Shigeyoshi Sakaki

A detailed theoretical investigation was performed on all of the transition states and intermediates involved in the Si−H oxidative addition of H−SiR3 (R = H, Cl, or Me) to Pt(PH3)2, ethylene insertion into Pt−H and Pt−SiR3 bonds, isomerization of the ethylene insertion product, and Si−C and C−H reductive eliminations. In a Chalk−Harrod mechanism, the rate-determining step is the isomerization of Pt(SiR3)(C2H5)(PH3) formed by ethylene insertion into the Pt−H bond and its activation barrier is 22

We report rhodium complexes bearing PAlP pincer ligands with an X-type aluminyl moiety. IR spectroscopy and single-crystal X-ray diffraction analysis of a carbonyl complex exhibit the considerable σ-donating ability of the aluminyl ligand, whose Lewis acidity is confirmed through coordination of pyridine to the aluminum center. The X-type PAlP-Rh complexes catalyze C2-selective monoalkylation of pyridine with alkenes.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOxidative addition reactions of saturated Si-X bonds (X = H, F, C, or Si) to Pt(PH3)2. An ab initio MO/MP4 studyShigeyoshi Sakaki and Masami IekiCite this: J. Am. Chem. Soc. 1993, 115, 6, 2373–2381Publication Date (Print):March 1, 1993Publication History Published online1 May 2002Published inissue 1 March 1993https://pubs.acs.org/doi/10.1021/ja00059a036https://doi.org/10.1021/ja00059a036research-articleACS PublicationsRequest reuse permissionsArticle V

Rh-catalyzed hydrosilylation of ethylene was theoretically investigated with the DFT, MP4(SDQ), and CCSD(T) methods, where RhCl(PH3)3 was adopted as a model catalyst. The rate-determining step in the Chalk−Harrod mechanism is Si−C reductive elimination, the activation barrier (Ea) of which is 27.4 (28.8) kcal/mol, where the values without parenthesis and in parenthesis are calculated with the DFT and MP4(SDQ) methods, respectively. The rate-determining step in the modified Chalk−Harrod mechanism

A newly synthesized copper(I) complex, [Cu(tmdcbpy)2]+ (tmdcbpy = 4,4′,6,6′-tetramethyl-2,2′-bipyridine-5,5′-dicarboxylic acid), was applied to a solar cell with TiO2, which provided successful results, a photocurrent of about 4 mA cm−2, photovoltage of 630 mV and an IPCE (incident monochromatic photon-to-current conversion efficiency) value of 30%, under visible light irradiation from a AM 1.5G sunlight simulator (100 mW cm−2).

The Cp2Zr-catalyzed hydrosilylation of ethylene was theoretically investigated with DFT and MP2−MP4(SDQ) methods, to clarify the reaction mechanism and the characteristic features of this reaction. Although ethylene insertion into the Zr−SiH3 bond of Cp2Zr(H)(SiH3) needs a very large activation barrier of 41.0 (42.3) kcal/mol, ethylene is easily inserted into the Zr−H bond with a very small activation barrier of 2.1 (2.8) kcal/mol, where the activation barrier and the energy of reaction calculat

Ab initio SCF/MP2 potentials are calculated on benzene–methane and benzene–benzene complexes. Although no energy stabilization appears at the Hartree–Fock level, a small but non-negligible stabilization in energy is observed at the MP2 level in both complexes, indicating the importance of the dispersion energy. Besides the dispersion energy, the electrostatic interaction plays some role in determining the relative stabilities in several cases. The most stable structure of the benzene–methane com

We report the magnesiation of aryl fluorides catalyzed by an Al-Rh heterobimetallic complex. We show that the complex is highly reactive to cleave the C-F bonds across the polarized Al-Rh bond under mild conditions. The reaction allows the use of an easy-to-handle magnesium powder to generate a range of arylmagnesium reagents from aryl fluorides, which are conventionally inert to such metalation compared with other aryl halides.

Oxidative addition of (HO)2B−XH3 to M(PH3)2 (X = C, Si, Ge, or Sn; M = Pd or Pt) was theoretically investigated with MP2-MP4(SDQ) and CCSD(T) methods. (HO)2B−XH3 easily undergoes oxidative addition to Pt(PH3)2 with a moderate activation energy for X = C and either a very small barrier or no barrier for X = Ge, Si, and Sn. Also, (HO)2B−SiH3, (HO)2B−GeH3, and (HO)2B−SnH3 undergo oxidative addition to Pd(PH3)2 with either a very small barrier or no barrier. Only the oxidative addition of (HO)2B−CH3

The insertion of M(PH3)2 (M = Pd or Pt) into BX2−BX2 (X = H or OH) was theoretically investigated with the ab initio MO/MP4SDQ, SD-CI, and coupled cluster with double substitutions (CCD) methods. The MP4SDQ method provides an activation energy (Ea) and an exothermicity (Eexo) similar to those of the SD-CI and CCD methods (the MP4SDQ values are given here). This reaction proceeds with a moderate Ea of ∼15 kcal/mol and a considerable Eexo of ∼20 kcal/mol for X = OH and M = Pt and a higher Ea of 20

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure and coordinate bonding nature of nickel(0) and copper(I) carbon dioxide complexes. An ab initio molecular orbital studyShigeyoshi Sakaki, Kazuo Kitaura, and Keiji MorokumaCite this: Inorg. Chem. 1982, 21, 2, 760–765Publication Date (Print):February 1, 1982Publication History Published online1 May 2002Published inissue 1 February 1982https://pubs.acs.org/doi/10.1021/ic00132a057https://doi.org/10.1021/ic00132a057research-articleACS Publications

A theoretical study of oxidative additions of H−CH3, CH3−CH3, H−SiR3, and SiR3−CH3 (RH, Cl, or Me) to Pt(PH3)2 was carried out with ab initio MO/MP2-MP4SDQ, CCD, and CCSD methods. The oxidative addition reactions of C−H and Si−H σ-bonds occur through a planar transition state (TS) structure, in accordance with the expectation from an orbital interaction diagram. However, the oxidative addition reactions of CH3−CH3 and SiH3−CH3 take place through a nonplanar TS structure, unexpectedly; the dihedr

In Ni(0)-catalyzed carboxylation reaction of aryl chloride with CO2, the formation of a Ni(I) species is crucial, because the CO2 insertion into the Ni(I)–Ph bond easily occurs but that into the Ni(II)–Ph bond cannot. This is a key point of this successful carboxylation reaction.