Construction of copper chains with new fluorescent guanidino-functionalized naphthyridine ligands

• Verfasst von: Krämer, Christoph [VerfasserIn]
• Verfasst von: Leingang, Simone [VerfasserIn]
• Verfasst von: Hübner, Olaf [VerfasserIn]
• Verfasst von: Kaifer, Elisabeth [VerfasserIn]
• Verfasst von: Wadepohl, Hubert [VerfasserIn]
• Verfasst von: Himmel, Hans-Jörg [VerfasserIn]
• Titel: Construction of copper chains with new fluorescent guanidino-functionalized naphthyridine ligands
• Verf.angabe: Christoph Krämer, Simone Leingang, Olaf Hübner, Elisabeth Kaifer, Hubert Wadepohl and Hans-Jörg Himmel
• E-Jahr: 2016
• Jahr: 03 Oct 2016
• Umfang: 18 S.
• Titel Quelle: Enthalten in: Dalton transactions
• Ort Quelle: Cambridge : RSC, 2003
• Jahr Quelle: 2016
• Band/Heft Quelle: 45(2016), 42, Seite 16966-16983
• ISSN Quelle: 1477-9226
• DOI: doi:10.1039/C6DT03166H
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1698770111

Abstract

The three new blue-fluorescent ligands 2,7-bis(tetramethylguanidino)-1,8-naphthyridine (1), 2,7-bis(N,N′-dimethylethylene-guanidino)-1,8-naphthyridine (2) and 2,7-bis(N,N′-diisopropylguanidino)-1,8-naphthyridine (3) are synthesized, and their optical properties (electronic absorption and emission spectroscopy) studied. Reactions of 1 or 2 with [Cu(CH3CN)4]BF4 yield the Cu4 chain compounds [Cu4(1)2](BF4)4 (that crystallizes as [Cu4(1)2(CH3CN)2](BF4)4·2CH2Cl2) and [Cu4(2)2](BF4)4. The variations of the optical properties upon coordination are evaluated, and the electronic transitions identified by time-dependent DFT (TD-DFT) calculations. Then the redox properties of the new Cu4 chain complexes are studied. In the course of these experiments, the new Cu6 complex [Cu4(1)2(CuCl2)2]2+, in which two CuCl2− units coordinate to the Cu4 chain in [Cu4(1)2]4+, was fully characterized. In addition, the Cu3 chain complexes [Cu3(1)3]3+ and [Cu3(1)2]3+ were isolated as products of redox-induced degradation processes. Finally, we show by quantum chemical calculations that in [M4(1)2]4+ complexes (M = coinage metal), the HOMO changes from a ligand-centered to a metal-centered orbital for replacement of M = Cu by Au.