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Phosphine oxide functionalised with two bipyridine subunits: a novel ligand for the engineering of sterically hindered complexes

2001; Royal Society of Chemistry; Volume: 25; Issue: 8 Linguagem: Inglês

10.1039/b102520c

1369-9261

Laurent Douce, Loı̈c J. Charbonnière, Michèle Césario, Raymond Ziessel,

Porphyrin and Phthalocyanine Chemistry

Ligand L, containing two 6-methyl-6′-methyl-yl-2,2′-bipyridine moieties linked by a "PhPO" spacer, has been prepared. Subsequent complexation with [Cu(CH3CN)4](BF4) led to a unique complex of formula [CuL](BF4). The molecular structure has been determined by X-ray crystallography in the solid state and NMR studies in solution. The complex displays an intense absorption band in the visible wavelength range with maxima at 418 and 509 nm, and is oxidised reversibly at +0.66 V (ΔEp = 80 mV) to the corresponding Cu(II) species, while two successive reductions of the coordinated bipyridine fragments occur at −1.60 (ΔEp = 66) and −1.84 V (ΔEp = 70 mV) s. SCE. Direct spectrophotometric titrations with global analysis allowed us to elicit stability constants for the emergent complex and to highlight the formation of a dinuclear complex in the presence of excess copper.