Metal Ion Coordination Research Articles

Long-Time Persisting Superhydrophilicity on Sapphire Surface via Femtosecond Laser Processing with the Varnish of TiO2.

The acquiring of superhydrophilic surfaces attracts the strong interest in self-cleaning, anti-fogging and anti-icing fields based on the unique features. However, the persistent time of superhydrophilic surfaces is still facing a big challenge because of easily adsorbing hydrophobic groups. Here, we propose a strategy to achieve a superhydrophilicity persisting for an unprecedently long time on sapphire surfaces, by compounding the femtosecond laser-induced hierarchical structures and the subsequent varnish of TiO2. The superhydrophilic effect (with a contact angle of CA = 0°) created by our method can be well prolonged to at least 180 days, even for its storage in air without additional illumination of UV lights. Based on comprehensive investigations, we attribute the underlying mechanisms to the coordination of laser-induced metal ions on the material surface via TiO2 doping, which not only prevents the adsorption of the nonpolar hydrocarbon groups, but also modulates the photo-response properties of TiO2. In addition, further experiments demonstrate the excellent anti-fogging properties of our prepared samples. This investigation provides a new perspective for further enhancing the durability of superhydrophilicity surfaces.

Construction of four new d10 metal ion coordination polymers: Synthesis, characterization and structural diversity

In this study, a N,N′ donor ligand, ((pyridin-4-yl)methylene)isonicotinohydrazide (4-pmi) has been utilized with two different d10 metal ion, Zn(II) and Cd(II), and four different dicarboxylate to synthesis four different coordination polymers, namely {[Zn(4-pmi)(fum)]·(solvent)}n (1), {[Cd(4-pmi)(suc)]·(H2O)}n (2), {[Zn(4-pmi)(2,2dmglut)]· (solvent)}n (3) and {[Zn(4-pmi)(adp)]·(H2O)0.5}n (4) [fum = fumarate, suc = succinate, 2,2dmglut = 2,2′-dimethyl glutarate and adp = adipate]. Full structure elucidations are done by single crystal X-ray diffraction (SXRD) which reveals that 1 is three dimensional fivefold interpenetrated structure with uni-directional pore filled with lattice solvent molecules. On moving from flexible succinate to rigid fumarate with same carbon chain length, resultant structure is a non-interpenetrated 3D structure in 2. Whereas, on moving to higher chain length dicarboxylate, resultant structures are two dimensional for 3 and 4. All of these CPs are fully characterized by powder X-ray diffraction (PXRD), thermo gravimetric analysis (TGA), UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR) etc. Apart from this different gas sorption studies are also performed with all of them.

DPPH and nitric oxide free radical scavenging potential of phenyl quinoline derivatives and their transition metal complexes

In the present study phenyl quinoline (PQ) derivatives and their newly synthesized transition metal (Cu2+, Co2+, Fe3+) complexes were screened for their free radical scavenging potential against DPPH and nitric oxide free radicals. All compounds showed activity against these two free radicals but it was found that coordination of metal ions with ligands increased their antioxidant potential. PQ4Co showed more inhibition potential for DPPH than ascorbic acid with IC50 values 16.30 µg/mL. Among copper(II) complexes PQ5Cu is the most poent antioxidant compounds with IC50 values 8.38 µg/mL while PQ7Fe is the most potent compound among iron(III) complexes with IC50 value 16.00 µg/mL. Similarly formation of metal complexes quinoline derivatives make them much more potent for nitric oxide scavenging. PQ6Cu is the most potent (IC50 = 5.24 µg/mL) among the copper(II) complexes while compounds Q13Fe is the most potent nitric oxide inhibitors with IC50 values 1.90 µg/mL among iron(III) complexes. Job's method was applied to check the ligand metal ratio for the formation of stable complex (ligand and metals with 2:1 ratio). All synthesized complexes were characterized by using different spectroscopic techniques. Iron(III) complexes showed greater thermal stability with melting points higher than 300°C. Comparative FTIR spectra of all synthesized compounds indicated that phenyl quinoline compounds acted as bidentate ligand with CN and NH2 groups as coordination sites. CN stretching peak in the region of 2200–2100 cm−1 in ligands shifted in 2300–2200 cm−1 region while NH2 peaks become weak and non-prominent in FTIR spectra of complexes which confirms the contribution of these two groups in the formation of coordination compounds. Comparative UV–Visible spectra of ligand and complexes also showed different absorption pattern. XRD study of compounds PQ1, PQ1Cu, PQ2 and PQ2Co showed that crystal sizes are 16.11 nm, 14.91 nm, 13.46 nm and 12.68 nm respectively.

