Fluorescent chemosensors based on 9-cycloheptatrienylidene fluorenes (9-CHFs)

Fulvenyl-Functionalized Polyisocyanides: Cross-Conjugated Electrochromic Polymers with Variable Optical and Electrochemical Properties

“…The chemistry of tria-, penta-, and heptafulvenes − and fulvalenes ,,− (Figure A), their synthetic preparation, and the study of their physical properties have been the subject of continuous interest throughout the past decades. These nonalternant hydrocarbons do not exhibit classic Hückel aromaticity but can form ionic species upon reduction (pentafulvenes) or oxidation (tria- and heptafulvenes) that experience substantial aromatic stabilization via cyclic delocalization.…”

Role of Crystal Packing and Weak Intermolecular Interactions in the Solid State Fluorescence of N-Methylpyrazoline Derivatives

“…The design of new solid luminescent materials with desirable optical and physical properties has drawn a great attention over recent years owing to their potential use in material science , and biology. − Several conditions, such as a simple route of synthesis, photochemical stability, color purity, and high quantum efficiency, are essential for the development of new luminescent compounds. Understanding the role of self-assembly and interactions of molecules in determining fluorescent properties is an important goal in material sciences. , Fluorescence of organic compounds in the solid state depends not only on the structure of the fluorophore but also on the architecture of the crystal packing and intermolecular interactions. , Supramolecular aggregations may be achieved with various interactions, such as hydrogen bonds (O–H···O, N–H···O, C–H···O), π···π stacking, and weak noncovalent forces. , It has been revealed that strong intermolecular π···π interaction is a principal factor of fluorescence quenching in the solid state.…”

Directed Gas‐Phase Synthesis of Triafulvene under Single‐Collision Conditions

“…[5,6] Theu nique reactivity associated with the cross-conjugated p-electronic structure has led to the broad use of fulvenes in the synthesis of natural products,s uch as loganin and sarracenin, [7,8] and in transition-metal complexes, such as {(h 5 -C 5 Me 5 )Ti(h 6 -C 5 H 4 = C(pC 7 H 7 ) 2 )} 2 (m 2 ,h 1 ,h 1 -N 2 ). [9,10] Fulvenes also serve as fundamental molecular building blocks in fluorescent aromatic hydrocarbons,including 9-(cycloheptatrienylidene)fluorene, [11] 9-(methylidenecyclopropabenzene)fluorene,a nd 5-(methylidenecyclopropabenzene)dibenzocycloheptatriene. [12] Tr iafulvene (1, c-C 4 H 4 ,m ethylenecyclopropene)-a thermodynamically less stable (99 kJ mol À1 ) [13] isomer of vinylacetylene (5,H CCC 2 H 3 )a nd butatriene (6,H 2 CCCCH 2 ; Scheme 2)-has received particular attention as it resembles the prototype of the fulvene family,d efining the simplest cross-conjugated hydrocarbon carrying am ethylidene functional group in conjugation with as ingle carbon-carbon double bond within the cycloalkene.A lthough triafulvenes equipped with bulky phenyl substituents,s uch as 2,3-diphenyl-4,4-dicyanotriafulvene (C 18 H 8 N 2 ), are stable monomers at room temperature, [14] triafulvene (1), first synthesized by dehalogenation of 2-bromomethylenecyclopropane,w as found to polymerize at temperatures above 80 K. [15,16] In alater study on triafulvene (1)synthesis,its head-to-tail C 8 H 8 dimer 7 was successfully isolated at temperatures above 198 K, [17] and its formation was attributed to the strong dipole moment (1.90 D) associated with the dipolar resonance structure of triafulvene (1,S cheme 3).…”