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Levodopa, a widely prescribed drug in Parkinson's disease treatment, stands as the foremost prodrug of dopamine. An affordable self‐testing kit is utilized to monitor levodopa content in anti‐parkinson drugs in human serum. A photoluminescent trinuclear Zn(II) complex [Zn3(L)2(κ1‐OAc)2(κ2‐OAc)2] has been synthesized, which cleaves into mononuclear ZC in aqueous solution. ZC was found to detect L‐Dopa in Tris‐HCl buffer, exhibiting a moderate decrease in PL‐emission. The real‐life utility of the ZC probe is limited, for its lower sensitivity (LOD 35.3 μM) and separation challenges. Therefore, an interface between homogeneous and heterogeneous supports has been explored, leading to the strategic development of NGOZC, where ZC was grafted onto NGOQD (Graphene oxide quantum dots). This material enables naked‐ eye detection under both ambient and UV light with color change from bright cyan to green, followed by dark. The nitrogen doping effect was investigated by several comparative investigations involving the synthesis of ZC‐grafted GOQD, leading to enhanced quenching performance. Steady‐state and time‐resolved fluorescence titration study, morphological analysis, and computational calculations have been performed to get insights into the sensing mechanism. To the best of our knowledge, this as‐synthesized NGOZC (LOD 1.78 nM) represents a promising strategy and platform for applications in biosensors, especially for Parkinson's and Alzheimer's diseases. [ABSTRACT FROM AUTHOR]

In this study, three different solvent systems have been employed to investigate the effect of reaction parameters on the synthesis of four alkaline earth metal-based MOFs namely [Ca(0.5 1,4-phenyl diacetic acid)2(H2O)DMF]∞ (Ca-MOF-1), [Ca(1,4-naphthalene dicarboxylate)DMF]∞ (Ca-MOF-2), [Ca2(0.5 1,2,4,5-benzene tetracarboxylate)2(H2O)3DMF]∞ (Ca-MOF-3) and [Ca2(2,6-naphthalene dicarboxylate)2(H2O)6]∞ (Ca-MOF-4). The crystal structures of these four MOFs have been resolved through single crystal X-ray analysis and the bulk phase purity of these MOFs was assessed using PXRD and FT-IR analysis. To check the stability of these MOFs, thermogravimetric analysis (TGA) was carried out. To analyze the robustness of these MOFs, the PXRD of the samples was also collected at different pH levels. These MOFs were further explored as Lewis acid catalysts for the alcoholysis of epoxides and the activity of these catalysts depend on the open metal sites present in the MOFs. The catalytic activity follows the order: Ca-MOF-2 > Ca-MOF-4 > Ca-MOF-1 > Ca-MOF-3. The activity was also checked with various epoxide substrates using Ca-MOF-2. Density functional theory (DFT) calculations also support this trend with the help of the thermodynamic feasibility of epoxide binding, considering model MOF structures. The weak interaction between the epoxide oxygen and the metal centre of the most stable MOF structure has also been clarified by computational studies. [ABSTRACT FROM AUTHOR]

