A quantum chemical study on the stability of [3(n)]-allenophanes (n=2-4)

The stability of n-membered cyclic [3(n)]-allenophanes (n = 2-4) is investi gated by means of density functional and ab initio calculations. We report relative energies of various isomers of these species, constructing homodes motic reactions such as to provide a means for the comparison of different oligomers in terms of ring strain. Vibrational frequencies are analysed to characterize the stationary points of the potential surfaces and to answer the question whether the isomers can be distinguished via infrared spectros copy.