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Multiple interactions of three typhoons and a mid-latitude cloud band-associated with a trough (MLCT) were investigated from 1 July to 10 July 2015, using the Korea Communication, Ocean, and Meteorological Satellite (COMS) satellite images and two kinds of meteorological models, such as UM-KMA (U.K.) and WRF-3.6 (U.S.A.), to generate the horizontal structure of wind and relative humidity, streamline, and moisture flux. As severe tropical storm (STS) Linfa moved toward the warmer area with a sea surface temperature (SST) of 31 °C in the northern South China Sea, it obtained not only more moisture by thermal convection of water vapor from the sea surface toward the lower atmosphere but also more momentum by its multiple interactions with both the MLCT and Typhoon (TY) Chan-Hom. Through their mutual interactions, mutual feedback of moisture and momentum fluxes could accelerate the formation of clouds in their systems and an asymmetric structure of their circulations. After Linfa weakened due to the increased friction of the shallower sea bottom close to the Chinese coast and its disconnection from the MLCT, later it became re-intensified with the increased wind speeds by a stronger interaction with more intensified TY Chan-Hom entering the path of the Kuroshio Current of SST 31 °C, which could supply additional moisture through thermal convection of water vapor into its system. Then, further interaction between the rapidly developed TY Nangka following behind and the MLCT enhanced the transfer of moisture and momentum fluxes from Chan-Hom into Linfa. Finally, after STS Linfa made landfall on the Chinese coast, it decayed into a weak low-pressure system before its dissipating, due to the weakening of its cyclonic circulation through the increased friction by the shallower sea bottom and the surrounding lands. [ABSTRACT FROM AUTHOR]

The roles of medium- and long-chain triacylglycerols (MLCT) on health benefits under high fat diet (HFD) conditions remain in dispute. This study was conducted to investigate the effects of novel LaPLa-rich MLCT on the glycolipid metabolism and gut microbiota in HFD-fed mice when pork fat is half replaced with MLCT and palm stearin (PS). The results showed that although MLCT could increase the body weight in the mouse model, it can improve the energy utilization, regulate the glucose and lipid metabolism, and inhibit the occurrence of inflammation. Furthermore, 16S rRNA gene sequencing of gut microbiota indicated that PS and MLCT affected the overall structure of the gut microbiota to a varying extent and specifically changed the abundance of some operational taxonomic units (OTUs). Moreover, several OTUs belonging to the genera Dorea, Streptococcus, and g_Eryipelotrichaceae had a high correlation with obesity and obesity-related metabolic disorders of the host. Therefore, it can be seen that this new MLCT has different properties and functions from the previous traditional MLCT, and it can better combine the advantages of MLCT, lauric acid, and sn-2 palmitate, as well as the advantages of health function and metabolism. In summary, this study explored the effects of LaPLa-enriched lipids on glycolipid metabolism in mice, providing theoretical support for future studies on the efficacy of different types of conjugated lipids, intending to apply them to industrial production and subsequent development of related products. [ABSTRACT FROM AUTHOR]

New low-bandgap unimers, with the central thiophene-(1-thioxophosphole)-thiophene (TPT) ring sequence and 2,2′:6′,2″-terpyridin-4′-yl (tpy) end groups connected to the central unit via conjugated linkers of different size, are prepared and assembled with Zn(II) and Fe(II) ions to metallo-supramolecular polymers (MSPs) that are studied regarding their properties. The most interesting feature of Zn-MSPs is the luminescence extended deep into the NIR region. Fe-MSPs not only show the metal-to-ligand charge transfer (MLCT) manifested by the MLCT band (an expected feature) but also an as-yet-undescribed remarkable phenomenon: specific damping of the bands of the TPT sequence in the resonance Raman spectra taken from solid Fe-MSPs using the excitation to the MLCT band (532 nm). The damping is highly reversible at the low laser power of 0.1 mW but gradually becomes irreversible as the power reaches ca. 5 mW. The revealed phenomenon is not shown by the same Fe-MSPs in solutions, nor by Fe-MSPs containing no phosphole units. A hypothesis is proposed that explains this phenomenon and its dependence on the irradiation intensity as a result of the interplay of three factors: (i) enhancement of the MLCT process by excitation radiation, (ii) the electron-acceptor character of the 1-thioxophosphole ring, and (iii) morphological changes of the lattice and their dependence on the population of new structures in the lattice. [ABSTRACT FROM AUTHOR]

Dye is the key to the efficiency of harvesting solar energy in dye-sensitized solar cells (DSSCs). The dye performances such as light absorption, electron injection, and electron regeneration depend on the dye molecule structure. To predict it, one needs to compute the optimized molecule geometry, HOMO level, LUMO level, electron density distribution, energy gaps, and dipole moment in the ground and excited state. Chlorophyll-related chlorin and porphyrin, as well as their κ2O,O' complexes with Fe(II/III), were investigated with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) computations using the B3LYP method and def2-TZVP basis set. NPA charges also were calculated to know the valence of the metal cations exactly. In general, the calculations show that the metal cations introduced occupied d orbitals with lower oxidation potentials than the chlorophyll ligand orbitals, which are responsible for the emergence of additional absorption bands. The states result in effective band broadening and the redshift of spectrum absorbance that is expected to improve DSSC performance. Another requirement that has to be possessed is the ability of electron regeneration, electron injection, and dipole moment. The Fe(II) complex has fulfilled these requirements, but not the Fe(III) complex due to having a low electron injection capability. However, this work has shown that Fe(III) complex exhibits a non-innocence ligand. It results in trivalent to divalent state change, in the appearance of a ligand radical cation, an extra hole, and a broader absorption spectrum. It also can affect its other electronic properties, such as electron injection capability. Thus, it can be considered an attractive candidate for the sensitizer in DSSCs. [ABSTRACT FROM AUTHOR]

