Ylid complexes of organotin and -lead halides

Synthesis, characterization, and spectroscopic studies of palladium(II) and silver(I) complexes of 4-methoxybenzoylmethylenetriphenylphosphorane and 4-fluorobenzoylmethylenetriphenylphosphorane

“…In the present study, the m(P + -C -) values for all five complexes were shifted to lower frequency (Table 1), suggesting some removal of electron density from the P-C bond. The 1 HNMR spectra of complexes (1)-(4) show a doublet or broad signal attributed to the proton methine CH at 4.3-4.5 ppm with 2 J (PH) = 25 Hz (1); these values are close to those observed in other O-bound complexes [6,[12][13][14][15].…”

“…Carbonyl-stabilized phosphorus ylides are interesting ligands because they can behave as C-or Odonors owing to the delocalization of the ylidic electron pair [5]. This delocalization also makes these ligands weak nucleophiles, but this does not reduce their interest as ligands; indeed it was their weak donor ability that allowed other groups to prepare new types of ylide complexes [5,6]. This ambidentate character facilitates the preparation of stable metal complexes (Scheme 1) in which the ylide can be O-(both cisoid and transoid forms, b) [6] or C-coordinated (a) [7].…”

“…In the compounds reported to date, the chemical behavior of the a-ketostabilized phosphorus ylides has been clearly dominated by the C-coordinated form [7][8][9][10][11], and very few examples of O-coordinated ylides are known [6,[12][13][14][15]. Some of these examples contain the ylide O-coordinated to a hard, very exophilic metal center, as Sn(IV) [12] or group 4 metals in high oxidation number [13].…”

X-ray and Spectroscopy Studies of Mercury (II) and Silver (I) Complexes of α-Ketostabilized Phosphorus Ylides

“…Difference between two distances in these complexes might be arising from steric effects of the large ylidic groups. The angles around mercury in complex 4 vary from 87.39 (13) to 139.45 (11), indicating a much distorted tetrahedral environment. This distortion must be due to the higher s character of the sp3 hybrid mercury orbital involved in the above bonds and the steric effects of phosphine group needing the C-Hg-Cl angle to be larger mercury with a bridging structure.…”

“…[6][7][8][9][10][11][12][13][14][15][16][17][18][19] They are versatile ligands for catalysts in a very small number of catalytic reactions such as, for example, the hydrogenation of olefins 20 and the cyclotrimerization 21 and polymerization of acetylenes, 22 but the most important application is in the industrially used SHOP process. 23 The α-keto-stabilized phosphorus ylides are distinguishable from no stabilized ylides, since they can be easily handled due to an additional stabilization from delocalization of the negative charge.…”