Indium(iii)/2-benzoylpyridine chemistry: interesting indium(iii) bromide-assisted transformations of the ligand. Issue 41 (30th September 2022)

• Record Type: Journal Article
• Authors: Stamou, Christina; Lada, Zoi G.; Chasapis, Christos T.; Papaioannou, Dionissios; Dechambenoit, Pierre; Perlepes, Spyros P.
• Is Part Of: Dalton transactions. Volume 51:Issue 41(2022)
• Page Start: 15771
• Page End: 15782
• Publication Date: 2022-09-30
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d2dt02851d
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : The chemistry of the InX3 /2-benzoylpyridine reaction systems (X = Cl, Br) is interesting, including InBr3 -assisted reactivity patterns of the coordinated ligand. Abstract : Reactions of 2-benzoylpyridine, (py)(ph)CO, with InX3 (X = Cl, Br) in EtOH at room temperature have been studied. The InCl3 /(py)(ph)CO system has provided access to complex [InCl3 {(py)(ph)CO}(EtOH)]·{(py)(ph)CO} (1 ) and the byproduct {(pyH)(ph)CO}Cl (2 ). The reaction of InBr3 with (py)(ph)CO has led to a mixture of (L)[InBr4 {(py)(ph)CO}] (3 ) and [In2 Br4 {(py)(ph)CH(O)}2 (EtOH)2 ] (4 ), where L + is the 9-oxo-indolo[1, 2- a ]pyridinium cation and (py)(ph)CH(O) − is the anion of (pyridin-2-yl)methanol. Based on solubility and crystallisation time differences between the two components of the mixture, complex 4 was isolated in pure form, i.e. free from 3 . The formations of the counterion L + and the coordinated (py)(ph)CH(O) − anion represent clearly InBr3 -promoted/assisted transformations. Reaction mechanisms have been proposed for the formation of 2, 3 and 4 . Complex 4 could also be isolated by the reaction of InBr3 and pre-formed (py)(ph)CH(OH) in EtOH. The solid-state structures of 1, 3 and 4 were determined by single-crystal X-ray crystallography, while the identity of the salt 2 was confirmed by microanalyses and a variety of spectroscopic techniques, including ESI-MS spectra. In the indium(iii ) complexes, the metal ions are 6-coordinate with a distorted octahedral geometry. The halogeno groups (Cl −, Br − ) in the three complexes are terminal. The (py)(ph)CO molecule behaves as a N, O-bidentate (1.11) ligand in 1 and 3 . A terminal EtOH ligand completes the coordination sphere of In III in 1 . The alkoxo oxygen atoms of the two 2.21 (py)(ph)CH(O) − ligands doubly bridge the In III centers in 4 creating a {InIII2(μ-OR)2 } 4+ core; a nitrogen atom of one reduced organic ligand, two bromo ions and one terminal EtOH molecule complete the 6-coordination at each metal centre. Complexes 1, 3 and 4 were characterised by IR and Raman spectroscopies, and the data were discussed in terms of their known solid-state structures. Molar conductivity data and 1 H NMR spectra were used in an attempt to probe the behaviour of the complexes in DMSO. The to-date observed metal ion-assisted/promoted transformations of (py)(ph)CO are also discussed.