Herein, we present a dark-green crystalline tetranuclear Cu(II) Schiff base complex {C1 = [Cu4L4](ClO4)4(DMF)4(H2O)} using a N,N,O donor ligand (HL), namely 2-(((2-hydroxypropyl)imino)methyl)-6-methoxyphenol. Spectro-photometrical investigation on the β-lactamase-like activity of this coordinately saturated system revealed its catalytic inefficiency towards hydrolysis of nitrocefin as a model substrate. This complex has attracted significant interest as a promising photo-catalyst owing to its narrow band gap (2.40 eV) as predicted from DFT calculations and its higher responsivity towards UV light. Therefore, C1 is effectively involved in the photocatalytic reduction of perchlorate to Cl− in the presence of a hole scavenger (H2O–MeOH) under prolonged UV irradiation and itself becomes photo-cleaved to yield a new dark-brown colored chlorobridged dinuclear crystalline complex C2 {[CuL(H2O)2Cl3]H2O}. Furthermore, C2 was deployed as a functional β-lactamase model and was found to show a remarkable catalytic proficiency towards the hydrolysis of nitrocefin in 70 : 30 (V/V) MeOH–H2O medium. This pro-catalyst C2 has been speculated to generate an aqua bridged active catalyst that plays a crucial factor in hydrolysis. This phenomenon was again experimentally established by potentiometric pH titration where C2 displays only one pKa value (7.11) in the basic pH range, indicating the deprotonation of the bridged water molecule. Based on several other kinetic studies, it may be postulated that the hydrolysis of nitrocefin is initiated by the nucleophilic attack of a bridging hydroxide, followed by very fast protonation of the intermediate to furnish the hydrolyzed product. It is noteworthy that the rate of nitrocefin hydrolysis is greatly inhibited in the presence of external chloride concentration. To the best of our knowledge, this is the first report on the photochemical behavior of such a tetranuclear copper(II) Schiff base complex. Our current interest is focused on inventing a potent β-lactamase inhibitory therapeutic as well as elucidating its mechanism through comprehensive chemical analysis. [ABSTRACT FROM AUTHOR]

Bimetallic sandwich complexes based on the borazocine (B4N4H8) ligand have been studied using density functional theory (DFT). The studied Ca–Ca covalent bond length agrees well with the experimental Ca2 bond length. For the studied complexes, the non-nuclear attractor (NNA) is found at the Ca–Ca bond of K2(B4N4H8)2Ca2 and Na2(B4N4H8)2Ca2. The negative Laplacian at the NNA is noticed for these two complexes, indicating that these complexes are electrides. This study for the first time reports the electride complexes based on the B4N4H8 ligand. Interestingly, upon asymmetric doping with Na and K, no NNA point is found for the complex NaK(B4N4H8)2Ca2, indicating that this complex is not an electride. Our study points out one of the fascinating outcomes that asymmetric doping can affect the occurrence of the NNA in a system. The complex Na2(B4N4H8)2Ca2 exhibits the highest second hyperpolarizability value of 2.2 × 106 au at the ωB97XD/6-311++G(3df,3pd) level among the studied sandwich complexes. [ABSTRACT FROM AUTHOR]

Context: Phytic acid is the major storage form of phosphorus in cereals and is considered an anti-nutritional factor because it chelates major mineral micronutrient cations, resulting in micronutrient malnutrition in humans. For monogastric animals fed maize (Zea mays L.) grains, the stored phosphorus does not release into the digestive tract, leading to phosphorus deficiency and environmental pollution. Aims: The aim of the study was to develop maize lines with a lower level of phytic acid that might substantially enhance the nutritional value of maize. Methods: The lpa1 mutant allele conferring low phytic acid was transferred into the parental lines of popular maize hybrid DMH 121 (i.e. BML 6 and BML 45) through marker-assisted backcross breeding. Foreground selection was performed using a co-dominant single nucleotide polymorphism marker through a high-resolution melting approach, and background selection was undertaken using 50–55 polymorphic sequence-tagged microsatellite site markers. Key results: Near-isogeneic lines were produced with >90% recurrent parental genome and reduction of phytic acid content by up to 44–56% compared with the original lines. Conclusions: The near-isogeneic lines carrying lpa1 can be used to reconstitute DHM 121 with low phytate content. Implications: The low-phytate maize hybrids produced can be useful in reducing micronutrient malnutrition in humans, as well as environmental pollution. Phytic acid is an anti-nutritional factor that chelates major mineral micronutrient cations, resulting in micronutrient malnutrition in humans. In this study, the lpa1 mutant allele was transferred into the parental lines of DMH 121 (i.e BML 6, and BML 45) through marker-assisted backcross breeding. Near-isogeneic lines were produced with 44–56% reduction of phytic acid content relative to the original lines. [ABSTRACT FROM AUTHOR]