Molecule-based photonically switched half and full adder

A single molecule logic gate using electronically excited states and ionization/fragmentation can take advantage of the differences in cross-sections for one and two photon absorption. Fault tolerant optically pumped half adder and full adder are discussed as applications. A full adder requires two separate additions, and the logic concatenation that is required to implement this is physically achieved by an intramolecular transfer along the side chain of 2-phenylethyl-N,N-dimethylamine (PENNA). Solutions of the kinetic equations for the temporal evolution of the concentration of different states in the presence of time-varying laser fields are used to illustrate the high contrast ratios that are potentially possible for such devices.     

Deoxyribozyme-based half-adder

We have constructed a solution-phase array of three deoxyribozyme-based logic gates that behaves as a half-adder. Two deoxyribozymes mimic i(1)ANDNOTi(2) and i(2)ANDNOTi(1) gates that cleave a fluorogenic substrate, reporting through an increase in fluorescence emission at 570 nm. The third deoxyribozyme mimics an i(1)ANDi(2) gate and cleaves the other fluorogenic substrate, reporting through an increase in fluorescence emission at 520 nm. Together, this system represents the first example of a decision-making enzymatic network with two inputs and two outputs. Similar systems could be applied to control autonomous therapeutic and diagnostic devices.     

All-photonic molecular half-adder

One molecule acts as both an AND and an XOR Boolean logic gate that share the same two photonic inputs. The molecule comprises a half-adder, adding two binary digits with only light as inputs and outputs, and consists of three covalently linked photochromic moieties, a spiropyran and two quinoline-derived dihydroindolizines. The AND function is based on the absorption properties of the molecule, whereas the XOR function is based on an off-on-off response of the fluorescence to the inputs that results from interchromophore excited-state quenching interactions. The half-adder is simple to operate and can be cycled many times.     

Molecular beacon-based half-adder and half-subtractor

This work demonstrates two DNA-based logic circuits that behave as a half-adder and a half-subtractor. A half-adder is composed of an AND gate and an XOR gate, whereas a half-subtractor consists of an INH gate and an XOR gate. The proposed designs are inspired by molecular beacons.     

Molecule-based modeling of heavy oil

A molecular-level kinetics model has been developed for the pyrolysis of heavy residual oil. Resid structure was modeled in terms of three attribute groups: cores, inter-core linkages, and side chains. The concentrations of attributes were constrained by probability density functions (PDFs) that were optimized by minimizing the difference between the properties of the computational representation-which were obtained by juxtaposing the attributes-to measured properties, which were obtained by analytical chemistry measurements. Computational tools were used to build a reaction network that was constructed based upon model compounds and their associated kinetics. For cases with an intractable number of species, equations were written in terms of the three attribute groups and the molecular composition was retained implicitly through the juxtaposition. These modeling methods were applied to the Shengli and Daqing resids. The composition of the simulated molecular feedstock fit well with analytical chemistry measurements. After simulated pyrolysis, both resids showed representative increases in the weight fractions of lighter hydrocarbons. Relevant end-use properties were predicted for the product mixtures.     

A new redox-resettable molecule-based half-adder with tetrathiafulvalene

A new redox molecule-based half-adder with tetrathiafulvalene (TTF) was reported for the first time. This half-adder employs electrochemical and chemical oxidations (NOPF6) as input signals and absorbances at 350 and 435 nm as output signals. It is interesting to note that this new molecule-based half-adder shows reset capability by making use of the unique redox behaviors of TTF.     

普鲁士蓝类分子磁体研究的新进展

在分子磁体的研制中,多氰金属盐是一类非常合适的分子前体。它有可能组装成高自旋基态、高居里温度或具有各向异性的分子基磁体。本文将介绍此类分子磁体的研究新成果及发展前景。     

Molecule-based kinetic modeling by Monte Carlo methods for heavy petroleum conversion

A methodology for kinetic modeling of conversion processes is presented.The proposed approach allows to overcome the lack of molecular detail of the petroleum fractions and to simulate the reactions of the process by means of a two-step procedure.In the first step,a synthetic mixture of molecules representing the feedstock is generated via a molecular reconstruction method,termed SR-REM molecular reconstruction.In the second step,a kinetic Monte Carlo method,termed stochastic simulation algorithm(SSA),is used to simulate the effect of the conversion reactions on the mixture of molecules.The resulting methodology is applied to the Athabasca vacuum residue hydrocracking.An adequate molecular representation of the vacuum residue is obtained using the SR-REM algorithm.The reaction simulations present a good agreement with the laboratory data for Athabasca vacuum residue conversion.In addition,the proposed methodology provides the molecular detail of the vacuum residue conversion throughout the reactions simulations.     