Effective photoinduced charge transfer makes molecular bimetallic assemblies attractive for applications as active light-induced proton reduction systems. Developing competitive base metal dyads is mandatory for a more sustainable future. However, the electron transfer mechanisms from the photosensitizer to the proton reduction catalyst in base metal dyads remain so far unexplored. A Fe─Co dyad that exhibits photocatalytic H 2 production activity is studied using femtosecond X-ray emission spectroscopy, complemented by ultrafast optical spectroscopy and theoretical time-dependent DFT calculations, to understand the electronic and structural dynamics after photoexcitation and during the subsequent charge transfer process from the Fe II photosensitizer to the cobaloxime catalyst. This novel approach enables the simultaneous measurement of the transient X-ray emission at the iron and cobalt K-edges in a two-color experiment. With this methodology, the excited state dynamics are correlated to the electron transfer processes, and evidence of the Fe→Co electron transfer as an initial step of proton reduction activity is unraveled., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Multiple interactions of three typhoons and a mid-latitude cloud band-associated with a trough (MLCT) were investigated from 1 July to 10 July 2015, using the Korea Communication, Ocean, and Meteorological Satellite (COMS) satellite images and two kinds of meteorological models, such as UM-KMA (U.K.) and WRF-3.6 (U.S.A.), to generate the horizontal structure of wind and relative humidity, streamline, and moisture flux. As severe tropical storm (STS) Linfa moved toward the warmer area with a sea surface temperature (SST) of 31 °C in the northern South China Sea, it obtained not only more moisture by thermal convection of water vapor from the sea surface toward the lower atmosphere but also more momentum by its multiple interactions with both the MLCT and Typhoon (TY) Chan-Hom. Through their mutual interactions, mutual feedback of moisture and momentum fluxes could accelerate the formation of clouds in their systems and an asymmetric structure of their circulations. After Linfa weakened due to the increased friction of the shallower sea bottom close to the Chinese coast and its disconnection from the MLCT, later it became re-intensified with the increased wind speeds by a stronger interaction with more intensified TY Chan-Hom entering the path of the Kuroshio Current of SST 31 °C, which could supply additional moisture through thermal convection of water vapor into its system. Then, further interaction between the rapidly developed TY Nangka following behind and the MLCT enhanced the transfer of moisture and momentum fluxes from Chan-Hom into Linfa. Finally, after STS Linfa made landfall on the Chinese coast, it decayed into a weak low-pressure system before its dissipating, due to the weakening of its cyclonic circulation through the increased friction by the shallower sea bottom and the surrounding lands.

The roles of medium- and long-chain triacylglycerols (MLCT) on health benefits under high fat diet (HFD) conditions remain in dispute. This study was conducted to investigate the effects of novel LaPLa-rich MLCT on the glycolipid metabolism and gut microbiota in HFD-fed mice when pork fat is half replaced with MLCT and palm stearin (PS). The results showed that although MLCT could increase the body weight in the mouse model, it can improve the energy utilization, regulate the glucose and lipid metabolism, and inhibit the occurrence of inflammation. Furthermore, 16S rRNA gene sequencing of gut microbiota indicated that PS and MLCT affected the overall structure of the gut microbiota to a varying extent and specifically changed the abundance of some operational taxonomic units (OTUs). Moreover, several OTUs belonging to the genera Dorea, Streptococcus, and g_Eryipelotrichaceae had a high correlation with obesity and obesity-related metabolic disorders of the host. Therefore, it can be seen that this new MLCT has different properties and functions from the previous traditional MLCT, and it can better combine the advantages of MLCT, lauric acid, and sn-2 palmitate, as well as the advantages of health function and metabolism. In summary, this study explored the effects of LaPLa-enriched lipids on glycolipid metabolism in mice, providing theoretical support for future studies on the efficacy of different types of conjugated lipids, intending to apply them to industrial production and subsequent development of related products.

Ruthenium had up to date been pivotal in electro- and photocatalytic applications involving reduction of CO2 and H2O, and dye-sensitized solar cells. Commercial applications would seek use of earth-abundant metals instead. Towards this goal, it is key to review the synthesis, electrochemical and spectroscopical properties of associated metal-to-ligand charge transfer complexes of row-4 (Mn, Fe & Co) and column-8 (Fe, Ru & Os). The present report is limited to data obtained under exactly similar conditions, providing scientifically valid correlations. Only tris-coordinated bipyridyl and phenanthroline complex derivatives are considered, being representative of catalysts and dyes traditionally used in the above-mentioned fields. The accuracy of theoretical DFT techniques to simulate complex properties is highlighted.

© 2015 Elsevier B.V. Dual emission is a reality in many, but not all, ruthenium complex ions, even at room temperature and in fluid solution. It requires significantly different ligands and is more obvious in rigid media such as glasses at low temperature and crystalline powders. However, there are not just two unique lifetimes. Rather, there is a continuum of similar but slightly different lifetimes drawn from a bimodal distribution. In some of the cases that do not show dual emission, there still seems to be a continuum within a unimodal distribution. After reviewing a wide range of data, we describe possible interpretations. Most novel, but in our view most attractive, is a major role for ion pairing. If one admits that ions near charge transfer orbitals should have a stabilizing effect, and if one doubts that there would be any unique configuration for ion pairs, then it would seem that a continuous variation of excited state behavior is mandatory. This mechanism accounts for the fact that highly asymmetric substitutions at the 4-position of the phen ligand that most affects charge transfer always show dual emission and offer the most exaggerated differences between the two emissions. Other possibilities remain, given the data available at this time.

New low-bandgap unimers, with the central thiophene-(1-thioxophosphole)-thiophene (TPT) ring sequence and 2,2′:6′,2″-terpyridin-4′-yl (tpy) end groups connected to the central unit via conjugated linkers of different size, are prepared and assembled with Zn(II) and Fe(II) ions to metallo-supramolecular polymers (MSPs) that are studied regarding their properties. The most interesting feature of Zn-MSPs is the luminescence extended deep into the NIR region. Fe-MSPs not only show the metal-to-ligand charge transfer (MLCT) manifested by the MLCT band (an expected feature) but also an as-yet-undescribed remarkable phenomenon: specific damping of the bands of the TPT sequence in the resonance Raman spectra taken from solid Fe-MSPs using the excitation to the MLCT band (532 nm). The damping is highly reversible at the low laser power of 0.1 mW but gradually becomes irreversible as the power reaches ca. 5 mW. The revealed phenomenon is not shown by the same Fe-MSPs in solutions, nor by Fe-MSPs containing no phosphole units. A hypothesis is proposed that explains this phenomenon and its dependence on the irradiation intensity as a result of the interplay of three factors: (i) enhancement of the MLCT process by excitation radiation, (ii) the electron-acceptor character of the 1-thioxophosphole ring, and (iii) morphological changes of the lattice and their dependence on the population of new structures in the lattice.

© 2015 Elsevier B.V. Dual emission is a reality in many, but not all, ruthenium complex ions, even at room temperature and in fluid solution. It requires significantly different ligands and is more obvious in rigid media such as glasses at low temperature and crystalline powders. However, there are not just two unique lifetimes. Rather, there is a continuum of similar but slightly different lifetimes drawn from a bimodal distribution. In some of the cases that do not show dual emission, there still seems to be a continuum within a unimodal distribution. After reviewing a wide range of data, we describe possible interpretations. Most novel, but in our view most attractive, is a major role for ion pairing. If one admits that ions near charge transfer orbitals should have a stabilizing effect, and if one doubts that there would be any unique configuration for ion pairs, then it would seem that a continuous variation of excited state behavior is mandatory. This mechanism accounts for the fact that highly asymmetric substitutions at the 4-position of the phen ligand that most affects charge transfer always show dual emission and offer the most exaggerated differences between the two emissions. Other possibilities remain, given the data available at this time.

