Mimicking zeolite to its core: porous sodalite cages as hangers for pendant trimeric M3(OH) clusters (M = Mg, Mn, Co, Ni, Cd)

A new class of zeolite-type porous materials in which 3D frameworks are covalently functionalized with crystallographically ordered pendant metal clusters have been synthesized. This work demonstrates a new paradigm for and the feasibility of functionalizing zeolite-type frameworks through the conversion of extraframework sites in mineral zeolites into part of the framework for occupation by dangling metal clusters in metal-organic frameworks.     

Towards constructing multi-bit binary adder based on Belousov-Zhabotinsky reaction

It has been proposed that the spatial excitable media can perform a wide range of computational operations, from image processing, to path planning, to logical and arithmetic computations. The realizations in the field of chemical logical and arithmetic computations are mainly concerned with single simple logical functions in experiments. In this study, based on Belousov-Zhabotinsky reaction, we performed simulations toward the realization of a more complex operation, the binary adder. Combining with some of the existing functional structures that have been verified experimentally, we designed a planar geometrical binary adder chemical device. Through numerical simulations, we first demonstrated that the device can implement the function of a single-bit full binary adder. Then we show that the binary adder units can be further extended in plane, and coupled together to realize a two-bit, or even multi-bit binary adder. The realization of chemical adders can guide the constructions of other sophisticated arithmetic functions, ultimately leading to the implementation of chemical computer and other intelligent systems.     

Temperature dependence of vibrational modes of CH3?CC(ads) and I(ads) coadsorbed on Ag(111): Ab initio molecular dynamics approach

Ab initio molecular dynamics simulations accompanied by a Fourier transform of the dipole moment (aligned perpendicular to the surface) autocorrelation function are implemented to investigate the temperature‐dependent infrared (IR) active vibrational modes of CH₃? C_(β)?C_(α)(ads) and I_(ads) when coadsorbed on an Ag(111) surface at 200 and 400 K, respectively. The analytic scheme of the Fourier transform of a structural coordinate autocorrelation function is used to identify two distinguishable IR active peaks of C_(β)?C_(α) stretching, which are characterized by two types of dynamic motion of adsorbed CH₃? C_(β)?C_(α)(ads) at 200 K, namely, the motion of the tilted ? C? C_(β)?C_(α)? axis and the motion of the stand‐up ? C? C_(β)?C_(α)? axis. These two recognisable IR active peaks of C_(β)?C_(α) stretching are gradually merged into one peak as a result of the dominant motion of the stand‐up ? C? C_(β)?C_(α)? axis as the temperature increases from 200 to 400 K. The calculated intensities of the IR active peaks of the asymmetrical deformation mode of CH₃ and the asymmetrical stretching mode of CH₃, with their dynamic dipole moments nearly perpendicular to the ? C? C_(β)?C_(α)? axis, become relatively weak; however, the symmetrical deformation mode of CH₃ and the symmetrical stretching mode of CH₃, with their dynamic dipole moments randomly directed away from the ? C? C_(β)?C_(α)? axis, will not have direct correspondence between the intensities of their IR active peaks and the angle between the Ag(111) surface and the ? C? C_(β)?C_(α)? axis as the temperature increases from 200 to 400 K. Finally, the increased flipping from the motion of the tilted ? C? C_(β)?C_(α)? axis to the motion of the stand‐up ? C? C_(β)?C_(α)? axis followed by its diffusion, resulting from the increasing temperature from 200 to 400 K or even higher, seems to be the initial event that initiates the alkyne self‐coupling reaction that leads to the final production of H₃C? C?C? C?C? CH₃. © 2012 Wiley Periodicals, Inc.     

