In organic chemistry, thioketenes are organosulfur compounds analogous to ketenes with the general formula R2C=C=S, where R is alkyl or aryl. The parent thioketene (ethenthione) has the formula CH2=C=S. It is the simplest thioketene. [1] Thioketene is stable as a gas, but like most thioketenes, it polymerizes upon condensation.
Some thioketenes are produced as transient species upon pyrolysis of 1,2,3-thiadiazoles. [2] It has been suggested that thioketene could be involved in cell damage processes. [3]
Thioketenes can be stabilized by either steric protection or by electronic effects. Thus, di-tert-butylthioketene is easily isolated and air-stable. [4] Several examples have been characterized by X-ray crystallography. The C=S distance is 157 pm and the C=C distance is 124 pm, both bonds being suitable for the C=C=S assignment. The violet color characteristic of thioketenes indicates the small HOMO-LUMO gap. [5] These compound are prepared by treatment of the acid chloride with phosphorus pentasulfide as described by the following idealized equation:
Bis(trifluoromethyl)thioketene ((CF3)2C=C=S) is an example of an electronically stabilized thioketene. [6]
Thioketenes are electrophilic. They add amines to give thioamides: [4]
With peroxyacids, they produce thioketene-S-oxides: [5]
Thioketenes bind to metal carbonyls giving adducts. [7]
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In organic chemistry, thioketenes are organosulfur compounds analogous to ketenes with the general formula R2C=C=S, where R is alkyl or aryl. The parent thioketene (ethenthione) has the formula CH2=C=S. It is the simplest thioketene. [1] Thioketene is stable as a gas, but like most thioketenes, it polymerizes upon condensation.
Some thioketenes are produced as transient species upon pyrolysis of 1,2,3-thiadiazoles. [2] It has been suggested that thioketene could be involved in cell damage processes. [3]
Thioketenes can be stabilized by either steric protection or by electronic effects. Thus, di-tert-butylthioketene is easily isolated and air-stable. [4] Several examples have been characterized by X-ray crystallography. The C=S distance is 157 pm and the C=C distance is 124 pm, both bonds being suitable for the C=C=S assignment. The violet color characteristic of thioketenes indicates the small HOMO-LUMO gap. [5] These compound are prepared by treatment of the acid chloride with phosphorus pentasulfide as described by the following idealized equation:
Bis(trifluoromethyl)thioketene ((CF3)2C=C=S) is an example of an electronically stabilized thioketene. [6]
Thioketenes are electrophilic. They add amines to give thioamides: [4]
With peroxyacids, they produce thioketene-S-oxides: [5]
Thioketenes bind to metal carbonyls giving adducts. [7]
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)