The impact of metal‐to‐ligand charge transfer towards the redox noninnocence of 2,2′‐azobis(benzothiazole) (abbt) has been highlighted on coordination to {RuII(acac)2} (acac=2,4‐pentanedionato). It led to the authentication of a series of mononuclear and dinuclear complexes incorporating variable oxidation states of abbt (abbt0/.−/2−). Mononuclear 1 was identified as [RuIII(abbt.−)], a MLCT excited state of [RuII(abbt)]. Dinuclear 2 was however recognized as two discrete redox isomers: (i) radical bridged mixed‐valent meso‐[Ru2.5(μ‐abbt.−)Ru2.5] (2a) and (ii) dianionic ligand bridged isovalent meso‐[RuIII(μ‐abbt2−)RuIII] (2b), demonstrating unprecedented structural confirmation of valence tautomerism in azo‐based ligand systems. A crystal structure of [2]ClO4 validated the formation of [RuIII(μ‐abbt.−) RuIII]ClO4. Analysis of electronic structural forms of 1 and 2 in accessible redox states via spectroelectrochemistry and DFT revealed their electron reservoir feature. [ABSTRACT FROM AUTHOR]

A simple practical method to compute both d–d and metal‐to‐ligand charge‐transfer (MLCT) excited states of iron(II) polypyridyl complexes is proposed for use in simulation studies. Specifically, a model electronic Hamiltonian developed previously for d–d excited states of [Fe(bpy)3]2+ is extended to deal with low‐lying MLCT excited states simultaneously by including the MLCT electronic configurations into the basis functions of the model Hamiltonian. As a first attempt, parameters in the model Hamiltonian matrix elements are determined by using density functional theory (DFT) and time‐dependent (TD‐)DFT calculation results as benchmarks. To examine the performance of the model Hamiltonian, the potential energy curves along the interpolation between the lowest singlet and quintet state structures are compared to those from the (TD‐)DFT calculations and to those from CASPT2 calculations in literature. The electronic absorption spectrum computed through molecular dynamics simulation is compared to the experimental spectrum. The spin‐orbit couplings at the ground state structure are also compared to those from wavefunction‐based ab initio electronic structure calculations. The results indicate that the constructed model Hamiltonian provides reasonable information on both the low‐lying d–d and MLCT excited states of [Fe(bpy)3]2+. [ABSTRACT FROM AUTHOR]

A simple practical method to compute both d–d and metal‐to‐ligand charge‐transfer (MLCT) excited states of iron(II) polypyridyl complexes is proposed for use in simulation studies. Specifically, a model electronic Hamiltonian developed previously for d–d excited states of [Fe(bpy)3]2+ is extended to deal with low‐lying MLCT excited states simultaneously by including the MLCT electronic configurations into the basis functions of the model Hamiltonian. As a first attempt, parameters in the model Hamiltonian matrix elements are determined by using density functional theory (DFT) and time‐dependent (TD‐)DFT calculation results as benchmarks. To examine the performance of the model Hamiltonian, the potential energy curves along the interpolation between the lowest singlet and quintet state structures are compared to those from the (TD‐)DFT calculations and to those from CASPT2 calculations in literature. The electronic absorption spectrum computed through molecular dynamics simulation is compared to the experimental spectrum. The spin‐orbit couplings at the ground state structure are also compared to those from wavefunction‐based ab initio electronic structure calculations. The results indicate that the constructed model Hamiltonian provides reasonable information on both the low‐lying d–d and MLCT excited states of [Fe(bpy)3]2+. [ABSTRACT FROM AUTHOR]

Woven covalent organic frameworks (COF) possess three dimensional frameworks with spatially isolated Cu(I) centers and have promising optoelectronic properties because of metal to ligand charge transfer (MLCT). However, despite their potential, woven COFs have not yet been investigated as photocatalysts. In this study, we developed a new woven COF, Cu-PhenBDA-COF, functionalized with diacetylene bonds. Cu-PhenBDA-COF was fully characterized, and the optoelectronic and photocatalytic properties were compared to previously reported Cu-COF-505. The diacetylene bonds of the linker positively impacted the optoelectronic properties of Cu-PhenBDA-COF and resulted in a narrower band gap and better charge separation efficiency. When the Cu(I) center was removed from both woven COFs, the absorption edge was blue shifted, resulting in a wider band gap, and there was a considerable decrease in the charge separation efficiency, underscoring the pivotal role of MLCT. This trend was reflected in the photocatalytic activity of the woven COFs toward the degradation of sulfamethoxazole in water, where the highest reaction rate constant ( k app ) was recorded for the metallated diacetylene functionalized woven COF, Cu-PhenBDA-COF., Competing Interests: Conflict of Interest The authors declare no conflict of interest.

Exploiting earth-abundant iron-based metal complexes as highperformance photosensitizers demands long-lived electronically excited metal-to-ligand charge-transfer (MLCT) states, but these species suffer typically from femtosecond timescale charge-transfer (CT)- state quenching by low-lying nonreactive metal-centered (MC) states. Here, we engineer supermolecular Fe(II) chromophores based on the bis(tridentate-ligand)metal(II)-ethyne-(porphinato)zinc(II) conjugated framework, previously shown to give rise to highly delocalized lowlying ³MLCT states for other Group VIII metal (Ru, Os) complexes. Electronic spectral, potentiometric, and ultrafast pump–probe transient dynamical data demonstrate that a combination of a strong σ-donating tridentate ligand and a (porphinato)zinc(II) moiety with low-lying π*-energy levels, sufficiently destabilize MC states and stabilize supermolecular MLCT states to realize Fe(II) complexes that express ³MLCT state photophysics reminiscent of their heavy-metal analogs. The resulting Fe(II) chromophore archetype, FeNHCPZn, features a highly polarized CT state having a profoundly extended ³MLCT lifetime (160 ps), ³MLCT phosphorescence, and ambient environment stability. Density functional and domain-based local pair natural orbital coupled cluster [DLPNO-CCSD(T)] theory reveal tripletstate wavefunction spatial distributions consistent with electronic spectroscopic and excited-state dynamical data, further underscoring the dramatic Fe metal-to-extended ligand CT character of electronically excited FeNHCPZn. This design further prompts intense panchromatic absorptivity via redistributing high-energy absorptive oscillator strength throughout the visible spectral domain, while maintaining a substantial excited-state oxidation potential for wide-ranging photochemistry––highlighted by the ability of FeNHCPZn to photoinject charges into a SnO2/FTO electrode in a dye-sensitized solar cell (DSSC) architecture. Concepts enumerated herein afford opportunities for replacing traditional rare-metal–based emitters for solar-energy conversion and photoluminescence applications. [ABSTRACT FROM AUTHOR]