Orchestrating copper binding: structure and variations on the cupredoxin fold.

A large number of copper binding proteins coordinate metal ions using a shared three-dimensional fold called the cupredoxin domain. This domain was originally identified in Type 1 "blue copper" centers but has since proven to be a common domain architecture within an increasingly large and diverse group of copper binding domains. The cupredoxin fold has a number of qualities that make it ideal for coordinating Cu ions for purposes including electron transfer, enzyme catalysis, assembly of other copper sites, and copper sequestration. The structural core does not undergo major conformational changes upon metal binding, but variations within the coordination environment of the metal site confer a range of Cu-binding affinities, reduction potentials, and spectroscopic properties. Here, we discuss these proteins from a structural perspective, examining how variations within the overall cupredoxin fold and metal binding sites are linked to distinct spectroscopic properties and biological functions. Expanding far beyond the blue copper proteins, cupredoxin domains are used by a growing number of proteins and enzymes as a means of binding copper ions, with many more likely remaining to be identified.

Pulse Dipolar Electron Paramagnetic Resonance Spectroscopy Reveals Buffer-Modulated Cooperativity of Metal-Templated Protein Dimerization.

Self-assembly of protein monomers directed by metal ion coordination constitutes a promising strategy for designing supramolecular architectures complicated by the noncovalent interaction between monomers. Herein, two pulse dipolar electron paramagnetic resonance spectroscopy (PDS) techniques, pulse electron–electron double resonance and relaxation-induced dipolar modulation enhancement, were simultaneously employed to study the CuII-templated dimerization behavior of a model protein (Streptococcus sp. group G, protein G B1 domain) in both phosphate and Tris-HCl buffers. A cooperative binding model could simultaneously fit all data and demonstrate that the cooperativity of protein dimerization across α-helical double-histidine motifs in the presence of CuII is strongly modulated by the buffer, representing a platform for highly tunable buffer-switchable templated dimerization. Hence, PDS enriches the family of techniques for monitoring binding processes, supporting the development of novel strategies for bioengineering structures and stable architectures assembled by an initial metal-templated dimerization.

Visible-Light-Responsive Self-Assembled Complexes: Improved Photoswitching Properties by Metal Ion Coordination.

A photoswitchable ligand based on azobenzene is self‐assembled with palladium(II) ions to form a [Pd2(E‐L)4]4+ cage. Irradiation with 470 nm light results in the near‐quantitative switching to a monomeric species [Pd(Z‐L)2]2+, which can be reversed by irradiation with 405 nm light, or heat. The photoswitching selectivity towards the metastable isomer is significantly improved upon self‐assembly, and the thermal half‐life is extended from 40 days to 850 days, a promising approach for tuning photoswitching properties.

Visible‐Light‐Responsive Self‐Assembled Complexes: Improved Photoswitching Properties by Metal Ion Coordination**

AbstractA photoswitchable ligand based on azobenzene is self‐assembled with palladium(II) ions to form a [Pd2(E‐L)4]4+ cage. Irradiation with 470 nm light results in the near‐quantitative switching to a monomeric species [Pd(Z‐L)2]2+, which can be reversed by irradiation with 405 nm light, or heat. The photoswitching selectivity towards the metastable isomer is significantly improved upon self‐assembly, and the thermal half‐life is extended from 40 days to 850 days, a promising approach for tuning photoswitching properties.

