CAM‐B3LYP optical rotations at different wavelengths: Comparison with CCSD results

Abstract

A hierarchical sequence of basis sets along with one long‐range corrected functional (CAM‐B3LYP) were used to calculate electronic optical rotations (OR) at three wavelengths (355.0, 589.3, and 633.0 nm) of 14 rigid chiral molecules whose experimental values are available in the literature. As the results showed to be sensitive to the basis set quality, complete basis set limits were estimated. Special attention was given to five particularly difficult compounds. In these cases, one verifies that vibrational corrections (taken from the literature) must be added to the CAM‐B3LYP equilibrium OR to correct signs. In general, the complete basis set limits reported in this work are in good agreement with the experimental data and with those obtained at a higher level of theory. For some compounds, solvent effects are taken into account by means of the polarizable continuum model. For the solvated systems, the dependence between OR and cavity size is also examined. © 2015 Wiley Periodicals, Inc.

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

“…Other types of basis sets were also investigated [27,29,33] including also basis sets especially optimized for these types of calculations. [34,45,46] Jorge and co-workers [24,29,38] tested the AXZP basis sets in DFT calculations with the BP86, B3LYP, PBE0, M06, M06-2X and CAM-B3LYP functionals on different sets of three-, four-and higher membered rings and extrapolated to the basis set limit with an inverse cubic formula with the conclusion that quadruple zeta basis sets give results close to the basis set limit. Baranowska-Łaczkowska and coworkers [34,27,39] investigated both the performance of the LPol-n basis sets and of the especially for optical rotation optimized ORP basis set [34] at the DFT/B3LYP level, in the latter case for 31 small and medium-size molecules.…”

“…Computationally solvent effects are mostly treated by continuum models such as PCM, [26,57,71] CPCM [28] and COSMO [22] mostly in combination with DFT and the B3LYP functional but also in combination with Coupled Cluster methods. [43] Jorge et al [38] studied e. g. the effect of changing the size of the cavity in PCM calculations by varying the electrostatic scaling factor. They found for some molecules a significant dependence of the calculated optical rotation on this parameter.…”

“…The probably most often studied molecule is methyloxirane. [17,[19][20][21]24,[29][30][31][32]34,35,38,[41][42][43][44][45]49,50,51,53,55,56,60,[71][72][73][74][75][76] We have for this study, therefore, chosen to calculate the ORP for five oxirane and two aziridine derivatives, which to our knowledge so far have not been investigated, in addition to methyl-and fluorooxirane. Furthermore, most of the calculations so far have been carried out at the DFT level, but the only basis sets, which explicitly are optimized for DFT calculations, the polarization consistent basis sets, pc-n and aug-pc-n, [77] have to our knowledge not been employed in calculations of the ORP.…”

“…Furthermore, most of the calculations so far have been carried out at the DFT level, but the only basis sets, which explicitly are optimized for DFT calculations, the polarization consistent basis sets, pc-n and aug-pc-n, [77] have to our knowledge not been employed in calculations of the ORP. Third, in treating the solvent effects with PCM, mostly the default settings are employed, with the exception of the study by Jorge et al [38] Both of these aspects we want also address in this study for the first time.…”

“…[85] Furthermore, the (R)-and (S)-2-methylaziridine are useful intermediates for the synthesis of alcohols, amino acids, and nitrogen-containing heterocycles. [86] The optical rotation of (S)-2-fluorooxirane, (S)-2-methyloxirane have been studied extensively, both theoretically, [10,[17][18][19][20][21]24,26,[29][30][31][32]34,35,38,[40][41][42][43][44][45][46][49][50][51]53,55,56,60,68,69,[71][72][73][74][75][76]87,88] and experimentally [60,64,89] and several of the other compounds were after their synthesis characterized by measuring the optical rotation in some solvent. [90][91][92][93][94]…”