Nonempirical calculations of the one‐bond ²⁹Si–¹³C spin–spin coupling constants taking into account relativistic and solvent corrections

Abstract

The computational study of the one-bond (29)Si-(13)C spin-spin coupling constants has been performed at the second-order polarization propagator approximation (SOPPA) level in the series of 60 diverse silanes with a special focus on the main factors affecting the accuracy of the calculation including the level of theory, the quality of the basis set, and the contribution of solvent and relativistic effects. Among three SOPPA-based methods, SOPPA(MP2), SOPPA(CC2), and SOPPA(CCSD), the best result was achieved with SOPPA(CCSD) when used in combination with Sauer's basis set aug-cc-pVTZ-J characterized by the mean absolute error of calculated coupling constants against the experiment of ca 2 Hz in the range of ca 200 Hz. The SOPPA(CCSD)/aug-cc-pVTZ-J method is recommended as the most accurate and effective computational scheme for the calculation of (1)J(Si,C). The slightly less accurate but essentially more economical SOPPA(MP2)/aug-cc-pVTZ-J and/or SOPPA(CC2)/aug-cc-pVTZ-J methods are recommended for larger molecular systems. It was shown that solvent and relativistic corrections do not play a major role in the computation of the total values of (1)J(Si,C); however, taking them into account noticeably improves agreement with the experiment. The rovibrational corrections are estimated to be of about 1 Hz or 1-1.5% of the total value of (1)J(Si,C).

Relativistic Environmental Effects in 29Si NMR Chemical Shifts of Halosilanes: Light Nucleus, Heavy Environment

“…A vast amount of structural studies of organosilicon compounds by means of 29 Si NMR is presented in the literature. , Nowadays, within the progress of theory of magnetic resonance parameters derived from a spin-Hamiltonian as the linear response functions, − the question of the high-accuracy high-level computation of 29 Si NMR magnetic resonance parameters arises. In continuation of our previous results on the computation of 29 Si NMR chemical shifts, − and 29 Si– 1 H and 29 Si– 13 C spin–spin coupling constants, − in this paper we investigate the “environmental” relativistic effects of halogens in 29 Si NMR shielding constants of halosilanes.…”

New pecJ-n (n = 1, 2) Basis Sets for High-Quality Calculations of Indirect Nuclear Spin–Spin Coupling Constants Involving 31P and 29Si: The Advanced PEC Method

“…Namely, these are the aug-cc-pVTZ-J basis sets of Provasi and Sauer [ 7 ] and the basis sets of Jensen’s series, (aug)pcJ- n ( n = 0–4) [ 8 , 25 ]. With these basis sets, the calculations of the silicon and phosphorus SSCCs of different types, in particular, J ( 29 Si, 1 H) [ 7 , 14 , 32 , 33 , 34 ], J ( 29 Si, 13 C) [ 35 ], J ( 29 Si, 19 F) [ 7 ], J ( 31 P, 1 H) [ 7 , 36 , 37 , 38 , 39 ], J ( 31 P, 13 C) [ 40 ], J ( 31 P, 17 O) [ 37 ], J ( 31 P, 15 N) [ 37 ], J ( 31 P, 19 F) [ 7 ], J ( 31 P, 33 S) [ 37 ], J ( 31 P, 77 Se) [ 37 , 41 ], and J ( 31 P, 125 Te) [ 41 ], were carried out mostly within the second-order polarization propagator approach (SOPPA) [ 9 ], including its coupled cluster-modified versions [ 9 , 42 ], and within the density functional theory (DFT) [ 43 ]. In a scant number of papers, it was shown that specialized J -oriented Jensen’s and Sauer’s basis sets for silicon and phosphorus do reproduce the results obtained using much larger basis sets with favorable accuracy [ 7 , 8 ].…”