Amine adducts of (4-ClC6H4)3B3O3, Lewis acidity of triarylboroxines, and an XRD study on the related tetraphenylboroxinate(1-) salt, [C6H11NMe3][Ph4B3O3]

Publication date: Available online 11 January 2018 Source:Journal of Organometallic Chemistry Author(s): Michael A. Beckett, Simon J. Coles, Peter N. Horton, Charlotte L. Jones, Elizabeth V. Marshall, Thomas Perry The stoichiometric reactions of amines with tri(4-chlorophenyl)boroxine (CPB) led to the formation of adducts CPB.L {L = morpholine (1a), benzylamine (1b) cyclohexylamine (1c), 2-picoline (1d), 4-picoline (1e), piperidine (1f)} and (CPB)2 .(4,4′-trimethylenedipiperidine) (1g). Compounds 1a-1g have been characterized by NMR (11B, 1H, 13C), IR spectroscopy and powder-XRD. VT 1H NMR spectra on 1a and 1d-1g were consistent with a ligand exchange/recombination process and activation energies of 49–58 kJ mol-1 were obtained. The synthesis of [C6H11NMe3][Ph4B3O3] (2) from Ph2BOBPh2, PhB(OH)2 and [C6H11NMe3][OH] in a 1:4:2 ratio in MeOH/H2O is also reported. Compound 2 was characterized by thermal analysis (TGA/DSC), spectroscopy (IR, NMR) and 1a, 1b and 2 were further characterized by single-crystal XRD studies. Graphical abstract
Source: Journal of Organometallic Chemistry - Category: Chemistry Source Type: research