59532-48-8

Basic information

• Product Name: trans-stilbene radical cation
• Synonyms: trans-stilbene radical cation
• CAS NO: 59532-48-8
• Molecular Weight: 180.249
• Mol File: 59532-48-8.mol

Chemical Properties

• CAS DataBase Reference: trans-stilbene radical cation(CAS DataBase Reference)
• NIST Chemistry Reference: trans-stilbene radical cation(59532-48-8)
• EPA Substance Registry System: trans-stilbene radical cation(59532-48-8)

Safety Data

• Hazardous Substances Data: 59532-48-8(Hazardous Substances Data)

Upstream product

• 645-49-8 cis-stilben 
• 103-30-0 cis-stilbene radical cation 
• 54515-63-8 cis,trans,cis-1,2,3,4-tetraphenylcyclobutane 
• 54515-64-9 trans,trans,trans-1,2,3,4-tetraphenylcyclobutane 
• 103-30-0 (E)-1,2-diphenyl-ethene 
• 70152-65-7 trans-stilbene radical cation/fumaronitrile radical anion 
• 118-75-2 chloranil 

Downstream Products

• 103-30-0 cis-stilbene radical cation 
• 103-30-0 (E)-1,2-diphenyl-ethene 
• 118-75-2 chloranil 
• 85-01-8 phenanthrene radical cation 

Relevant articles and documents

An esr study of aromatic olefin radical cations

γ-Irradiation of phenyl-and diphenylethenes in CFCl3 matrix at 77 K resulted in the formation of the substrate radical cations. 1,1-Diphenyl-2-methylpropene radical cations exhibit a spin density (ρ=0.45) at the β carbon much higher than those of stilbene and 2-styrylnaphthalene radical cations and comparable to those of styrene and α-methylstyrene radical cations. The spin density at the vinyl carbons appears to play an important role in governing the reactivity of the olefin radical cations with molecular oxygen.

Involvement of triplet excited states and olefin radical cations in electron-transfer cycloreversion of four-membered ring compounds photosensitized by (thia)pyrylium salts

Cycloreversion of 1,2,3,4-tetraphenylcyclobutanes 1a,b and oxetane 2 is achieved using (thia)pyrylium salts as electron-transfer photosensitizers. Radical cation intermediates involved in the electron-transfer process have been detected using laser flash

Photodynamics of the Paterno-Buechi cycloaddition of stilbene to quinone. Unusual modulation of electron-transfer kinetics by solvent and added salt

Oxetanes are produced in the Paterno-Buechi cycloaddition of stilbene (S) to quinone (Q) via an efficient photoinduced electron transfer. Kinetics analysis of the time-resolved absorption spectra over three distinctive (ps, ns, μs) timescales establishes the coupling (kC) of the initially formed ion-radical pair 3[S+?, Q-?] to the 1,4-biradical ?SQ? as the critical step toward oxetane formation. The (rather slow) rate constant of kC ≤ 107 s-1 in acetonitrile must compete with other faster decay pathways of the ion pair involving ionic separation, ion exchange (with added salt) and back electron transfer. As such, solvent polarity and donicity as well as added salts play an unusually prominent role in modulating the ion-pair microdynamics. Donor-acceptor complexation of the photoexcited quinone with the solvent and cis→trans isomerization of (Z)-stilbene must also be considered in the overall photodynamics of electron transfer.

Dynamics of ionization reactions of β-substituted radicals, substituent and solvent effects

The dynamics of reactions of carbon-centered 1-arylalkyl radicals with bromine or chlorine attached to the carbon adjacent (β) to the radical center have been examined using nanosecond laser flash photolysis. The primary reaction of the radicals containing the electron-donating 4-methoxy group on the phenyl ring is highly dependent on the solvent composition. In weakly ionizing solvents such as acetonitrile, the radicals decay in a second-order manner indicating that coupling of two radical centers is the primary mode of radical decay. However, when the ionizing ability of the solvent is increased by addition of water, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), or 2,2,2-trifluoroethanol (TFE), heterolysis of the β-substituent becomes the dominant mode of decay. The occurrence of the heterolysis reaction is demonstrated unambiguously by direct observation of the radical cation produced as the primary, heterolysis product. The rate constants for and yield of the heterolysis reaction are found to be dependent on both the solvent ionizing ability and radical structure. In neat water or neat HFIP the reactions become extremely fast and occur with rate constants in the 107 s-1 to ≤ 108 s-1 range. For the β-bromophenethyl and β-bromo-4-methyphenethyl radicals, no heterolysis is observed even under strongly ionizing conditions, indicating that the rate constant for ionization is strongly influenced by the substituent on the phenyl ring. For radicals with an additional β-phenyl substituent, rapid heterolysis takes place leading to the formation of the stilbene radical cation. The formation of a radical/radical cation equilibrium was observed under the appropriate conditions only for the 4-methoxyphenethyl radical derivatives.

