Quantitative Investigation of Intermolecular Te···A (A = π/Te/H) Interactions in Organotellurium Compounds from the Cambridge Structural Database

Abstract

Chalcogen bonds, which involve the interaction of an electrophilic region associated with a chalcogen atom and a nucleophilic region in an adjacent atom, have emerged as a new frontier in supramolecular chemistry. In this study, the formation of tellurium (Te)-containing chalcogen bonds along with weak hydrogen-bonds has been demonstrated, via an investigation of the crystal structures, obtained from the Cambridge Structural Database (CSD). A statistical analysis of the occurrence of short and directional tellurium-centered contacts in organic molecules, namely, Te•••Te, Te•••C, and Te•••H−C, has been performed. This was followed by the analysis of molecular electrostatic potentials, a Hirshfeld surface analysis, the three-dimensional deformation densities, and the energetics associated with the existence of different interactions in tellurium-containing molecules, having a diverse array of functional groups. Our findings indicate that Te functions as a σ-hole chalcogen bond donor, engaging with the nucleophilic π-rich system that functions as a chalcogen bond acceptor. This is an important supramolecular feature that governs the packing of molecules in the crystalline state, in addition to the presence of other tellurium-centered contacts. Thus, the current study is an attempt to consider the potential of Te-containing compounds, showing simultaneous chalcogen bond "donor" and "acceptor" characteristics, in the design of new materials.

Unveiling the Intermolecular Interactions between Drug 5-Fluorouracil and Watson–Crick/Hoogsteen Base Pairs: A Computational Analysis

“…The 5FU drug adsorbed on base pairs is visualized in Figure S10. Due to the directional interaction, the positive regions in a molecule will interact with the negative region, leading to a decrease or increase in the positive or negative values . In the most stable 5FU–AT complex, the V s,min value observed on the oxygen atom of the adenine group is reduced from −35.3 to −6.0 kcal mol –1 , the carbonyl oxygen on the 5FU unit attached to the N–H group is reduced from −31.7 to −20.6 kcal mol –1 , and the other carbonyl group of the 5FU drug has gained a marginal increase in V s,min value.…”

Te⋯I secondary-bonding interactions in crystals containing tellurium(ii), tellurium(iv) and iodide atoms: supramolecular aggregation patterns, nature of the non-covalent interactions and energy considerations

“…33,34 Instances of bifurcated 35–37 and charge-assisted 38,39 chalcogen bonds are also known. Computational chemistry calculations on the aforementioned neutral systems 31–37 and other non-charged systems 26,40 confirm that the energy imparted by the different interactions involving the tellurium are like or exceed those imparted by conventional hydrogen bonding. 41…”

“…Other interactions are sometimes observed, such as π-hole interactions, where the electron deficient region is located perpendicular to a framework sustained by covalent bonds. [27][28][29] In crystals of chalcogen-containing molecules, π-hole interactions can cooperate with σ-hole interactions [30][31][32] or even operate independently. 33,34 Instances of bifurcated [35][36][37] and charge-assisted 38,39 chalcogen bonds are also known.…”

“…33,34 Instances of bifurcated [35][36][37] and charge-assisted 38,39 chalcogen bonds are also known. Computational chemistry calculations on the aforementioned neutral systems [31][32][33][34][35][36][37] and other non-charged systems 26,40 confirm that the energy imparted by the different interactions involving the tellurium are like or exceed those imparted by conventional hydrogen bonding. 41 While the focus of the present study is upon the crystals, secondary-bonding interactions are known to persist in solution, 42,43 with recent studies highlighting the presence of intramolecular Te⋯F (ref.…”