Table 1. The v(OH) bands of phenol involved in the H-bonds with 1--3, the basicity factors, and the v(CO) bands of 1--3 in the H-complexes and protonated forms aRer the addition of PFB and HBF 4 ... Corn- v(OH)/cm -1 Av Ej v(CO)/cm -1 ... 1 3388 198 0.86 1978 vs 2013 w, 2085 rn,