Exploring a Ni-N4 Active Site-Based Conjugated Microporous Polymer Z-Scheme Heterojunction Through Covalent Bonding for Visible Light-Driven Photocatalytic CO2 Conversion in Pure Water.

Designing photocatalysts with efficient charge transport and abundant active sites for photocatalytic CO2 reduction in pure water is considered a potential approach. Herein, a nickel-phthalocyanine containing Ni-N4 active sites-based conjugated microporous polymer (NiPc-CMP), offering highly dispersed metal active sites, satisfactory CO2 adsorption capability, and excellent light harvesting properties, is engineered as a photocatalyst. By virtue of the covalently bonded bridge, an atomic-scale interface between the NiPc-CMP/Bi2 WO6 Z-scheme heterojunction with strong chemical interactions is obtained. The interface creates directional charge transport highways and retains a high redox potential, thereby enhancing the photoexcited charge carrier separation and photocatalytic efficiency. Consequently, the optimal NiPc-CMP/Bi2 WO6 (NCB-3) achieves efficient photocatalytic CO2 reduction performance in pure water under visible-light irradiation without any sacrificial agent or photosensitizer, affording a CO generation rate of 325.9 µmol g-1 with CO selectivity of 93% in 8 h, outperforming those of Bi2 WO6 and NiPc-CMP, individually. Experimental and theoretical calculations reveal the promotion of interfacial photoinduced electron separation and the role of Ni-N4 active sites in photocatalytic reactions. This study presents a high-performance CMP-based Z-scheme heterojunction with an effective interfacial charge-transfer route and rich metal active sites for photocatalytic CO2 conversion.

In situ growth of a cobalt porphyrin-based covalent organic framework on multi-walled carbon nanotubes for ultrasensitive real-time monitoring of living cell-released nitric oxide.

Nitric oxide (NO), as a critical transcellular messenger, participates in a variety of physiological and pathological processes. However, its real-time detection still faces challenges due to its short half-life and trace amounts. Here, MWCNTs@COF-366-Co was prepared by in situ growth of a cobalt porphyrin-based covalent organic framework (COF-366-Co) on multi-walled carbon nanotubes (MWCNTs), and a unique biosensing platform for ultrasensitive real-time NO determination was established. Remarkably, MWCNTs@COF-366-Co contains plenty of atomically arranged M-N4 active sites for electrocatalysis, which provides more efficient electron transfer pathways and resolves the random arrangement issue of active sites. COF-366-Co with a high surface area contains a large number of exposed active M-N4 sites, providing faster NO transport/diffusion and more efficient electron transfer pathways. Due to the synergy of atomic-level periodic structural features of COF-366-Co and high conductivity of MWCNTs, the MWCNTs@COF-366-Co electrochemical biosensor exhibited excellent NO determination performance in a wide range from 0.09 to 400 µM, with high sensitivity (8.9 µA µM-1 cm-2) and a low limit of detection (16 nM). Moreover, the biosensor has been successfully used to sensitively monitor NO molecules released from human umbilical vein endothelial cells (HUVECs). This research not only designed a multifunctional intelligent biosensor platform, but also provided a broad prospect for continuous dynamic monitoring of the activity of living cells and their released metabolites.

Laser ablative TiO2 and tremella-like CuInS2 nanocomposites for robust and ultrasensitive photoelectrochemical sensing of let-7a.

A photoelectrochemical (PEC) biosensor based on a multiple signal amplification strategy was established for highly sensitive detection of microRNA (miRNA). TiO2 was prepared on the surface of titanium sheet by laser etching to improve its stability and photoelectrical properties, and CuInS2-sensitized TiO2 was used to form a superior photoelectrical layer, which realized the initial signal amplification. The electron donor dopamine (DA) was modified to H2 as a signal regulator, which effectively increased the photocurrent signal. To further amplify the signal, an enzyme-free hybridization reaction was implemented. When target let-7a and fuel-DNA (F-DNA) were present, the base of H1 specifically recognized let-7a and forced dopamine@AuNPs-H2 away from the electrode surface. Subsequently, the end base of H1 specifically recognized F-DNA, and let-7a was replaced and recycled to participate in the next cycle. Enzyme-free circulation, as a multifunctional amplification method, ensured the recycling of target molecules. This PEC sensor for let-7a detection showed an excellent linear response from 0.5 to 1000 pM with a detection limit of 0.12 pM. The intra-batch RSD was 3.8% and the recovery was 87.74-108.1%. The sensor was further used for clinical biomolecular monitoring of miRNA, showing excellent quantitative detection capability.

