A Zinc-Sensing Glucose-Based Naphthyl Imino Conjugate as a Detecting Agent for Inorganic and Organic Phosphates, Including DNA

Synthesis of Fluorescent Pyrazoline Sensors as Versatile Tool for Zinc ion Detection: A Mini-Review

Zinc ions are one of the 2nd most abundant mineral after iron and it is important for immune system, enzymatic catalysis, DNA synthesis, and maintaining structural integrity in humans. But, monitoring the Zn levels in human body poses more challenges. This review paper investigates (paper from 2010 to 2023) the synthesis of pyrazoline derivatives by different methods, including conventional methods and green chemistry protocol. These Pyrazoline derivatives highlighted for their potential application as chemo-sensor for Zn2+ ions recognition. Pyrazoline compounds exhibit excellent sensitivity & selectivity and emitting blue-light with high quantum yields and electroluminescence, along with a superior limit of detection. These derivatives are stable bioactive molecule, with well-known diverse biological activities. This review not only gives valuable insights into the essential role of Zinc in human physiology but also provides a practical method for accurate Zinc detection in various samples. Which holds the potential for advancements in health diagnostics and environmental monitoring. Because of their significant biological application and selectivity as sensors, researchers have much more attention to prepare green environmentally-friendly pyrazoline derivatives.

Saccharified Uranyl Ions: Self-Assembly of UO2 2+ into Trinuclear Anionic Complexes by the Coordination of Glucosamine-Derived Schiff Bases

The reaction of UO2 (OAc)2  ⋅ 2H2 O with the biologically inspired ligand 2-salicylidene glucosamine (H2 L1 ) results in the formation of the anionic trinuclear uranyl complex [(UO2 )3 (μ3 -O)(L1 )3 ]2- (12- ), which was isolated in good yield as its Cs-salt, [Cs]2 1. Recrystallization of [Cs]2 1 in the presence of 18-crown-6 led to formation of a neutral ion pair of type [M(18-crown-6)]2 1, which was also obtained for the alkali metal ions Rb+ and K+ (M=Cs, Rb, K). The related ligand, 2-(2-hydroxy-1-naphthylidene) glucosamine (H2 L2 ) in a similar procedure with Cs+ gave the corresponding complex [Cs(18-crown-6)]2 [(UO2 )3 (μ3 -O)(L2 )3 ([Cs(18-crown-6)]2 2). From X-ray investigations, the [(UO2 )3 O(Ln )3 ]2- anion (n=1, 2) in each complex is a discrete trinuclear uranyl species that coordinates to the alkali metal ion via three uranyl oxygen atoms. The coordination behavior of H2 L1 and H2 L2 towards UO2 2+ was investigated by NMR, UV/Vis spectroscopy and mass spectrometry, revealing the in situ formation of the 12- and 22- dianions in solution.

Triazole-Linked Quinoline Conjugate of Glucopyranose: Selectivity Comparison among Zn2+, Cd2+, and Hg2+ Based on Spectroscopy, Thermodynamics, and Microscopy, and Reversible Sensing of Zn2+ and the Structure of the Complex Using DFT

A water-soluble triazole-linked quinoline conjugate of glucopyranose (L) has been synthesized and characterized, and its single-crystal X-ray diffraction (XRD) structure has been established. Binding of L toward different biologically relevant metal ions has been studied using fluorescence and absorption spectroscopy in HEPES buffer at pH 7.4. The conjugate L detects Zn2+ and Cd2+ with 30 ± 2 and 14 ± 1-fold fluorescence enhancement, respectively, but in the case of Hg2+, only a fluorescence quench was observed. The stoichiometry of the complex is 1:2 metal ion to the ligand in the case of Zn2+ and Cd2+ resulting in [Zn(L)2] and [Cd(L)2], and it is 1:1 in the case of Hg2+, as confirmed from their electrospray ionization mass spectrometry (ESIMS) spectra. Zn2+ shows greater exothermicity over Cd2+, whereas Hg2+ shows endothermicity , which supports the differences in their binding strength and the nature of the corresponding complex. L exhibits rod-shaped particles and upon complexation with Zn2+, it exhibits sphere-like morphological features in scanning electron microscopy (SEM) images. However, clustered aggregates are observed in Cd2+, whereas the [HgL] complex exhibits small fused spherical structures, and therefore the signature of these ions is seen in microscopy images. The computational studies revealed that the syn-[Zn(L)2] complex is stabilized by 9.7 kcal mol-1 more than that in the case of anti-[Zn(L)2] owing to the formation of hydrogen bonds between the two glucosyl moieties within the syn-complex. Among the anions studied, [Zn(L)2] is sensitive and selective toward the phosphate ion (H2PO4 -) with a minimum detection limit of 16 ± 2 ppb. Similarly, the [HgL] can act as a secondary sensor for CN- while also exhibiting reversibility. Based on the input-output characteristics, INHIBIT logic gate was built in the case of Zn2+ vs H2PO4 - and IMPLICATION logic gate was built in the case of Hg2+ vs CN-.

