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General Description

"(Z)-1,2-Diphenylethene", also known as (Z)-stilbene, is a organic compound, which is a part of the group of the alkene family. The compound's molecular formula is C14H12 and its structure consists of a two phenyl rings attached at either end of an ethene backbone, with the hydrogen atoms in a cis configuration. It is different from its geometric isomer, (E)-stilbene, due to the location of its phenyl rings. (Z)-1,2-diphenylethene is a colorless, crystalline solid that has a weak, aromatic odor. It is primarily used in research settings.

Check Digit Verification of cas no

The CAS Registry Mumber 645-49-8 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 6,4 and 5 respectively; the second part has 2 digits, 4 and 9 respectively.
Calculate Digit Verification of CAS Registry Number 645-49:
78 % 10 = 8
So 645-49-8 is a valid CAS Registry Number.

645-49-8 Well-known Company Product Price

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  • Alfa Aesar

  • (A11924)  cis-Stilbene, 97%   

  • 645-49-8

  • 1g

  • 171.0CNY

  • Detail
  • Alfa Aesar

  • (A11924)  cis-Stilbene, 97%   

  • 645-49-8

  • 5g

  • 549.0CNY

  • Detail
  • Alfa Aesar

  • (A11924)  cis-Stilbene, 97%   

  • 645-49-8

  • 25g

  • 2182.0CNY

  • Detail



According to Globally Harmonized System of Classification and Labelling of Chemicals (GHS) - Sixth revised edition

Version: 1.0

Creation Date: Aug 12, 2017

Revision Date: Aug 12, 2017


1.1 GHS Product identifier

Product name cis-stilbene

1.2 Other means of identification

Product number -
Other names Benzene, 1,1‘-(1,2-ethenediyl)bis-, (Z)-

1.3 Recommended use of the chemical and restrictions on use

Identified uses For industry use only.
Uses advised against no data available

1.4 Supplier's details

1.5 Emergency phone number

Emergency phone number -
Service hours Monday to Friday, 9am-5pm (Standard time zone: UTC/GMT +8 hours).

More Details:645-49-8 SDS

645-49-8Relevant articles and documents

Redox behaviour of ([fc(NPiPr2)2]Fe)2, formation of an iron-iron bond and cleavage of azobenzene

Pick, Fraser S.,Leznoff, Daniel B.,Fryzuk, Michael D.

, p. 10925 - 10931 (2018)

The redox behaviour of the dimeric tetrairon complex, ([fc(NPiPr2)2]Fe)2 (where fc(NPiPr2)2 = 1,1′-(C5H4NPiPr2)2Fe) has been investigated. Upon reduction with KC8 an Fe-Fe bond is formed with the complex maintaining a high spin configuration and having the formula [K(THF)6]([fc(NPiPr2)2]Fe)2. In contrast, oxidation of the complex is ligand based; for example, addition of the 1,2-diiodoethane (I2 equivalent) results in the formation of the monomeric iron(ii) diiodide [fc(NiPr2I)2]FeI2 wherein the phosphine is oxidized. The dimeric tetrairon complex reacts photolytically with azobenzene, cleaving the NN double bond and forming the new monomeric bis(phosphoramidate) iron complex. [fc(NP(NPh)iPr2)2]Fe. Characterization of these paramagnetic complexes was accomplished by magnetic susceptibility studies and X-ray analyses.


, p. 3201 (1967)

Cluster and barrier effects in the temperature and pressure dependence of the photoisomerization of trans-stilbene

Schroeder, J.,Schwarzer, D.,Troe, J.,Voss, F.

, p. 2393 - 2404 (1990)

The pressure and temperature dependence of the photoisomerization rate coeficient of trans-stilbene in the S1 state have been measured in the solvents C2H6, C3H8, C4H10, Xe, Co2, SF6, and CHF3.At constant temperature, the pressure dependences up to 6 kbar can be well represented by the Kramers-Smoluchowski model.The comparison of results in different solvents cleary indicates the importance of reactant-solvent cluster formation modifying the height and imaginary frequency of the barrier.The change of the temperature dependence with pressure points towards a multidimensional barrier of nonseparable character.Multidimensional barrier effects manifest themselves most clearly via the temperature dependence of the rate coefficient in the Kramers-Smoluchowski limit.

Visible-Light-Induced, Metal-Free Carbene Insertion into B-H Bonds between Acylsilanes and Pinacolborane

Ye, Jian-Heng,Quach, Linda,Paulisch, Tiffany,Glorius, Frank

, p. 16227 - 16231 (2019)

Carbene insertion reactions with B-H bonds are a challenging but promising method for the synthesis of organoboranes. Herein, we report visible-light-induced B-H insertions of HBpin with acylsilane. This metal-free and operationally simple reaction proceeds in an atom-economical way with broad substrate scope under mild reaction conditions, affording a variety of important α-alkoxyorganoboronate esters in quantitative yields. Control experiments and density functional theory calculations suggest that the siloxycarbene generation from the T1 state of acylsilane and the carbene insertion into the B-H bond occurred in a concerted manner.

