title: Tripodal borate ligands from tris(dimethylamino)borane: the first synthesis of a chiral tris(methimazolyl)borate ligand, and the crystal structure of a single diastereomer pseudo-C3-symmetric Ru(II) complex.
abstract: The activation of tris(dimethylamino)borane towards reaction with a chiral methimazole by N-methylimidazole has been used to prepare the first example of a chiral tris(methimazolyl)borate ligand. Coordination of this neutral ligand to Ru(II) has been achieved by reaction with [(p-cymene)RuCl(2)](2) to provide a single diastereomer complex in which the chirality of the methimazolyl substituents dictate the chirality of the bicyclo[3.3.3]cage formed by the ligand on coordination to the metal. The alternative approach to chiral tris(methimazolyl)borate ligands involving the introduction of a chiral group onto the boron atom has been explored by replacing N-methylimidazole in the above reaction by chiral oxazolines as activating bases in reaction with simple methimazole. However, although the B(NMe(2))(3) is activated to reaction with methimazole by these oxazolines, an intramolecular oxazoline ring-opening by a coordinated methimazolyl sulfur occurs and prevents the successful synthesis of these ligands.
authors.affiliation: School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JJ, UK. Philip.Bailey@ed.ac.uk
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Bailey
authors.forename: Chiara
authors.initials: C
authors.lastname: McCormack
authors.forename: Simon
authors.initials: S
authors.lastname: Parsons
authors.forename: Felix
authors.initials: F
authors.lastname: Rudolphi
authors.forename: Alejandro Sanchez
authors.initials: AS
authors.lastname: Perucha
authors.forename: Peter
authors.initials: P
authors.lastname: Wood