DNAzyme-Triggered Visual and Ratiometric Electrochemiluminescence Dual-Readout Assay for Pb(II) Based on an Assembled Paper Device.

Currently, portable, low-cost, and easy to operate on-chip analytical units are urgently demanded to meet the requirement for point-of-care testing in resource-limited regions. Herein, a dual-mode lab-on-paper platform is presented, which integrates distance-based visualized readout with ratiometric electrochemiluminescence (ECL) assay in one device. The distance-based measurement is based on a brown visualized strip generated from the oxidation reaction of 3,3'-diaminobenzidine in the presence of H2O2 initiated by horseradish peroxidase (HRP). Notably, visualized semiquantitative results are displayed as the length of a brown bar chart directly on the device-without the need for any data processing or plotting steps, thus avoiding the error caused by the naked eye for distinguishing the color depth. On the contrary, a ratiometric ECL technique was employed for accurate analysis based on the specific biorecognition between Pb2+-dependent DNAzymes and targets. Concretely, upon addition of Pb2+ into the fabricated device, cleaved oligonucleotide fragments connected with HRP functionalized Au nanocubes could permeate through the cellulose on account of their size that is smaller than paper pores, quench the ECL signal of the CdS quantum dots because of resonance energy transfer, and synchronously boost the ECL intensity generated from luminol by catalyzing H2O2. As a consequence, satisfied prediction and accurate monitoring performance was obtained in the range 0.1-2000 nM and 0.01-2000 nM by measuring the length of colored product and the ratio of ECL intensity, respectively. The beneficial advantages of low cost, high efficiency, and the capacity to perform dual-mode assay qualify this innovative device for use with diverse applications.

Noninvasive and Wearable Respiration Sensor Based on Organic Semiconductor Film with Strong Electron Affinity.

Interventional medical detection techniques require expensive devices and cause inconvenience and discomfort to the human body, which restricts their application to the frequency and duration of measurements. A noninvasive respiration test is urgently required for the next-generation medical technologies in early disease warning and postoperative monitoring. This article describes a noninvasive and wearable sensing device that shows high sensitivity toward acetone in respiratory gases with excellent stability, low energy consumption, and reliable flexibility. To obtain such a sensor, the organic semiconductor compound La(TBPP)(TBNc) (TBPP = tetrakis(4-tert-butylphenyl)porphyrin; TBNc = tetrakis(4-tert-butylphenyl)naphthalocyanine) was synthesized and further self-assembled into a highly ordered flexible film via a simple solution-vapor annealing method. The fabricated flexible film was deposited on an interdigitated electrode with poly(ethylene terephthalate) substrate and employed as an electrical identification component for a respiration sensor. Thanks to the attractive electron-transfer properties of highly ordered films and strong electron affinity of La(TBPP)(TBNc) molecules, the as-prepared sensor shows a low detection limit (200 ppb) and acceptable selectivity. The wrinkled/rippled structure of films endows the fabricated sensors with the ability of mechanical flexibility. More importantly, the experimental results suggest the potential application of acetone identification in real respiratory gases and provide a new concept for the development of noninvasive and wearable medical diagnostic devices.

Low-Power and High-Performance Trimethylamine Gas Sensor Based on n-n Heterojunction Microbelts of Perylene Diimide/CdS.