Pyrene-benzoylthiophene bichromophores as selective triplet photosensitizers

Perez-Prieto, Julia,Perez, Lourdes Pastor,Gonzalez-Bejar, Maria,Miranda, Miguel A.,Stiriba, Salah-Eddine

, p. 5569 - 5571 (2005)

Combination of the pyrene and benzoylthiophene units constitutes an interesting approach to design bichromophoric photosensitizers with increased intersystem crossing quantum yield and enhanced selectivity. The potential of this strategy has been illustrated in the present work by using a model photoisomerization reaction. The Royal Society of Chemistry 2005.

Donor-Stabilized Silacyclobutanone: A Precursor of 1-Silaketene via Retro-[2 + 2]-Cycloaddition Reaction at Room Temperature

Troadec, Thibault,Lopez Reyes, Morelia,Rodriguez, Ricardo,Baceiredo, Antoine,Saffon-Merceron, Nathalie,Branchadell, Vicen?,Kato, Tsuyoshi

, p. 2965 - 2968 (2016)

The synthesis of donor-stabilized silacyclobutanone 2 was successfully realized by the reaction of silacyclopropylidene 1 with benzaldehyde in the presence of a Lewis acid catalyst. Of particular interest, silacyclobutanone 2 evolves at room temperature via a retro-[2 + 2]-cycloaddition reaction, leading to an original NHC-stabilized 1-silaketene 4 and cis-stilbene.

Solvent dielectric effects on isomerization dynamics: Investigation of the photoisomerization of 4,4'-dimethoxystilbene and t-stilbene in n-alkyl nitriles

Sivakumar, N.,Hoburg, E. A.,Waldeck, D. H.

, p. 2305 - 2316 (1989)

New data for the photoisomerization dynamics of t-stilbene and 4,4'-dimethoxystilbene in polar sovents are reported.These data demonstrate that in n-alkyl nitriles, nonassociated polar solvents, it is possible to extract a solvated barrier for the isomerization.This result is contrasted with recent studies in n-alkyl alcohols, associated polar solvents, where this separation is not possible and clarifies the origin of the changing barrier height in n-alkyl alcohols.Comparison of reduced isomerization rates with models of chemical reaction dynamics in solution are drawn.Good agreement of the data with a coupled oscillator model is found.

Vinyl radicals. Stereoselectivity in hydrogen atom transfer to equilibrated isomeric vinyl radicals.

Singer, Lawrence A.,Kong, Noland P.

, p. 2089 - 2094 (1966)


Barrier crossing and solvation dynamics in polar solvents: Photoisomerization of trans-stilbene and E,E-diphenylbutadiene in compressed alkanols

Mohrschladt, R.,Schroeder, J.,Schwarzer, D.,Troe, J.,Voehringer, P.

, p. 7566 - 7579 (1994)

The viscosity dependence of the photoisomerization of trans-stilbeme in compressed liquid ethanol shows deviations from a simple power law description in the viscosity range from 1 to 4 mPa s.Corresponding deviations are observed in the solvents methanol, n-propanol, and n-butanol.This behavior is attributed to a competition between solvent relaxation and barrier crossing in the S1 state of trans-stilbene.The relative time scales of barrier crossing and solvent relaxation change as the pressure increases, because the dielectric relaxation rate of the solvent decreases more rapidly with increasing viscosity than the barrier crossing rate.Consequently, the reaction takes place in an increasingly retarded solvent environment which no longer relaxes completely around the changing charge distribution of the solute along its reaction path, giving rise to "dielectric friction".In contrast to trans-stilbene, the corresponding reaction of diphenylbutadiene in n-alkanols shows a much weaker sensitivity to solute-solvent interaction and, consequently, a simple inverse viscosity dependence of the photoisomerization rate is observed in all alkanols such as described by the Kramers-Smoluchowski theory.This significant difference is probably caused by smaller sudden polarization effects along the reaction path in diphenylbutadiene.The observed dependence of the trans-stilbene barrier crossing rate on pressure is compared either to a model with density dependent effective barrier height, or to a simple continuum model of the frequency dependence of the dielectric friction in the limit of weak coupling.Neither model works well unless a very strong viscosity dependence of the dielectric relaxation time of the solvent (τDη10) is employed to obtain agreement with the observed viscosity dependence of the barrier crossing rate.

Rates of Photoisomerization of trans-Stilbene in Isolated and Solvated Molecules: Experiments on the Deuterium Isotope Effect and RRKM Behavior

Felker, Peter M.,Zewail, Ahmed H.

