Synthesis, structure and π-delocalization of a phosphaalkenyl based neutral PNP-pincer

Abstract

Graphical abstractA novel bis-phosphaalkenyl based PNP-pincer was prepared and its crystal structure indicates delocalization over the entire π-system including all three donor sites which is also supported by spectroscopic measurements and DFT calculations. The coordination chemistry of the pincer and its precursor have been explored using Cu(I).Highlights► A novel bis-phosphaalkenyl based PNP-pincer was prepared. ► The crystal structure indicates delocalization over the entire π-system including all three donor sites. ► DFT calculations and UV–Vis measurements support the interpretation of the structural findings. ► The coordination behavior towards Cu(I) is explored on a preliminary base.

Asymmetrically Substituted Phospholes as Ligands for Coinage Metal Complexes

“…The most obvious change was found for gold complex 5 , which shows a resonance at 32.5 ppm. These changes are comparable with other phosphorus containing coinage metal complexes [ 24 , 25 , 26 , 27 , 28 ].…”

C2-Symmetric P-Stereogenic Ferrocene Ligands with Heavier Chalcogenophosphinous Acid Ester Donor Sites

“…For 77 Se, coordination of M(I) (M = Cu, Ag, and Au) deshielding was observed in all cases (Cu: +14 ppm, Ag: +11 ppm, and Au: +55 ppm). For 31 P, shielding was observed for Cu (−6 ppm), as in related cases [ 26 , 32 , 33 ], but deshielding was observed for Ag and Au coordination (Ag: +18 ppm and Au: +28 ppm). An intriguing feature of meso bischalcogenophosphinous acid esters with Se and Te was the observation of a resolved coupling of 77 Se and 125 Te to both chemically equivalent but magnetically inequivalent phosphorus nuclei within the molecule.…”

Copper(I) Complexes of Pyridine-Bridged Phosphaalkene-Oxazoline Pincer Ligands

“…Moreover, copper(I) complexes of phosphaalkene-pyridine ligands have been reported previously. 7,10,11,29,30 A mixture of 1a and Cu(MeCN) 4 OTf in CH 2 Cl 2 was stirred for 2 h over which time a color change from red to deep brown was observed (Scheme 3). Analysis of an aliquot using 31 P{ 1 H} NMR spectroscopy revealed quantitative conversion of the signals for both isomers of phosphaalkene 1a to a single new resonance at 186 ppm, a value shifted considerably upfield relative to pincer precursor E-1a (Δδ = −62).…”