Rings with four long chains attached

Another possibility is that the ring structure may have long hydrocarbon chains attached at the comers so that they stand up at one side. These chains provide the hydrophobic component and the polarizable ring stmcture provides the hydrophilic moiety. There are studies with porphyrins bearing four long hydrocarbon chains and whose hydrophilic moieties are associated with the ring stmcture [80, 81]. However, these materials did not lead to the formation of ordered multilayers. The same general principle applied to phthalocyanines led to stable films at the water-air interface and could produce multilayers by the LB technique [82. 83]. 

A natural question chemistry students ask is Why are there so many compounds of carbon The answer Carbon contains four valence electrons and so can form four covalent bonds to other carbons or elements. (A common mistake organic chemistry students make when drawing structures is not ensuring that every carbon has four bonds attached to it.) The bonds that carbon forms are strong covalent bonds (Chapter 7 covers covalent bonds), and carbon has the ability to bond to itself in long chains and rings. It can form double and triple bonds to another carbon or to another element. No other element, with the possible exception of silicon, has this ability. (And the bonds silicon makes aren t nearly as strong as carbon s.) These properties allow carbon to form the vast multitude of compounds needed to make an amoeba or a butterfly or a baby. 

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