Substituent Effects on the Stability of Thallium and Phosphorus Triple Bonds: A Density Functional Study.

Title Substituent Effects on the Stability of Thallium and Phosphorus Triple Bonds: A Density Functional Study.
Authors J.S. Lu; M.C. Yang; M. Der Su
Journal Molecules
DOI 10.3390/molecules22071111

Three computational methods (M06-2X/Def2-TZVP, B3PW91/Def2-TZVP and B3LYP/LANL2DZ+dp) were used to study the effect of substitution on the potential energy surfaces of RTl?PR (R = F, OH, H, CH?, SiH?, SiMe(SitBu?)?, SiiPrDis?, Tbt (=C?H?-2,4,6-(CH(SiMe?)?)?), and Ar* (=C?H?-2,6-(C?H?-2, 4,6-i-Pr?)?)). The theoretical results show that these triply bonded RTl?PR compounds have a preference for a bent geometry (i.e., ?R?Tl?P ? 180° and ?Tl?P?R ? 120°). Two valence bond models are used to interpret the bonding character of the Tl?P triple bond. One is model [I], which is best described as TlP. This interprets the bonding conditions for RTl?PR molecules that feature small ligands. The other is model [II], which is best represented as TlP. This explains the bonding character of RTl?PR molecules that feature large substituents. Irrespective of the types of substituents used for the RTl?PR species, the theoretical investigations (based on the natural bond orbital, the natural resonance theory, and the charge decomposition analysis) demonstrate that their Tl?P triple bonds are very weak. However, the theoretical results predict that only bulkier substituents greatly stabilize the triply bonded RTl?PR species, from the kinetic viewpoint.

Citation J.S. Lu; M.C. Yang; M. Der Su.Substituent Effects on the Stability of Thallium and Phosphorus Triple Bonds: A Density Functional Study.. Molecules. 2017;22(7). doi:10.3390/molecules22071111

Related Elements


See more Thallium products. Thallium (atomic symbol: Tl, atomic number: 81) is a Block P, Group 13, Period 6 element with an atomic weight of 204.38. Thallium Bohr ModelThe number of electrons in each of thallium's shells is 2, 8, 18, 32, 18, 3 and its electron configuration is [Xe] 4f14 5d10 6s2 6p1. The thallium atom has a radius of 170 pm and a Van der Waals radius of 196 pm. Thallium was discovered by Sir William Crookes in 1861 and first isolated by Claude-Auguste Lamy in 1862. Thallium is a post-transition metal that is not found free in nature. Thallium is primarily used for its electrical conductivity as thallium sulfide, which changes with exposure to infrared light. This ability makes the compound useful in photocells. Elemental ThalliumThallium bromide-iodide crystals have been used as infrared optical materials. Thallium has also been used with sulfur, selenium or arsenic to produce low melting glasses which become fluid between 125 and 150 °C, while thallium oxide has been used to produce glasses with a high index of refraction, and is also used in the manufacture of photo cells. Its name is derived from the Greek word thallos, which means twig or green shoot.


Phosphorus Bohr ModelSee more Phosphorus products. Phosphorus (atomic symbol: P, atomic number: 15) is a Block P, Group 15, Period 3 element. The number of electrons in each of Phosphorus's shells is 2, 8, 5 and its electronic configuration is [Ne] 3s2 3p3. The phosphorus atom has a radius of and its Van der Waals radius is Phosphorus is a highly-reactive non-metallic element (sometimes considered a metalloid) with two primary allotropes, white phosphorus and red phosphorus its black flaky appearance is similar to graphitic carbon. Compound forms of phosphorus include phosphates and phosphides. Phosphorous was first recognized as an element by Hennig Brand in 1669 its name (phosphorus mirabilis, or "bearer of light") was inspired from the brilliant glow emitted by its distillation.