Boron-11 NMR Spectroscopy

Abstract

This chapter discusses boron-11 NMR spectroscopy along with many new boron compounds. Unlike many other branches of spectroscopy, that dealing with 11 B is infrequently a free-standing discipline and is used more often as a characterization tool to probe structure and reactivity in boron compounds. The chapter explores that outstanding efforts have been made to develop a deeper theoretical understanding of 11 B chemical shifts and coupling constants. Moreover, a sufficient body of empirical data is available to at least partially deduce gross structural features of large polyboron molecules directly from measurements of chemical shifts, coupling constants, and spin-lattice relaxation times. The chapter illustrates that the instruments are now designed so that spectroscopic techniques requiring sophisticated data manipulation have become practical, examples of which are two-dimensional correlated 1 H– 11 B NMR, multiple resonance experiments, line narrowing, and measurement of T 1 and T 2 . Finally, 11 B chemical shifts are expressed in ppm with respect to external BF 3 .O (C 2 H 5 ) 2 , followed by multiplicity relative area, and B–H coupling constant.