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Side-on or end-on? Rhodium and iridium complexes featuring aminoboranes (R2N= BH2) as ligands have been synthesized and structurally characterized. Crystallographic measurements show that the ligands-in contrast to isoelectronic alkene donors-bind in an end-on fashion through a bis(o-borane) binding motif (see structure). (Figure Presented) © 2010 Wiley-VCH Verlag GmbH and Co. KGaA.

Lithium borohydride absorbs anhydrous ammonia to form four stable ammoniates; Li(NH(3))(n)BH(4), mono-, di-, tri-, and tertraammoniate. This paper focuses on the monoammoniate, Li(NH(3))BH(4), which is readily formed on exposure of LiBH(4) to ammonia at room temperature and pressure. Ammonia loss from Li(NH(3))BH(4) commences around 40 degrees C and the compound transforms directly to LiBH(4). The crystal structure of Li(NH(3))BH(4) is reported here for the first time. Its close structural relationship with LiBH(4) provides a clear insight into the facile nature and mechanism of ammonia uptake and loss. These materials not only represent an excellent high weight-percent ammonia system but are also potentially important hydrogen stores.

The reaction of LiGaH4 with an excess of the hydrochloride of a primary amine RNH2 in ether solution yields in [(RH2N)2GaH2]Cl (R = Me, 1, or iPr, 2) additional examples of cationic gallane derivatives. The cation [(iPrH2N)2GaH2]+ reacts further with LiGaH4, also in ether solution, with H2 elimination and formation of the trigallium cationic derivative [{(iPrH2N)GaH2NHiPr}2GaH2]Cl, 3. Prolonged standing of [(iPrH2N)2GaH2]Cl in the presence of LiCl results in partial exchange of Ga–H by Ga–Cl bonds, with the isolation in low yield of crystals, 4, of [(iPrH2N)2GaH2]Cl in which about 7 % of the H atoms attached to Ga were replaced by Cl. All of the compounds 1–4 having been characterized crystallographically, the results are discussed in relation to the different reaction pathways open to [RNH3]Cl and LiMH4 (M = Al or Ga). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Lithium borohydride absorbs anhydrous ammonia to form four stable ammoniates; Li(NH(3))(n)BH(4), mono-, di-, tri-, and tertraammoniate. This paper focuses on the monoammoniate, Li(NH(3))BH(4), which is readily formed on exposure of LiBH(4) to ammonia at room temperature and pressure. Ammonia loss from Li(NH(3))BH(4) commences around 40 degrees C and the compound transforms directly to LiBH(4). The crystal structure of Li(NH(3))BH(4) is reported here for the first time. Its close structural relationship with LiBH(4) provides a clear insight into the facile nature and mechanism of ammonia uptake and loss. These materials not only represent an excellent high weight-percent ammonia system but are also potentially important hydrogen stores.