Reactivity of a Pd(I)−Pd(I) Dimer with O2: Monohapto Pd Superoxide and Dipalladium Peroxide in Equilibrium
摘要:
The Pd(I)-Pd(I) dimer [((PNP)-P-F)Pd-](2) reacts with O-2 upon exposure to light to produce either the superoxide ((PNP)-P-F)PdO2 or the peroxide [((PNP)-P-F)PdO-] 2, which exist in equilibrium with free O-2. Both complexes contain square-planar Pd(II) centers. The unpaired electron density in ((PNP)-P-F)PdO2 is localized on the superoxide ligand.
Covalent palladium–zinc bonds and their reactivity
作者:Claudia M. Fafard、Chun-Hsing Chen、Bruce M. Foxman、Oleg V. Ozerov
DOI:10.1039/b709364k
日期:——
Photolysis of (FPNP)PdâEt in the presence of Et2Zn leads to the formation of (FPNP)PdâZnâPd(PNPF), the first example of a compound with a covalent PdâZn bond.
Addition of Ammonia, Water, and Dihydrogen Across a Single Pd−Pd Bond
作者:Claudia M. Fafard、Debashis Adhikari、Bruce M. Foxman、Daniel J. Mindiola、Oleg V. Ozerov
DOI:10.1021/ja0731571
日期:2007.8.1
photochemical conversion to a dimeric (PNP)Pd−Pd(PNP) complex with a single Pd−Pd bond. Dissociation of the dimer into monomeric (PNP)Pd species is kinetically accessible thermally and photochemically. (PNP)Pd−Pd(PNP) reacts with ammonia, water, and dihydrogen by adding the H−X bond of the substrate (X = NH2, OH, H) across the Pd−Pd bond. For ammonia, this represents a rare example of conversion of NH3
Reduction of CO<sub>2</sub>to free CO by a Pd(<scp>i</scp>)–Pd(<scp>i</scp>) dimer
作者:Chandra Mouli Palit、Daniel J. Graham、Chun-Hsing Chen、Bruce M. Foxman、Oleg V. Ozerov
DOI:10.1039/c4cc02438a
日期:——
Reaction of CO2 with a Pd(I)âPd(I) dimer supported by amido/bis(phosphine) pincer PNP ligands produces free CO in the presence of Me3SiCl and Me3SiOTf.
Understanding Pd–Pd Bond Length Variation in (PNP)Pd–Pd(PNP) Dimers
作者:Justin R. Walensky、Claudia M. Fafard、Chengyun Guo、Christina M. Brammell、Bruce M. Foxman、Michael B. Hall、Oleg V. Ozerov
DOI:10.1021/ic301629m
日期:2013.3.4
Analysis of the structures of three (PNP)Pd-Pd(PNP) dimers [where PNP stands for anionic diarylamido/bis(phosphine) pincer ligands] has been carried out with the help of single-crystal X-ray diffractometry and density functional theory (DFT) calculations on isolated molecules. The three dimers under study possess analogous ancillary ligands; two of them differ only by an F versus Me substituent in a remote (five bonds away from Pd) position of the pincer ligand. Despite these close similarities, X-ray structural determinations revealed two distinct structural motifs: a highly symmetric molecule with a long Pd-Pd bond or a highly distorted molecule with Pd-Pd bonds ca. 0.14 angstrom shorter. DFT calculations on a series of (PNP)Pd-Pd(PNP) dimers (as molecules in the gas phase) confirmed the existence of these distinct minima for dimers carrying large isopropyl substituents on the P-donor atoms (as in the experimental structure). These minima are nearly isoergic conformers. Evidently, the electronically preferred symmetric structure for the dimer (with a square-planar environment about Pd and a linear N-Pd-Pd-N vector) is not sterically possible with the preferred Pd-Pd distance. Thus, the minima correspond to either a symmetric structure with a long Pd-Pd bond distance or a structure with a short Pd-Pd distance but with substantial distortions in the Pd coordination environment to alleviate steric conflict. This notion is supported by finding only a single minimum (symmetric and with short Pd-Pd bonds) for each of the dimers carrying smaller substituents (H or Me) on the P atoms, regardless of the remote substitution.