Deltaarenes; novel macrocyclic molecules that are readily available from 1,4-benzoquinone and benzene dithiols

New types of macrocyclic compounds, deltaarenes, are prepared. The compounds were readily synthesized in three steps from an arenedithiol and benzoquinone, and the yields of the macrocyclization reaction reached up to 40% under high dilution conditions. X-ray crystallographic analysis revealed that the macrocycle has a relatively rigid trimeric structure with a unique triangular hole, the size of which was approximately 11?Å along each side. NMR data suggests that the ring has a C3-symmetric structure. The X-ray analysis showed that the hole is large enough to capture one molecule of chlorobenzene. Use of a variety of dithiols allowed the synthesis of different types of deltaarene derivatives. MO calculations showed that the hole size depends on the dithiol unit. Deprotection of the twelve methoxyl groups was easily achieved by treatment with BBr₃ and yielded the free-OH deltaarene derivative.     

Synthesis of poly(quinoxaline‐2,3‐diyl)s with alkoxy side chains by aromatizing polymerization of 4,5‐dialkoxy‐substituted 1,2‐ diisocyanobenzenes

Poly(quinoxaline‐2,3‐diyl)s bearing alkoxy pendants was synthesized by living polymerization of 4,5‐dialkoxy‐3,6‐dimethyl‐1,2‐diisocyanobenzenes, which were easily accessible from 3,6‐dimethylcatechol, using organonickel complexes as initiators. Thermal properties of the obtained polymers were fully determined by thermogravimetric analysis and differential scanning calorimetry, exhibiting strong dependence on their side chains. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Inversion or retention? Effects of acidic additives on the stereochemical course in enantiospecific Suzuki-Miyaura coupling of α-(acetylamino)benzylboronic esters

The stereochemical course of the stereospecific Suzuki-Miyaura coupling of enantioenriched α-(acetylamino)benzylboronic esters with aryl bromides can be switched by the choice of acidic additives in the presence of a Pd/XPhos catalyst system. Highly enantiospecific, invertive C-C bond formation takes place with the use of phenol as an additive. In contrast, high enantiospecificity for retention of configuration is attained in the presence of Zr(Oi-Pr)(4)·i-PrOH as an additive.     

Interaction analysis of the carcinoembryonic antigen (CEA) with its monoclonal antibody immobilized on a gold surface using Fourier transform infrared reflection-absorption spectroscopy (FT-IR RAS).

A monoclonal antibody for the carcinoembryonic antigen (CEA) was immobilized on a gold chip surface covered by a self-assembled monolayer of 11-mercaptoundecanoic acid. Upon the addition of CEA, a Fourier transform infrared reflection-absorption spectroscopy (FT-IR RAS) measurement showed an increased absorption at around 1500 - 1700 cm(-1), corresponding to its amide structures. Another addition of CEA polyclonal antibody on this chip caused a further increase of the absorption in this region only after a treatment with CEA. This result shows that an antibody-fixed gold surface coupled with an FT-IR RAS measurement provides a new tool for detecting the antibody-antigen interaction.     

Nickel-catalyzed addition of C-H bonds of terminal alkynes to 1,3-dienes and styrenes

The C-H bond of a terminal alkyne adds to a carbon-carbon double bond of 1,3-dienes, styrenes, and norbornene at room temperature in the presence of a nickel catalyst in regio- and stereoselective manners. Reaction of triisopropylsilylacetylene with 1-substituted 1,3-butadiene derivatives afforded hydroalkynylation products via introduction of a hydrogen atom and a triisopropylsilylethynyl group to 4- and 3-positions of the dienes, respectively. Likewise, 1-triisopropylsiloxy-1,3-butadiene, 1,3-pentadiene, 1-cyclohexen-1-yl-1,3-butadiene, and 1,3-cyclohexadiene underwent the hydroalkynylation reaction, giving the corresponding 1,4-enyne derivatives in good yields at room temperature. Reaction of p-substituted styrene with triisopropylsilylacetylene also proceeded in the presence of the nickel catalyst, giving the branched hydroalkynylation products in good yields. Norbornene gave a exo-addition product in good yield under the same reaction conditions.     

Sharp remainder of a critical Hardy inequality

An explicit representation is given to the remainder of a critical Hardy inequality in \({L^{n}(\mathbb{R}^{n})}\) with \({n \ge 2}\).     

Theoretical study on the molecular structures of X-, α-, and β-types of lithium phthalocyanine dimer

We report here the results from theoretical calculations of the potential energy curves, the geometry optimizations, and the electronic structures for three dimers of lithium phthalocyanine (LiPc) by using three types of functional systems: PBE1PBE, B3LYP, and M06. The results were discussed in comparison with those obtained for the dimers of magnesium phthalocyanine (MgPc). The long-range dispersive interactions were considered in part using these functional systems in the increasing order of PBE1PBE, B3LYP, and M06. The mechanism whereby the dispersive interactions affect the geometric and electronic structures of the LiPc and MgPc dimers is discussed. The calculated results provide insight into the computational methods for both open- and closed-shell metal phthalocyanine (MPc) dimers: Although the PBE1PBE and B3LYP functional systems cannot evaluate a weak dispersion interaction appropriately, the M06 functional can estimate a weak dispersion interaction well in both open- and closed-shell MPc dimers. Basis set superposition error (BSSE) corrections play an important role for the quantitative analysis; however, the calculation results without BSSE corrections may be sufficient for the qualitative discussion on the properties of these dimers such as geometries, stabilities, electronic structures, and so on.