Computational Molecular Electronic Spectroscopy with TD-DFT

“…Although to date most applications of TD-DFT vibronic calculations have been performed for organic structures, there have also been several simulations for inorganic dyes [113][114][115]. An example of such successful work is given in Figure 4 that presents a direct comparison between measured and TD-DFT absorption and emission spectra for a rhodacyclopentadiene chromophore [115].…”

Validation of a computational protocol to simulate near IR phosphorescence spectra for Ru(II) and Ir(III) metal complexes

“…On the grounds of several previous studies [16,33,37,38,[41][42][43], we have chosen the B3PW91 functional [44][45][46] in conjunction with the so-called LANL2DZ basis set, which includes a pseudopotential for describing inner electrons of large atoms with polarization functions on C (d; 0.587), N (d; 0.736), O (d; 0.961), Ru (f; 1.235), Cl (d; 0.648) and Ir (f; 0.938) [47][48][49][50]. Solvent effects (CH 2 Cl 2 ) have been modelled using the Polarizable Continuum Model (PCM) [51,52].…”

“…In this study, it has been shown that the recent implementation of the so-called virtual multifrequency spectrometer (VMS) [35,36] offers a powerful and cheap tool for RR predictions, even when one includes a large number of effects (solvent, anharmonicity and Duschinsky couplings) modulating the spectra. Last year we used the VMS to perform simulations in order to reproduce the phosphorescence spectra of three ruthenium terpyridine derivatives to evaluate the reliability of our tool [37]. It turned out that the inclusion of vibrational contributions to electronic transitions improved our results with respect to experiment, allowing a direct vis-à-vis with the observed spectra.…”

Vibronic coupling to simulate the phosphorescence spectra of Ir(III)-based OLED systems: TD-DFT results meet experimental data

“…As a matter of fact, chemists performing quantum chemical computations are now able to give crucial information on these electronic processes, namely those relevant to excitation and emission phenomena and the nature of the reached excited states, especially thanks to the very recent developments in this area. [18][19][20][21][22][23] Moreover, Density Functional Theory (DFT) and its time dependent extension (TD-DFT) are now routinely used to get both electronic and vibrational information from small organic to large-size organometallic and transition metal complexes systems. [10,[24][25][26][27][28][29][30] Indeed, DFT calculations are now accurate enough to predict or confirm the stability or existence of compounds, and they can also explain the luminescent and/or spectroscopic properties of complex systems.…”

“…[50][51][52][53][54][55][56][57][58][59] Indeed, in the last years, the VMS approach has been used to simulate with high precision anharmonic and phosphorescence spectra of organometallics and transition metal complexes. [9,18,[21][22][23] New tridentate chelate Ir(III) complexes have been very recently synthesized and characterized by Chi and coworkers [personal communication]. These neutral complexes (Scheme 1) involving bis(imidazolylidene) benzene and 2-(5-trifluoromethyl-1H-pyrazol-3-yl)-6-(2,4-difluorophenyl) pyridine (pzpyF2p) or 2,6-bis(5-trifluoromethylpyrazol-3-yl) pyridine (pz2py) ligands, exhibit phosphorescence at short wavelengths very suitable for OLED devices.…”