In
organosulfur chemistry
Organosulfur compounds are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur derivatives, e.g., saccharin. Nature abounds with organosulfur compounds—sulfur ...
, a sulfenyl chloride is a
functional group
In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the re ...
with the connectivity , where R is
alkyl
In organic chemistry, an alkyl group is an alkane missing one hydrogen.
The term ''alkyl'' is intentionally unspecific to include many possible substitutions.
An acyclic alkyl has the general formula of . A cycloalkyl is derived from a cycloa ...
or
aryl
In organic chemistry, an aryl is any functional group or substituent derived from an aromaticity, aromatic ring, usually an aromatic hydrocarbon, such as phenyl and naphthyl. "Aryl" is used for the sake of abbreviation or generalization, and "Ar ...
. Sulfenyl chlorides are reactive compounds that behave as sources of . They are used in the formation of and bonds. According to
IUPAC
The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...
nomenclature they are named as alkyl thiohypochlorites, i.e.
ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides a ...
s of thiohypochlorous acid.
Preparation
Sulfenyl chlorides are typically prepared by
chlorination Chlorination may refer to:
* Chlorination reaction
In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transform ...
of
disulfide
In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In ...
s:
:
R2S2 + Cl2 -> 2 R-SCl
This reaction is sometimes called the Zincke disulfide reaction, in recognition of
Theodor Zincke. Typically, sulfenyl halides are stabilized by
electronegative
Electronegativity, symbolized as , is the tendency for an atom of a given chemical element to attract shared electrons (or electron density) when forming a chemical bond. An atom's electronegativity is affected by both its atomic number and the d ...
substituents. This trend is illustrated by the stability of obtained by chlorination of
carbon disulfide
Carbon disulfide (also spelled as carbon disulphide) is a neurotoxic, colorless, volatile liquid with the formula and structure . The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical n ...
.
Some
thioether
In organic chemistry, an organic sulfide (British English sulphide) or thioether is an organosulfur functional group with the connectivity as shown on right. Like many other sulfur-containing compounds, volatile sulfides have foul odors. A su ...
s () with
electron-withdrawing substituent
In chemistry, an electron-withdrawing group (EWG) is a substituent that has some of the following kinetic and thermodynamic implications:
*with regards to electron transfer, electron-withdrawing groups enhance the oxidizing power tendency of t ...
s undergo chlorinolysis of a bond to afford the sulfenyl chloride.
Reactions
Perchloromethyl mercaptan () reacts with bonds in the presence of base to give the
sulfenamides:
:
CCl3SCl + R2NH -> CCl3SNR2 + HCl
This method is used in the production of the fungicides
Captan
Captan is a general use pesticide (GUP) that belongs to the phthalimide class of fungicides. It is a white solid, although commercial samples appear yellow or brownish.
Applications
Although it can be applied on its own, Captan is often add ...
and
Folpet
Folpet is the tradename for the organic compound with the formula C6H4(CO)2NSCCl3. It is a fungicide derived from phthalimide (C6H4(CO)2N-) and trichloromethylsulfenyl chloride. The compound is white although commercial samples can appear bro ...
.
Sulfenyl chlorides add across
alkene
In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond.
Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...
s, for example
ethylene:
:
CH2=CH2 + R-SCl -> R-SC2H4Cl
They undergo
chlorination Chlorination may refer to:
* Chlorination reaction
In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transform ...
to the
trichlorides:
[
:R-SCl + Cl2 -> -SCl2l
Sulfenyl chlorides react with water and alcohols to give sulfenyl esters ():
:R-SCl + H2O -> R-SOH + HCl
:R-SCl + R'-OH -> R-SO-R' + HCl
]
Route to sulfinyl halides
Sulfenyl chlorides can be converted to sulfinyl chlorides (RS(O)Cl). In one approach, the sulfinyl chloride is generated in two steps starting with reaction of a thiol
In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl gro ...
() with sulfuryl chloride
Sulfuryl chloride is an inorganic compound with the formula SO2Cl2. At room temperature, it is a colorless liquid with a pungent odor. Sulfuryl chloride is not found in nature, as can be inferred from its rapid hydrolysis.
Sulfuryl chloride is ...
(). In some cases the sulfenyl chloride results instead, as happens with 2,2,2-trifluoro-1,1-diphenylethanethiol
Ethanethiol, commonly known as ethyl mercaptan, is an organosulfur compound with the formula CH3CH2SH. is a colorless liquid with a distinct odor. Abbreviated EtSH, it consists of an ethyl group (Et), CH3CH2, attached to a thiol group, SH. Its st ...
. A trifluoroperacetic acid
Trifluoroperacetic acid (trifluoroperoxyacetic acid, TFPAA) is an organofluorine compound, the peroxy acid analog of trifluoroacetic acid, with the condensed structural formula . It is a strong oxidizing agent for organic oxidation reactions, such ...
oxidation then provides a general approach to formation of sulfinyl chlorides from sulfenyl chlorides:
Related compounds
Sulfenyl fluorides and bromide
A bromide ion is the negatively charged form (Br−) of the element bromine, a member of the halogens group on the periodic table. Most bromides are colorless. Bromides have many practical roles, being found in anticonvulsants, flame-retardant ...
s are also known. Simple sulfenyl iodide
An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt, which many governments mandate. Worldwide, iodine de ...
s are unknown because they are unstable with respect to the disulfide
In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In ...
and iodine:
:2 R-SI -> (R-S)2 + I2
Sulfenyl iodides can be isolated as stable compounds if they bear alkyl steric protecting groups as part of a cavity-shaped framework, illustrating the technique of kinetic stabilization of a reactive functionality, as in the case of sulfenic acids.
A related class of compounds are the alkylsulfur trichlorides, as exemplified by methylsulfur trichloride, .
The corresponding selenenyl halides, , are more commonly encountered in the laboratory. Sulfenyl chlorides are used in the production of agents used in the vulcanization
Vulcanization (British: Vulcanisation) is a range of processes for hardening rubbers. The term originally referred exclusively to the treatment of natural rubber with sulfur, which remains the most common practice. It has also grown to includ ...
of rubber.
References
{{functional groups
Organosulfur compounds
Functional groups