Guest Signaling Compound:  trans-3,3‘-Bis(diphenylhydroxymethyl)azobenzene

Abstract

A chromogenic azobenzene compound, (E)-(3,3‘-(diazene-1,2-diyl)bis(3,1-phenylene))bis(diphenylmethanol), forms lattice inclusion compounds with a range of common solvents. It is yellow in the unsolvated crystalline form, but orange or orange-red when crystallized as solvates with guest molecules that contain hydrogen-bond acceptors. Close examination of crystal structures of unsolvated and solvated forms reveals that differences in hydrogen bonding and a change in conformation of the azobenzene core are responsible for the change in λ of absorption of the chromophore and hence color of the crystals. Hirshfeld surfaces and fingerprint plots reveal subtle differences in intermolecular interactions in the solvated and unsolvated crystalline forms.

A new class of thermo- and solvatochromic metal–organic frameworks based on 4-(pyridin-4-yl)benzoic acid

“…It arises as a result of a change in the energy gap between ground and excited states, which in turn is caused by interactions between chromophores and solvent molecules. Solvatochromism has been observed in organic conjugated polymers, 9 which change conformation in certain solvents, in supramolecular systems as a result of changes in hydrogenbonding interactions, 10 and in transition metal complexes, usually as a result of changes in the coordination centre which leads to changes in the visible d-d energy transitions. [11][12][13] The latter is often accompanied by large changes in the structure of the complex.…”

Inclusion of pyridine and acetone by a diol host: structure, thermal stability and kinetics of desolvation

“…Recently, Scott and Tanaka, 12 have exploited the chromogenic properties of the host (E)-(3,39-(diazene-1,2-diyl)bis(3,1phenylene))bis(diphenylmethanol), which changes colour when it enclathrates a variety of guests, which are hydrogen bond acceptors. Here we present the structures of the inclusion compounds formed by the host 1,4-di-(5H-dibenzo[a,d]cyclohepten-5-ol)-buta-1,3-diyne, H, with pyridine (PYR) and acetone (ACE), their thermal characteristics, and their kinetics of desolvation.…”

Stacks of Azobenzene Stars: Self-Assembly Scenario and Stabilising Forces Quantified in Computer Modelling

“…To more closely examine the intermolecular interactions in the crystals of azo-stars experimentally characterized by Lee et al [17], the Hirshfeld surfaces [65,66] are generated using CrystalExplorer (Version 3.1) [75]. This method has been successfully utilized to characterize aminoazobenzene polymorphs [76], to investigate the intermolecular interactions in azobenzenes revealing photoinduced crystal–melt transition [77], and to explain the molecular origin of the color changes of guest signaling azobenzene [78,79], to name a few.…”