Metal ions-doped electrospinning nanofiber films with changeable hydrophobic surface and adjustable tensile properties

The preparation of hydrophobic surfaces has long been a question of great interest in a wide range of fields. Among them, the electrospinning technique stands out for its convenience, simplicity, and ease of manipulation. In this work, porous and uniform size CA-P(AA-AM) nanofiber films were prepared by the electrospinning method. Subsequently, the metal ions were introduced to form CA-P(AA-AM)-metal ions nanofiber films. The morphology and structure of the films were characterized through SEM, EDS-Mapping, XRD, and XPS. Besides, the tensile properties of P(AA-AM)-metal ions nanofiber films were tested by Tensile test, and the hydrophobicity of nanofiber membranes was analyzed by the water contact angle (WCA) test. The results showed that all P(AA-AM)-metal ion nanofiber membranes exhibited good hydrophobicity. And after 12 h of immersion treatment, the water contact angle increased by more than 60%. Furthermore, CA/P(AA-AM)-Cu nanofiber films and CA/P(AA-AM)-Cd nanofiber films show enhanced elastic moduli due to the coordination of metal ions to P(AA-AM).

Tannic acid-mediated interfacial layer-by-layer self-assembly of nanofiltration membranes for high-efficient dye separation

Layer-by-layer (LBL) self-assembly is believed as a simple and versatile strategy to fabricate wastewater purification membranes, whose separation efficiency is highly dependent on the stability of the self-assembly membranes. In this work, a composite nanofiltration membrane was prepared using carboxyl-functionalized poly (arylene ether nitrile) (CPEN) as the substrate, on which the cross-linked nanostructures derived from tannic acid (TA), metal ions, and bovine serum albumin (BSA) were immobilized via the layer-by-layer self-assembly. Particularly, several interfacial interactions, including hydrogen bonding, metal ions coordination, and hydrophobic interaction, were explored to manipulate the surface structures, wettability, and pore morphology of composite membranes. Consequently, the optimized membrane exhibited a low pressure (0.09 MPa) driven dye permeability of 52.04 L m−2 h−1 bar−1, as well as a high rejection rate for Congo Red (CR ∼ 99.9%) and Methylene Blue (MLB ∼ 99.8%), respectively. Thanks to the stable separation performance, structural stability, and dye removal, the protocol reveals in the current work would open new ways for the fabrication of water purification membranes.

Interligand Charge-Transfer Processes in Zinc Complexes

Electron donor–acceptor (EDA) complexes are characterized by charge-transfer (CT) processes between electron-rich and electron-poor counterparts, typically resulting in a new absorption band at a higher wavelength. In this paper, we report a series of novel 2,6-di(imino)pyridine ligands with different electron-rich aromatic substituents and their 1:2 (metal/ligand) complexes with zinc(II) in which the formation of a CT species is promoted by the metal ion coordination. The absorption properties of these complexes were studied, showing the presence of a CT absorption band only in the case of aromatic substituents with donor groups. The nature of EDA interaction was confirmed by crystallographic studies, which disclose the electron-poor and electron-rich moieties involved in the CT process. These moieties mutually belong to both the ligands and are forced into a favorable spatial arrangement by the coordinative preferences of the metal ion.