Power Generation Capabilities of Microbial Fuel Cells with Different Oxygen Supplies in the Cathodic Chamber

Two microbial fuel cells (MFCs) inoculated with activated sludge of a wastewater treatment plant were constructed. Oxygen was provided by mechanical aeration in the cathodic chamber of one MFC, whereas it was obtained by the photosynthesis of algae in the other. Electrogenic capabilities of both MFCs were compared under the same operational conditions. Results showed that the MFC with mechanical aeration in the cathodic chamber displayed higher power output than the one with photosynthesis of algae. Good linear relationship between power density and chemical oxygen demand (COD) loading rate was obtained only on the MFC with mechanical aeration. Furthermore, the relationships between power density and effluent COD and between Coulombic efficiency and COD loading rate can only be expressed as binary quadratic equations for the MFC with mechanical aeration and not for the one with photosynthesis of algae.     

Drops sitting on a tilted plate: receding and advancing pinning

The wetting behavior of a liquid drop sitting on an inclined plane is investigated experimentally and theoretically. Using Surface Evolver, the numerical simulations are performed based on the liquid-induced defect model, in which only two thermodynamic parameters (solid-liquid interfacial tensions before and after wetting) are required. A drop with contact angle (CA) equal to θ is first placed on a horizontal plate, and then the plate is tilted. Two cases are studied: (i) θ is adjusted to the advancing CA (θ(a)) before tilting, and (ii) θ is adjusted to the receding CA (θ(r)) before tilting. In the first case, the uphill CA declines and the downhill CA remains unchanged upon inclination. When the tilted drop stays at rest, the pinning of the receding part of the contact line (receding pinning) and the depinning of the advancing part of the contact line (advancing depinning) are observed. The free energy analysis reveals that upon inclination, the reduction of the solid-liquid free energy dominates over the increment of the liquid-gas free energy associated with shape deformation. In the second case, the downhill CA grows and the uphill CA remains the same upon inclination. Advancing pinning and receding depinning are noted for the tilted drop at rest. The free energy analysis indicates that upon inclination, the decrease of the liquid-gas free energy compensates the increment of the solid-liquid free energy. The experimental results are in good agreement with those of simulations.     

Thieno[3,4‐b]thiophene‐Based Organic Dyes for Dye‐Sensitized Solar Cells

New dipolar sensitizers containing an ethyl thieno[3,4‐b]thiophene‐2‐carboxylate (ETTC) entity in the conjugated spacer have been synthesized in two isomeric forms. These compounds were used as the sensitizers of n‐type dye‐sensitized solar cells (DSSCs). The best conversion efficiency (5.31 %) reaches approximately 70 % of the N719‐based (7.41 %) DSSC fabricated and measured under similar conditions. The ETTC‐containing compounds exhibit a bathochromic shift of the absorption compared to their thiophene congeners due to the quinoid effect, however, charge‐trapping at the ester group of ETTC was found to jeopardize the electron injection and lower the cell efficiency. Charge trapping is alleviated as the ester group of ETTC is replaced with a hydrogen atom, as evidenced from the theoretical computation.     

Control of Light‐Promoted [2+2] Cycloaddition Reactions by a Remote Ancillary Regulatory Group That Is Covalently Attached to Rhenium Rectangles

The high‐yielding self‐assembly of three neutral rhenium(I) rectangles, [Re₂(CO)₆(L)(bpe)]₂ ( 1 a , L=2,2′‐biimidazolate (biim); 1 b , L=2,2′‐bisbenzimidazolate (bbim); 1 c , L=2,2′‐bis(4,5‐dimethylimidazolate) (bdmim); bpe=trans‐1,2‐bis(4‐pyridyl)ethylene), under hydrothermal conditions is described. The rectangles were structurally characterized by spectroscopic techniques and further confirmed by single‐crystal X‐ray diffraction. Upon irradiation with a Hg lamp at 365 nm, the bpe ligands of rectangles 1 a and 1 b underwent [2+2] photocycloaddition reactions to produce [{(Re(CO)₃)₂L}₂(4,4′‐tpcb)₂] ( 2 a , L=biim; 2 b , L=bbim; 4,4′‐tpcb=1,2,3,4‐tetrakis(4‐pyridyl)cyclobutane) through a single‐crystal‐to‐single‐crystal (SCSC) transformation. However, rectangle 1 c , which contained methyl groups on the 2,2′‐biimidazolate ligand, failed to undergo cycloaddition, even after prolonged irradiation. This result indicates that the light‐induced cycloaddition reaction can be preferentially controlled by the remote regulatory substituents, which are attached onto the same backbone of the rectangle complex. This transformation is the first reported utilization of a remote ancillary regulatory ligand that is covalently attached onto a coordination compound to control the [2+2] cycloaddition reaction.     