, p. 5402 - 5411 (1985)

In this paper we consider the dynamics of the photoisomerization of trans-stilbene and related molecules.New measurements of the deuterium isotope effect on reaction rates are presented, and details of RRKM behavior in isolated and solvated trans-stilbene are discussed.From measurements of fluorescence decay rates as a function of the excess vibrational energy in jet-cooled trans-stilbene-d12, an energy threshold to the rates is found at ca. 1200-cm-1 excess energy in the first excited singlet state.The threshold behavior is similar to that which occurs in the photoisomerization of trans-stilbene-h12.The overall magnitudes of the perdeuterio rates are smaller, however, than the perprotio ones.As with trans-stilbene-h12 themeasured rates are found to be slower than those calculated by standard RRKM theory.Nevertheless, the observed slowing of the rates upon deuteration is predicted by the theory.The results and their interpretation are discussed in light of the results of other jet studies of trans-stilbene derivatives and of studies of the photoisomerization reaction in solution.The role of intramolecular vibrational energy redistribution and the nonadiabatic influences on the reaction are also discussed.



, p. 701 - 708 (1984)

The interaction of singlet trans-stilbene with several trialkylamines, alpha , omega -diaminoalkanes, and the bicyclic diamine Dabco in benzene solution has been investigated. The rate constants for fluorescence quenching equal or exceed the rate of diffusion and are not subject to steric hindrance. Exciplex energies and monoamine oxidation potentials show little variation with structure, suggesting that steric destabilization and inductive stabilization counterbalance each other. Intersystem crossing to yield triplet trans-stilbene is the predominant exciplex decay pathway at low amine concentrations. At higher amine concentrations, exciplex quenching by ground-state amines occurs and is subjected to a pronounced steric effect in the case of monoamines and chain-length effect in the case of diaminoalkanes.


, p. 1195,1200 (1971)

Direct Observation of the Rate for Cis->Trans and Trans->Cis Photoisomerization of Stilbene with Picosecond Laser Photolysis

Sumitani, Minoru,Yoshihara, Keitaro

, p. 85 - 89 (1982)

The rates for direct cis->trans and trans->cis photoisomerizations of stilbene in solution were measured with a newly developed monitor light source for picosecond laser photolysis in the UV region. The rate constant of the trans->cis isomerization is 1.2*1010 s-1 in hexane at 295 K. The fluorescence decay rate constant of the S1 state of trans-stilbene has the same value. Thus, the decay of the S1 state is the rate limiting step and the lifetime of an intermediate perpendicular state (1p) has to be very short. The cis->trans isomerization is very fast and the half life of the excited cis-isomer is less than a few picosecond. These observations strongly indicate that the isomerization reaction proceeds through the potential surface of the singlet excited states.

Stereoselective Hydrogenation of Alkynes, Enynes, and Dienes by Interlamellar Montmorillonite-Diphenylphosphinepalladium(II) Complex

Sharma, G. V. M.,Choudary, B. M.,Sarma, M. Ravichandra,Rao, K. Koteswara

, p. 2997 - 2998 (1989)

Stereoselective hydrogenation of alkynes, enynes, and dienes catalyzed by a heterogenized homogeneous catalyst, interlamellar montmorillonite-diphenylphosphinepalladium(II) anchored complex, has been reported. '

Physical chemistry of the lowest excited singlet state of trans-stilbene in solution as studied by time-resolved Raman spectroscopy

Hamaguchi, Hiro-O,Iwata, Koichi

, p. 883 - 897 (2002)

Structure and dynamics of the lowest excited singlet state of trans-stilbene (the S1 state of tSB) in solution are discussed with an emphasis placed on the elucidation of the mechanism of the trans-cis photoisomerization. Structure of S1 tSB in solution is first discussed based on the time-resolved Raman spectral data and their isotope substitution effects. Original data for an asymmetrically deuteriated tSB, tSB-d5, are presented to confirm the ethylene-like structure of the central C-C linkage of S1 tSB. Next, the time-, temperature-, and solvent-dependent band shape changes of the olefinic C=C stretch band are discussed in terms of the solvent induced dynamic polarization. It is shown that the dynamic polarization model accounts very well, not only for the observed band shape changes, but also for their relevance to the isomerization mechanism. A new microscopic view on the photoisomerization of tSB is thus presented. Picosecond energy dissipation process of S1 tSB is then discussed in relation to the microscopic solvation structure in chloroform. Finally, the mechanism of a new bimolecular reaction between S1 tSB and carbon tetrachloride is discussed on the basis of the diffusion-controlled reaction model.

Thomas et al.

