Organoborates containing coordinative covalent B-N bonds

INOR 246

David M. Schubert, dave.schubert@riotinto.com1, Mandana Z. Visi2, Carolyn B. Knobler3, Saeed I Khan3, and Kenneth I. Hardcastle4. (1) U.S. Borax Inc., Rio Tinto Minerals, P.O. Box 6609, Englewood, CO 80155, (2) Rio Tinto Minerals, (3) Department of Chemistry and Biochemistry, University of California, Los Angeles, (4) Department of Chemistry, Emory University, Atlanta, GA 30322
Boric acid reacts with organoamines to form a range of polyborate compounds, some finding commercial applications in industrial fluids. Organoamines may also attach to borate moieties via B-N coordinative covalent (CC) bonds to form organoborate adducts. A number of organoammonium polyborate salts have recently been structurally characterized, some containing unusual polyborate anions. However, although classic examples of organoborates exhibiting B-N CC bonds exist (e.g. the triethanolamine borate ester 1), relatively few structurally characterized examples of amine-polyborate adducts exist. Here we review the literature of organoborates with B-N CC bonds and describe syntheses and structures of a series diaminoalkane-pentaborate adducts and related compounds. These include the zwitterions, B5O6(OH)4-NH2(CH2)nNH3 with n = 5, 6 (2) and the adduct salt [H3N(CH2)8NH3][B5O6(OH)4-NH2(CH2)8NH2-B5O6(OH)4] (3). Depending on conditions, 1,7-diaminoalkane may form salts of either an octaborate anion, [B8O10(OH)6]2-, or a unique isomer of a heptaborate anion, [B7O9(OH)5]2- rather than B-N adducts.

 

Main Group Chemistry
7:00 PM-10:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Inorganic Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007