Quantum yield cycloalkanes

Table 6 Quantum Yields and G Values of C H2 Aliphatic Alkenes in the 7.6-eV Photolysis and Radiolysis of C H2 Cycloalkanes...

At the conical intersection the C1-C2-C3 valence angle <0 is close to 90°, suggesting that in strained systems, where this value is hard to reach, the excited-state barrier on the pathway to the conical intersection or the conical intersection itself may be so high in energy that the photoreaction cannot take place. The quantum yields for cyclobutene formation in dimethylene-cycloalkanes summarized in Scheme 29 (Aue and Reynolds, 1973 Leigh and Zheng, 1991) are in agreement with this expectation. 

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