Analysis of organophosphate-Zn metalloporphyrin interactions via UV-vis spectroscopy and molecular modeling

UV-vis absorption spectra of zinc tetraphenylporphine (ZnTPP) on interaction with six organophosphorus (OP) compounds in cyclohexane were compared using ab initio methods and the molecular and solvation ligand descriptors π(*), Vx, and σ. OPs with polarizable hydrocarbon substituents in the homologous series tri-ethyl, -pentyl, -octyl, and -phenyl phosphates and the toxicologically relevant methyl paraoxon (1a-e) each gave a red shift in the Soret band (λsor) of ZnTPP in the range of 8-10 nm. Sensitivity as ΔAsor-b/Δug OP for the spectral band of the ligand bound ZnTPP (λsor-b) decreased with increasing extent of alkyl and aromatic substitution. Calculated and combined energies for OP and ZnTPP examined as a function of distance (Å) between ligand and porphyrin center suggest increased steric crowding with increasing Vx, and aromatic content of the OP. Spectrally fitted K1:1 and ΔAsor-b/ug OP each vary exponentially with Vx/σ. Lack of a red shift in λsor-b where ZnTPP was titrated with the toxic diethyl chlorophosphate (1g) is consistent with a model in which the magnitude of ΔEsor is proportional to the donor capacity of the phosphoryl-O ligand.

Dithieno[3,2-a:2′,3′-c]phenazine-based chemical probe for anions: a spectroscopic study of binding

The synthesis and binding studies of N,N′-(2,5-bis(4-(tert-butyl)phenyl)dithieno[3,2-a:2′,3′-c]phenazine-9,10-diyl)bis(4-methylbenzenesulfonamide) (1) are reported.

A highly selective turn-on ATP fluorescence sensor based on unmodified cysteamine capped CdS quantum dots

Unmodified cysteamine capped nanocrystalline cadmium sulfide quantum dots (Cys-CdS QDs) were demonstrated as a selective turn-on fluorescence sensor for sensing adenosine-5'-triphosphate (ATP) in aqueous solution for the first time. The fluorescence intensity of the Cys-CdS QDs was significantly enhanced in the presence of ATP. In addition, the fluorescence intensity of the Cys-CdS QDs increased when increasing ATP concentrations. On the other hand, other phosphate metabolites and other tested common anions did not significantly alter the fluorescence intensity of the Cys-CdS QDs. In addition, this sensor showed excellent discrimination of pyrophosphate (PPi) from ATP detection. The proposed sensor could efficiently be used for ATP sensing at very low concentration with LOD of 17 μM with the linear working concentration range of 20-80 μM. The feasibility of the proposed sensor for determining ATP in urine samples was also studied, and satisfactory results were obtained.

Chromogenic and fluorogenic chemosensors and reagents for anions. A comprehensive review of the years 2010-2011

This review focuses on examples reported in the years 2010-2011 dealing with the design of chromogenic and fluorogenic chemosensors or reagents for anions.

Synthesis of glucopyranosyl Schiff base zinc(II) complexes capable of interacting with mononucleotides, and their DNA-cleavage activities

New glucopyranosyl Schiff base zinc complexes, [Zn(GlcSal)(2) ] (1; GlcSalH=N-(2-deoxy-β-D-glucopyranos-2-yl-salicylaldimine) and [Zn(AcOGlcSal)(2) ] (2; AcOGlcSalH=N-(2-deoxy-β-D-1,3,4,6-tetraacetylglucopyranos-2-yl-salicylaldimine) were synthesized, and characterized by spectral and analytical methods. The interaction between the Zn complexes and mononucleotides was investigated by (1)H-NMR, (31)P-NMR and UV/VIS spectroscopies. Mononucleotides, cytidine 5'-monophosphate (CMP) and uridyl 5'-monophosphate (UMP), interacted with these complexes to form a 1:1 complex with 1 and a 1:2 complex with 2, depending on the presence of the OH group of glucopyranosyl substituents. The DNA-cleavage activities of 1 and 2 were studied using plasmid DNA (pBR322) in a medium of 5 mM Tris·HCl/50 mM NaCl buffer in the presence of H(2)O(2). The DNA-cleavage activity decreased in the order of 2>1>Zn(OAc)(2), indicating the significant promoting effect of the glucopyranosyl Schiff base ligand and the participation of the glucopyranosyl OH groups in the cleavage mechanism. The mechanism of the DNA cleavage by 1 and 2 was investigated by evaluation of the effect of a HO· radical scavenger and a singlet-oxygen ((1)O(2)) quencher under aerobic conditions. The former exhibited little effect, excluding the HO· radical as an active species and supporting the hydrolysis mechanism for the main process of the DNA cleavage. The latter quencher somewhat hindered the cleavage, indicating the partial participation of a (1)O(2) as a competitive active species in the present system.