Boron Clusters Come of Age

Abstract

Polyhedral clusters containing boron, alone or in combination with other elements, have been known for nearly a century, and intensive studies of their structures, bonding, and reactivity have been under way for more than half that period; yet interest and practical applications in this area continue to grow. Two main reasons can be identified for this attention: the three-dimensional delocalized bonding that confers exceptional stability in these clusters is now recognized to have broad significance for deepening our understanding of covalent bonding, with implications for both organic and inorganic chemistry; secondly, many of the special properties of boron clusters are uniquely suited to specific applications. This article attempts to summarize the current state of the art, illustrated by examples selected to convey some of the excitement and possibilities for future exploitation of these remarkable compounds.

Nitrogen removal from natural gas using solid boron: A first-principles computational study

“…In the recent article "Boron Cluster Come of Age", Grimes commented the variety of boron clusters, such as neutral boranes, polyhedral boranes, and their derivatives, motivating us to reconsider the concept of covalent chemical bonding. [20] Among boron clusters, B 12 icosahedron is the basic structural unit for the elementary boron solids (e.g. the well-known α-B 12 and γ-B 28 crystals) although the B 12 icosahedron is not stable when it is treated as a single isolated cluster.…”

Non-intercalative, Deoxyribose Binding of Boric Acid to Calf Thymus DNA

“…In a manner analogous to carbon atoms in organic compounds, boron atoms can be linked in a series of covalent bonds to form a number of structures, such as polyhedral boranes, that display properties of considerable interest for biomedical applications. These properties include a low chemical reactivity and a high resistance to enzymatic degradation and have triggered the design of various boronbased materials to be utilized in biological systems [1]. Other medical applications of boron are primarily related to the element's capacity to absorb neutrons, and the potential of this element for use in cancer therapy was recognized as early as the 1950s [2].…”

“…Other medical applications of boron are primarily related to the element's capacity to absorb neutrons, and the potential of this element for use in cancer therapy was recognized as early as the 1950s [2]. Boric acid in particular is principally utilized in boron neutron capture therapy (BNCT), a non-invasive therapeutic method for the treatment of various cancers [3] and especially brain tumors [1,4]. To date, several strategies have been employed to selectively deliver boron atoms or boron derivative drugs into tumor cells [5] by the use of various agents, such as liposomes [6,7] and nanoparticles [8].…”

Synthesis, Crystal Structure and Photoluminescence of 1,2-Bis(phenylselenyl)-1,2-dicarba-closo-dodecaborane(12)

“…One direction of this field lies in the study of carborane cluster ligands (especially those based on o-carborane or closo-C 2 B 10 H 12 ) and their metal coordination compounds [1,2], utilizing the excellent thermal, oxidative and chemical stability and the many potential applications imparted by the carborane moieties [3,4]. Besides the well-known metallacarborane clusters [2], the ligand systems combining the o-carborane skeleton and functional groups such as cyclopentadienyls [5,6], phosphines [7 -11] and Si/Sn [12] or S/Se heteroatoms [13,14] etc.…”