• A strongly luminescent Re (I) complex with anionic cyanopentafluorophosphate [NCPF 5 ]–. • Characterizations of isocyanopentafluorophosphate [CNPF 5 ]– and cyanopentafluorophosphate [NCPF 5 ]– through vibrational spectroscopy. • Detailed investigation revealed the exceptionally strong π-accepting ability of anionic [NCPF 5 ]–. A tricarbonyl Re (I) phenanthroline complex (1) with anionic cyanopentafluorophosphate [NCPF 5 ]– ligand has been synthesized and characterized. Although the structure of the complex has also been determined by X-ray crystallography, the identity of the [NCPF 5 ]– needs to be confirmed by the vibrational spectroscopic study. The cyanopentafluorophosphate Re (I) phenanthroline complex 1 also exhibits phosphorescence derived from a 3MLCT excited state. Importantly, as the MLCT absorption and emission energies of 1 are comparable to those of the structurally related complexes with the strongest π-accepting anionic isocyanoborate ligands, it reveals the exceptionally strong π-accepting ability of [NCPF 5 ]–. This result suggests that [NCPF 5 ]– is a promising alternative to isocyanoborate ligands for designing phosphorescent materials, catalysts and photocatalysts. [ABSTRACT FROM AUTHOR]

Abstract Coenzyme B 12 (Adenosylcobalamin = AdoCbl)-dependent enzymes catalyze complex molecular transformations where cleavage of the Co C bond initiates the catalytic cycle. Alternatively, the Co C bond can be cleaved with light. In both cases, rupture of the Co C bond results in the formation of Co(II)/Ado radical pair (RP). Within the field of B 12 chemistry, there has been a suspicion that photolytic cleavage can be used as a probe or a direct comparison of the native reaction. Herein, we seek to resolve what the connection between light induced RP formation and the native catalytic cycle is. We used a combined QM/MM approach to construct PESs for AdoCbl-dependent ethanolamine ammonia-lyase (EAL) as a function of axial bonds to describe the reaction mechanism. We have found that there is no direct comparison that can be made between photolysis and enzymatic cleavage as the mechanism associated with these involves different electronic states. With that being said, we have explored an alternate hypothesis for the connection which involves the one-electron reduced form of the AdoCbl cofactor. This hypothesis is in line with the concept based on proton-coupled electron transfer (PCET), which involves the formation of AdoCbl cofactor-tyrosine diradical complex. The topology of the PES for the one-electron reduced (D 1) cofactor is very similar to the PES associated with photo-induced cleavage (S 1). Both surfaces contain two energy minima that are, similarly, the result of two distinct electronic states. Thus, it appears that the reaction mechanism associated with the D 1 surface and the S 1 surface are very similar, providing a plausible connection between photolysis and native catalysis. Graphical Abstract Unlabelled Image Highlights • The photolysis and catalysis of AdoCbl-dependent enzymes both involve the generation of the Co(II) and Ado radical pair. • The generation of the radical pairs in both cases involve different electronic states. • Understanding the mechanism of photolysis may provide insight into whether or not photochemistry can be used as a mimic for native catalysis. • The connection between photolysis and catalysis can be established by considering the one electron reduced cofactor. [ABSTRACT FROM AUTHOR]

Abstract A new optical chemical sensor based on medicinal compound, jaeschkeanadiol p -hydroxyben-zoate (Ferutinin), has been designed and utilized for Ca(II) ions detections. This natural optical sensor exhibits immense selectivity including fluorescence and absorption ratiometric for Ca(II) ions within precious physiological pH range. Further, the chelation process of the Ca(II) ions with the medicinal optical sensor ferutinin yields a 1:1 (metal: ligand) complex which is accompanied by fluorescence enhancement of the main emission band centered at 355 nm of the medicinal probe. The fluorescence “turn-on” effect is a clear evidence for the chelation process between ferutinin medicinal probe and Ca(II) ions and this could be simply detected. The new sensor was proposed depending on significant fluorescence mechanism, (MLCT, metal-ligand charge transfer). However, the interaction of the medicinal optical sensor with Ca(II) in presence of other cations was examined without any significant interference. Also, the new developed optical sensor consecutively exhibits low limit of detection (LOD) 1.5 nM for Ca(II) which is detected in very significant physiological pH range (pH = 7.4). Also, the probe provides high binding affinity towards Ca(II) with large binding constant K b 5.97 × 104 M−1. As a result, this optical sensor may apply for detection Ca(II) in cell or biological samples. Graphical Abstract A novel optical chemical sensor was developed for Ca(II) ions detection. The chemosensor is designed based on jaeschkeanadiol p -hydroxyben-zoate, Ferutinin (Fh-25). The chemosensor probe shows high selectivity, sensitivity and reversibility depending on their fluorescence properties and recognition abilities within very low detection (LOD 1.5 nM) in physiological pH = 7.4. Unlabelled Image Highlights • A novel optical chemical sensor based ferutinin medical probe for Ca(II) detection was developed. • The sensor provides fast response, high sensitivity and selectivity. • LOD was detected in nanomolar range (1.5 nM for Ca(II)). • The sensing mechanism of the Medical probe for Ca(II) is MLCT as suggested. [ABSTRACT FROM AUTHOR]

Abstract Methylcobalamin (MeCbl)-dependent enzyme methionine synthase (MetH), plays a critical role in the catalysis of methyl group transfer from methyltetrahydrofolate (CH 3 -H 4 folate) to homocysteine. It often performs a side reaction to generate cob(II)alamin through photolysis of the organometallic Co C σ bond. A hybrid QM/MM method has been applied to explore the photochemistry of MeCbl-bound MetH. The photolytic properties of MeCbl inside MetH are mediated by its manifold of low-lying excited states. The corresponding potential energy surfaces (PESs) of the electronically excited S 1 state has been constructed as a function of axial bond lengths to elucidate the mechanism of photo-induced activation of Co C bond inside the enzyme. The analysis of the S 1 PES has revealed that the two different electronic states of the S 1 PES, namely metal-to-ligand charge transfer (MLCT) and the ligand field (LF), are relevant to the photodissociation of the Co C bond. There are two possible pathways identified, Path A and Path B, that connect the MLCT to LF state that represent possible photodissociation mechanisms. In the case of MetH, one possible photodissociation pathway (Path B) was identified based on the energetics of the MLCT and LF states. The energetically accessible Path B involves the initial detachment of the Co-N Im bond followed by a subsequent displacement of the Co C bond prior to the formation of cob(II)alamin / CH 3 radical pair (RP). The photochemical data of base-on MeCbl in solution was compared with the computed result of MeCbl-bound MetH to understand the effect of the enzymatic environment on the photolytic properties of MeCbl. Graphical Abstract Unlabelled Image Highlights • The Co C bond of MeCbl can be cleaved by light • The mechanism of Co C bond photolysis is mediated by low-lying excited states • The photodissociation mechanism can be understood by scrutinizing the corresponding S 1 PES • The S 1 PES is the result of crossing of two electronic states namely MLCT and LF • The MLCT state is energetically stabilized than the LF state [ABSTRACT FROM AUTHOR]