Reactivities of Isomerization, Oxidation, and Dimerization of Radical Cations of Stilbene Derivatives

Reactions of radical cations of eight stilbene derivatives (S(.+)) have been studied using pulse radiolysis and γ-ray radiolysis in 1,2-dichloroethane or butyl chloride.Unimolecular isomerization from cis-S(.+) to trans-S(.+) and bimolecular reactions with O2 (oxidation) and a neutral stilbene (dimerization) occur depending on the substituents.The unimolecular c-t isomerization and the oxidation proceed preferably in S(.+) substituted with a p-methoxyl group (as an electron-donating substituent) with rate constants of ki = 4.5E6 to 1,4E7 s-1 and k02 = (1.2-4.5)E7 M-1 s-1, respectively.On the basis of transient absorption measurements, it is concluded that separation and localization of a positive charge and an unpaired electron play the most important role as the controlling factors in the reactivities of the unimolecular isomerization and the oxidation.The dimerization involves initial formation of a ?-complex with overlapping of two benzene rings and is inhibited by steric hindrance of substituents on the benzene rings and olefinic carbons.

Lifetimes and Transient Phenomena of Stilbene Radical Cations in the Second Excited Doublet State

Radical cations of cis- and trans-stilbene (c-St.+, t-St.+) and of 1,2-diphenylcyclo-1-butene (CB.+) in the second excited doublet state (D2) have been generated using sequential pulse radiolysis-laser flash photolysis, and their lifetime have been measured using selective hole transfer quenching with anisole.In the deactivation of the D2 state of c-St.+, the internal conversion competes with the isomerization to t-St.+ in a quantum yield of 0.49 +/- 0.12 and conversion to another product as a minor process, whereas the D2 state of t-St.+ and CB.+ are only deactivated via internal conversion.Lifetimes of the t-St.+ and c-St.+ D2 states are estimated to be approximately 240 and 120 ps, respectively, while that of the CB.+ D2 state is approximately 380 ps.The shorter lifetime of the c-St.+ D2 state is attributed to isomrization and conversion to another product via twisting about the central C=C double bond.The analogous process in CB is severely hindered by structural constraints.The transient phenomena of the D2 states of c-St.+, t-St.+, and CB.+ are compared in terms of their lifetimes, structures, energies, and reaction processes.

Photochemistry of Stilbene Adsorbed on Silica Gel and NaX Zeolite. A Diffuse Reflectance Laser Flash Photolysis Study

Diffuse reflectance laser flash photolysis (266, 308, or 355 nm) of either cis- or trans-stilbene (St) adsorbed on silica gel or included in NaX zeolite leads to the formation of the trans-St radical cation with λmax at 475 nm at high laser powers.At low laser intensities trans-St also yields radical cation while cis-St photocyclizes to give dihydrophenanthrene with λmax at 450 nm.In contrast to the results for irradiation of stilbene alone on solid supports, irradiation of the cis-St/TNM charge transfer complex on silica or zeolite leads to a mixture of both trans- and cis-St.+ (λmax at 510 nm), demonstrating that the cis radical cation is stable with respect to isomerization on these two solids.This result, in combination with product studies which demonstrate that there is substantial cis-trans isomerization within a single laser pulse, leads to the conclusion that the formation of trans-St.+ following laser irradiation of cis-St occurs via cis-trans isomerization followed by photoionization of trans-St.Laser irradiation of St or pyrene on NaX zeolite results in strong transient signals in the 500-600 nm region due to trapped electrons, in addition to the signals due to radical cations.The effects of both water and oxygen on the trapped electron and radical cation have been examined.The trapped electron can be photobleached with a second 532 nm laser pulse.The bleaching does not lead either to trapping of the electron by ground state aromatic to give its radical anion or to recombination with the radical cation to regenerate the starting material.This suggests that irradiation leads to a redistribution of the electron to other zeolite sites.

Role of Contact and Solvent-Separated Radical Ion Pairs in the Diffusional Quenching of trans-Stilbene Excited Singlet State by Fumaronitrile

Picosecond absorption spectroscopy is used to examine the question of wether contact radical ion pairs (CRIP) or solvent-separated radical ion pairs (SSRIP) are formed upon the quenching, by electron transfer, of the first excited singlet state of trans-stilbene (S1) by fumaronitrile (FN).Prior to these experiments, it was generally believed that for exothermic reactions in polar solvents, SSRIP are formed upon quenching by electron transfer.However the present experiments reveal that the quenching of S1 by FN in acetonitrile leads to the formation of CRIP.To establish the nature of the radical ion pair formed upon electron transfer, the kinetics for the decay of the CRIP and the SSRIP are established.

Effects of Salt on Isomerization of Stilbene Cation Radicals. Direct Observation of their Cis -> Trans Conversion

Unimolecular cis-trans conversion of stilbene cation radicals generated from 9,10-dicyanoanthracene-biphenyl co-sensitization under air was directly observed in the presence of salt such as LiClO4 in acetonitrile, and the activation parameters of this pro

Chemical Behavior of Aromatic Radical Cations under Superoxide-Free Electron Transfer Photooxygenation Conditions

The electron transfer photooxygenations of aromatic compounds were carried out with trityl salts.Under these superoxide-free reactions conditions, only anthracene and 1,1-diarylethylenes were photooxygenated, stilbenes isomerized, and quantitatively recovered were naphthalene, phenanthrene, alkylnaphthalenes, tetraphenylethylen and 1,1,4,4-tetraaryl-1,3-butadienes.The reactivities of their radical cations toward triplet oxygenation were discussed on the basis of the quantum yield measurements and product analyses.