vinylidene

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/02/13 11:30:51」(JST)

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Methylidenecarbene (systematically named λ²-ethene and dihydrido-1κ²H-dicarbon(C—C)) is an organic compound with the chemical formula C=CH
2 (also written [CCH
2] or C
2H
2). It is a metastable proton tautomer of acetylene, which only persists as an adduct. It is a colourless gas that phosphoresces in the far-infrared range. It is the simplest unsaturated carbene.

Nomenclature

The systematic names λ²-ethene, and dihydrido-1κ²H-dicarbon(C—C), valid IUPAC names, are constructed according to the substitutive and additive nomenclatures, respectively.

In appropriate contexts, methylidenecarbene can be viewed as ethene with two hydrogen atoms removed, or as ethane with four hydrogens removed; and as such, ethen-1-ylidene (or vinylidene) or ethane-1-diylidene, respectively, may be used as a context-specific systematic names, according to substitutive nomenclature. By default, these names pay no regard to the radicality of the methylidenecarbene molecule. In even more specific context, these can also name the non-radical singlet ground state, whereas the diradical state is named ethene-1,1-diyl, or ethane-1,1-diylylidene, and the long-lived, tetraradical triplet state^[1] is named ethane-1,1,1,2-tetrayl.

Ethenylidene (without the -1- locant) or vinylidene, is used, systematically, to refer to the substituent group (=C=CH
2). It is used, non-systematically, to refer to substituent group ethene-1,1-diyl (>C=CH
2). Care should be taken to avoid confusing the names of the groups for the context-specific names for methylidenecarbene given above.

Chemical properties

The 1λ²-ethenediyl group (>C=C) in 1λ²-alk-1-enes such as methylidenecarbene can accept or donate a pair of electrons by adduction. Because of this acceptance or donation of the electron pair, methylidenecarbene has Lewis-amphoteric character.

Structure

With a half-life on the order of hundreds of femtoseconds, free methylidenecarbene will spontaneously decay via tautomerisation to acetylene,^[2] with an energy barrier of between 4 and 21 kJ mol⁻¹.^[1] Besides tautomerisation, methylidenecarbene can also autopolymerise to form various oligomers, the simplest of which, is the cumulene butatriene. Calculations determine that the ground state of methylidenecarbene is a non-radical singlet state.^[1]

Although, free methylidenearbene is quickly destroyed by tautomerisation into acetylene, its adducts are quite stable. One such adduct ([Ru(Cl)
2(PCy
3)
2(CCH
2)]) is useful as a catalyst for the polymerisation of norbornene.^[3]

Production

Most methylidenecarbene is produced in an adduct form by transition metal ethynation:

ML
n + HC≡CH → M(C=CH
2)L
n

References

^ ^a ^b ^c Bruce, Michael I. (March 1991). "Organometallic chemistry of vinylidene and related unsaturated carbenes" (PDF). Chemical Reviews (American Chemical Society) 91 (2): 197–257. doi:10.1021/cr00002a005. Retrieved 2 October 2013.
^ Hayes, Robin L.; Fattal, Eyal; Govind, Niranjan; Carter, Emily A. (31 January 2001). "Long live vinylidene! A new view of the H₂C=C: → HC≡CH rearrangement from ab initio molecular dynamics". Journal of the American Chemical Society 123 (4): 641–657. doi:10.1021/ja000907x.
^ Bruneau, Christian; Dixneuf, Pierre (18 December 1998). "Metal vinylidenes in catalysis". Accounts of Chemical Research (American Chemical Society) 32 (4): 311–323. doi:10.1021/ar980016i. Retrieved 6 October 2013.

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English Journal

Electrochemical biosensor for quantitation of anti-DNA autoantibodies in human serum.

Rubin RL, Wall D, Konstantinov KN.SourceDepartment of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA. Electronic address: rlrubin@salud.unm.edu.
Biosensors & bioelectronics.Biosens Bioelectron.2014 Jan 15;51:177-83. doi: 10.1016/j.bios.2013.07.041. Epub 2013 Aug 1.
Measurement of serum autoantibody is a critical tool in the diagnosis and management of autoimmune diseases. However, rapid and convenient methods at the point-of care have not been achieved in large part because any one antibody species is a heterogeneous and miniscule fraction of the total serum i
PMID 23955019

Preparation and characterization of polysaccharides/PVA blend nanofibrous membranes by electrospinning method.

