Enhanced acidity and Facile Complexation of Amines with a Phenol Trimer

ABSTRACT

The phenol trimer, 5,5′,5″-trichloro-1,1′:3′,1″-terphenyl-2,2′,2″-triol (1), facilely affords the 1:1 complex (I) with triethylamine owing to its enhanced acidity. IR spectra reveal that I is a proton transfer complex. In the X-ray structure of I, a long phenoxide C–O bond is observed that may be due to unusual sp³ hybridization of the phenoxide oxygen atom caused by strong intra- and inter-molecular hydrogen bonding.

Keywords:

• amine complex
• bond length
• phenoxide
• proton transfer complex
• X-ray structure

Acknowledgments

Financial support of this work by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology, Japan (90281104) is gratefully acknowledged. The authors are also grateful to the Ministry of Education, Culture, Sports, Science, and Technology, Japan for purchasing the high-field NMR instruments (JEOL JNM-A500 and JNM-EX270) by the special fund to K. M. in 1992.