Shinji Toyota

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTRotational Isomerism Involving Acetylene CarbonShinji Toyota*View Author Information Department of Chemistry, Faculty of Science, Okayama University of Science, 1-1 Ridaicho, Kita-ku, Okayama 700-0005, Japan* E-mail: [email protected]Cite this: Chem. Rev. 2010, 110, 9, 5398–5424Publication Date (Web):June 3, 2010Publication History Received22 February 2010Published online3 June 2010Published inissue 8 September 2010https://pubs.acs.org/doi/10.1021/cr100

Abstract The molecular structures of a set of intramolecular boron-amine complexes, 9-[2-(dialkylaminomethyl)phenyl]-9-borabicyclo[3.3.1]nonanes (alkyl = Me and Et) and 2-[2-(dimethylaminomethyl)phenyl]-4,4-diphenyl-1,3,2-dioxaborolane, were determined by the X-ray analyses. The boron atom has a tetrahedral geometry and the five-membered ring is puckered with the nitrogen atom out of the plane in every complex. The distances of the N–B coordination bonds, which are in the range of 1.74–1.77Å, ar

In the swing: The Sonogashira coupling reaction has been used to synthesize a cyclic tetramer composed of 1,8-anthrylene and ethynylene units. This tetramer adopts a diamond-prism structure and interconverts between enantiomers by skeletal swing (see picture); the energy barrier to interconversion is approximately 38 kJ mol−1. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2004/z53647_s.pdf or from the author. Please note: The publi

An anthracene cyclic hexamer was synthesized by the coupling reaction as a macrocyclic hydrocarbon host. This disk-shaped host included a C₆₀ guest in 1:1 ratio to form a Saturn-type supramolecular complex in solution and in crystals. X-ray analysis unambiguously revealed that the guest molecule was accommodated in the middle of the host cavity with several CH⋅⋅⋅π contacts. The association constant K_a determined by NMR titration measurements was 2.3×10³ L mol<sup

To distinguish between dissociation of a B−N coordination bond by SN1- and SN2-type mechanisms, two series of 1,3,2-dioxaborolanes (boronates) and BEt2 (borane) complexes carrying a 2,6-bis((dimethylamino)methyl)phenyl group as a third substituent were synthesized by the reaction of the corresponding organolithium compound with an appropriate boron reagent. In the solid state, the boronate complex exhibits a structure in which only one NMe2 group is coordinated to a tetracoordinated boron atom a

Saturn-like systems consisting of nanoscale rings and spheres are fascinating motifs in supramolecular chemistry. Several ring molecules are known to include spherical molecules at the center of the cavity via noncovalent attractive interactions. In this Minireview, we generalize the molecular design, the structural features, and the supramolecular chemistry of such "nano-Saturns", which consist of monocyclic rings and fullerene spheres (mainly C₆₀ ), on the basis of previous experime

Design principles in polynuclear coordination complexes have been based on the idea that metal ions would acquire donor atoms up to the metal's ligand field preference, and donor ligands, such as 1,10-phenanthroline, would not leave donor atoms uncoordinated to a metal ion. The geometry of the simple molecular grid formed from a series of 3,3′-biphenanthrolines complexed with CuI or AgI ions sets up a cleft that binds uncoordinated ligands through a combination of intercalation, solvation, and C

Polycyclic aromatic hydrocarbons consisting of three fused anthracene units were designed as new π-conjugated compounds having helical structures. These expanded helicenes were synthesized by Pt-catalyzed cycloisomerization of the corresponding ethynyl-substituted precursors. The nonplanar and helical structure was confirmed by X-ray analysis and DFT calculations, and the barrier to helical inversion was estimated to be 34 kJ mol^-1 . The enantiomers of the diphenyl derivative were suc

Abstract The rates of dissociation of the N–B bonds in the title compounds were reexamined by the dynamic NMR technique to get further insight into the mechanism of dissociation. Entropies of activation were fairly large positive to suggest that the dissociation of a bond of ionic characters is the rate-limiting step. The rates of dissociation were generally larger in nonpolar solvents than in polar solvents, suggesting that the stabilization of the ground state by solvation was important in det

Abstract The title π-conjugated oligomers consisting of anthracene and acetylene units were synthesized to construct a new type of three-dimensional organic architecture. An acyclic chain was extended by the sequence of the Sonogashira coupling and the desilylation from 1,8-diethynylanthracene derivatives and 1,8-diiodoanthracene to form a tetramer, which was then coupled intramolecularly to afford a cyclic tetramer as orange crystals. It is characteristic that a substituent free cyclic tetramer

Facile exchange between the intramoleculariy coordinated and uncoordinated amine ligands in the title compounds is evidenced by NMR spectroscopy in solution, whereas the dynamic process is frozen in the solid phase as shown by X-ray crystallography.

Invited for the cover of this issue is Shinji Toyota and co-workers at Tokyo Institute of Technology and Okayama University of Science. The image depicts a spirally rising dragon to represent the helical molecular structures in the manuscript. Read the full text of the article at 10.1002/chem.202004720.

Abstract The structures and stereochemistries of the five borane–amine complexes, (N–B)-{2-(Me2NCH2)C6H4}BPhX (X = Cl, F, Me, –OCOCF3, and –OCOC2F5), were studied by some spectroscopic methods. The Cl complex prepared by the standard method was converted to each of the other complexes by the treatment with an appropriate reagent (MeLi or AgX). The enantiomers of the two perfluoroacyloxy complexes were resolved by chiral HPLC as a novel intramolecular borane–amine complex with a chiral center at

Abstract We propose strategies to construct chiral macrocycles by modification of the fundamental compound, 1,8-anthrylene–ethynylene cyclic tetramer, which features a diamond-prism structure. The incorporation of other anthracene units or diacetylene linkers produces structures of various symmetries. The enantiomers of some chiral derivatives could be resolved by chiral HPLC. The structures, dynamic behavior, and chiroptical properties of these macrocycles are summarized.