Spectroscopic study of charge-transfer complexes of some dicyclohexano-crown ethers with Pi-acceptors in dichloromethane solution

A spectrophotometric study was conducted on solutions of dicyclohexano-18-c rown-6 and dicyclohexano-24-crown-8 with some Pi-acceptors in methylene cho ride at 25 degrees C. The spectroscopic data indicate the formation of a ch arge-transfer complex. In contrast to previous results, our study shows tha t the Ph-O-CH2 structure is not essential for the formation of charge-trans fer complexes. The formation constants (K-f) were calculated and the effect of KCl and NaCl salts on the formation and stability of the complexes is d iscussed.