Correlated ab initio calculations of one-bond 31 P77 Se and 31 P125 Te spin-spin coupling constants in a series of PSe and PTe systems accounting for relativistic effects (part 2).

Synthetic chalcogen-phosphorus chemistry permanently makes new challenges to computational Nuclear Magnetic Resonance (NMR) spectroscopy, which has proven to be a powerful tool of structural analysis of chalcogen-phosphorus compounds. This paper reports on the calculations of one-bond 31 P77 Se and 31 P125 Te NMR spin-spin coupling constants (SSCCs) in the series of phosphine selenides and tellurides. The applicability of the combined computational approach to the one-bond 31 P77 Se and 31 P125 Te SSCCs, incorporating the composite nonrelativistic scheme, built of high-accuracy correlated SOPPA (CC2) and Coupled Cluster Single and Double (CCSD) methods and the Density Functional Theory (DFT) relativistic corrections (four-component level), was examined against the experiment and another scheme based on the four-component relativistic DFT method. A special J-oriented basis set (acv3z-J) for selenium and tellurium atoms, developed previously by the authors, was used throughout the NMR calculations in this work at the first time. The proposed computational methodologies (combined and 'pure') provided a reasonable accuracy for 31 P77 Se and 31 P125 Te SSCCs against experimental data, characterizing by the mean absolute percentage errors of about 4% and 1%, and 12% and 8% for selenium and tellurium species, respectively. The present study reports typical relativistic corrections to 77 Se31 P and 125 Te31 P SSCCs, calculated within the four-component DFT formalism for a broad series of tertiary phosphine selenides and tellurides with different substituents at phosphorus.

Crystal structures of bis-[2-(di-phenyl-phosphino-thio-yl)phen-yl] ether and bis-{2-[diphen-yl(selanyl-idene)phosphan-yl]phen-yl} ether.

The title compounds, C36H28OP2S2, (1), and C36H28OP2Se2, (2), exhibit remarkably similar structures although they are not isomorphous. The whole mol-ecule of compound (2) is generated by twofold symmetry, with the ether O atom located on the twofold axis. Both compounds have intra-molecular π-π inter-actions between terminal phenyl rings with centroid-centroid distances of 3.6214 (16) and 3.8027 (14) Šin (1) and (2), respectively. In the crystal of (1), short C-H⋯S hydrogen bonds link the mol-ecules, forming chains along [001], while in (2) there are no analogous C-H⋯Se inter-actions present.