Sulfamate, silver

Sulfamic acid and its salts retard the precipitation of barium sulfate and prevent precipitation of silver and mercury salts by alkah. It has been suggested that salts of the type AgNHSO K [15293-60 ] form with elemental metals or salts of mercury, gold, and silver (19). Upon heating such solutions, the metal deposits slowly ia mirror form on the wall of a glass container. Studies of chemical and electrochemical behavior of various metals ia sulfamic acid solutions are described ia Reference 20. 

After successful application of the silver catalyst shown in olefin aziridination (Section 6.1.1), He and coworkers showed that intramolecular amidation was possible with both hydrocarbon-tethered carbamates and sulfamate esters.24 They found that only the Bu3tpy silver complex could catalyze efficient intramolecular amidation, while other pyridine ligands gave either dramatically lower yields or complicated product mixtures. In an interesting control study, both copper and gold were also tested in this reaction. Both the copper and gold Bu tpy complexes can mediate olefin aziridination, but only silver can catalyze intramolecular C-H amidation, indicating that the silver catalyst forms a more reactive metal nitrene intermediate. 

Oxathiazines 575 have been prepared by the reaction of sulfamates 574 with (diacetoxyiodo)benzene in the presence of rhodium catalysts (Scheme 259) <2001JA6935>. This type of reaction can also be catalyzed by silver complexes <2004AGE4210, CHEC-III(9.10.9.1)548>. 

Silver(I) sulfamate is remarkable for its considerable solubility in water over a wide range of temperatures and the fact that the anion is normally nonoxidizing. The substance is also a very important starting material for numerous syntheses of other sulfamates, imidodisulfates, and their derivatives. 

The first recorded synthesis of silver(I) sulfamate was that by Berglund in 1876 he used the very slow reaction between silver(I) sulfate and barium(II) sulfamate. Later methods have employed the reaction between sulfamic acid and silver(I) oxide or silver(I) carbonate an electrolytic process has also been described. ... 

The synthesis- offered below is probably best in terms of availability of starting materials and ease of their purification, using, as it does, silver(I) nitrate, potassium hydrogen carbonate, and high-purity commercial sulfamic acid. 

The light-yellow precipitate of silver(I) carbonate that forms is washed twice with 100 mL of warm distilled water by decantation, and a solution of 10 g (0.1 mole) of sulfamic acid in 100 mL of distilled water at 60° is added carefully. After the reaction has subsided, the solution of silver(I) sulfamate is heated briefly to 100° to expel dissolved carbon dioxide and is then filtered rapidly into a crystallizing dish. The solution is allowed to stand overnight in the dark. 

Alternatively, when the precipitated silver(I) carbonate from the first stage of the preparation has been washed by decantation, a solution of 10 g (0.1 mole) of sulfamic acid in 50 mL of hot, distilled water is carefully added. The concentrated solution of silver(I) sulfamate is filtered rapidly with suction and, on cooling, deposits a large crop of tiny, transparent crystals. Purification is achieved by recrystallization from warm water. Anal. Calcd. for NHaSOaO Ag, 52.89. Found Ag, 52.73 (Volhard method). 

Silver(I) sulfamate forms colorless, rhombic crystals that darken slowly on exposure to light. The substance has the following solubilities in water. ... 

U.S. 4992195 Dolan et al. Sulfamic acid or Protection of silver items ... 

Sulfamates 175 were found to react with PhI(OAc)2, MgO, in the presence of rhodium catalysis, to provide oxathiazines 176 via C-H insertion (Equation 47) <2001JA6935>. This type of reaction can be catalyzed also by silver(l) complexes to give products 178 from substrates 177 (Equation 48) <2004AG(E)4210>. 

Erom the various methods reported for the preparation of 1,2,3-oxathiazine 2,2-dioxides, the intramolecular amidation of sulfamates catalyzed by rhodium and silver (Equations 47 and 48) reveals itself as the best approach, in view of the high yields. 

With the same silver catalyst, an oxidative intramolecular cy-clization of carbamates and sulfamates allows the generation of A-heterocycles through amidation of CH bonds. ... 

According to the label on the consumer product, the liquid silver cleaning product TarnX contains thiourea, a detergent, and sulfamic acid. 

Silver Nitrate Sodium Thiosulfate Stannous Chloride Tin (II) Chloride Potassium Bisulfite Potassium Hydrogen Sulfite Ammonium Sulfamate Sodium Chlorate Sodium Chromate... 

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