title: Ditopic hydridoborates and hydridoboranes: bridging ligands in coordination polymers and versatile hydroboration reagents.
abstract: Single crystals of the meta- and para-phenylene-bridged ditopic trihydridoborates (Li(THF)(2))(2)[m-C(6)H(4)(BH(3))(2)] and (Li(THF)(2))(2)[p-C(6)H(4)(BH(3))(2)] have been prepared and investigated by X-ray crystallography. The compounds turned out to be coordination polymers in which each trihydridoborate substituent is connected with one trihydridoborate substituent of a neighbouring monomer via two bridging Li(THF)(2)(+) ions. (Li(THF)(2))(2)[m-C(6)H(4)(BH(3))(2)] and (Li(THF)(2))(2)[p-C(6)H(4)(BH(3))(2)] suffer from poor solubility in all common non-protic solvents. Thus, a more soluble derivative of (Li(THF)(2))(2)[p-C(6)H(4)(BH(3))(2)], equipped with n-hexyl groups at the positions 2 and 5 of the phenylene ring, has been used for all further investigations (i.e., compound Li(2)[6]). Treatment of Li(2)[6] with Me(3)SiCl in the presence of excess N(Me)(2)Et leads to the abstraction of one hydride ion per boron atom under formation of the ditopic amine-borane adduct p-C(6)H(2)(n-hexyl)(2)(BH(2)-N(Me)(2)Et)(2) (7). The compound turned out to be an efficient hydroboration reagent both for internal olefins (i.e., 1,5-cyclooctadiene) and terminal alkynes (i.e., tert-butyl acetylene) to give p-C(6)H(2)(n-hexyl)(2)(9-BBN)(2) (8; 9-BBN = 9-borabicyclo[3.3.1]nonyl) and p-C(6)H(2)(n-hexyl)(2)(B(C(H)=C(H)tBu)(2))(2) (9), respectively.
authors.affiliation: Institut für Anorganische Chemie, J.W. Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, D-60438, Frankfurt (Main), Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Franz
authors.forename: Michael
authors.initials: M
authors.lastname: Bolte
authors.forename: Hans-Wolfram
authors.initials: HW
authors.lastname: Lerner
authors.forename: Matthias
authors.initials: M
authors.lastname: Wagner
mesh_terms: D001880:Boranes / Q000737:chemistry*; D001881:Borates / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008024:Ligands; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry*
chemical_list: D001880:Boranes; D001881:Borates; D008024:Ligands; D011108:Polymers