In this work, low-power and high-performance gas sensors toward trimethylamine (TMA) are presented for the food quality control in the Internet of Things. An amphiphilic perylene diimide derivative (1,6,7,12-tetra-chlorinated perylene- N-(2-hydroxyethyl)- N'-hexylamine-3,4,9,10-tetracarboxylic bisimide, TC-PDI) is synthesized and further employed to construct the organic microrods of TC-PDI and organic/inorganic microbelts of TC-PDI/CdS by a phase transfer method. Due to the formation of n-n heterojunctions, the TC-PDI/CdS microbelts exhibit higher conductivity than the TC-PDI microrods alone, which present an efficient gas sensing platform for TMA determination at room operating temperature with high reproducibility and selectivity. Remarkably, the limit of detection, stability, and selectivity of the TC-PDI/CdS gas sensor are significantly improved, which ascribes to the efficient charge separation of n-n heterojunctions. More importantly, the fabricated gas sensor provides potential application of "on-site" and "on-line" TMA identification in real systems and suggests an efficient way to develop new hybrid n-n heterojunctions for a low-power and high-performance gas sensor.

[Assessment of left ventricular twist in type 2 diabetes mellitus by using two-dimensional ultrasound speckle tracking imaging].

OBJECTIVE: To evaluate the left ventricular twist characteristics in patients with type 2 diabetes by using two-dimensional speckle tracking imaging (STI). METHODS: Ninety-three patients with type 2 diabetes admitted in Zhejiang Hospital from May 2012 to September 2013 were enrolled. According to left ventricular ejection fraction (LVEF), patients were divided into two groups: normal left ventricular systolic function group (group A, LVEF≥0.50, n=46) and abnormal left ventricular systolic function group (group B, LVEF <0.50, n=47). Forty-six healthy subjects were selected as normal controls. STI was applied to quantitatively analyze the left ventricular twist. Correlation of the peak of left ventricular twist angle (Peaktw), aortic valve closure time twist angle (AVCtw), and mitral valve opening time twist angle (MVOtw) with LVEF, Tei index, E/A, and E/e was evaluated. Consistency check for STI was conducted to assess its stability and reliability. RESULTS: The Peaktw, AVCtw, and MVOtw in group A were significantly elevated than those in normal controls (P<0.05). The Peaktw, AVCtw, and MVOtw in group B was lower than those in normal controls and group A (P<0.05). In diabetic patients, the Peaktw, AVCtw, MVOtw were positively correlated with LVEF (r=0.968, 0.966, 0.938;P<0.05) and E/A (r=0.798, 0.790, 0.788; P<0.05), and were negatively correlated with Tei index (r=-0.834, -0.811, -0.797; P<0.05) and E/e (r=-0.823, -0.805, -0.771; P<0.05). The agreement between measurers and within measurers of Peaktw was satisfactory (between measurers: R=0.957, bias=-0.1, 95% consistency limit=-2.8-2.7; within measurer: R=0.964, bias=-0.2, 95% consistency limits=-2.7-2.2). CONCLUSION: STI can be used for early recognition of abnormal changes of cardiac function in type 2 diabetic mellitus patients, with high stability and reliability.

Self-standing perylene diimide covalent organic framework membranes for trace TMA sensing at room temperature.

The unprecedented demand for highly selective, real-time monitoring and low-power gas sensors used in food quality control has been driven by the increasing popularity of the Internet of Things (IoT). Herein, the self-standing perylene diimide based covalent organic framework membranes (COFMPDI-THSTZ) were prepared via liquid-liquid interfacial synthesis method. By incorporating the perylene diimide monomer into the COFM through molecular engineering, COFMPDI-THSTZ based sensor demonstrated an outstanding trimethylamine (TMA)-sensing performance at room temperature. Benefited from the TMA-accessible self-standing membrane morphology, π-electron delocalization effect, and extensive surface area with continuous nanochannels, the specific and highly sensitive TMA measurement has been achieved within the range of 0.03-400 ppm, with an exceptional theoretical detection limit as low as 10 ppb. Moreover, the primary internal mechanism of COFMPDI-THSTZ for this efficient TMA detection was investigated through in-situ FT-IR spectra, thereby directly elucidating that the chemisorption interaction of oxygen modulated the depletion layers on sensing material surface, resulting in alterations in sensor resistance upon exposure to the target gas. For practical usage, COFMPDI-THSTZ based sensor exhibited exceptional real-time in-situ sensing capabilities, further confirmed their potential for application in dynamic prediction evaluation of marine fish products and quality monitoring in IoT.

