42 



SECTIONAL ADDRESSES 



C,H, 



Br 



C.H, 



Au 



NH, 



A mminodiethylbromogold . 

 Col. doubly refracting needles. 



C..H5 



Br 



C2H5 



Au 



S(C,H,), 



Dibensylsulphidodiethylbromogold. 

 m.p. 91°. Col. needles. 



Acetylacetonediethylgold. 

 Col. plates, m.p. 10°. 



All these and analogous compounds are soluble in hydrocarbon and other 

 organic solvents and some interest attaches to the fourth and fifth com- 

 pounds. Dibenzylsulphidodiethylbromogold (Brain and Gibson 1938) 

 is the first auric compound of this type to be prepared by the direct 

 addition of an organic sulphide to an auric compound. The compound 

 separates rapidly and no reduction of the auric compound or oxidation 

 of the sulphide takes place. Acetylacetonediethylgold is the first of 

 these organic gold compounds containing no halogen to be prepared. 

 It was the first organic gold compound from which brilliant gold films 

 were obtained. These films are obtained when the compound in solu- 

 tion in a solvent such as ethanol is exposed to light at ordinary tempera- 

 tures and also on gentle warming. Obviously, the compound prepared 

 easily by the action of thallousacetylacetone on diethylmonobromogold 

 is but one of a number of similarly constituted gold compounds which 

 can be obtained from metallic derivatives of (i-diketones. The decomposi- 

 tion of such compounds by suitable alkali salts is a convenient method 

 of preparing chlorine and iodine derivatives of the parent dialkyl gold 

 compounds. 



One would expect that non-electrolytes analogous to the above ammino 

 and pyridino derivatives containing ethylenediamine should exist. The 

 first compound of the type : 



Br 



R— Au^NHa— CgH^- 



I 

 R 



-H^N- 



Br 



Au— R 



R 



was prepared from di-n-propylmonobromogold (R = Pr*) and no ana- 

 logous compound was obtained from diethylmonobromogold ; but 

 analogous cyanogen compounds are easily obtained both in the ethyl 

 and propyl series. Monoethylenediaminotetra-w-propyldibromodigold 

 (Burawoy and Gibson 1934) is a fairly stable colourless crystalline, 

 4-covalent auric compound soluble in certain organic solvents. On 



