Aspects of the Chemical Energetics of Species with Carbon–Boron Bonds and Related Compounds

Abstract

Abstract In this chapter, we discuss selected energetics and thermochemical aspects of species with carbon–boron bonds. Although they lack a carbon–boron bond, atomic boron, its anion, and binary metal borides—the hypothetical alkali metal borides MB—and structurally complex metal borides are briefly introduced. Consideration of species with carbon–boron bonds begins with binary species such as the gas‐phase diatomic BC and the solid B 4 C and proceeds to the highly reactive methyl and phenyl derivatives of univalent borylene, BH. The question of regular behavior as homologous series is addressed for the relatively stable and long‐known classes of compounds, trialkylboranes and carboranes, with their normal (threefold) and higher boron‐coordination numbers. Trivalent boron and nitrogen species are then compared, first as organoboranes and amines, then as their organoborate and ammonium ions, and also as their “dimer” anions and cations. Pyridine borane complexes are likewise discussed and compared with benzene derivatives. Species with boron in the ring, borabenzenes and their amine complexes, are much more poorly understood. However, aromatic derivatives with both boron and nitrogen in the ring have evinced considerable interest, and the derivatives of the isomeric 1,2‐, 1,3‐, and 1,4‐azaborinines are described at some length. The chapter closes with species that contain oxygen along with boron, carbon, and hydrogen. Borane carbonyl (BH 3 CO), boronic acid derivatives, and boroxines are discussed.