Exploring the structure and redox activity of hexacoordinate bis(bipyridyl)silicon(IV) complexes. (7th July 2015)

• Record Type: Journal Article
• Authors: Maguylo, Christina; Chukwu, Chika; Aun, Mya; Blake Monroe, T.; Ceccarelli, Christopher; Jones, Daniel S.; Merkert, Jon W.; Donovan-Merkert, Bernadette T.; Schmedake, Thomas A.
• Is Part Of: Polyhedron. Volume 94(2015)
• Page Start: 52
• Page End: 58
• Publication Date: 2015-07-07
• Subjects: Hexacoordinate silicon -- Bipyridine -- Coordination chemistry -- Electrochemistry -- Crystallography; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2015.04.001
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: The structures of a series of hexacoordinate bis(bipyridyl)silicon(IV) complexes are reported. The hexafluorophosphate salts of each complex cation exhibit a reversible, first reduction wave around −1 V (versus Fc + /Fc) in acetonitrile, nearly independent of the alkoxide or diolate substituent. The complexes with bidentate diolate ligands possess multiple, reversible reduction waves. Abstract: A series of hexacoordinate bis(bipyridyl)silicon(IV) complexes was synthesized by allowing [Si(bpy)2 I2 ]I2 to react with the alcohols or phenols: methanol, ethylene glycol, phenol, 2, 2′-biphenol, or 1, 2-benzendiol. Crystal structures were obtained for the corresponding complexes: [Si(bpy)2 (OMe)2 ] (I)(I3 ) (1 ), [Si(bpy)2 (-OCH2 CH2 O-)]I2 (2 ), [Si(bpy)2 (OPh)2 ](I3 )2 (3 ), [Si(bpy)2 (bph)](PF6 )2 (4 ), and [Si(bpy)2 (cat)](PF6 )2 (5 ), (bpy = 2, 2′-bipyridine, cat = 1, 2-benzenediolato, bph = 2, 2′-biphenolato ligand). All five complexes exist as distorted octahedral dications with readily exchangeable counterions. The hexafluorophosphate salts of each complex cation exhibit a reversible, first reduction wave around −1 V (versus Fc + /Fc) in acetonitrile, nearly independent of the alkoxide or diolate substituent. This is consistent with DFT calculations indicating a LUMO localized on the bipyridyl ligands. The complexes with bidentate diolate ligands possess multiple reversible reduction waves.