Silver picolinate

The use of silver (II) salts, particularly argentic picolinate, as reagents for hydroxyl oxidation has also been disclosed recently. The reaction may be run in acid, neutral or basic media in aqueous or polar organic solvents at room or slightly elevated temperatures. Primary alcohols may be oxidized to aldehydes or acids depending on the conditions used. Amines and trivalent phosphorous compounds are more sensitive to oxidation with this reagent than are hydroxyl groups. 

Picolinate and pyridine-2,6-carboxylate give stable complexes, with 4- and 6-coordination. Macrocycles like porphyrins afford silver(II) derivatives most remarkable is the reaction of the macrocycle meso-Me6[14]ane (Figure 4.13). 

Two papers concerning the reduction of chlorinated quinolines have been published [116, 117]. Electrolysis of 3,4,5,6-tetrachloro-2-picolinic acid at a silver... 

In THF-H20 (1 1), pentachloropyridine is reduced at a silver cathode to 2,3,5,6-tetrachloropyridine and further to 2,3,5-trichloropyridine. 3,4,5,6-Tetrachloro-2-picolinic acid may similarly be stepwise reduced.441,442... 

Quadricovalent complexes of silver(II) should have the same planar configuration as those of copper(II). This has been verified33 for the silver(II) salt of picolinic acid, which is isomorphous with the cop-per(II) salt and which shows moreover the high birefringence expected for a parallel arrangement of planar molecules with the structure... 

The crystal structure of silver(I) pyridine-2-carboxylate monohydrate has been determined.93 Each Ag atom was coordinated by two N atoms (Ag—N = 220.7(3) pm) and two carboxylic O atoms (Ag—O = 252.4(4) pm). The H atoms of the C02H groups were located on centres of symmetry making symmetrical hydrogen bonds between non-coordinated carboxylate O atoms. Thus the H atoms were equally shared by the C02H groups and there was no distinct molecule of silver(I) picolinate. 

Silver(n) and Silvery hi).—The cationic complex bis-(2,2, 2"-terpyridyl)Ag2+ has been isolated as its peroxydisulphate salt.217 The presence of a d-+d band at 15600 cm-1 is indicative of a six-co-ordinate ion. X-ray photoelectron spectra have provided Ag(3d5/2>3/2) binding energies for this complex and the mono-terpy complex. The influence of pyridine and 2-, 3-, and 4-picoline on bis(diethyl dithio-carbamato)AgH has been examined by e.s.r. spectroscopy.218 The results indicate formation of mono-addition products and the spin hamiltonian parameters for these complexes have been determined. 

Oxidation of (1) with silver(II) picolinate (3, 16) in DMSO ciTccted oxidation of the 2-methyl group to give the benzyl alcohol (3) in 25 % yield. 

According to Kyriacou and coworkers [279], reduction of 3,4,5,6-tetrachloro-2-pico-linic acid at a silver electrode in an aqueous medium yields 3,4,6-trichloro-2-picolinic acid, which can be further reduced to 3,6-dichloro-2-picolinic acid. 

Silver nitrate, 109,213,243,429-430 Silver oxide. 111, 430-431 Silver(II) oxide, 431-432 Silver perchlorate, 264,432-435 SilverQI) picolinate, 432 Silver sulfate, 435... 

The major products were -( ) and y- (II) picolines traces of pyridine and small amounts of ethylpyridines and higher molecular weight bases were also formed. Similar products have been observed when the same reactants were passed over silica-alumina 148). Zeolite catalysts, notably silver-exchanged X-type faujasites, have also proven effective in the synthesis of methylpyridines from acetylene and NHs, and methylacetylene and NHs, at temperatures ranging from 100° to 300° 149). 

Preparation.1 The reagent is prepared by the reaction of picolinic acid (pyridine-2-carboxylic acid) with silver nitrate and potassium persulfate. The material is stable on storage in the dark at room temperature for several months. 

Similarly, silver(II) picolinate and lead tetraacetate can be used to produce carbonyl compounds. 

Silver(n) complexes, 839-850 amino adds, 846 aqua,844,850 biguanides, 849 2,2 -bipyridyl, 843 carboxylates, 844 cinchomeronic acid, 842 dipicolinic acid, 842 dithiocarbamates, 845 isodnchomcronic add, 842 isonicotinates, 840 lutidinic acid, 842 N-heterocyclic ligands, 839 nicotinates, 840 1,10-phenanthroline, 843 phthalocyanines, 848 picolinates, 840... 

Perchloric acid Phosphomolybdic acid Phosphorus oxychloride Phosphorus pentachloride Phosphorus trichloride y-Picoline Polyphosphoric acid Potassium silicate Rhodium Selenium Selenium dioxide Silica gel Silver oxide (ous) Sodium borohydride Sodium silicate Strontium carbonate Sulfur dioxide Tantalum Tellurium Tetraisopropyl di (dioctylphosphito) titanate Titanocene dichloride Trichloromethylphosphonic acid Tristriphenylphosphine rhodium carbonyl hydride Tungsten carbide Vermiculite Ytterbium oxide Zinc chloride Zinc dust Zinc 2-ethylhexanoate Zirconium potassium hexafluoride... 

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