A chemosensor is a synthetic chemical system which is capable of binding with an analyte in a selective and reversible manner followed by change in one or more properties of the system in the form of color or fluorescence or redox potentials. The choice of a chromophore has tremendous effect on these properties. The well established and indispensable role of metal ions in connection to their medicinal, biological and environmental concern makes their sensing one of the major research domains out of other domains including detection of anions, bio molecules, pesticides, explosives, etc. Therefore, the number of research articles is growing at a high rate dedicated to pave path for more reliable and sophisticated chemosensors. In this context, continuous compilation of research work is highly desirable (or acceptable) in order to generate a library of chromophores helping the budding researchers to access the present trends in limited (short) time. In this review, we have focused on colorimetric sensors for metal ions, viz. alkali and alkaline earth, Al 3+ , Cr 3+ , Mn 2+ , Fe 3+ /Fe 2+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ /Cd 2+ , Hg 2+ , Ag + , Sn 4+ /Sn 2+ , Pd 2+ , Pb 2+ , Zr 4+ , Mo 6+ , due to their numerous advantages such as, easy detection without requiring sophisticated instruments, high selectivity and sensitivity in terms of different color change for different species, over other chemosensors. This work is a comprehensive survey of colorimetric sensors for metal ions developed in the years from 2011 to 2016 (>450 references). [ABSTRACT FROM AUTHOR]

A neutral ligand L is prepared by condensation of benzil dihydrazone and acetone in 1:2 mol ratio and used for the syntheses of [CuL 2 ]ClO 4 , [CuL 2 ]PF 6 , [AgL 2 ]ClO 4 and [AgL 2 ]PF 6 . The X-ray crystal structures of L and the two perchlorate salts have been determined. The metal complexes are found to be mononuclear containing tetrahedral N 4 coordination spheres for Cu(I) and Ag(I). Cyclic voltammetrically, the Cu(II/I) and Ag(II/I) potentials are 1.23 and 0.76 V vs NHE respectively in CH 2 Cl 2 at a Pt electrode. The reason for the such a low Ag(II/I) potential is that the silver(I) complex is adsorbed on the electrode surface with a free energy of adsorption of ∼ −14.99 kcal mol −1 . DFT calculations at the BP86/LanL2DZ level show that the HOMO’s in [CuL 2 ]ClO 4 and [AgL 2 ]ClO 4 are both metal based and the LUMO’s have no contribution from the metals. Both complexes show weak emissions from the MLCT states upon excitation at 270 nm in ethanol solution at room temperature. Changing the counterion to PF 6 − leads to higher quantum yields for these processes. It is consistent with the general observation that ClO 4 − being more coordinating than PF 6 − , it binds the metals in the MLCT state to form exciplexes leading to a lower ϕ or total quenching. At 77 K in ethanol glass, L, [CuL 2 ] + and [AgL 2 ] + show ligand centered (LC) emissions. Thus the MLCT and LC states are thermally equilibrated in the silver(I) and copper(I) complexes. In keeping with this, a mixture of the two processes, MLCT and LC emissions, is observed at room temperature for [AgL 2 ]ClO 4 and [CuL 2 ]ClO 4 when they are incorporated in a rigid polymethyl methacrylate matrix. [ABSTRACT FROM AUTHOR]

Medium-and-Long Chain Triacylglycerol (MLCT) is a type of structured lipid that is made up of medium chain, MCFA (C8-C12) and long chain, LCFA (C16-C22) fatty acid. Studies claimed that consumption of MLCT has the potential in reducing visceral fat accumulation as compared to long chain triacylglycerol, LCT. This is mainly attributed to the rapid metabolism of MCFA as compared to LCFA. Our study was designed to compare the anti-obesity effects of a enzymatically interesterified MLCT (E-MLCT) with physical blend of palm kernel and palm oil (B-PKOPO) having similar fatty acid composition and a commercial MLCT (C-MLCT) made of rapeseed/soybean oil on Diet Induced Obesity (DIO) C57BL/6 J mice for a period of four months in low fat, LF (7%) and high fat, HF (30%) diet. The main aim was to determine if the anti-obesity effect of MLCT was contributed solely by its triacylglycerol structure alone or its fatty acid composition or both. Out of the three types of MLCT, mice fed with Low Fat, LF (7%) E-MLCT had significantly ( P < 0.05) lower body weight gain (by ~ 30%), body fat accumulation (by ~ 37%) and hormone leptin level as compared to both the LF B-PKOPO and LF C-MLCT. Histological examination further revealed that dietary intake of E-MLCT inhibited hepatic lipid accumulation. Besides, analysis of serum profile also demonstrated that consumption of E-MLCT was better in regulating blood glucose compared to B-PKOPO and C-MLCT. Nevertheless, both B-PKO-PO and E-MLCT which contained higher level of myristic acid was found to be hypercholesterolemic compared to C-MLCT. In summary, our finding showed that triacylglycerol structure, fatty acid composition and fat dosage play a pivotal role in regulating visceral fat accumulation. Consumption of E-MLCT in low fat diet led to a significantly lesser body fat accumulation. It was postulated that the MLM/MLL/LMM/MML/LLM types of triacylglycerol and C8-C12 medium chain fatty acids were the main factors that contributed to the visceral fat suppressing effect of MLCT. Despite being able to reduce body fat, the so called healthful functional oil E-MLCT when taken in high amount do resulted in fat accumulation. In summary, E-MLCT when taken in moderation can be used to manage obesity issue. However, consumption of E-MLCT may lead to higher total cholesterol and LDL level. [ABSTRACT FROM AUTHOR]

The electronic structures and spectroscopic properties of two complexes [M(pic)] (M = Ir, Rh) containing picolinate as bidentate ligands have been calculated by means density functional theory (DFT) and time-dependent DFT/TD-DFT using three hybrid functionals B3LYP, PBE0 and mPW1PW91. The PBE0 and mPW1PW91 functionals, which have the same HF exchange fraction (25%), give similar results and do not differ drastically from B3LYP results. Calculated geometric parameters of the complexes are in good agreement with the available experimental data. The UV absorptions observed in acetonitrile were assigned on the basis of singlet state transitions. The most intense band observed in the UV-C region corresponds to ligand-to-ligand charge transfer states (LLCT) in both complexes. The theoretical spectrum of the rhodium complex is characterized by a large degree of mixing between metal-to-ligand-charge-transfer (MLCT), LLCT and metal centered (MC) states in the UV-A region. The presence of low-lying excited states with MC character affects the absorption spectrum under spin-orbit coupling (SOC) effects and play important roles in the photochemical properties. [ABSTRACT FROM AUTHOR]