(Invited) Coordination Controlled Electrodeposition of Metal Nanostructures

It is the combination of features related to surface chemistry, charge transfer, and interfacial energies which makes self-assembled monolayers (SAMs) attractive templates for electrodeposition. However, as in other additive processes such as atomic layer or electroless deposition where SAMs are harnessed for area selective deposition, one is faced with substantial challenges when advancing to the ultrasmall scale. Based on defects in a chemically inert SAM, the established scheme of SAM controlled electrodeposition offers a very convenient way to generate patterns but is only applicable down to the length scale of a few tens of nanometers. The statistical nature of defects does not provide the level of control over the deposition process required to move further towards the bottom range of the nanoscale.For this reason we have been exploring a deposition scheme which builts on features intrinsic to the SAM molecules and, therefore, promises a more precise control over decisive steps in the deposition process.1 The essential point is the paradigm shift from a mushroom like deposition at defects to a deposition via coordinated metal ions using a suitably functionalized SAM. As illustrated in the cartoon, nuclei generated by discharging a two-dimensional layer of ions act as seeds for the deposition from the bulk electrolyte. Yielding layers on top of the SAM, this coordination controlled deposition not only enables a further reduction in lateral dimensions of patterns to below 20 nm but also shifts the percolation threshold, yielding continuous layers at a thickness of about 2 nm. In relation to this the average roughness of below 0.4 nm is substantial and further improvement is needed. Key to this and a further reduction in dimensions is the understanding of the processes determining the seed formation and how these can be controlled by the design of the SAM. Informed by calculations which show a strong interaction between metal atoms and the terminating aromatic unit of the SAM,2 studies of binary layers consisting of coordinating and non-coordinating molecules have been performed. The average size and size distribution of the particles depend on the composition and mixing ratio, and a significant reduction in size to about 2 nm can be achieved, suggested that the diffusion length is reduced and nucleation is promoted in mixed SAMs. The results show that SAMs provide a range of design opportunities through which coordination controlled electrodeposition can be further developed towards ultrasmall structures.1. Z. She, Z. Yao, H. Ménard, S. Tobish, D. Lahaye, N. R. Champness, M. Buck, Coordination controlled electrodeposition and patterning of layers of palladium/copper nanoparticles on top of a self-assembled monolayer, Nanoscale 11, 13773-13782 (2019).2. Z. Yao, M. Buck, M. Bühl, A Density Functional Theory Study of Pd Aggregation on a Pyridine-Terminated Self-Assembled Monolayer, Chem. Eur. J. 26, 10555-10563 (2020). Figure 1

(Digital Presentation) Vanadium Intercalated Cobalt Trimesic MOF Composite for Enhanced Solid-State Asymmetric Supercapacitor Storage

Metal organic framework (MOF) is a supramolecular coordination material composed of metal ions coordination, nodes, and organic ligands. MOFs were used as active materials for chemical capacitors to realize the high electrochemical performance, providing adequate redox sites and accelerating ion diffusion rate. Using MOF as a template to fabricate a novel platform can deliver large specific surface areas and abundant oxidation-active sites to augment electrical conductivity. The electrode material based on a MOF has a unique morphology that can significantly shorten charge transport paths to alleviate the electron transport and diffusion, thus strengthening the catalytic performance of the electrode materials. Also, the incorporation of vanadium in the intermediate leads to a broad impact on the morphology and the electrochemical energy storage of Cobalt-Trimesic matrix worked as a base for fabricating the composite. The DMF is a solvent to prepare the vanadium cobalt oxide composite derived using the MOF matrix. Trimesic acid is used as an initial organic linker precursor to initiate the formation of MOF of cobalt in DMF solvent. Then the vanadium ion is integrated into the same material matrix. In this study, the impact of organic system precursors and the integration of annealing play a pivotal role in alleviating the enhanced electrochemical storage response. After analyzing through XRD, the corresponding MOF crystal peaks are prominently affirmed. The high intensified peaks in the obtained patterns symbolize the oxide phase of cobalt vanadium and confirm the formation derived from MOF. The FTIR spectroscopy investigation depicted the proper presence of cobalt, vanadium, carbon, and nitrogen. The observed FESEM morphology illustrated the dissimilar structure and involved in the charge storage likewise. The morphology significantly impacts surface-dependent charge storage with having porosity introduced. High-temperature annealing also consists of the crystal orientation of the bi-metallic MOF matrix and creates porosity on the effective surface area.The Co-MOF-V oxide composite is thoroughly investigated individually in three-electrode arrangements for analyzing the electrochemical charge storage in 2MKOH represented in Fig.1 (c-d). Firstly, the oxide is scrutinized as working positive electrodes and measured in the potential window of -0.2 to 0.6 V w.r.t the saturated calomel reference electrode. The accomplished specific capacitance value from the cyclic voltammetry plot is 549 F/g at 2mV/s scan rate. Furthermore, the charge-discharge analysis of the composite delineated an admirable discharge time at 3mA/cm2 current density. It portrayed 349 F/g specific capacitance, leading to higher specific energy and specific power of 31.02Wh/kg and 159.53W/kg at the value of the same current density. The Nyquist plot corroborates that the electrode resistance, electrode-electrolyte interfacing resistance, and the value of diffuse layer resistance are significantly less. This study can bestow a greater pathway of ion transportation from the electrolyte to active electrode material that abetted to conversate superior storage using complete morphology. The transition metal possesses a variational oxidation state that directly contributes to this MOF composite's pseudocapacitive charge storage process. Alternatively, comparable analysis is directed over anode material that is lignocellulose derived activated porous carbon. It is depicted in Fig.1(e-f) in the potential window of -1 to 0v w.r.t the Ag/AgCl electrode in 2M KOH. The gained specific capacitance from the cyclic voltammetry analysis is 426 F/g at a 2mV/s scan rate. Besides, the charge-discharge study of the same carbon depicted admirable discharge time at 0.5A/g current density and portrayed 565 F/g specific capacitance. The specific energy and power of 78.47Wh/kg and 282W/kg at the same current density. Also, the integrated porous system with the high active surface area, which significantly comes from the MOF matrix, provides an added phase to strengthen the amount of storage like EDLC formation.Furthermore, combining both of those active materials, the asymmetric supercapacitor storage is made up [Fig.1 (g-h)]. That system works upon 0 to 1.4V windows. The attained areal capacitance is 0.54 F/cm2, and volumetric capacitance is 0.68 F/cm3 in the current density of 4mA/cm2. The Ragone plot shows its perfect positioning in the region of asymmetric storage. This ASC system delineated coulombic efficiency 79% of capacitive retention 75% after the 10,000 long cycle stability study. From the electrochemical impedance spectroscopy analysis, the obtained interfacing and electrode resistance diffuse layer resistance is found significantly lesser and upwards. Figure 1