, p. 4645 (1976)


Kauffmann, Thomas,Koenig, Rolf,Kriegesmann, Reinhard,Wensing, Michael

, p. 641 - 644 (1984)

The recently found (1) stereospecific transformation of benzaldehyde by the reagents Ph3M-CH(I)Li (M= Si, Ge) to Ph3M-substituted oxiranes renders possible a method for olefination of benzaldehyde to give Z- or E-olefins, alternatively.This is demonstrated with two examples. - The synthesis of Ph3Sn-CH(I)Li is described.

Influence of solvent viscosity on the photoisomerization of a novel trans-stilbene derivative with hindered single bond torsion


, p. 211 - 217 (1999)

Fluorescence life-time measurements were performed at elevated pressure and temperature to examine the viscosity dependence of the rate of photoinduced isomerization, kiso, in a stilbene derivative in which the single bond torsion is hindered by the introduction of CH2 bridges. The results obtained with n-hexane and methylcyclohexane as solvents (0.2 mPa siso=C·(η/mPa s)-a·exp(-EA/RT). The value for a drops from about 0.30 in n-hexane to about 0.15 in methylcyclohexane thus pointing to solvent specific contributions to the friction. The derived activation energies EA are about 12.8 and 12.5 kJ mol-1 in n-hexane and methylcyclohexane, respectively.

Electrochemical Proton Reduction over Nickel Foam for Z-Stereoselective Semihydrogenation/deuteration of Functionalized Alkynes

Valiente, Alejandro,Martínez-Pardo, Pablo,Kaur, Gurpreet,Johansson, Magnus J.,Martín-Matute, Belén

, (2021/12/22)

Selective reduction strategies based on abundant-metal catalysts are very important in the production of chemicals. In this paper, a method for the electrochemical semihydrogenation and semideuteration of alkynes to form Z-alkenes was developed, using a simple nickel foam as catalyst and H3O+ or D3O+ as sources of hydrogen or deuterium. Good yields and excellent stereoselectivities (Z/E up to 20 : 1) were obtained under very mild reaction conditions. The reaction proceeded with terminal and nonterminal alkynes, and also with alkynes containing easily reducible functional groups, such as carbonyl groups, as well as aryl chlorides, bromides, and even iodides. The nickel-foam electrocatalyst could be recycled up to 14 times without any change in its catalytic properties.

Iodine promoted reduction of aromatic carbonyl compounds with phosphonic acid to access hydrocarbons

Deng, Jinfeng,Xiao, Jing,Wang, Xiaoyi,Luo, Huang,Jia, Zhicheng,Wang, Jie

, (2022/04/19)

A novel method for selective reduction of aromatic carbonyl compounds by phosphorus acid under metal-free conditions is achieved to produce the corresponding reduced products in good to excellent yields. By using H3PO3/I2 system, various aromatic ketones and aldehydes could be reduced to the corresponding hydrocarbons. Diketone compounds could also be reduced to the corresponding Z-alkenes. The protocol is low-cost and easily scaled up, which provides a simple and practical approach to access corresponding hydrocarbons.

A Photorobust Mo(0) Complex Mimicking [Os(2,2′-bipyridine)3]2+and Its Application in Red-to-Blue Upconversion

Bilger, Jakob B.,Kerzig, Christoph,Larsen, Christopher B.,Wenger, Oliver S.

supporting information, p. 1651 - 1663 (2021/02/01)

Osmium(II) polypyridines are a well-known class of complexes with luminescent metal-to-ligand charge-transfer (MLCT) excited states that are currently experiencing a revival due to their application potential in organic photoredox catalysis, triplet-triplet annihilation upconversion, and phototherapy. At the same time, there is increased interest in the development of photoactive complexes made from Earth-abundant rather than precious metals. Against this background, we present a homoleptic Mo(0) complex with a new diisocyanide ligand exhibiting different bite angles and a greater extent of π-conjugation than previously reported related chelates. This new design leads to deep red emission, which is unprecedented for homoleptic arylisocyanide complexes of group 6 metals. With a 3MLCT lifetime of 56 ns, an emission band maximum at 720 nm, and a photoluminescence quantum yield of 1.5% in deaerated toluene at room temperature, the photophysical properties are reminiscent of the prototypical [Os(2,2′-bipyridine)3]2+ complex. Under 635 nm irradiation with a cw-laser, the new Mo(0) complex sensitizes triplet-triplet annihilation upconversion of 9,10-diphenylanthracene (DPA), resulting in delayed blue fluorescence with an anti-Stokes shift of 0.93 eV. The photorobustness of the Mo(0) complex and the upconversion quantum yield are high enough to generate a flux of upconverted light that can serve as a sufficiently potent irradiation source for a blue-light-driven photoisomerization reaction. These findings are relevant in the greater contexts of designing new luminophores and photosensitizers for use in red-light-driven photocatalysis, photochemical upconversion, light-harvesting, and phototherapy.

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