Names | |
---|---|
Preferred IUPAC name
2,1,3-Benzothiadiazole | |
Other names
| |
Identifiers | |
3D model (
JSmol)
|
|
ChemSpider | |
ECHA InfoCard | 100.005.442 |
EC Number |
|
PubChem
CID
|
|
UNII | |
CompTox Dashboard (
EPA)
|
|
| |
| |
Properties | |
C6H4N2S | |
Molar mass | 136.17 g·mol−1 |
Melting point | 54.0 °C (129.2 °F; 327.1 K) |
Boiling point | 203.0 °C (397.4 °F; 476.1 K) |
Related compounds | |
Related compounds
|
1,2,3-Benzothiadiazole |
Hazards | |
GHS labelling: | |
Warning | |
H315, H319, H335 | |
P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501 | |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
2,1,3-Benzothiadiazole is a bicyclic molecule composed of a benzene ring that is fused to a 1,2,5-thiadiazole.
2,1,3-Benzothiadiazole has been known since the 19th century. It is readily prepared in at least 85% yield from o-phenylenediamine by reaction with two equivalents of thionyl chloride in pyridine. The by-products are sulfur dioxide and HCl. [1]
There are a number of alternative methods used to make this heterocycle and these have been reviewed. [2] [3] The crystal structure of the compound was determined in 1951, when it had the common name piazthiol(e). [4]
The extent of the aromaticity of the compound was examined by a study of its proton NMR spectrum and comparison with naphthalene, which allowed the conclusion that it and related oxygen and selenium heterocycles did behave as 10-electron systems in which the 2-heteroatom contributed its lone pair to the ring current, in accordance with Hückel's rule. [5]
As a result, 2,1,3-benzothiadiazole undergoes the standard chemistry of aromatic compounds, for example readily forming nitro [1] and chloro derivatives. [6] The chemistry of this heterocycle and its simple derivatives has been reviewed. [7]
Under reducing conditions, 2,1,3-benzothiadiazoles can be converted back to the 1,2-diaminobenzene compounds from which they were prepared. This can be a useful way to protect a pair of reactive amino groups while other transformations are performed in the benzene ring to which they are attached. [8]
Bromination of 2,1,3-Benzothiadiazole is commonly performed to synthesize 4,7-dibromo-2,1,3-benzothiadiazole. This derivative is extensively used as building block in the design and synthesis of larger molecules and conductive polymers via Suzuki-Miyaura cross-coupling reactions. [9]
2,1,3-Benzothiadiazole derivatives containing carbazole units have been found to be luminiscent, with high emission intensity and quantum efficiency. [10]
Different π-extended molecular systems based on 2,1,3-benzothiadiazole have been built to study fundamental structure–property relationships. [8] One example of this type of oligomer consist of extended thiophene building blocks as electron donors and 2,1,3-benzothiadiazole as electron aceptor. This oligomer was synthesized using a Sonogashira cross-coupling reaction and it showed low HOMO–LUMO gaps which could be interesting for organic semiconductor applications. [11]
Asymmetric derivatives with diphenylamine donors, cyanoacrylic acid acceptors and thiophene linkers bridged by a 2,1,3-benzothiadiazole have been designed as organic dyes with improved charge separation properties [12] when compared to classic cyanine [13] and hemicyanine [14] dyes.
2,1,3-Benzothiadiazole has been of interest as a redox-active organic component in flow batteries owing to its favourable solubility, low reduction potential and fast electrochemical kinetics. [15]
Such properties in derivatives containing this heterocycle have made it of growing interest in dyestuffs, [16] white light-emitting polymers, [8] [17] solar cells, [18] and in luminescence studies. [19]
Names | |
---|---|
Preferred IUPAC name
2,1,3-Benzothiadiazole | |
Other names
| |
Identifiers | |
3D model (
JSmol)
|
|
ChemSpider | |
ECHA InfoCard | 100.005.442 |
EC Number |
|
PubChem
CID
|
|
UNII | |
CompTox Dashboard (
EPA)
|
|
| |
| |
Properties | |
C6H4N2S | |
Molar mass | 136.17 g·mol−1 |
Melting point | 54.0 °C (129.2 °F; 327.1 K) |
Boiling point | 203.0 °C (397.4 °F; 476.1 K) |
Related compounds | |
Related compounds
|
1,2,3-Benzothiadiazole |
Hazards | |
GHS labelling: | |
Warning | |
H315, H319, H335 | |
P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501 | |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
2,1,3-Benzothiadiazole is a bicyclic molecule composed of a benzene ring that is fused to a 1,2,5-thiadiazole.
2,1,3-Benzothiadiazole has been known since the 19th century. It is readily prepared in at least 85% yield from o-phenylenediamine by reaction with two equivalents of thionyl chloride in pyridine. The by-products are sulfur dioxide and HCl. [1]
There are a number of alternative methods used to make this heterocycle and these have been reviewed. [2] [3] The crystal structure of the compound was determined in 1951, when it had the common name piazthiol(e). [4]
The extent of the aromaticity of the compound was examined by a study of its proton NMR spectrum and comparison with naphthalene, which allowed the conclusion that it and related oxygen and selenium heterocycles did behave as 10-electron systems in which the 2-heteroatom contributed its lone pair to the ring current, in accordance with Hückel's rule. [5]
As a result, 2,1,3-benzothiadiazole undergoes the standard chemistry of aromatic compounds, for example readily forming nitro [1] and chloro derivatives. [6] The chemistry of this heterocycle and its simple derivatives has been reviewed. [7]
Under reducing conditions, 2,1,3-benzothiadiazoles can be converted back to the 1,2-diaminobenzene compounds from which they were prepared. This can be a useful way to protect a pair of reactive amino groups while other transformations are performed in the benzene ring to which they are attached. [8]
Bromination of 2,1,3-Benzothiadiazole is commonly performed to synthesize 4,7-dibromo-2,1,3-benzothiadiazole. This derivative is extensively used as building block in the design and synthesis of larger molecules and conductive polymers via Suzuki-Miyaura cross-coupling reactions. [9]
2,1,3-Benzothiadiazole derivatives containing carbazole units have been found to be luminiscent, with high emission intensity and quantum efficiency. [10]
Different π-extended molecular systems based on 2,1,3-benzothiadiazole have been built to study fundamental structure–property relationships. [8] One example of this type of oligomer consist of extended thiophene building blocks as electron donors and 2,1,3-benzothiadiazole as electron aceptor. This oligomer was synthesized using a Sonogashira cross-coupling reaction and it showed low HOMO–LUMO gaps which could be interesting for organic semiconductor applications. [11]
Asymmetric derivatives with diphenylamine donors, cyanoacrylic acid acceptors and thiophene linkers bridged by a 2,1,3-benzothiadiazole have been designed as organic dyes with improved charge separation properties [12] when compared to classic cyanine [13] and hemicyanine [14] dyes.
2,1,3-Benzothiadiazole has been of interest as a redox-active organic component in flow batteries owing to its favourable solubility, low reduction potential and fast electrochemical kinetics. [15]
Such properties in derivatives containing this heterocycle have made it of growing interest in dyestuffs, [16] white light-emitting polymers, [8] [17] solar cells, [18] and in luminescence studies. [19]