Isothiouronium
In organic chemistry, isothiouronium is a functional group with the formula [RSC(NH2)2]+ (R = alkyl, aryl) and is the acid salt of isothiourea. The H centres can also be replaced by alkyl and aryl. Structurally, these cations resemble guanidinium cations. The CN2S core is planar and the C–N bonds are short.[1]
Synthesis
[edit | edit source]Salts comprising these cations are typically prepared by alkylation of thiourea:
- SC(NH2)2 + RX → [RSC(NH2)2]+X−
Reactions
[edit | edit source]Hydrolysis of isothiouronium salts gives thiols.[2]
- [RSC(NH2)2]+X− + NaOH → RSH + OC(NH2)2 + NaX
Isothiouronium salts in which the sulfur has been alkylated, such as S-methylisothiourea hemisulfate (CAS number: 867-44-7), will convert amines into guanidinium groups. This approach is sometimes called the Rathke synthesis[3] after Bernhard Rathke[4] who first reported it in 1881.[5]
- RNH2 + [CH3SC(NH2)2]+X− → [CH3N(H)C(NH2)2]+X− + CH3SH
Chelating resins with isothiouronium groups are used to recover mercury and other noble metals including platinum from solutions.[6]
References
[edit | edit source]- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).; Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)..
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).