The synthesis and properties of the transannularly bonded electron-rich olefin derived from 1,4,8,11-tetra-azacyclotetradecane; X-ray crystal structure of the chelating cis-dicarbenerhodium(I) salt obtained therefrom

Abstract

Reaction of 1,4,8,11-tetra-azacyclotetradecane with HC(OMe)₂NMe₂ yields the olefin (abbreviated as L₂ ^cyclam), formed by filling the macrocyclic cavity with a transannularly bound CC bond, this being cleaved by (a) insertion therein of a Rh^I moiety upon treatment with [{Rh(cod)Cl}₂](cod = cyclo-octa-1,5-diene) to furnish [Rh(cod)(L₂ ^cyclam)][Rh(cod)Cl₂](3), or (b) oxidation to give a bis(urea); X-ray analysis of the chelating dicarbenerhodium(I) complex, obtained from (3) and CO, to R= 0·0357, R′= 0·0716, shows Rh–C(carb, av.) 2·02 and Rh–(cod)_av 2·20 Å, and C(carb)–Rh–C(carb′)= 78·1(2)°.