Tunable Capacitive Behavior in Metallopolymer-based Electrochromic Thin Film Supercapacitors.

Volumetric capacitance is a more critical performance parameter for rechargeable power supply in lightweight and microelectronic devices as compared to gravimetric capacitance in larger devices. To this end, we report three electrochromic metallopolymer-based electrode materials containing Fe2+ as the coordinating metal ion with high volumetric capacitance and energy densities in a symmetric two-electrode supercapacitor setup. These metallopolymers exhibited volumetric capacitance up to 866.2 F cm-3 at a constant current density of 0.25 A g-1. The volumetric capacitance (poly-Fe-L2: 544.6 F cm-3 > poly-Fe-L1: 313.8 F cm-3 > poly-Fe-L3: 230.8 F cm-3 at 1 A g-1) and energy densities (poly-Fe-L2: 75.5 mWh cm-3 > poly-Fe-L1: 43.6 mWh cm-3 > poly-Fe-L3: 31.2 mWh cm-3) followed the order of the electrical conductivity of the metallopolymers and are among the best values reported for metal-organic systems. The variation in the ligand structure was key toward achieving different electrical conductivities in these metallopolymers with excellent operational stability under continuous cycling. High volumetric capacitances and energy densities combined with tunable electro-optical properties and electrochromic behavior of these metallopolymers are expected to contribute to high performance and compact microenergy storage systems. We envision that the integration of smart functionalities with thin film supercapacitors would warrant the surge of miniaturized on-chip microsupercapacitors integrated in-plane with other microelectronic devices for wearable applications.

An artificial metalloprotein with metal-adaptive coordination sites and Ni-dependent quercetinase activity

Engineering non-native metal active sites into proteins using canonical amino acids offers many advantages but is hampered by significant challenges. The TIM barrel protein, imidazole glycerol phosphate synthase from the hyperthermophilic organism Thermotoga maritima (tHisF), is well-suited for the construction of artificial metalloenzymes by this approach. To this end, we have generated a tHisF variant (tHisFEHH) with a Glu/His/His motif for metal ion coordination. Crystal structures of ZnII:tHisFEHH and NiII:tHisFEHH reveal that both metal ions bind to the engineered histidines. However, the two metals bind at distinct sites with different geometries, demonstrating the adaptability of tHisF. Only ZnII additionally ligates the Glu residue and adopts a tetrahedral geometry. The pseudo-octahedral NiII site comprises the two His and a native Ser residue. NiII:tHisFEHH catalyzes the oxidative cleavage of the flavanols quercetin and myricetin, providing an unprecedented example of an artificial metalloprotein with quercetinase activity.