Helical self-assembly of optically active phthalocyanine derivatives: effect of Zn-O coordination bond on morphology and handedness of nanostructures.

Two optically active phthalocyanine derivatives with eight peripheral chiral (S)-4'-(2-methylbutoxy)biphenyl moieties on the ß-position of the phthalocyanine ring are synthesized. The circular dichroism (CD) spectra show signals in the Q absorption region for both compounds 1 and 2 in chloroform solution, indicating the effective chiral-information transfer from the peripheral chiral (S)-4'-(2-methylbutoxy)biphenyl side chains to the phthalocyanine chromophore at the molecular level. Their self-assembling properties are further investigated by using electronic absorption and Fourier transform infrared spectroscopy, transmission electronic microscopy, scanning electronic microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Experimental results reveal the effect of the metal-coordination bond on molecular packing models in these nanostructures, which in turn results in the self-assembled nanostructures with different morphologies, from nanosheets for 1 to helical nanofibers for 2. In addition, good semiconducting properties of the nanostructures fabricated from phthalocyanine derivatives 1 and 2 are revealed by current-voltage measurements.

How does income and green technology innovation influence the emissions reduction effect of renewable energy: evidence from Chinese provincial data.

The development of renewable energy is a key measure to achieving carbon neutrality in China. Considering the significant regional differences in income levels and green technology innovation, it is essential to discuss the impact of renewable energy development on carbon emissions from the Chinese provincial level. Based on the panel data of 30 provinces in China from 1999 to 2019, this study first explores the impact of renewable energy on carbon emissions and regional heterogeneity. Moreover, the moderating effects of income levels on the nexus between renewable energy and carbon emissions, and the impact mechanism of green technology innovation are further examined. Results show that, first, renewable energy development can significantly reduce carbon emissions in China, and there exist obvious regional differences. Second, income levels present a non-linear moderating effect on the relationship between renewable energy and carbon emissions. The increase in income levels can effectively enhance the emission reduction effect of renewable energy only in high-income regions. Third, renewable energy development is an important mediating mechanism for green technology innovation to achieve emission reduction. Finally, policy implications are proposed to help China in advancing the development of renewable energy and achieve carbon neutrality.

Porphyrin-Based Covalent Organic Frameworks with Donor-Acceptor Structure for Enhanced Peroxidase-like Activity as a Colorimetric Biosensing Platform.

Hydrogen peroxide (H2O2) and glucose play a key role in many cellular signaling pathways. The efficient and accurate in situ detection of H2O2 released from living cells has attracted extensive research interests. Herein, a new porphyrin-based porous covalent organic framework (TAP-COF) was fabricated via one-step condensation of 1,6,7,12-tetrachloroperylene tetracarboxylic acid dianhydride and 5,10,15,20-tetrakis (4-aminophenyl)porphyrin iron(III). The obtained TAP-COF has high surface areas, abundant surface catalytic active sites, and highly effective electron transport due to its precisely controllable donor-acceptor arrangement and 3D porous structure. Then, the new TAP-COF exhibited excellent peroxidase-like catalytic activity, which could effectively catalyze oxidation of the substrate 3,3',5,5'-tetramethylbenzidine by H2O2 to produce a typical blue-colored reaction. On this basis, simple, rapid and selective colorimetric methods for in situ H2O2 detection were developed with the detection limit of 2.6 nM in the wide range of 0.01 to 200 µM. The colorimetric approach also could be used for in situ detection of H2O2 released from living MCF-7 cells. This portable sensor based on a COF nanozyme not only opens a new path for point-of-care testing, but also has potential applications in the field of cell biology and clinical diagnosis.

Photoelectrochemical sensors based on paper and their emerging applications in point-of-care testing.

