Mono- and Di-μ-hydrido-bridged carbodications in acyclic systems
μ-Hydrido-bridging in carbocations (C-H-C)+ involves a two-electron three-center bond. Such structures have previously been observed only when the two carbons are part of a medium ring (monocyclic, bicyclic, or tricyclic frameworks). Using appropriately constructed carbodications, acyclic systems are now shown to form such structures, including a novel example containing two μ-hydrido-bridged units.
Sun, Fang,Sorensen
p. 77 - 81
(2007/10/02)
Rates and Alkyl Group Size in Solvolysis of Alkyl Derivatives
The logarithm of solvolysis rate constants in 80percent aqueous ethanol of 1,1-dimethyl-1-alkyl chlorides 1 and 1-phenyl-1-alkyl chlorides 2 decrease monotonically with increasing number of carbon atoms in the alkyl group.The first member of both series deviates from the corresponding correlation lines which have the some slope.In contrast, solvolysis rates in 80percent aqueous ethanol of 1-methyl-1-alkyl tosylates 3 do not depend upon the size of the alkyl group.The results are rationalized in terms of a mechanism that is very similar in reactions of series 1 and 2 but different from that of series 3.