Santos C, Silva CJ, Büttel Z, Guimarães R, Pereira SB, Tamagnini P, Zille A.SourceCentro de Nanotecnologia e Materiais Técnicos, Funcionais e Inteligentes (CeNTI), 4760-034 Vila Nova de Famalicão, Portugal. Electronic address: carla.correiasantos@gmail.com.
Carbohydrate polymers.Carbohydr Polym.2014 Jan;99:584-92. doi: 10.1016/j.carbpol.2013.09.008. Epub 2013 Sep 8.
A series of polyvinyl alcohol (PVA), PVA/chitosan (CS) and PVA/cyanobacterial extracellular polymeric substances (EPS) blended nanofibrous membranes were produced by electrospinning using a microfiltration poly(vinylidene fluoride) (PVDF) basal membrane, for potential applications in water filtratio
PMID 24274547

β-Phase poly(vinylidene fluoride) films encouraged more homogeneous cell distribution and more significant deposition of fibronectin towards the cell-material interface compared to α-phase poly(vinylidene fluoride) films.

Low YK, Zou X, Fang YM, Wang JL, Lin WS, Boey FY, Ng KW.SourceSchool of Materials Science and Engineering, Nanyang Technological University, N4.1 50 Nanyang Avenue, Singapore 639798, Singapore.
Materials science & engineering. C, Materials for biological applications.Mater Sci Eng C Mater Biol Appl.2014 Jan 1;34:345-53. doi: 10.1016/j.msec.2013.09.029. Epub 2013 Oct 2.
The piezoelectric response from β-phase poly(vinylidene fluoride) (PVDF) can potentially be exploited for biomedical application. We hypothesized that α and β-phase PVDF exert direct but different influence on cellular behavior. α- and β-phase PVDF films were synthesized through solution castin
PMID 24268268

Japanese Journal

Effect of Ferroelectric Polarization on Carrier Transport in Controlled Polarization-Type Ferroelectric Gate Field-Effect Transistors with Poly(vinylidene fluoride--tetrafluoroethylene)/ZnO Heterostructure

Yamada Hiroaki,Yoshimura Takeshi,Fujimura Norifumi
Jpn J Appl Phys 51(11), 11PB01-11PB01-4, 2012-11-25
… The carrier transport properties of ferroelectric gate field-effect transistors composed of oxide polar semiconductors, ZnO, and organic ferroelectrics, poly(vinylidene fluoride--tetrafluoroethylene) [P(VDF--TeFE)], were investigated. …
NAID 150000105256

垂直配向フッ化ビニリデン薄膜の面内分極反転による強誘電特性 (有機エレクトロニクス)

井上敬章,小柴康子,三崎雅裕 [他]
電子情報通信学会技術研究報告 : 信学技報 112(304), 21-25, 2012-11-19
NAID 40019523351

Effect of Ferroelectric Polarization on Carrier Transport in Controlled Polarization-Type Ferroelectric Gate Field-Effect Transistors with Poly(vinylidene fluoride-tetrafluoroethylene)/ZnO Heterostructure (Special Issue : Applied Physics on Materials Research)

Yamada Hiroaki,Yoshimura Takeshi,Fujimura Norifumi
Japanese journal of applied physics : JJAP 51(11), 11PB01-1-4, 2012-11
NAID 40019495838

Related Pictures

[Bruce1991-1] Bruce, Michael I. (March 1991). "Organometallic chemistry of vinylidene and related unsaturated carbenes" (PDF). Chemical Reviews (American Chemical Society) 91 (2): 197–257. doi:10.1021/cr00002a005. Retrieved 2 October 2013.

[Hayes2001-2] Hayes, Robin L.; Fattal, Eyal; Govind, Niranjan; Carter, Emily A. (31 January 2001). "Long live vinylidene! A new view of the H₂C=C: → HC≡CH rearrangement from ab initio molecular dynamics". Journal of the American Chemical Society 123 (4): 641–657. doi:10.1021/ja000907x.

[Bruneau1998-3] Bruneau, Christian; Dixneuf, Pierre (18 December 1998). "Metal vinylidenes in catalysis". Accounts of Chemical Research (American Chemical Society) 32 (4): 311–323. doi:10.1021/ar980016i. Retrieved 6 October 2013.

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