Formation of Zwitterionic Fullerodendron Using a New DBN-Focal Dendron

A new poly(amidoamine) dendron having 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) at the focal point was synthesized. Interestingly, formation of zwitterionic fullerodendrons (λmax = 930 nm for C60 and 795 nm for C70) were observed by Vis-NIR spectroscopy upon the reaction of C60 or C70 with the DBN-focal dendron. In particular, the C70 anion was effectively stabilized by the site isolation effect of the dendritic wedge. The half-life of fullerodendron 12b having C70 anion at the focal point reaches 7,345 min, which is 20 times longer than that of complex between C60 and pristine DBN. Furthermore, in order to confirm the structure of the zwitterionic complex, fullerodendron 12a was reprecipitated from benzonitrile/1,2,4-trimethylbenzene, and was observed using IR spectroscopy and APPI-MS

Synthesis of a Stable Stibabismuthene; the First Compound with an Antimony-Bismuth Double Bond (BIOORGANIC CHEMISTRY-Organoelement Chemistry)

Condensation reaction of an overcrowded dihydrostibine with dibromobismuthine using 1,8- diazabicyclo[5.4.0]undec-7-ene as a base afforded the first stable stibabismuthene, the formation of which was evidenced by the UV-vis and Raman spectra and its chemical reactivity

Synthesis of rhodium–carbonyl complexes bearing a novel P,N-chelating ligand of Schiff-base type

Schiff-base type N, P-chelating ligands, phosphorus analogues of imino–anilido ligands, were designed and synthesized as a new type of ligands toward transition metals, and the rhodium–carbonyl complexes bearing the novel imino–phosphido and phosphaalkenyl-anilido ligands were synthesized as stable crystalline compounds. Their structures were definitively revealed by X-ray crystallographic analysis, showing the unique electronic features of the ligands. In addition, the effective trans-influence of the phosphorus atom was suggested on the basis of the structural parameters and spectroscopic features of the isolated complexes

Synthesis of a Dichlorodigermasilane: Double Si–Cl Activation by a Ge=Ge Unit

Halogenated oligosilanes and oligogermanes are interesting compounds in oligosilane chemistry from the viewpoint of silicon-based-materials. Herein, it was demonstrated that a 1, 2-digermacyclobutadiene derivative could work as a bis-germylene building block towards double Si–Cl activation to give a halogenated oligometallane, a bis(chlorogermyl)dichlorosilane derivative

Synthesis, structure and reactivity of a 1-bromoalumole.

A stable 1-bromoalumole has been synthesized by the reaction of a 1, 4-dilithio-1, 3-butadiene derivative with AlBr[3]. The 1-bromoalumole was found to exist as a dimeric structure in the crystalline state. Reaction of the 1-bromoalumole with Mes[*]Li afforded the corresponding Mes[*]-substituted alumole (Mes[*] = 2, 4, 6-(t-Bu)[3]C[6]H[2]), demonstrating the potential of the 1-bromoalumole for the functionalization of alumoles

Syntheses and structures of a stable gallole free of Lewis base coordination and its dianion

A stable Lewis base-free gallole bearing a bulky Mes[*] group (=2, 4, 6-(t-Bu)[3]C[6]H[2]) was synthesized by the treatment of Mes[*]GaCl[2] with a 3, 6-dilithio-3, 5-octadiene derivative. Reduction of the gallole with lithium metal afforded the corresponding gallole dianion species as a lithium salt. Structures of the gallole and the lithium salt of the gallole dianion have been elucidated by using X-ray crystallographic analysis, NMR spectroscopies, and density functional theory calculation

Synthesis and Structure of a Ferrocenylsilane-Bridged Bisphosphine

A bisferrocenylsilane-bridged bisphosphine, i.e., a bisphosphine bridged by bis(1’-dicyclohexylphosphino-1-ferrocenyl)dimethoxysilane, was synthesized and structurally characterized. Its redox behavior was examined by cyclic voltammetry and differential pulse voltammetry, which revealed two-step oxidation processes

Acid-Responsive Absorption and Emission of 5-N-Arylaminothiazoles: Emission of White Light from a Single Fluorescent Dye and a Lewis Acid

Solutions of 5-N-arylaminothiazoles containing pyridyl groups exhibited clear halochromism and halofluorism upon addition of Brønsted and Lewis acids. The addition of triflic acid to solutions of 5-N-arylaminothiazoles in Et2O induced bathochromic shifts of the absorption and emission bands. DFT calculations suggested that the spectral changes arise from the protonation of the pyridyl group of the thiazoles in Et2O. Single-crystal X-ray diffraction analysis of a thiazole and its protonated form revealed the change of the conformation around the thiazole ring. The emission of white light was accomplished from a single fluorescent dye by adjusting the ratio of dye and B(C6F5)3, whereby the International Commission on Illumination coordinates showed a linear change from blue to orange

Asymmetric aldol reaction via memory of chirality.

Asymmetric aldol reactions of α-amino acid derivatives via memory of chirality were developed. Chiral oxazolidones with contiguous tetra- and trisubstituted chiral centers were obtained in 78-94% ee by the asymmetric aldol reaction followed by intramolecular acylation

Oxidative kinetic resolution of racemic alkyl aryl carbinols by an electronically tuned chiral nitroxyl radical

A method for oxidative kinetic resolution of racemic alcohols catalyzed by chiral nitroxyl radical (R, R)-1 has been developed. This method is especially effective for the kinetic resolution of tert-butyl aryl carbinols (s = up to 23)