complex between the C s #2 form of boric acid acting as a double hydrogen bond
donor to hydroxide was not stable at B3LYP/6-31G* and MP2/6-31G*, reverting
instead to a oxodihydroxoborate-water complex via proton transfer. At the other
levels, an imaginary frequency gave rise to the stable C 1 structure, which was 10–
25 kJ/mol less stable than the corresponding oxodihydroxoborate form. Upon
Fig. 14 Variation of BO(OH) 2
− vibrational frequencies (0–1700 cm
−1
) as a function of hydration
and structure
C s
C 1
C 1 #1
C 1 #2
C 1 #3
C 1 #1
C 1 #2
Fig. 15 Structure of boric acid-hydroxide complex, B(OH) 3 +OH
− +nH 2 O
170
C. C. Pye