Fluorescent hexaaryl- and hexa-heteroaryl[3]radialenes: Synthesis, structures, and properties

Abstract

SummaryThe syntheses of three new [3]radialenes – hexakis(3,5-dimethylpyrazolyl)-, hexakis(3-cyanophenyl)-, and hexakis(3,4-dicyanophenyl)[3]radialene (1–3) – are reported. Compound 3 is obtained in five steps with an excellent yield of 76% in the key step. Compared to that, the respective steps of the syntheses of 1 and 2 result in lower yields. All compounds adopt a double bladed propeller conformation in solution. Compound 3 is considerably more electron deficient than previously reported hexaaryl[3]radialenes, with reduction potentials of −0.06 and −0.45 V in CH2Cl2. The compounds mostly display red fluorescence with large Stokes shifts.

Pre-organisation or a hydrogen bonding mismatch: silver(I) diamide ligand coordination polymers versus discrete metallo-macrocyclic assemblies

“…20,21,26,[34][35][36][37][38] Such self assembled metallosupramolecular species have been employed as anion sensors. 39 In this latter context, we have directed our attention toward two major types of organic ligand, namely, electron deficient [3]radialene compounds [40][41][42][43][44] and heterocyclic amide ligands, [45][46][47] in an effort to generate simple metallo-supramolecular assemblies and coordination polymers that encapsulate anions. Flexible bis-amide containing ligands (Diagram 1) were chosen to probe the effects of having two different and potential competing, orthogonal, supramolecular synthons in the same component; namely metal donor sites and hydrogen bond donor/acceptor moieties.…”

Synthesis and Diels–Alder Reactions of a Benzo[5]radialene Derivative

“…Radialenes are cross conjugated cyclic compounds in which all ring carbons are sp 2 hybridized and contain the maximum possible number of exocyclic double bonds . Initially considered as an academic curiosity due to their aesthetically interesting structure, these compounds are finding their way into some applications such as building blocks for organic conductors, optic materials, charge transfer complexes, and precursors of more complex polycyclic molecules by cycloadditions . Since the publication on the first of such compounds, numerous reports concerning their synthesis, aromaticity, conformation, and reactivity ,, emerged.…”

Phospharadialenes—A New Kid in Town

“…[14] The countless practical applications for which squaraines have been investigated include for photoconductivity, [20] data storage, [21] light-emitting field-effect transistors, [22] solar cells, [23] fluorescence patterning, [24] and photosensitizers for photodynamic therapy. [25] Among the more recent applications of the squaraines in "molecular electronics", an example from the solar cell area is noteworthy. [26] It is a constant challenge in the development of organic photovoltaic (OPV) cells to find donors that improve the OPV efficiency by extending the cell photoresponse into the visible and near-IR region.…”