Affine group formulation of the Standard Model coupled to gravity

In this work we apply the affine group formalism for four dimensional gravity of Lorentzian signature, which is based on Klauder’s affine algebraic program, to the formulation of the Hamiltonian constraint of the interaction of matter and all forces, including gravity with non-vanishing cosmological constant Λ$\Lambda$, as an affine Lie algebra. We use the hermitian action of fermions coupled to gravitation and Yang–Mills theory to find the density weight one fermionic super-Hamiltonian constraint. This term, combined with the Yang–Mills and Higgs energy densities, are composed with York’s integrated time functional. The result, when combined with the imaginary part of the Chern–Simons functional Q$Q$, forms the affine commutation relation with the volume element V(x)$V\left(x\right)$. Affine algebraic quantization of gravitation and matter on equal footing implies a fundamental uncertainty relation which is predicated upon a non-vanishing cosmological constant.     

Columnar metallomesogens derived from unsymmetrical pyrazoles

The synthesis and mesomorphism for two series of unsymmetrical pyrazoles and their nickel(II) complexes were described. This is the first example of nickel complexes exhibiting columnar phase. The derivatives with two alkoxy chains exhibited smectic A or smectic C phases; however, all derivatives with four alkoxy chains formed hexagonal columnar phases. In contrast, all nickel(II) complexes 1a formed hexagonal columnar phases. The crystal and molecular structures of 1-(4-propyloxyphenyl)-2-(3-(4-propyloxyphenyl)-1H-pyrazol-5-yl)ethanone were determined, and it crystallizes in the triclinic space group P-1. The overall molecular shape is considered as rod-shaped. The pyrazole and one phenyl ring were coplanar, however, they were not coplanar with other phenyl ring by a dihedral angle of ca. 66.2°. A dimeric structure formed by an intermolecular H-bond (2.11 Å) and a weak π-π interaction (3.51 Å) was observed, which was probably attributed to the formation of the mesophase. The XRD experiments confirmed their structures of the mesophases.     

Quinoxaline-based U-shaped septuple-bridged [7,7]orthocyclophanes: synthesis, solid-state structure, and self-assembly

We report a three-step synthesis of 12 septuple-bridged [7,7]orthocyclophanes 11 comprising (i) two quinoxaline-based sidewalls and (ii) a linker built-in with a succinimide ring that carries phenyl, p-methoxyphenyl, p-hydroxyphenyl, or p-methoxybenzyl appendants. The synthesis began from the Diels-Alder adduct of 1,2,3,4-tetrachloro-5,5-dimethoxycyclopentadiene (1) and succinimide ring-fused dioxatetracyclodecadiene 9, followed by ruthenium-promoted oxidation of dichloroetheno-bridges in the adduct to generate a bis-α-diketone, which was then condensed with an arene-1,2-diamine to construct sidewalls (phane parts), furnishing U-shaped septuple-bridged [7,7]orthocyclophanes 11 embedding quinoxaline, dimethylquinoxaline, or benzoquinoxaline rings. Concentration-variant ¹H NMR spectra of N-p-methoxybenzyl substituted orthocyclophanes (11zd, 11xd, and 11yd) and single-crystal structures of four orthocyclophanes (11xa, 11yd, 11zb, and 11zd) revealed that the U-shaped septuple-bridged [7,7]orthocyclophanes 11 have a tendency of self-assembly, forming V-shaped dimeric entities driven chiefly by intermolecular π-π stacking interaction in both solid state and solution of high concentration.