Synthesis and structure of orthopalladated complexes derived from prochiral iminophosphoranes and phosphorus ylides

Synthesis, spectroscopic and structural characterization of orthopalladated complexes with 4-phenylbenzoylmethylene triphenyl phosphorane ylide

“…Similar behavior was observed earlier in the case of ylide complexes of palladium(II) [19]. The expected downfield shifts of 31 P and 1 H signals for the PCH group upon complexation in the case of C-coordination were observed in their corresponding spectra.…”

“…The Pd1-C7 bond distance (2.002(6) Å ) is similar to those found in other ortho-palladated complexes [1,13] and the Pd-N(1) distance falls also in the usual range found for this bond [25]. The bond length of P(1)-C (19) in the similar ylide is 1.706 Å [1,26] which shows that the above bond has considerably elongated to 1.775 (6) [29,30]). Likewise, the C(19)-P(1) bond lengths in similar ylides were 1.7194(17) Å [1,29] which showed that the corresponding bonds in 2 have considerably elongated to 1.775 (6) or (5) Å .…”

“…The absorption due to the carbonyl stretch appears at lower energies than expected (about 1,720 cm -1 ), due to the conjugation of the C=O bond with the P=C bond. The localization of the density charge in the P-C-C-O bond system is responsible for the stability of these compounds and can also be inferred from the 31 P{ 1 H} NMR spectra [13,14,19]. These spectra show a single peak at about 17.2 ppm, a position shifted to low field with respect to that observed in other non-stabilized systems (about 0-6 ppm) and showing the lower shielding of the P atom in the stabilized compounds due to delocalization.…”

“…These crystals were grown by the diffusion of n-hexane into a CH 2 Cl 2 solution. In complex 2, each palladium atom has a slightly distorted square-planar environment, surrounded by the orthometalated C(7) atom, the ylide C (19), that forms a five-member cycle, one chlorine (Cl1) and one phosphorus (P1) atom. Complex 2 crystallized in the triclinic system with space group P -1.…”

Synthesis and structure of mono- and di-nuclear complexes of ortho-palladated derived from phosphorus ylides

“…Although the orthometallated ligand is remarkably warped (especially 4a), the environment around the Pd is planar. The Pd(1A)eC(0BA) [2.191 (3) [31]. The mutual trans positions of carbon and phosphorus ligands in palladium(II) complexes 3a and 4a lead to a weakening of both PdeC aryl and PdeP bonds (see Table 3) that is called transphobia effect [32,33] due to p-acceptor ability of phosphorus atom but this is not exist on complexes with s-donor N atoms in ligands such as bipyridine [35].…”