Solvent polarity influence on NMR parameters a (OC)4Cr-biscarbene complex: A Computational investigation

In this study, using the MPW1PW91 method, quantum chemical calculations were used to analyze the solvent effect on NMR parameters of a (OC)4Cr-biscarbene complex at the ground state (S0) and first singlet excited state (S1). Using the self-consistent reaction field theory (SCRF) based on the Polarizable Continuum Model (PCM), the solventeffects were examined. Selected solvents are dichloromethane, tetrahydrofuran, cyclohexanone, propanonitrile, and acetonitrile. The 13C NMR chemical shifts of thecomplex were calculated for both gas and solution phases. One-bond nuclear spin-spin coupling constants of Cr-CO and Cr-CCarbene bonds were estimated [1-3]. The correlations of these parameters and solvent polarity functions including both the dielectric constant (ε) and refractive index (nD) of the liquid medium were explored further. In addition, the most significant Ramsey terms involved significantly in 1J(Cr-CO) and 1J(Cr-CCarbene) values were determined [4-6]. Finally, the correlations between 1J(Cr-CO) and 1J(Cr- CCarbene) and Cr-CO and Cr-CCarbene bond distances were studied [7].