Preparation of Ion2+-COS/SA Multifunctional Gel Films for Skin Wound Healing by an In Situ Spray Method.

The rapid preparation of safe and efficient wound dressings that meet the needs of the entire repair process remains a major challenge for effective therapeutic wound healing. Natural, sprayable Ion2+-COS/SA multifunctional dual-network gel films created by the in situ coordination of chitooligosaccharide (COS), metal ions and sodium alginate (SA) using casting and an in-situ spray method were synthesized. The gel films exhibited excellent physicochemical properties such as swelling, porosity and plasticity at a COS mass fraction of 3%. Furthermore, at this mass fraction, the addition of bimetallic ions led to the display of multifunctional properties, including significant antioxidant, antibacterial and cytocompatibility properties. In addition, experiments in a total skin defect model showed that this multifunctional gel film accelerates wound healing and promotes skin regeneration. These results suggest that the sprayable Ion2+-COS/SA multifunctional pro-healing gel film may be a promising candidate for the clinical treatment of allodermic wounds.

Assembly of three sulfonylcalix[4]arene-based multinuclear complexes: Tunable structures and guest encapsulation properties

Understanding and controlling the structure of polymetallic clusters plays a fundamental role in supramolecular chemistry. Herein we describe the preparation of three sulfonylcalix[4]arenebased multinuclear cluster complexes, namely, [Fe4(TBSC)2(DMF)4(µ3-H2O)2(H2O)2·2MeCN] (1), [Fe2Na4(TBSC)2(DMF)4(µ6-H2O)(H2O)2] (2), and [Fe4(TBSC)(Py)4(µ4-H2O)] (3) from trivalent iron ions and p-tert-butylsulfonylcalix[4]arene ligands by the metal-directed assembly. These complexes exhibit interesting tunable core structures, exo cavities, supramolecular packing characteristics in the solid state. As a result, the three multinuclear complexes exhibit selective molecular recognition toward the dye molecules.

Nanomolar affinity of EF-hands in neuronal calcium sensor 1 for bivalent cations Pb2+, Mn2+, and Hg2.

Abiogenic metals Pb and Hg are highly toxic since chronic and/or acute exposure often leads to severe neuropathologies. Mn2+ is an essential metal ion but in excess can impair neuronal function. In this study, we address in vitro the interactions between neuronal calcium sensor 1 (NCS1) and divalent cations. Results showed that non-physiological ions (Pb2+ and Mn2+) bind to EF-hands in NCS1 with nanomolar affinity and lower equilibrium dissociation constant than the physiological Ca2+ ion. (Kd, Pb2+ = 7.0±1.0nM; Kd, Mn2+ = 34.0±6.0nM; K). Native ultra-high resolution mass spectrometry (FT-ICR MS) and trapped ion mobility spectrometry-mass spectrometry (nESI-TIMS-MS) studies provided the NCS1-metal complex compositions-up to four Ca2+ or Mn2+ ions and three Pb2+ ions (M⋅Pb1-3Ca1-3, M⋅Mn1-4Ca1-2, and M⋅Ca1-4) were observed in complex-and similarity across the mobility profiles suggests that the overall native structure is preserved regardless of the number and type of cations. However, the non-physiological metal ions (Pb2+, Mn2+, and Hg2+) binding to NCS1 leads to more efficient quenching of Trp emission and a decrease in W30 and W103 solvent exposure compared to the apo and Ca2+ bound form, although the secondary structural rearrangement and exposure of hydrophobic sites are analogous to those for Ca2+ bound protein. Only Pb2+ and Hg2+ binding to EF-hands leads to the NCS1 dimerization whereas Mn2+ bound NCS1 remains in the monomeric form, suggesting that other factors in addition to metal ion coordination, are required for protein dimerization.