Point-of-care testing (POCT) technology is urgently required owing to the prevalence of the Internet of Things and portable electronics. In light of the attractive properties of low background and high sensitivity caused by the complete separation of excitation source and detection signal, the paper-based photoelectrochemical (PEC) sensors, featured with fast in analysis, disposable and environmental-friendly have become one of the most promising strategies in POCT. Therefore, in this review, the latest advances and principal issues in the design and fabrication of portable paper-based PEC sensors for POCT are systematically discussed. Primarily, the flexible electronic devices that can be constructed by paper and the reasons why they can be used in PEC sensors are expounded. Afterwards, the photosensitive materials involved in paper-based PEC sensor and the signal amplification strategies are emphatically introduced. Subsequently, the application of paper-based PEC sensors in medical diagnosis, environmental monitoring and food safety are further discussed. Finally, the main opportunities and challenges of paper-based PEC sensing platforms for POCT are briefly summarized. It provides a distinct perspective for researchers to construct paper-based PEC sensors with portable and cost-effective, hoping to enlighten the fast development of POCT soon after, as well as benefit human society.

Ferrocene-decorated (phthalocyaninato)(porphyrinato) double- and triple-decker rare earth complexes: synthesis, structure, and electrochemical properties.

A series of four mixed (phthalocyaninato)(porphyrinato) rare earth double-decker complexes (Pc)M[Por(Fc)(2)] [Pc = phthalocyaninate; Por(Fc)(2) = 5,15-di(ferrocenyl)-porphyrinate; M = Eu (1), Y (2), Ho (3), Lu (4)] and their europium(III) triple-decker counterpart (Pc)Eu(Pc)Eu[Por(Fc)(2)] (5), each with two ferrocenyl units at the meso-positions of their porphyrin ligands, have been designed and prepared. The double- and triple-decker complexes 1-5 were characterized by elemental analysis and various spectroscopic methods. The molecular structures of two double-deckers 1 and 4 were also determined by single-crystal X-ray diffraction analysis. Electrochemical studies of these novel sandwich complexes revealed two consecutive ferrocene-based one-electron oxidation waves, suggesting the effective electronic coupling between the two ferrocenyl units. Nevertheless, the separation between the two consecutive ferrocene-based oxidation waves increases from 1 to 4, along with the decrease of rare earth ionic radius, indicating the effect of rare earth size on tuning the coupling between the two ferrocenyl units. Furthermore, the splitting between the two ferrocene-based one-electron oxidations for triple-decker 5 is even smaller than that for 1, showing that the electronic interaction between the two ferrocene centers can also be tuned through changing the linking sandwich framework from double-decker to triple-decker. For further understanding of the electronic coupling between ferrocenyl groups, DFT calculation is carried out to clarify the electronic delocalization and the molecular orbital distribution in these double-decker complexes.

Strength Enhancement of Regenerated Cellulose Fibers by Adjustment of Hydrogen Bond Distribution in Ionic Liquid.

To improve the physical strength of regenerated cellulose fibers, cellulose dissolution was analyzed with a conductor-like screening model for real solvents in which 1-allyl-3-methylimidazolium chloride (AMIMCl) worked only as a hydrogen bond acceptor while dissolving the cellulose. This process could be promoted by the addition of urea, glycerol, and choline chloride. The dissolution and regeneration of cellulose was achieved through dry-jet and wet-spinning. The results demonstrated that the addition of hydrogen bond donors and acceptors either on their own or in combination can enhance the tensile strength, but their effects on the crystallinity of the regenerated fibers were quite limited. Compared with the regenerated fibers without any additives, the tensile strength was improved from 54.43 MPa to 139.62 MPa after introducing the choline chloride and glycerol, while related the crystallinity was only changed from 60.06% to 62.97%. By contrast, a more compact structure and fewer pores on the fiber surface were identified in samples with additives along with well-preserved cellulose frameworks. Besides, it should be noted that an optimization in the overall thermal stability was obtained in samples with additives. The significant effect of regenerated cellulose with the addition of glycerol was attributed to the reduction of cellulose damage by slowing down the dissolution and cross-linking in the cellulose viscose. The enhancement of the physical strength of regenerated cellulose fiber can be realized by the appropriate adjustment of the hydrogen bond distribution in the ionic liquid system with additives.

Indirect biamperometric determination of o-phenylenediamine in lab-on-valve format using reversible indicating redox system.

