Platinum cyanates

Platinum(II) halides react with cyanate salts to give cyanato complexes. Reacting the compounds Pt(NCO)4 with triphenylphosphine gives Pt(NCO)2(PPh3)2.1628 These platinum(II) complexes are N-bonded. Treatment with carbon monoxide and alcohol yields the complex (172 equation 476).1629... 

The coordination chemistry of the cyanate, thiocyanate and selenocyanate ligands has been recently reviewed.1874 Platinum(II) forms the complex ion Pt(SCN)2-, and the corresponding homoleptic platinum(IV) complex Pt(SCN)i can be prepared. Numerous mixed ligand complexes of platinum(II) are known containing the thiocyanate ligand and other ligands, although there are fewer platinum(IV) examples. 4... 

P NMR spectroscopy.53 Steric factors account for the different coordination modes, while the influence of electronic factors is evidenced by the difference in structure between analogous palladium(II) and platinum(II) compounds, for example, the thiocyanates are N- and S-bonded in [Pd(NCS)(SCN)(diars)], but only S-bonded in [Pt(SCN)2(diars)].54 These and other diphosphine or diarsine complexes of palladium(II) with thio- or seleno-cyanate ligands are further discussed in Section 51.8.2.6. 

The oxidation of free cyanide ion yields cyanogen or cyanate, never fulminate. It might seem that when the carbon atom is attached to hydrogen or a metal, addition of oxygen to the nitrogen atom should be possible, but there is no record of such an oxidation ever having been achieved. The reverse process, conversion of combined fulminate into combined cyanide, has, however, been demonstrated for platinum(II) and iron(ll) complexes. 

They wasted no time. Berzelius supplied the young student with a platinum crucible, a wash bottle, a balance and a set of weights, advised him to buy his own blowpipe, and set him to work on the examination of minerals. That was to be his first training m accurate analysis. When Woehler hurried,to Berzelius to show him the result of his work his teacher warned him, Doctor, that was quick but bad." Woehler remembered this valuable advice. Woehler now turned once more to his recently discovered cyanic acid and succeeded in preparing silver cyanate, a compound of this acid. 

CO2 and N2. Excess chlorine gas (i.e., chlorine which did not form hypochlorite) converted the cyanide to cyanate, which was subsequently oxidized by hypochlorite. Cadmium was precipitated from the water due to an increase in the solution pH. A platinum-plated niobium screen was the anode and a stainless steel screen was used as the cathode. At an applied potential of 6.0 V, resulting in a current of 6.0 A, the cadmium concentration decreased from 17.4mg/dm to 0.01 mg/dm, while the cyanide concentration declined from 54 mg/dm to zero in 80 min of cell operation. 

In contrast, anodic cyanation of diphenylacetylene occurs exclusively at the aromatic ring and the triple bond remains intact 4-cyanodiphenylacetylenc is formed in 60% yield. The reaction was run at 2 V (vs. S.C.E.) for 3-9 F mol" using a platinum anode in methanol containing sodium cyanide. Anodic cyanation results in preferred attack at the aromatic nucleus in other systems toluene, mesitylene and hexamethylbenzene give nuclear substitution and little side-chain cyanation under similar conditions in contrast with the corresponding acetoxylation or methoxylation reactions. 

Platinum, catalytic, 28, 29, 55 Poachers for gun cotton, 95, 96 Polyglycerines, 91 Potassinm cyanate, 73... 

Nucleophilic attack by cyanate ion upon the coordinated ethylene in (48) leads to an A-ethyl-eneisocyanate ligand whieh adds electrophilically to the platinum (assisted by another cyanate) to form a metallaazacyclopentane (49) (Equation (8)), the structure of which was definitively established by x-ray crystallography <82JA7661>. Surprisingly, other nucleophiles which are known to be less reactive to ethylene and more towards Pt(II) did not lead to metallacycles <83CC40>. 

Anodic cyanation of tertiary aliphatic and heterocyclic amines in sodium cyanide-aqueous methanol solutions using platinum electrodes takes place a-to the nitrogen atom to form the a-cyano-amines in reasonable yields. ... 

The synthesis of nitriles by anodic cyanation has been studied by several groups of workers but there are few examples of practical value [98-l6l]. One is the synthesis of p-cyanodiphenylamines which was carried out in a two com partment H-type cell with platinum electrodes. The anolyte was a methanolic solution of the reactant and sodium cyanide and the catholyte was a methanolic solution of sodium cyanide. 

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