Novel Bi‐ and Trinuclear Gallium Halides and Hydrides with Acyclic and Bicyclic Guanidinate Substituents: Synthesis and Reactivity

Abstract

We report on the synthesis and characterization of new molecular Ga halides and hydrides with acyclic guanidinate substituents with bicyclic guanidinate substituents. Acyclic guanidinates were found to adopt terminal bonding modes like in the dimeric GaII compound [(iPr2N)C(NiPr)2GaI]2. In contrast, bicyclic guanidinates prefer bridging bonding modes. Hence, the reaction between Me3N·GaH3 and htbo (1,4,6‐triazabicyclo[3.3.0]oct‐4‐ene) affords the binuclear GaIII hydride [H2Ga(μ‐tbo)]2. This new hydride turned out to be unstable in solution at 25 °C, dihydrogen is slowly eliminated. In the solid state, however, the hydride is stable up to 80 °C. The thermodynamic properties of this and similar dehydrogenation reactions were studied my means of quantum chemical calculations. With Ga2H5(μ3‐O)(μ‐tbn)2 and Ga2H5(μ3‐O)(μ‐hpp)2, two new hydrides were synthesized which can be regarded as the first hydrolysis intermediates of binuclear Ga hydrides with bridging guanidinate substituents.

Three asymmetric guanidinato metal complexes: Synthesis, crystal structures and their use as pre-catalysts in the Meerwein–Ponndorf–Verley reduction

“…The compound 1 was recrystallized from hexanediethylether (1:1) solution. Crystalline 1 is centrosymmetric dimer with Li 2 N 2 quadrilateral core structure which is closely to that of reported guanidinatolithium compound [( i Pr) 2 NC(NCy) 2 LiOEt 2 ] 2 [25]. The planar Li1N3Li1 0 N3 0 core is flanked by planar Li1N3 0 C9 0 N1 0 and Li1 0 N1C9N3 rings, which form a fused tricyclic ladder motif.…”

“…for C 39 H 51 AlN 6 : C, 74. 25;H,8.15;N,13.32. Found: C,74.12;H,8. 14, 124.41, 124.91, 128.76, 128.96, 129.13, 134.58, 135.58, 144.76, 148.16 (C 6 H 5 ), 164.43 (NCN).…”

Lanthanide amidinates and guanidinates in catalysis and materials science: a continuing success story

“…These are well established in d-transition metal chemistry, but their coordination chemistry with rare-earth metals still awaits more extensive exploration. 2,18 Most important for potential catalytic applications is the design of polyfunctional amidinate and guanidinate ligands which in combination with lanthanides could lead to analogues of the well-established ansa-metallocene and ''pendant-arm'' half-metallocene catalysts. 6 For example, Scheme 9 illustrates the synthetic pathway to a new bis(amidine) ligand with a conformationally rigid naphthalene linker, 1,8-…”

Boron, aluminium, gallium, indium and thallium

“…The partial hydrolysis products Ga 2 H 5 (m 3 -O)(m-tbn) 2 and Ga 2 H 5 (m 3 -O)(m-hpp) 2 have also been described. 250 DFT quantum chemical calculations have been employed in an investigation into the nature of {GaX} (X = F-I) moieties as ligands to transition metal complexes.…”