The miniaturized lab-on-valve (LOV) manifold well hyphenated with indirect biamperometry is presented for automated determination of trace level concentrations of organic environmental pollutants by programmable flow. The experimental procedure was carried out by means of taking o-phenylenediamine (OPDA) as a model analyte, relying on the Fe(iii)/Fe(ii) couple that served as an indicating redox system. The miniaturized electrochemical flow cell (EFC) designed and processed was integrated into the LOV module which is assembled with two identical polarized platinum electrodes between which a small potential difference (ΔE) was applied, to implement automated on-line analysis in a closed system. Factors affecting analytical performance are discussed, including indicating redox systems, concentration of indicating system, the acidity, the potential difference, and flow variables in the LOV. The calibration curve showed an excellent linearity in the concentration range of 5.0 × 10(-7) to 1.0 × 10(-4) mol L(-1) (R(2) = 0.9993). The limits of detection (LOD) and quantitation (LOQ) for OPDA were found to be 1.1 × 10(-7) and 3.7 × 10(-7) mol L(-1), respectively. A sampling frequency of 40 h(-1) was obtained along with an R.S.D. of 2.8% at 1.0 × 10(-6) mol L(-1) OPDA (n = 11). The proposed procedure was successfully applied to the assay of OPDA in industrial waste water.

Bis{1-[(4-methyl-phen-yl)imino-meth-yl]-2-naphtho-lato-κN,O}nickel(II).

In the title complex, [Ni(C(18)H(14)NO)(2)], the Ni(II) ion lies on an inversion center and is coordinated in a slightly distorted square-planar environment. The 1-[(4-methyl-phen-yl)imino-meth-yl]-2-naphtho-late ligands are coordinated in a trans arrangement with respect to the N and O atoms. In the symmetry-unique ligand, the dihedral angle between the naphthalene ring system and the benzene ring of the methyl-phenyl group is 49.03 (7)°.

Dual-Mode Aptasensor Assembled by a WO3/Fe2O3 Heterojunction for Paper-Based Colorimetric Prediction/Photoelectrochemical Multicomponent Analysis.

The programed bimodal photoelectrochemical (PEC)-sensing platform based on DNA structural switching induced by targets binding to aptamers was innovatively designed for the simultaneous detection of mucin 1 (MUC1) and microRNA 21 (miRNA-21). To promote excellent current intensity as well as enhance the sensitivity of aptasensors, the evenly distributed WO3/Fe2O3 heterojunction was prepared as a transducer material, notably reducing the background signal response and extending the absorption of light. The multifunctional paper-based biocathode was assembled to provide a visual colorimetric assay. When introducing the integrated signal probe (ISP) composed of signal probe 1 (sP1) and signal probe 2 (sP2) on paper-based working units modified with gold nanoparticles (AuNPs), recognition sites of two targets were formed. In the presence of MUC1 protein, both sP1 and the target on the working unit were released into the corresponding colorimetric unit because of the DNA specific recognition. The horseradish peroxidase-streptavidin (HRP-SA) carried by free sP1 could oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to turn a blue-colored oxidized TMB (oxTMB) in the presence of hydrogen peroxide (H2O2), which ultimately gained a higher photocurrent signal. Furthermore, miRNA-21 was modified on another working unit by binding with sP2, leading to changes in the current signal and thus enabling real-time detection of analytes with the assistance of a digital multimeter. The PEC aptasensor offered a wide dynamic range of 10 fg·mL-1-100 ng mL-1 for MUC1 and 0.1 pM-10 nM for miRNA-21, with a low detection limit of 3.4 fg·mL-1 and 36 fM, respectively. It laid the foundation for synchronous detection of multiple analytes and initiated a new way for the enhancement in modern next-generation disease diagnosis.

Porphyrin-Based Covalent Organic Framework Thin Films as Cathodic Materials for "On-Off-On" Photoelectrochemical Sensing of Lead Ions.