Spectral properties and photophysical processes of meso styryl substituent triphenylamine-porphyrin derivatives

This work reports the synthesis and spectral properties of meso-styryl substituted triphenylamine-porphyrin derivatives, mP-BLP, mPPC-BLP and their metal coordinated complexes. The photophysical processes were analyzed and related to the meso-groups and centre metal ions. The meso styryl substituent in mP-BLP and its complexes are able to extend the conjugation of porphyrin macrocycle to the styryl motif, increase light harvesting ability and accelerate intersystem crossing (ISC) process. A large dihedral angle between the meso-styryl group and porphyrin macrocycle would prohibit the delocalization of electrons between the two motifs and induce the occurrence of solvation decay process. Increasing the electron-withdrawing ability of meso-substituent via additional pyrimidine group could promote the photoinduced intramolecular electron transfer (PIET) process for mPPC-BLP. Moreover, the coordination of metal ions would significantly accelerate the photophysical processes of both mP-BLP and mPPC-BLP. Specially, the Mg[Formula: see text] is helpful to the ISC process whereas Zn[Formula: see text] is adverse to the ISC process, while Cu[Formula: see text] would boost the non-radiation process. Furthermore, Zn[Formula: see text] is able to promote the PIET process of mPPC-BLP, exhibiting the highest charge-separated tendency among these porphyrins. mPPC-ZnBLP-based dye-sensitized solar cell (DSSC) devices show the highest power conversion efficiency (PCE). The photovoltaic performance of DSSC devices reveals the significancy of the photoinduced charge-separated tendency for the design of porphyrin sensitizers.

An atlas of Arabidopsis protein S-acylation reveals its widespread role in plant cell organization and function.

S-acylation is the addition of a fatty acid to a cysteine residue of a protein. While this modification may profoundly alter protein behaviour, its effects on the function of plant proteins remains poorly characterized, largely as a result of the lack of basic information regarding which proteins are S-acylated and where in the proteins the modification occurs. To address this gap in our knowledge, we used an optimized acyl-resin-assisted capture assay to perform a comprehensive analysis of plant protein S-acylation from six separate tissues. In our high- and medium-confidence groups, we identified 1,849 cysteines modified by S-acylation, which were located in 1,640 unique peptides from 1,094 different proteins. This represents around 6% of the detectable Arabidopsis proteome and suggests an important role for S-acylation in many essential cellular functions including trafficking, signalling and metabolism. To illustrate the potential of this dataset, we focus on cellulose synthesis and confirm the S-acylation of a number of proteins known to be involved in cellulose synthesis and trafficking of the cellulose synthase complex. In the secondary cell walls, cellulose synthesis requires three different catalytic subunits (CESA4, CESA7 and CESA8) that all exhibit striking sequence similarity and are all predicted to possess a RING-type zinc finger at their amino terminus composed of eight cysteines. For CESA8, we find evidence for S-acylation of these cysteines that is incompatible with any role in coordinating metal ions. We show that while CESA7 may possess a RING-type domain, the same region of CESA8 appears to have evolved a very different structure. Together, the data suggest that this study represents an atlas of S-acylation in Arabidopsis that will facilitate the broader study of this elusive post-translational modification in plants as well as demonstrating the importance of further work in this area.

Exploration of Role of Concentration on Sensing Activities using Novel unsymmetrical Schiff bases

Simultaneous condensation reaction of thiocarbohydrazide with simple aromatic aldehyde and highly reactive ferrocenecarboxaldehyde resulted with unusual unsymmentric Schiff bases associated with multi metal ion sensing property. Spectral characterization methods indicate the formation of the new materials. Guest- host relationship established between various metal ions and receptors changes the electronic spectra drastically and for the addition of Cu2+ ions, formation of MLCT charge transfer band responsible for the coordination of metal ion with receptor has been noticed. Data calculated from the results of responses recorded for the applied potential to the metal added and metal free receptor solution exposes the concentration of metal ions required for the effective sensing process.