A silyl cation with a three-center si-h-si bond

The unusually high kinetic stability of the silyl cation 1 is due to the presence of a three-center, two-electron Si-H-Si bond. NMR data ((1) H, (2) H, (13) C, (29) Si) are consistent with the static, symmetrical structure shown, which was further corroborated by the results of density functional calculations.

Evolutionary roots of catalysis by nicotinamide and flavins in C-H oxidoreductases and in photosynthesis

The evolutionary information obtained from sequencing proteins and RNA's fades out completely for early periods in evolution. Information for tracing evolution even further could stem from the analysis of coenzyme mechanisms. Likewise, placing cofactors in their proper evolutionary context gives new hints concerning their actual mechanisms of catalysis.