A chloro-bridged dimeric copper(I) complex with the ambiphilic phosphinoborane ligand tBu 2PCH2BPh2 is reported. The molecular structure was determined by single-crystal X-ray diffraction analysis, revealing a secondary η1-C interaction of the ligand with the metal center. The complex exhibits green fluorescence when exposed to UV light at 366 nm. [ABSTRACT FROM AUTHOR]

A novel bismuth biimidazole compound, [(BiCl4)-( μ2-Cl)2-(BiCl4)][(CH3)4-2,2'-biimidazole]2 ( 1) with the (CH3)4-2,2'-biimidazole moiety generated in situ, was successfully prepared under hydrothermal conditions and structurally characterized using a single-crystal X-ray diffraction technique. Compound 1 is characteristic of an isolated structure, consisting of [(BiCl4)-( μ2-Cl)2-(BiCl4)] and (CH3)4-2,2'-biimidazole moieties. Solid-state photoluminescence measurement reveals that it shows a strong emission in the blue region. Time-dependent density functional theory studies show that this emission is ascribed to metal-to-ligand charge transfer. The solid-state diffuse reflectance spectrum reveals the existence of an optical band gap of 2.09 eV, indicating that it is a semiconductor. [ABSTRACT FROM AUTHOR]

In the present work, we report two methoxy-substituted phenyl-terpyridine ruthenium complexes with pyridine carboxyquinoline and NCS as ancillary ligands, [Ru(OMePhtpy)(pcqH)(NCS)](PF6) (1) and [Ru(triOMePhtpy)(pcqH)(NCS)](PF6) (2) (where OMePhtpy = (4′-(4-methoxy)phenyl-2,2′:6′,2″-terpyridine, triOMePhtpy = (4′-(3,4,5-trimethoxy)phenyl-2,2′:6′,2″-terpyridine and pcqH = pyridine-carboxyquinoline). Both complexes have been characterized by spectroscopic techniques e.g., mass,1H-NMR and FTIR. UV–vis spectrophotometric and electrochemical studies for both complexes have been performed. The substitution pattern of the –OMe groups have been successfully utilized to tune the redox potential of the metal complexes. On the anodic side of cyclic voltammogram,1and2show an irreversible wave corresponding to RuII/IIIcouple at 0.95 and 0.85 V, respectively. The lower RuII/IIIoxidation potential for2may be attributed to increased electron density on ruthenium due to three (+R) methoxy–groups appended to the phenyl moiety of triOMePhtpy. DFT optimization of structure and energy calculation reveals that in both complexes, HOMO is metal- and thiocyanate-based, whereas the LUMO is based on pcqH. Correlation of TDDFT results with experimental electronic spectrum indicates that bands at 502 nm (1) and 528 nm (2) are of MLLCT character from ruthenium-thiocyanate to pcqH. [ABSTRACT FROM AUTHOR]

[Display omitted] • Redox non-innocence of metalated azoheteroarenes. • Varying strategies for the sequential azo reductions including its scission. • Catalytic activity by virtue of reversible electron storage feature of the azo core. • Light induced E - Z isomerism and application potential towards molecular materials. • A brief overview of synthetic methodologies and bio-relevance of azoaromatics. Reversible electron reservoir feature of redox non-innocent ligand is an important event from the broader perspectives of metal–ligand cooperativity in catalysis as well as in introducing the molecular bistability. In this context, facile reductions of the metal bound azo core ([-N N-]0 → [-NN-] −→[-N N-]2−) of azoheteroarenes such as 2,2′-azobis(pyridine), 2,2′-azobis(benzazole), azo-pincers as well as four-electron reduction mediated cleavage of the azo bond ([-N N-]0 + 4e−→2[=N-]2−) to form metal-imido fragment have been highlighted. Structural authentication of the redox states of azo core under selective coordination situations and their application towards aerobic alcohol oxidation and cycloaddition reactions have been reviewed. It also elaborates strategies towards multi-electron reductions and scission of azoaromatics via (i) metal-to-ligand charge transfer (MLCT) induced inner-sphere electron transfer, (ii) metathesis reaction pathway, where metal–metal bond breaking delivers electrons to the empty π*, σ* orbitals of the azo function, and (iii) synergism of metal with other reducing agent. An account for the synthetic methodologies of azoaromatics and its light triggered cis – trans isomerization including application potential to molecular materials and biological processes have been addressed. [ABSTRACT FROM AUTHOR]

The first crystal structure of [Cu(terpy)2](PF6 )2 , where terpy=2,2':6',2"-terpyridine is reported. Green crystals of [Cu(terpy)2](PF6 )2 were grown by ether diffusion into an acetonitrile solution of the complex. Crystal structure of this complex is tetragonal ( space group: P21c ) with a = 8.8916(3), c = 20.0214(13) Å, and z = 2. The structure was refined by using 1828 independent reflections with I > 2σ(I) to a R factor of 0.0809. The terpy ligands are tridentate and linked to the Cu(II) via three N atoms. The CuN6 entities have compressed octahedral geometry with the shortest Cu-N bonds that form the axial positions. This complex represents z-in distortion at 293K and has a D2d point group. The effective magnetic moment ( μeff ) of [Cu(terpy)2](PF6 )2 was measured to be 1.95BM by Evans method. Cyclic voltammetry experiment of the complex shows that the Cu(II/I) couple is quasi-reversible.

Here we report second-order n-electron valence state perturbation theory excited state calculations on the low-lying transitions of the [Ru(4,4′-COOH-2,2′-bpy)2(NCS)2] complex, better known as the N3 dye, both in vacuo and water solution. The present results provide unprecedented insights into the crucial role of the solvation effects, previously reported at density functional theory (DFT) and time-dependent DFT (TDDFT) level of theory, to adequately reproduce the optical absorption spectrum. We find that the NEVPT2 results in gas phase, even if slightly blueshifted, already provide a reliable description and assignation of the electronic structure and low-lying excited states of N3, whereas these are achieved in a DFT/TDDFT approach only by means of the solvent, which properly polarizes the ground-state frontier molecular orbitals. Then, inclusion of the solvent at the NEVPT2 level does not substantially modify the ground-state electronic structure as well as the excited states picture found in vacuo, solely yielding the expected spectral blueshift. [ABSTRACT FROM AUTHOR]

