Organo-metal compounds

Certain types of organic compounds contain­ing metals have been known for a long time. Grignard reagents (organic compounds that include magnesium) are important in the artifi­cial production of organic compounds. Or­ganic compounds containing lithium are also well established, the best-known being butyl lithium. It is used in making compounds that are important intermediates (middle steps) during the long processes sometimes neces­sary in making synthetic (artificial) compounds.

Other useful organo-metallics include alu­minum trialkyls. These metal compounds, in conjunction with titanium salts, are used to speed up the chemical processes for making complex organic compounds. Another organo-metal compound is lead tetraethyl. This is an antiknock agent that until recently had been widely added to gasoline. It is now being mostly phased out because of fears that the lead discharged in exhaust fumes may be harmful.

* :^l ill ■

Sheep are dippedin a

liquid that contains organo-phosphorus compounds. These substances are partic­ularly effective in destroying ticks and other external par­asites.

Ferroceneis probably the best known of the group of organo-metal compounds called sandwich com­pounds. Structurally, it con­sists of an iron atom sand­wiched between, and bonded to, two parallel cy-clopentadiene rings, as il­lustrated in the diagram. Ferrocene can be prepared relatively easily. At room temperature, ferrocene is an orange solid and has a camphorlike smell. It is in­soluble in water but dis­solves in most organic sol­vents, such as ethanol and benzene.

Caffeine(the structure of which is illustrated above) occurs in the beans of the coffee plant (right). It is also found in tea leaves, cola nuts, and cacao. It is proba­bly the best known of the al­kaloids. Alkaloids are a group of nitrogen-contain­ing ring compounds that have physiological effects. Caffeine, for example, is a stimulant and diuretic.

Date: 2015-12-11; view: 1874