Homoleptic ‘sandwich’ complexes of substituted tris(methimazolyl)borate ligands with ruthenium, rhodium and palladium

Abstract

The pursuit of heteroleptic 'half-sandwich' complexes of boron substituted anionic and charge-neutral tris(methimazolyl)borate ligands is described. The formation of the homoleptic 'sandwich' complexes was found to be favoured when the metal precursor contains labile ligands. When unable to form these homoleptic complexes Tm is shown to preferentially coordinate in a κ²-[S,S] fashion. This study reinforces previous assertions that the Tm ligand preferentially adopts the κ²-[S,S] mode when coordinated to electron rich metal centres and demonstrates the strong electron donor properties of substituted Tm ligands.

A sandwich-type zinc complex from a rhodamine dye based ligand: a potential fluorescent chemosensor for acetate in human blood plasma and a molecular logic gate with INHIBIT function

“…Such homoleptic sandwich complexes are rare in the literature. 20 Also the current complex Zn-R1 belongs to a very small group of complexes containing rhodamine dye based ligands, especially those in which the rhodamine moiety exists in the ring opened spirolactam form. 4,5 Sensing properties of Zn-R1…”

“Homoleptic” Tetracoordinate Boron Compounds

“…Therefore, the homoleptic bisligand "sandwich" complexes can be regarded as the mimics of traditional cyclopentadienyl-based sandwich complexes (Scheme S14). 73 Thioxoimidazolyl and 2-mercaptothiazolyl are softer than the pyrazolyl analogues; hence, they are more useful to be used as supporting ligands with soft transition metals. To develop the tetrakis analogue of poly(pyrazolyl)borates, Silva et al prepared potassium tetrakis(2-mercaptothiazolyl)borate from KBH 4 and 2-mercaptothiazoline (Scheme S15).…”