A novel ruthenium-terpyridine based photosensitizer, Ru[( p -F-tpy)(pcqH)Cl] PF 6 ( 1 ); ( p -F-tpy = 4′-(4-fluorophenyl)-2,2′:6′,2″-terpyridine, pcqH = 2-(2-pyridyl)-4-carboxyquinoline) was synthesized and spectroscopically characterized. The electronic spectrum of the complex shows the lowest energy MLCT band at 536 nm in DMSO. The ground state pK a values of the acidic ligand (pcqH) and the Ru complex were spectrophotometrically determined. The pK a of the COOH group in the free ligand is 3.56, and this reduces to 2.89 when bound to the metal. The cyclic voltammetry of the complex shows a reversible Ru II/III oxidation at 0.825 V with respect to Ag/AgCl reference electrodes in DMF. The Cl group is very labile, substitution of the Cl group by H 2 O generates aqua species, which has been shown spectrophotometrically. A Pourbaix diagram for the Ru-aqua species has been constructed to show the detailed redox properties of the complex by means of cyclic voltammetry and differential pulse voltammetry at variable pH. Non-linear regression analysis was performed to generate the pK a values for the Ru-aqua species as 11.89 (Ru II ) and 4.00 (Ru III ). Photovoltaic measurements with the dye were performed after anchoring onto a TiO 2 surface with the I − / I 3 − redox electrolyte. Photovoltaic properties, like open-circuit photo-voltage (Voc = −0.35 V), short-circuit photocurrent density ( J sc = 1.428 × 10 −4 amp cm −2 ), fill factor (ff = 39.4%) and solar-to-electric conversion efficiencies ( η = 0.13%), of the DSSCs constructed from the [Ru( p -F-tpy)(pcqH)Cl]PF 6 sensitized TiO 2 electrodes were measured. A DFT and TDDFT study has been performed on the complex. The TDDFT calculated absorption spectrum nicely matches the experimental spectrum. [ABSTRACT FROM AUTHOR]

Silver assisted aquation of blue cis-trans-cis-RuCl2 (RaaiR')2 (1) leads to the synthesis of solvento species, blue-violet cis-transcis-[ Ru(OH2)2(RaaiR')2](ClO4)2 [RaaiR = p-R-C6H4-N=N-C3H2-NN, (2), abbreviated as N,N/-chelator, where N(imidazole) and N(azo) represent N and N/, respectively; R = H (a), p-Me (b), p-Cl (c) that have been reacted with NCS- in warm EtOH resulting in red-violet dithiocyanato complexes of the type, [Ru(NCS)2(RaaR)2] (3-5). The solution structure and stereoretentive transformation in each step have been established from 1H n.m.r. results. All the complexes exhibit strong MLCT transitions in the visible region. They are redox active and display one metal-centred oxidation and successive ligand-based reductions. Linkage isomerisation was studied by changing the solvent and then UV-Vis spectral analysis. [ABSTRACT FROM AUTHOR]

A new series of diisocyanide-bridged homodinuclear Re(I) complexes [(phen)(L x )(CO) 2 Re(CNRNC)Re(CO) 2 (L x )(phen)] 2+ and their mononuclear analogues [Re(PPh 3 )(CNRNC)(CO) 2 (phen)] + [L x = CO and PPh 3 ; CNRNC = 1,4-phenylenediisocyanide (CNC 6 H 4 NC) and 4,4′-biphenyldiisocyanide (CNC 6 H 4 C 6 H 4 NC)] have been synthesized. The X-ray crystal structures of two of the dinuclear complexes were determined. The photophysics and electrochemistry of these complexes have been investigated. The dicarbonyl phosphino Re(I) phenanthroline complexes display intense MLCT [dπ(Re)→π ∗ (phen)] phosphorescence in CH 2 Cl 2 solution with luminescence quantum yield ( ϕ em ) in the range of 0.127–0.171. In contrast, the tricarbonyl dinuclear Re(I) complexes exhibit LC [π→π ∗ (phen)] phosphorescence with ϕ em from 0.0498 to 0.0625. [ABSTRACT FROM AUTHOR]

In this work we report the preparation of six new donor–metal–acceptor (D–M–A) type complexes of ruthenium(II) with the highly absorbing “chromophoric” ligand 4,4′-bis(2-(4-methoxyphenyl)styryl)-2,2′-bipyridine, (L-OCH 3 , donor moiety) and substituted polypyridinic ligands with electron acceptor character (NN-A). The NN-A studied ligands were pyrazino[2,3-f][1,10]phenanthroline (ppl), 11-R-dipyrido[2,3-a:2′,3′-c]phenazine (dppz-R; R is H, NO 2 , or CN) and 10,11-[1,4-naphtalenedione]dipyrido[3,2-a:2′,3′-c]phenazine (Aqphen). The complexes were characterized by IR, NMR, UV–Vis spectroscopy and cyclic voltammetry. The potential NLO response of the complexes was evaluated by solvatochromic studies. Although the communication between D and A exists, the effect of the change of the acceptor moiety on the properties of the complexes is small and the behavior of the complexes is governed mainly by the donor ligand. The Metal to Ligand Charge Transfer bands (MLCT) exhibited by all complexes in the visible region have dominant electronic density transfer character from the metal to the chromophoric L-OCH 3 ligand. The hypsochromic shift of this low energy absorption band on going from a less polar (benzene) to a more polar solvent (acetonitrile) indicated that a redistribution of the electronic density among the metal and the donor ligand is observed. This behavior permits to predict a NLO response for these types of complexes. The combination of high molar absorptivity with intraligand charge transfer (ILCT) mixing into the MLCT bands are encouraging for the generation of new materials with interesting NLO properties. [ABSTRACT FROM AUTHOR]

The photophysical behavior of Ru(II) and Os(II) diimine complexes having complex aromatic hydrocarbon diimine ligands has received considerable attention as systems exhibiting intramolecular energy transfer to yield excited states with lifetimes much longer than the parent diimine complexes. Here we present a focused discussion of the photophysical behavior of transition metal complexes with modified terpyridyl ligands. The overview includes, as an example of approaches used to evaluate such systems, spectroscopic studies of a pair of Ru(II) mono- and bis-terpyridyl complexes modified with vinylpyrene (Pyr-v-tpy) to have ligand localized excited states that are equal to or lower than the energy of the known MLCT state of the parent complexes, [Ru(Mpt) 2 ] 2+ and [Ru(Mpt)(dien)] 2+ (Mpt = 4′-tolyl-2,2′:6′,2″-terpyridine, dien = diethylenetriamine). The common observation is that the presence of Pyr-v-tpy serves to lengthen the excited state lifetime of the complex through interaction of MLCT and ligand localized (IL) states. For [Ru(Pyr-v-tpy) 2 ] 2+ the excited state lifetime increases by a factor of more than 10 4 relative to [Ru(Mpt) 2 ] 2+ . For [Ru(Pyr-v-tpy)(dien)] 2+ , the 3 IL state is close in energy to the MLCT state of the parent [Ru(Mpt)(dien)] 2+ and, while the transient absorption spectrum is significantly perturbed relative to [Ru(Mpt)(dien)] 2+ , the excited state decay rate changes by only a factor of four. The long-lived excited state is formed in less than a ps, indicating strong coupling of the MLCT and ligand localized manifolds. [ABSTRACT FROM AUTHOR]

