Hydrogen Bonding and Proton Transfer Melvin D. J o e s t e n Vanderbilt University, Nashville, TN 37235 Historical Background The first definitive paper on hydrogen bonding was pubthe lished in 1920 bv Latimer and Rodehush (.1.) .Thevannlied . concept of hydrugen bonding to association of water nldecules and acknowledged Hugginsd the same lahuratory inr the ide3 of hydrogen bonding. 1\11three were working in the laboratory of C . N.I.c.w~swhu stated in his 19'23 clasilc hook on \.alenuv
hydrogen bonds include humo-intermolecular isclf-asswiattonj and hetero-intermolectl1:ir hsdruaen bonds. 'l'uhle ? rlves a range of hydrogen hond strengths with an arbitrary c l k fication as weak, moderate, s t r o w , and verv strona. Most of the emphasis in the literature has been on "moderate" or "normal" hydrogen bonds. However, strong and very strong hydrogen bonds are important in studies of the effect of hydrogen bonding on proton transfer.
.. . It seems to me that the most important addition to my theory of
Spectroscopic Studies of Hydrogen Bonding A varietv of snectrosconic and diffraction methods have been applied to the study of hydrogen bonding. Tables 3 and 4 list examnles with kev references. Time scale differences (Table 5) must be kept in mind when analyzing spectral data for hydrogen-bonded systems. For example, NMR gives a time-average spectrum of free and
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valence lies in the sueeestion of what has became known as the hv.... d n w n hmd. The idea uas tint surgeit4 try L h M. L. Huzgin,, and was alno nd\anrrd try Latimer and Hodt4)ush,whu ihuwru the grcnt value of the idea in their paper.. .
A review by Huggins in 1971 describes his interests in hydroeen bonding over a 50-vear neriod (3).Thousands of naners have been pubkshed on various aspect; of hydrogen boniing since the 1920 naner hv Latimer and Rodebush. Fortunatelv. a number of hboks (419) have been published which review hydrogen bonding, and several sections of the most recent series edited by Schuster, Zundel, and Sandorfy (9) will be cited in this Daner. T h e simultaneous development of hydrogen bonding concepts and Bronsted acid-base theory (10)led to early recognition of the influence of hydrogen bonding on proton transfer reactions. The present paper will focus on spectroscopic and diffraction studies which nrovide information about the effect of hydrogen bonding od the extent of proton transfer in A-H.. .B = -A,. .+H-B. This will include a consideration of (1) the strength of the hydrogen hond and (2) the molecular environment. A brief review of tvpes of hvdroaen bonds will be followed by a discussion of the-applicati& orspectroscopic and diffraction methods to studies of moderate and strong hydrogen bonds, symmetric and asymmetric hydrogen bonds, solvent effects, and hydrated proton species. The hydrogen bond can be represented as A-H.. .B where B is any a or a electron donor site (Lewis base) and A is an atom more electroneeative than hvdroeen. , .. Hvdroeen , .. bonds can he either intriimdtwllar ur intrrmulecular. 'Table 1 lists rxi~mplesof differmt typt.s of hydrogt!n ln)nd.
