Optical Rotation Calculations for Fluorinated Alcohols, Amines, Amides, and Esters

Abstract

We have calculated the optical rotation at λ = 589 nm for 45 fluorinated alcohols, amines, amides, and esters using both time-dependent density functional theory (TDDFT) with the CAM-B3LYP functional and the second-order approximate coupled-cluster singles and doubles (CC2) method, where the aug-cc-pVDZ basis set was adopted in both methods. Comparison of CAM-B3LYP and CC2 results to experiments illustrates that both methods are able to reproduce the experimental optical rotation results for both sign and magnitude. Several conformers for molecules containing the benzyloxy and naphthalene groups needed to be considered to obtain consistent signs with experiments, and these conformers are discussed in detail. We have also used a two-point inverse power extrapolation of the basis set to investigate the optical rotation in the basis set limit at the CC2 level, however, we only found small differences compared to the aug-cc-pVTZ results. Our results demonstrate that the least computationally expensive method investigated here, the CAM-B3LYP functional with the aug-cc-pVDZ basis set, is a reliable method to predict the optical rotation for large molecules and thereby the absolute configuration of chiral molecules.

A Density Functional Theory Study of Optical Rotation in Some Aziridine and Oxirane Derivatives

“…Hence computational calculations of chiroptical properties is an almost unavoidable step, which can provide a reference point on this respect, [8] making the combination of experimental measurements and theoretical calculations a useful tool for the determination of the absolute configuration. [9,10] Theoretical calculations of ORP have been made with many quantum chemical methods: [11][12][13][14][15] Hartree-Fock (HF) calculations employing polarized, medium and large basis sets show reasonable accuracy, [16,17,18] while correlated post-HF methods, i. e. density functional theory (DFT), [10, second order polarization propagator (SOPPA) [40] and coupled cluster (CC) [23,[25][26][27][28]33,37,[41][42][43][44][45] approaches, lead often to better agreement with experimental data. Nevertheless, the most employed approach is DFT with the B3LYP functional.…”

“…They found improved results for some molecules, where it did not deteriorate the agreement for other compounds. Haghdani et al [36,37] compared the performance of CAM-B3LYP with CC2 for 14 larger pyrrole containing molecules or 45 fluorinated compounds and found that the results from both methods are very similar. For 5 small and 2 medium size molecules at three frequencies, they found that CAM-B3LYP results are in better agreement with the CCSD results as B3LYP results.…”

“…Theoretical calculations of ORP have been made with many quantum chemical methods: [11–15] Hartree‐Fock (HF) calculations employing polarized, medium and large basis sets show reasonable accuracy, [16,17,18] while correlated post‐HF methods, i. e. density functional theory (DFT), [10,17–39] second order polarization propagator (SOPPA) [40] and coupled cluster (CC) [23,25–28,33,37,41–45] approaches, lead often to better agreement with experimental data. Nevertheless, the most employed approach is DFT with the B3LYP functional.…”

“…They found improved results for some molecules, where it did not deteriorate the agreement for other compounds. Haghdani et al [36,37] . compared the performance of CAM‐B3LYP with CC2 for 14 larger pyrrole containing molecules or 45 fluorinated compounds and found that the results from both methods are very similar.…”

Solvent Effects on Optical Rotation: On the Balance between Hydrogen Bonding and Shifts in Dihedral Angles

“…Hartree-Fock (HF) theory was introduced as the first quantum chemical method for predicting optical rotation. [17][18][19][20][21][22][23] However, density functional theory (DFT) [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] and coupled-cluster (CC) 28,31,34,35,[37][38][39][40][41][42][43][44][45][46][47][48] approaches have been used extensively to account for electron correlation and therefore give more accurate predictions.…”