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.
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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: 981