On the Crystal Engineering of Organogallium Alkoxides Derived from Primary-Amine Alcohols − Relationships between Hydrogen Bonding and Donor−Acceptor Bonds

Abstract

The crystal structure analysis of model organogallium amine‐alkoxides Me2Ga(OCH2CH2CH2NH2) (2) and [Me2Ga{μ‐OCH2CH(CH3)NH2}]2 (3), demonstrate how hydrogen bonding can effectively compete with metal−ligand coordination preferences in determining the molecular and crystal structure and how conformational changes in a ligand and increased steric bulk on the carbon atom adjacent to the amine group can impart on a network morphology and molecular aggregations.

Thermally induced Lengthening of weak Dative Bonds in Donor Functionalized Organoaluminum Alkoxides observed by X-ray Single Crystal Diffraction

“…Steiner et al have monitored the temperature dependent migration of protons in weak hydrogen bonds with neutron diffraction [13]. Furthermore, the expectation that weak dative bonds may also be promising candidates gains further support from the work of Lewiński et al, who have nicely demonstrated that hydrogen bonds and dative bonds have similar energies in the class of compounds considered in this work [14]. Consequently, we believed that some of the [R 2 AlϪOϪR'ϪY] 2 derivatives we were studying should show a thermal lengthening effect in their weak dative bonds.…”

Diorgano-gallium and -indium complexes with salen ligands: Synthesis, characterization, crystal structure and C–C coupling reactions

“…The structural preferences in these complexes are governed by the nature of R, M and L [13][14][15][16][17][18][19][20][21][22][23][24][25]. Recently we have described the synthesis of diorgano-gallium/-indium complexes containing internally functionalized anionic oxo ligands [9,10,26,27].…”

Aluminum alkoxide complexes from highly substituted 3,4‐epoxy alcohols: An NMR and computational study

“…1 and 6 ), we rationalized that due to the increased steric demands of the 2‐methyl‐3,4‐epoxy alcohol substrates, a monodentate intermediate IV could also be formed and may even produce the internal cleavage products via an intramolecular propynyl group transfer . Monodentate intermediates such as IV have been proposed as alternative coordination models for organoaluminum reaction . As with 2,3‐epoxy alcohol systems, it is not clear if the second alane equivalent, required for the reaction to proceed, associates with the epoxide or alkoxide oxygen or both.…”

“…It is known that, because of its electron deficiency, aluminum compounds readily form dimeric structures in non‐donor solvents This tendency has been well established for aluminum alkoxide, through NMR and X‐ray studies . Although to date, an X‐ray structure of an epoxide coordinated alkoxide has remained elusive, Lewinski was able to isolate and characterize the first group 13 metal‐epoxide complex using GaMe 3 . They showed that an equilibrium exists in solution between a closed‐shell, five coordinate gallium/glycerol complex V and the open‐shell four coordinate dimeric isomer VI , the latter being the predominant species.…”

“…The more accepted bidentate complex promotes the attack at the external C3 (route a) or the internal C2 (route b) epoxide carbons through an intermolecular or intramolecular alkyl or alkynyl transfer from a second oxygen‐coordinated alane equivalent (shown for I ). The second alane equivalent, required for the reaction to proceed, may associate with the epoxide or the alkoxide oxygen, or both . The regiochemical outcome of the cleavage reaction is controlled by the syn/anti epoxide–alcohol relationship and the cis/trans geometry of the epoxide.…”