Supramolecular Chromotropism of the Crystalline Phases of 4,5,6,7-Tetrafluorobenzo-2,1,3-telluradiazole

Abstract

The remarkable effect that secondary bonding interactions can have on the macroscopic properties of a material is illustrated by two polymorphs of the title compound. The phase which is most stable under ambient pressure and temperature consists of puckered supramolecular ribbon polymers assembled by Te--N secondary bonding interactions and displays a characteristic red-orange color. A second yellow phase consists of ribbons with alternating short and long intermolecular Te--N secondary bonding distances and is metastable; at 127 °C the material undergoes an exothermic irreversible transition to the red polymorph. A third phase consists of pyridine-solvated supramolecular dimers; it is also yellow and transforms into the red phase after the crystals effloresce. Computational DFT studies indicate that the observed changes in optical properties are related to intermolecular mixing of π orbitals enabled by the supramolecular interactions and the symmetry of the supramolecular synthon.

A Universal Quantitative Descriptor of the Dispersion Interaction Potential

“…Hence, LDP maps could reveal additional insight. Recently, the chalcogen bonding in 2Z‐2N squares was studied, where Z can be sulfur, selenium, or tellurium (Scheme ) …”

Chalcogen Bonding “2S–2N Squares” versus Competing Interactions: Exploring the Recognition Properties of Sulfur

“…Of the four unsubstituted 2,1,3-benzochalcogenadiazoles (O, S, Se and Te) 1a-1d,o nly the X-ray structure of tellurium 1d [81][82][83] containsh ighlya ligned,s ub-van der Waals 2Te-2N square interactions (CB ave = 2.70 , q ave = 69.18, f ave = 2.48, F ave = 178.78) ( Figure S8). Conversely,t he sulfur 1b [84][85][86] and selenium 1c [87,88] isostructures have significantly out-of-plane, distorted squares that are nearly identical (S;S e, respectively:C B ave = 3.40 ; 3.41 , q ave = 76.48;7 6.68, f ave = 20.08;2 3.48, F ave = 145.58; 144.48).…”

A survey of tellurium-centered secondary-bonding supramolecular synthons

“…In addition to the strength of the Te-N SBIs, telluradiazoles have received much attention because of their convenient synthesis as well as the many applications of their lighter analogues, including in electronic materials [74][75][76]. Recently, the chromotropism of two polymorphs of 4,5,6,7-tetrafluorobenzo-2,1,3-telluradiazole [77] was explained in terms of changes of the local symmetry of distorted [Te-N] 2 synthons. Also, noncentrosymmetric distortion of the supramolecular synthon was used to induce the crystallization of noncentrosymmetric lattices with nonlinear optical properties [78].…”