In analogy to peroxide, disulfide is an oxidant as well as a reductant. Accordingly, as a ligand of a reducing metal center, low-energy MLCT transitions can occur, while with oxidizing metals low-energy LMCT transitions should be observed. Such MLCT and LMCT excitations are expected to induce redox reactions. The complexes [CpFe(II)(CO) 2 ] 2 μ-S 2 (Cp C 5 H 5 ) and {[Fe(III)(CN) 5 ] 2 μ-S 2 } 6 − are suitable examples to explore this behavior. [ABSTRACT FROM AUTHOR]

Eleven ruthenium complexes of the type Ru(L)2(L0]2+ have been prepared by reacting Ru(L 2Cl2 (where L=2,2'-bipyridine (bpy)/ 1,10-phenanthroline (phenyl)/ dimethylsulfoxide (DMSO)) with ligands L,= HBT, FC1-HBT, IINH, N02-MPC, OCH3-MPC, N(CH3)2-MPC, Cl-MPC (where HBT=2-hydrazinyl- 1,3-benzothiazole, FC1-HBT =5-chloro-6-fluoro-2-hydrazinyl-l,3-benzothiazole, IINH=N-2 oxo-l,2- dihydro-3H-indol-3-ylidene]pyridine-4-carbo-hydrazide, N02-MPC=N(4-nitrophenyl) methylidenepyridine- 4-carbohydrazide,OCH3-MPC=N(4-methoxyphenyl)methylidene-pyridine-4-carbohydrazide, N(CH3)2-MPC=N(4-dimethylaminophenyl)methylidene-pyridine-4-carbo-hydrazide, C1-MPC=N(4- chlorophenyl)methylidene-pyridine-4-carbohydrazide. The title complexes were subjected to in vitro cytostatic activity testing against the human cervix carcinoma HeLa and T-lymphocyte CEM cell lines, and the murine leukemia tumor cell line L1210. The most active ruthenium complex TKA-9 [Ru(phen)2(N(CH3)2-MPC)] revealed a cytostatic activity of 16 uM against CEM, 20 pM against L1210 and 5.5 ^iM against HeLa tumor cells. All complexes were also tested for antiviral activity against a wide variety of DNA and RN A viruses, but found not to display selective activity at subtoxic concentrations. [ABSTRACT FROM AUTHOR]

Novozym-435-catalysed esterification of caprylic acid, capric acid and oleic acid with glycerol for the synthesis of medium- and long-chain triglycerides ( MLCT) in vacuum and solvent-free system was investigated in this study. Response surface methodology with a three-level, four-factorial design was applied to optimise the enzymatic esterification for the synthesis of MLCT. The optimum conditions were as follows: reaction temperature 90 °C, 4.80 wt% enzyme load (relative to the weight of total substrates) and substrate molar ratio (fatty acids/glycerol) of 3:1 and 12.37 h. Under above-mentioned conditions, Triglycerides ( TG) yield, MLCT and the residual free fatty acids ( FFA) content in the product were 93.54%, 72.19% and 4.21%, respectively. The content of caprylic acid, capric acid and long-chain fatty acids of TG was 24%, 10% and 66%, respectively. Novozym 435 in the study showed no selectivity for the different fatty acids and also could be used 14 times without obvious loss of enzyme activity. [ABSTRACT FROM AUTHOR]

Abstract: Ru–porphyrin complexes with pyridylpyrazine as metal coordination sites were synthesized. Introduction of Pd-alkyl units to the binding site led to the formation of a novel Pd–Ru–Pd trinuclear complex. The metalation causes drastic changes in the electrochemical and photophysical properties. The trinuclear complex exhibited a prominent metal-to-axial ligand charge transfer band in the visible region due to small energy gap between the Ru-based HOMO and the axial ligand-based LUMO. These changes resulted in the drastic color change from orange to green. [Copyright &y& Elsevier]

Abstract: A new chemosensor 3 having D–A–D type architecture of benzo[2,1,3]thiadiazole acceptor and thiophene donor with azomethine pendant arm was synthesized and its metal recognition capability was studied over the first row transition metal series. Compound 3 showed colorimetric sensitivity and selectivity towards for Fe(II) and Fe(III). Change in the strength of intramolecular charge transfer (ICT) due to metal to ligand charge transfer (MLCT) is responsible for color change. It has been established using CV and NMR titration. The sensitivity of 3 is in the range of μM concentration that leads to the visual detection by changing color from yellow to orange. [Copyright &y& Elsevier]

In this study, we utilize a photo-active Ir-metalloligand, Ir(C^N) 2 (L) (C^N = 2-(2,4-difluorophenyl) pyridine, L = [2,2'-bipyridine]-5,5'-dicarboxylic acid), to assemble with CdX 2 under hydrothermal conditions, yielding highly emissive crystals of two-dimensional metal-organic frameworks (2D MOFs) (named Ir-Cd 2 X 2 , X = Cl, Br). The Ir-Cd 2 X 2 MOFs exhibit μs-level phosphorescence lifetimes and more than 55% quantum yield (QY) at room temperature because of the rigid framework connected by Cd 2 X 2 clusters. By immersing Ir-Cd 2 X 2 in water solution for 5 min, a new MOF ( Ir-Cd ) was obtained, which is given a structure with hydrolyzed Cd-nodes by complete removal of halogen bridges as elucidated by single-crystal diffraction. Although the phosphorescence emission of pristine CdX 2 MLCT properties, showing a 3 MLCT properties, showing a K SV value as high as 14.5 with strictly linear relation ( R 2 = 0.995). This work differs from the traditional method for improving oxygen-sensing metrics by enhancing QY and phosphorescence lifetime in Ir complexes, while also demonstrating that the transformation in the surrounding coordination environment on adjacent metal centers can also constitute key factors for improved photoluminescence stability or responsive properties in Ir-based heteronuclear MOFs, providing clues for the development of either oxygen quenching blockers or sensors suitable for different occasions.

• Polypyridyl Mn, Fe and Co complexes as less expensive and non-toxic alternative to Ru and Os as electrocatalyst. • Comparison of redox and spectroscopic properties of row-4, Mn, Fe & Co, and of column-8; Fe, Ru & Os. • Experimental redox data correlates linearly with theoretically calculated energies for Mn, Fe, Co, Ru & Os. • The linear equations provide a means of predicting oxidation potentials of related compounds. Ruthenium had up to date been pivotal in electro- and photocatalytic applications involving reduction of CO 2 and H 2 O, and dye-sensitized solar cells. Commercial applications would seek use of earth-abundant metals instead. Towards this goal, it is key to review the synthesis, electrochemical and spectroscopical properties of associated metal-to-ligand charge transfer complexes of row-4 (Mn, Fe & Co) and column-8 (Fe, Ru & Os). The present report is limited to data obtained under exactly similar conditions, providing scientifically valid correlations. Only tris -coordinated bipyridyl and phenanthroline complex derivatives are considered, being representative of catalysts and dyes traditionally used in the above-mentioned fields. The accuracy of theoretical DFT techniques to simulate complex properties is highlighted. [ABSTRACT FROM AUTHOR]