Heterocyclic nitrogen donor complexes of aluminium, gallium and indium with weakly coordinating triflate anions. (1st October 2021)

• Record Type: Journal Article
• Authors: Cairns, Kelsey R.; Levason, William; Reid, Gillian; Zhang, Wenjian
• Is Part Of: Polyhedron. Volume 207(2021)
• Publication Date: 2021-10-01
• Subjects: Aluminium complexes -- Gallium complexes -- Indium complexes -- Diimine complexes -- 2, 2′:6′, 2″- terpyridyl; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2021.115367
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: The influence of the weakly coordinating triflate anion is explored by reaction of M(OTf)3 (M = Al, Ga, In) with a range of di- and tri-imine ligands, yielding a range of new complexes with κ 1 -coordnated and/or H-bonded triflate anions, and evidence that the triflate ligands are more readily displaced by MeCN (or H2 O) than the neutral imine ligands. Abstract: The reactions of M(OTf)3 (M = Al, Ga, In; OTf = CF3 SO3 – ) with 2, 2′:6′, 2′'- terpyridyl (terpy) in CH2 Cl2 gave mer -[M(OTf)3 (terpy)], whilst with 2, 2′-bipyridyl (bipy) and 1, 10-phenanthroline (phen) the products isolated were cis -[M"(OTf)2 (bipy)2 ]OTf (M" = Al, Ga), cis -[In(OTf)(H2 O)(bipy)2 ][OTf]2, cis -[Al(OTf)2 (phen)2 ][OTf] and [In(H2 O)2 (phen)2 ][OTf]3 . The X-ray structures of m er -[In(OTf)3 (terpy)], cis- [Ga(OTf)2 (bipy)2 ][OTf] and cis- [In(OTf)(H2 O)(bipy)2 ][OTf]2, along with those of the minor by-products, cis- [Ga(H2 O)2 (phen)2 ][OTf]3 and the hydroxide-bridged dimer [{In(terpy)(OTf)}2 (µ-OH)2 ][OTf]2 were also obtained, all of which show six-coordination at the metal ion. While the anhydrous complexes show κ 1 -coordination of the triflate to the metal ion, those species with coordinated water (or hydroxide) ligands show significant H-bonding interactions between the water H atoms and the O-atoms from triflate anions. The complexes were characterised by IR, 1 H, 13 C{ 1 H}, 19 F{ 1 H} and 27 Al NMR spectroscopy, together with microanalysis. The 19 F{ 1 H} NMR spectra suggest that in MeCN solution the coordinated triflates are displaced by the solvent, but the original complexes appear to reform on removal of the MeCN in vacuo .