Telluroamides
| Telluroamides |
|---|
 primary telluroamide |
 secondary telluroamide |
 tertiary telluroamide |
| R 1 , R 2 and R 3 are organic radicals ( alkyl , aryl or the like). The telluroamide group is marked in blue . |
Telluroamides are organic chemical compounds . They represent tellurium analogues of carboxamides and belong to the tellurocarbonyl compounds.
The basic structure of their functional group consists of a tellurium atom, which is bound to a carbon atom by a double bond . The carbon atom is linked to a nitrogen atom by a single bond . The number of bonded hydrogen atoms depends on the number of substituents . A distinction can be made between primary , secondary and tertiary telluroamides. Even if their membership of the chalcogen compounds implies similar properties as analogous sulfur or selenium compounds , recent reports point to different observations. Organic tellurium compounds such as telluroamides stand out due to the hypervalent properties of the tellurium atom , the possibility of forming 2-electron-3-center bonds and their behavior as Lewis acids . Nevertheless, they are more unstable than analogous selenium compounds. However, telluroamides are still little researched.
properties
Compared to telluroaldehydes and telluroketones, telluroamides are thermodynamically more stable . It was not until 1997 that crystalline structures of telluroamides were discovered. This property indicates a mesomeric boundary structure, which seems to be more stable and therefore more important.
Telluroamides are sensitive to light , oxygen and moisture , which has hindered their research so far. In addition, complex compounds between telluroamides and metals of the sixth group of the periodic table were investigated, whereby no stabilization of telluroamides by such metals could be determined.
synthesis
Two classes of substances , N, N -dialkylamides and selenoamides , are mainly used for the synthesis of telluroamides . The synthesis from N, N -dialkylamides is carried out by reacting them with bis (dimethylaluminum) telluride in toluene.
In order to synthesize telluroamides from selenoamides , the selenium atom must first be methylated with methyl trifluoromethylsulfonate . The resulting selenium salt is stable to oxygen . A telluroamide is obtained through the subsequent reaction with lithium aluminum hydride and elemental tellurium .
In this way the first aliphatic telluroamide could be isolated.
Reactions
Few reactions of telluroamides are known. For stabilization, the compounds can be converted into salts with methyl trifluoromethyl sulfonate and dichloromethane .
See also
Individual evidence
- ^ A b T. Chivers & RS Laitinen: Tellurium: a maverick among the chalcogens . In: Chemical Society Reviews . tape 44 , no. 7 , 2015, p. 1725-1739 , doi : 10.1039 / C4CS00434E .
- ↑ a b G.M. Li, RA Zingaro, M. Segi, JH Reibenspies & T. Nakajima: Telluroamides and selenoamides. The first crystallographic study of Telluroamides . In: Organometallics . tape 16 , no. 4 , 1997, p. 756-762 , doi : 10.1021 / om960883w .
- ↑ a b Thioamides, Thioureas, and Related Selenium and Tellurium Compounds . In: FA, Devillanova (Ed.): Handbook of chalcogen chemistry: new perspectives in sulfur, selenium and tellurium . Royal Soc. of Chemistry, Cambridge 2013, ISBN 978-1-84973-623-7 , pp. 111-112 .
- ↑ GM Li, JH Reibenspies & RA Zingaro: Telluroamides and selenoamides: Complexes with chromium, molybdenum, and tungsten pentacarbonyls . In: Heteroatom Chemistry . tape 9 , no. 1 , 1998, p. 57-64 , doi : 10.1002 / (SICI) 1098-1071 (1998) 9: 1 <57 :: AID-HC7> 3.0.CO; 2-% 23 .
- ↑ a b Y. Mutoh & T. Murai: Acyclic selenoiminium salts: Isolation, first structural characterization, and reactions . In: Organic letters . tape 5 , no. 8 , 2003, p. 1361-1364 , doi : 10.1021 / ol034334f .
- ^ Y. Mutoh, T. Murai & S. Yamago: Acyclic telluroiminium salts: Isolation and characterization . In: Journal of the American Chemical Society . tape 126 , no. 51 , 2004, p. 16696–16697 , doi : 10.1021 / ja044022n .