Formation and Characterization of the Cationic Gallane Derivatives [(RH₂N)₂GaH₂]Cl (R = Me or iPr) and [{(iPrH₂N)GaH₂NHiPr}₂GaH₂]Cl

Abstract

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)

Pincer‐Supported Gallium Complexes for the Catalytic Hydroboration of Aldehydes, Ketones and Carbon Dioxide

“…One of the crystallographically unique BH 3 :py units interacts with 3 via a hydrogen bond. A hydridic hydrogen atom on BH 3 is interacting with the protic hydrogen atom on NÀ H of the ligand backbone of 3 with a distance of 2.00( 4 t Bu, NH 2 s Bu), [43][44][45] and cationic systems such as [H 2 Ga(NH 2 R) 2 ] Cl (R = Me, i Pr, t Bu, s Bu), [46][47] and {[2,6-(Me 2 N(H)CH 2 ) 2 C 6 H 3 ] Ga(H)(OTf) 2 }(OTf), [48] are relatively rare and can, in principle, eliminate dihydrogen. The thermolysis of gallium hydride complexes has been well-documented.…”

“…Compound 3 is an interesting species insomuch as it contains a hydridic Ga−H bond in close proximity to an acidic N−H bond in the ligand backbone. Adducts of gallium hydrides with primary and secondary amines such as L ⋅ GaH 3 (L=NHMe 2 , NH t Bu 2 , NH 2 Me, NH 2 t Bu, NH 2 s Bu),[ 43 , 44 , 45 ] and cationic systems such as [H 2 Ga(NH 2 R) 2 ]Cl (R=Me, i Pr, t Bu, s Bu),[ 46 , 47 ] and {[2,6‐(Me 2 N(H)CH 2 ) 2 C 6 H 3 ]Ga(H)(OTf) 2 }(OTf), [48] are relatively rare and can, in principle, eliminate dihydrogen. The thermolysis of gallium hydride complexes has been well‐documented.…”