1120-53-2

Basic information

• Product Name: Cyclobuta-1,3-diene
• Synonyms: [4]Annulene;Cyclobuta-1,3-diene;Cyclobutadiene
• CAS NO: 1120-53-2
• Molecular Formula: C₄H₄
• Molecular Weight: 52.0746
• Mol File: 1120-53-2.mol
• Article Data: 8

Chemical Properties

• Boiling Point: 41.2°Cat760mmHg
• Flash Point: °C
• Appearance: /
• Density: 0.904g/cm³
• Vapor Pressure: 423mmHg at 25°C
• Refractive Index: 1.525
• CAS DataBase Reference: Cyclobuta-1,3-diene(CAS DataBase Reference)
• NIST Chemistry Reference: Cyclobuta-1,3-diene(1120-53-2)
• EPA Substance Registry System: Cyclobuta-1,3-diene(1120-53-2)

Safety Data

• Hazardous Substances Data: 1120-53-2(Hazardous Substances Data)

Usage

Definition

cyclobutadiene: A short-livedcyclic diene hydrocarbon, C4H4, withits four carbon atoms in a squarering. It is made by degradation of itsmetal complexes, and has a shortlifetime of a few seconds. It undergoesaddition reactions with alkynes.

InChI:InChI=1/C4H4/c1-2-4-3-1/h1-4H

Upstream product

• 94923-09-8 3,4-diiodocyclobutene 
• 31519-30-9 tricyclo<2.1.0.0^2,5>pentan-3-one 
• 10374-07-9 3-oxabicyclo<3.2.0>hept-6-ene-2,4-dione 
• 74-86-2 acetylene 
• 94923-08-7 2-diazo-1-(2-cyclopropen-1-yl)ethanone 
• 19192-82-6 tricyclo<2^3,6.1.1.0>pyran-2-one 
• 114068-57-4 3,4-Diaza-tricyclo[3.1.0.0^2,6]hex-3-ene 
• 94923-07-6 Cyclopropenylketen 

Downstream Products

• 74-86-2 acetylene 
• 822-35-5 cyclobutene 

Relevant articles and documents

Raman Spectrum of Matrix-Isolated Cyclobutadiene. Evidence for Environmental Hindrance to Heavy-Atom Tunneling?

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Laser Irradiation of Monomeric Acetylene and the T-Shaped Acetylene Dimer in Xenon and Argon Matrices

Irradiation of acetylene (4) in an argon matrix with an ArF laser (λ = 193 nm) yields the ethynyl radical C2H (5) and C2 (6). If the same wavelength is used to irradiate 4 in a xenon matrix, only the infrared signal of the compound Xe-C2 (7) can be detected. The same band is found on irradiation at λ = 248 nm (KrF laser) in a xenon matrix, despite the fact that acetylene (4) does not absorb light of this wavelength. Irradiation of the T-shaped acetylene dimer 9 in an argon or xenon matrix at λ = 193 nm yields butadiyne (11) and vinylacetylene (12). However, irradiation with a KrF laser (λ = 248 nm) in a xenon matrix additionally yields cyclobutadiene (13). The dependence of the mechanisms of the fragmentation and dimerization of acetylene (4) on the matrix material is discussed.

Ultraviolet and Polarized Infrared Spectroscopy of Matrix-Isolated Cyclobutadiene and Its Isotopomers

The UV and polarized IR spectra of argon matrix isolated cyclobutadiene and its 1-d-, 1,2-d2-, 1,4-d2-, 1-13C-, 1,2-13C2-, and 1,4-13C2- labeled derivatives are reported.Above 250 nm, the UV spectrum contains no peaks with an extinction coefficient larger than 10 L M-1 cm-1, but a weak absorption tail extends throughout the UV region.The absorption rises abruptly below 250 nm.The IR peak positions mostly agree with previous reports where these are available.Photoalignment studies support the symmetry assignment of fundamental vibrations and prove that the two Kekule forms interconvert rapidly even at 10 K.The spectral and photochemical effe ts of the presence of an adjacent CO2 molecule in the cyclobutadiene matrix site are elucidated.Its presence causes a substantial retardation of the photofragmentation of cyclobutadiene into two acetylenes.This is attributed to accelerated vibrational energy loss from the cyclobutadiene absorber.