Currently, cathodic photoelectrochemical (PEC) sensors, which could effectively reduce background interference, are urgently required for ultrasensitive environmental monitoring. Herein, porphyrin-based covalent organic framework (TAPP-COF) thin films were fabricated via a bottom-up growth approach on the liquid/liquid interface and applied as a photocathode material to "on-off-on" PEC sensing of Pb2+. Benefitting from the unique charge channels of COFs and the good photoelectric properties of porphyrin, the as-prepared TAPP-COF thin films presented an improved photocathodic current, with a strongly enhanced "signal-on" response with low background. Then, CdSe@SiO2 quantum dots (QDs), as a quenching agent, were introduced through a hybridization chain reaction (HCR) to obtain a "signal off" PEC response. Afterward, with the introduction of target Pb2+, CdSe@SiO2 QDs were detached from TAPP-COF thin films, and the PEC response transformed into a signal-on state. Benefiting from the multiple-quenching and steric hindrance effect of CdSe@SiO2 QDs and the photocathodic property of TAPP-COFs, accurate monitoring of Pb2+ in a wide detection range from 0.05 to 1000 nM with a lower detection limit of 0.012 nM was realized based on the proposed on-off-on PEC approach. Notably, the methodology provides an efficient platform for ultrasensitive determination of heavy metal ions, which would play a significant role in environmental monitoring and public safety fields.

Self-assembled organic-inorganic hybrid nanocomposite of a perylenetetracarboxylic diimide derivative and CdS.

A perylenetetracarboxylic diimide derivative, N-n-hexyl-N'-(2-hydroxyethyl)-1,7-di(4'-t-butyl)phenoxy-perylene-3,4:9,10-tetracarboxylic diimide (HO-PDI), was synthesized and self-assembled as a monolayer thin solid film on the modified surface of a quartz substrate by an ester bond between -OH groups of HO-PDI molecules and -COOH groups of p-phthalic acid grafted onto the hydrophilic pretreated SiO(2) surface. An analysis of the spectral change revealed the J-aggregate nature of HO-PDI molecules in the obtained thin solid film. With this thin solid film of HO-PDI as a template, CdS nanoparticles were deposited on it in situ, which were further characterized by electronic absorption, fluorescence, and energy-dispersive X-ray spectroscopy (EDS). The morphology of CdS nanoparticles is disklike, and the diameter is ca. 140 nm as determined by atomic force microscopy (AFM). Furthermore, electron transfer between the organic layer and CdS nanoparticles was deduced through fluorescence quenching and theoretical analysis.

Novel pathway to synthesize unsymmetrical 2,3,9,10,16,17,23-heptakis(alkoxyl)-24-mono(dimethylaminoalkoxyl)phthalocyanines.

A new pathway by means of transetherification has been developed to synthesize novel unsymmetrical 2,3,9,10,16,17,23-heptakis(alkoxyl)-24-mono(dimethylaminoalkoxyl)phthalocyanine compounds. Cyclic tetramerization of 4,5-di(alkoxyl)phthalonitrile in refluxing dimethylamino-alcohol with high boiling point such as dimethylaminoethanol (DMAE) and 1-dimethylamino-2-propanol in the presence of lithium and pyrazino[2,3-f][1,10]phenanthroline-2,3-dicarbonitrile followed by treatment with acetic acid led to the isolation of a series of unsymmetrical metal free 2,3,9,10,16,17,23-heptakis(alkoxyl)-24-mono(dimethylaminoalkoxyl)phthalocyanine compounds H(2){Pc(OR)(7)[OR'N(CH(3))(2)]} [R = C(4)H(9), C(5)H(11), C(8)H(17) and R' = C(2)H(4); R = C(4)H(9) and R' = CH(CH(3))CH(2)] (1-4). Metal insertion into unsymmetrical metal free phthalocyanines (Pc's) using Cu(OAc)(2)·H(2)O in dimethylformamide (DMF) at 140 °C easily afforded corresponding unsymmetrical phthalocyaninato copper complexes Cu{Pc(OR)(7)[OR'N(CH(3))(2)]} (5-8) in good yields. These novel unsymmetrical phthalocyanine compounds have been characterized by a series of spectroscopic methods including (1)H NMR, electronic absorption, IR, and mass spectroscopy in addition to elemental analysis. Their electrochemistry was also studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The present result will be helpful for designing and preparing unsymmetrical phthalocyanines with potential applications in dye-sensitized solar cells.