312 SECTIONAL TRANSACTIONS.— B. 



Diethylgold acetylacetone formed by the interaction of diethyl gold bromide on 

 thallous acetylacetone is a colourless liquid, m.p. 9-9-5°, having the constitution 



CH., 

 Et I 



\ 0— C 



\ / \ 

 Au C(H) 



/ X / 

 Et 0=C 



I 

 CHn 



■J s 



its physical properties being in marked contrast to those of dimethylthallium — and 

 trimethylplatinum acetylacetone, which are colourless, high melting solids recently 

 described by Menzies. Diethylgold acetylacetone undergoes spontaneous decom- 

 position by light and also on being gently heated, beautiful gold mirrors of varying 

 thicknesses being obtained. From this compound, by the action in alcoholic solution 

 of sodium iodide, diethylgold iodide has been obtained. 



The investigation is being extended in various directions. 



Dr. R. C. Menzies. — Some Organic Compounds of Thallium. 



The thallous atom, in virtue of its strongly electropositive nature, replaces the 

 hydrogen atoms of many hydroxy compounds — including simple and polyhydric 

 alcohols of the aliphatic series — with formation of stable compounds, which are 

 generally leas soluble than those of the alkaU metals and consequently more easily 

 prepared. 



In many cases, all the hydroxyl hydrogen atoms of polyhydric alcohols can be thus 

 replaced, dithalUum ethylene glycol, trithaUium glycerol, tetrathaUium erythritol, and 

 hexathalhum sorbitol being cases in point. 



The hydroxyl hydrogen of hydroxy acids can also be replaced by thallium as well 

 as the carboxyl hydrogen, dithallium glycoUate, tctrathalHum d-tartrate, tetrathaUium 

 meso-tartrate, and hexathaUium gluconate having been prepared by treating the 

 corresponding acids or their normal thallium salts with the necessary excess of aqueous 

 thaUous hydroxide solution. 



Well-defined thaUium salts of the reducing sugars have not yet been prepared 

 owing to the reduction of the metal with oxidation of the sugars and consequent 

 formation of mixtures of oxidation products. 



Methyl arabinoside, however, and a and ^-methyl glucosides and sucrose in which 

 the reducing groups are protected, all give weU-defined thaUium derivatives, forming 

 respectively trithallium methyl arabinoside, trithalUum a- and trithaUium [i-methyl 

 glucoside, and tetrathalUum sucrose. It vdW be noticed that whUe all three of the 

 replaceable hydrogens in methyl arabinoside can be exchanged for thalUum, in the 

 case of the methyl glucosides one of the four available hydrogens escapes replacement, 

 while sucrose on treatment with varj'ing quantities of thaUous hydroxide yields tetra- 

 thaUium sucrose in which four only of the eight avaUable hydrogen atoms are replaced. 



An explanation of these observations, which it is hoped to extend to other sugars, 

 has not yet been found, although it is significant that whUe tetrathaUium tartrate is 

 easily prepared, the dimethyl thaUium radical, which must take up more space than 

 the thallium atom only forms a tridimethj'l thaUium tartrate. 



Beginning with the simplest cases, attention may be called to Sidgwick's and 

 Sutton's recent paper showing that thallous ethoxide has in benzene solution a fourfold 

 molecular weight, and to their suggestion that the thalhum and oxygen atoms may be 

 arranged at alternate corners of a cube, the ethyl groups being attached, naturaUy, to 

 the oxygen atoms. If one of the [3 -hydrogen atoms in each ethyl group be now replaced 

 by OTl, a possible configuration for the thallium salt of ethylene glycol is seen to be 

 an arrangement of cubes having oxygen and thallium atoms at alternate corners, 

 each oxygen atom being joined to the oxygen atom at the corner of the adjacent cube 

 by the group — CHo.CHo — . This suggestion is, of course, put forward w-ith aU reserve. 



But the writer is of opinion that before any explanation of the results outUned 

 above can be forthcoming, it is necessary to explain the differences between thallous 

 ethoxide and dithaUium ethylene glycol, which are striking. He would welcome 

 further suggestions. 



