INVESTIGADORES
MALDONADO alejandro Fabian
artículos
Título:
NMR espectroscopic parameters of HX and Si(Sn)X4 (X = H, F, Cl, Br and I) and SnBr$_{4-n}$I$_n$ model compounds
Autor/es:
ALEJANDRO F. MALDONADO; CARLOS A. GIMENEZ; GUSTAVO A. AUCAR
Revista:
CHEMICAL PHYSICS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsternam; Año: 2012 vol. 395 p. 75 - 81
ISSN:
0301-0104
Resumen:
The NMR spectroscopic parameters are between the most influenced molecular properties by relativistic effects. They are highly dependent on the electronic behavior in the nuclear position. We reoptimized Dyall cVTZ basis set to calculate nuclear spin-spin couplings at relativistic RPA level of approach in the title compounds. Comparison with results applying some other basis set mostly used within the non relativistic (NR) domain is shown. We analyze its behavior in the whole range of values for the speed of light, starting from the full relativistic to the non relativistic regime. Several SOPPA calculations at NR level indicate that correlation effects may not be quite important for nuclear magnetic shieldings, but must be included with care for J-couplings calculations. Relativity should enlarge electron correlation effects in the J-coupling of HBr and HI. Results from the polarization propagator approach are reliable enough for nuclear magnetic shielding calculations. In this article show a new and easy way to obtain the absolute nuclear magnetic shielding on reference compounds for both, Si and Sn nuclei: $sigma[Si(Me)_4] = 421.28 pm 29.33$ ppm and $sigma [Sn(CH_3)_4] = 3814.96 pm 79.12 (2.5 %$) ppm. They are obtained from experimental chemical shifts and accurate nuclear magnetic shieldings calculations for different molecular systems.