Molecule-based valence tautomeric bistability synchronized with a macroscopic crystal-melt phase transition

Here, we show a synchronic bistability of valence tautomeric (VT) molecular interconversion and a macroscopic crystal-melt phase transition in long alkoxy-functionalized cobalt-dioxolene complexes. Studies have been carried out for a novel series of complexes, [Co(CnOpy) 2(3,6-DTBQ)2] (3,5-dialkoxy(C(n)H2(n+1)O-; n = 9, 12, and 17)pyridine (CnOpy) and 3,6-di-tert-butyl semiquinonate or catecholate ligands (3,6-DTBQ)). All complexes show the molecular VT interconversion with thermal hysteresis attributed to the synchronous crystal-melt phase transition. Thermodynamic analysis has revealed that the molecular VT interconversion is restricted over 50 K and crystal-melt phase transition is accelerated about 50 K by the synchronicity. The synchronicity is attributed to enthalpic and entropic effects of the alkoxy chains in the crystalline phase of the one tautomer and the melt phase of the other, respectively. Our results show efficient chemical and thermodynamic strategies to combine molecule-based and macroscopic bistabilities.     

调控供电子策略简易制备近红外二区有机小分子光学诊疗试剂

有机小分子凭借着明确的化学结构、出色的生物相容性、优异的可重复性等诸多优势被广泛应用于光学诊疗领域. 然而, 目前报道的有机小分子存在合成步骤复杂、成像波长位于近红外一区(NIR-I)、光热转换效率及单线态氧产率低等缺陷, 严重限制了其诊疗效果. 基于此, 本工作以吡咯并吡咯二酮作为缺电子单元、分别以苯、苯胺、邻苯二胺作为供电子单元, 通过一步偶联反应简易制备得到三种有机小分子DPP-0、DPP-2、DPP-4, 进一步利用纳米沉淀法制备得到对应的水溶性纳米粒子DPP-0 NPs、DPP-2 NPs和DPP-4 NPs. 研究发现, 随着氨基数量的增加, 纳米粒子吸收/发射均发生了红移, 其中DPP-4 NPs具有良好的NIR-I吸收能力且其最大荧光发射达到了近红外二区(NIR-II)区域, 表明可以通过改变供电子单元策略实现光学性能的调控. 在单一激光照射下, DPP-4 NPs可以同时产生NIR-II荧光信号、过高热及单线态氧, 其光热转换效率和单线态氧产率分别高达40.2%及34.3%, 可成功应用于肿瘤深层次NIR-II荧光成像诊断及高效光热/光动力联合治疗.     

Molecule-based room-temperature magnets: catalytic role of V(III) in the synthesis of vanadium-chromium Prussian blue analogues

A new synthetic procedure to obtain vanadium-chromium Prussian blue analogues is presented, using controlled amounts of V(III) in solution during the synthesis. The vanadium and chromium oxidation states and the chemical environment of the metal ions in the solids are characterized by infrared and X-ray absorption spectroscopies. The presence of weak amounts of V(III) during the synthesis provides materials which are better organized and present reproducible Curie temperature and magnetization at saturation in agreement with the observed V/Cr stoichiometry.     

分子基磁体[NCBzPy][Ni(dmit)2]的合成、表征和磁学性质

合成了一种新的取代苄基吡啶盐[NcBzpy]cl(1),1和NiCl2,dmit^2-反应生成分子基磁体[NCBzPy][Ni(dmit)2](2),其结构用元素分析、IR和UV进行了表征。并测定了2在2K～300K的变温磁化率,结果显示。相邻Ni^3 之间存在铁磁偶合作用。     

A potential and ion switched molecular photonic logic gate

A molecular photonic logic gate is demonstrated by integrating electrical (potential) and chemical (ionic) switching functions into molecules attached at an externally addressable semiconductor substrate.     

High performance optical absorbance detectors based on low noise switched integrators

Optical absorption detection is the most common analytical measurement principle in liquid phase analysis. The current state-of-the-art of commercially available detectors exhibit peak-to-peak (p-p) noise levels in the range of 1 x 10(-5)-2 x 10(-5) absorbance units (10-20 microAU). Using circuitry based on newly available switched integrator integrated circuit (IC) packages, it is possible to construct inexpensive absorbance detectors with p-p noise levels as low as 3 microAU under actual use conditions. The necessary electronics are described and performance data are reported with light emitting diodes (LEDs) as light sources. Even in the capillary format with a rectangular capillary (50 x 1000 microm cross section) with a slitwidth <50 microm and with the 1000 microm dimension as the nominal pathlength, p-p noise levels of 10 microAU are observed, from which a concentration limit of detection (LOD) of 10 nM for bromothymol blue (BTB) can be estimated with a 660 nm light source.