Organometallic compounds toxicity

Discuss the historical aspects of organometallic compound toxicity, including organoarsenicals used as pharmaceutical agents, gasoline antiknock additives, and compounds used in applications such as catalysis and chemical synthesis. 

Huang G, Bai Z, Dai S, Xie Q (1993) Accumulation and toxic effects of organometallic compounds on algae. Applied Organometallic Chemistry, 7 265-271. 

Mercury, tin, lead, arsenic, and antimony form toxic lipophilic organometallic compounds, which have a potential for bioaccumulation/bioconcentration in food chains. Apart from anthropogenic organometallic compounds, methyl derivatives of mercury and arsenic are biosynthesized from inorganic precursors in the natural environment. 

Reacts with many metals to give hydrogen, sometimes violently. With non-metals pyrophoric hydrides may result. Frequently initiates explosive reactions between other substances. Violent reactions with many non-metal and some metal halides and oxyhalides, also with many organometallic compounds. Many metal nonmetal-lides produce toxic, flammable or pyrophoric gases on contact with diprotium monoxide. 

Modem petrol contains small amounts of additives to inhibit this knocking. Leaded petrol, for example, contains the organometallic compound lead tetraethyl, PbEt. Although PbEQ is excellent at stopping knocking, the lead by-products are toxic. In fact, most EU countries now ban PbEt. ... 

Interest in the uses of HMPT has also been maintained, but a warning has been issued (by the E. I. du Pont de Nemours Company and the U.S. National Institute for Occupational Safety and Health) about its potential acute toxicity. HMPT has been used in the synthesis of 2,4-bis(dimethylamino)qui nolines,9 8 as a solvent for reactions between carbonyl compounds and sulphur," for the conversion of iV-benzylcarbox-amides into 3-phenylpropionitriles,100 in reactions between metals or organometallic compounds with a variety of organic substrates,101 and as a solvent for alkylation reactions of /J-keto-esters and related compounds in which the alkylation reaction is accompanied by de(alkoxycarbonylation) (Scheme 7).102... 

An alternative to gallium vapour is an organometallic compound of gallium. One preparation reacts trimethyl gallium (Ga (0113)3) with the highly volatile (although toxic) arsine (AsHs). 

Organo-metallic compounds, on the other hand, behave very much like organic compounds, e.g. they can be redistilled and may be soluble in organic solvents. A note of caution should be made about handling organometallic compounds, e.g. arsines, because of their potential toxicities, particularly when they are volatile. Generally the suppliers of such compounds provide details about their safe manipulation. These should be read carefully and adhered to closely. If in any doubt always assume that the materials are lethal and treat them with utmost care. The abbreviations are listed in Chapter 1, pp. 1 and 2. The same safety precautions about the handling of substances as stated in Chapter 3 should be followed here. 

Individual chapters deal with the determination of metals, non-metals, organic compounds and organometallic compounds in soil and in plants that grow in soil. A separate chapter deals with sampling procedures. A relationship between toxicant levels in soil and plants that grow in that soil has been established and is the subject of the concluding chapter. 

Industrial accidents in which the combustion of organometallic compounds generates respirable, toxic metal oxide fumes can certainly pose a hazard. 

Diphenylzinc illustrates the toxicity hazard that may obtain from the organic part of an organometallic compound upon decomposition. Under some conditions, this compound can react to release toxic phenol (see Chapter 14) ... 

In general, how should the toxicities of lithium organometallic compounds be regarded Do they have any unique toxicity characteristics ... 

It has been observed that quite generally the toxic effects of organometallic compounds are stronger than those of the underlying metal ions. This is particularly true for the antimicrobial effects. The metal tin shows this phenomenon in a rather dramatic way. Whereas scarcely any pronounced biological effect is known for tin, either in the stannous or the stannic form, certain trialkyltin compounds belong to the most active fungicides known at present. 

It will be clear from the above examples that hydride-forming elements especially are often subjected to such speciation studies. There are, of course, good reasons for this. These are the very elements which tend to form toxic organometallic compounds, and they are elements which may be determined with excellent sensitivity. Moreover, interferences are not usually a problem following a separation process. 

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