Multidentate Schiff Base Ligand Research Articles

A stable hybrid catalyst (POM-PPPh3/L/Ni) for the reduction of toxic nitroarene compounds in water.

Reduction of nitroarenes to aminoarenes using novel and selective catalysts is an important and desirable approach in green chemistry. In this work, a new heterogeneous nanocatalyst, POM-PPPh3/L/Ni, was designed and prepared via functionalizing a Keggin-type polyoxometalate (H3PMo12O40) with (3-bromopropyl)triphenylphosphonium bromide (BPPPh3Br) through strong electrostatic interactions to prepare [PMo12O40][PPPh3]3 (denoted as POM-PPPh3). The obtained compound was modified via nucleophilic attack of the nitrogen donor of a multidentate Schiff base ligand (L) on its propyl chain to produce [PMo12O40][PPPh3/L]2 (denoted as POM-PPPh3/L), which was finally metallated with nickel cations to achieve [PMo12O40][PPPh3/L/Ni]2 (denoted as POM-PPPh3/L/Ni). After full characterization of the prepared material with various physicochemical methods, its catalytic behavior was investigated in the catalytic nitroarene reduction. The influence of various factors on catalytic conversion and selectivity was considered. The synthesized nanocatalyst showed excellent performance in the reduction of nitroarenes in aqueous media in the presence of NaBH4 as a reducing agent. Mild reaction conditions and a short reaction time (10 min) are the prominent features of this new nanocatalyst. In addition, the catalyst was recovered and reused for up to four cycles of catalytic reduction without any significant loss of conversion.

Construction of three novel Ln3 compounds using multidentate Schiff base ligand: Crystal structures, fluorescence properties, and biological activities

Three new trinuclear lantharide-based compounds: [Ln3(dbm)5(L)2(CH3OH)]·CH2Cl2 (LnIII = Nd(1), Sm(2), and Tb(3), dbm− = diphthaloylmethae) have been synthesized via the solvothermal method by using a polydentate Schiff base ligand (H2L = (E)-6-(hydroxymethyl)-N'-((6-methoxypyridin-2-yl)methylene)picolinohydrazide) reacting with Ln(dbm)3·2H2O. X-ray diffraction study reveals that all compounds 1–3 belong to monoclinic crystal system with space group C2/c, and compounds 1–3 are isostructural and possess a broken-line Ln3 core. The solid-state luminescence properties measurements indicate that compound 3 displays the characteristic lanthanide luminescence at room temperature. Moreover, photoluminescence properties study show that 1 and 2 display typical NIR luminescence of Nd(III) and Sm(III) ions at room temperature. Furthermore, biological activities research reveals that compounds 1–3 have greater antibacterial activity than the ligand H2L and Ln(dbm)3·2H2O (LnIII = Nd (1), Sm (2), and Tb (3)). The interaction between compounds 1–3 and calf thymus DNA was studied and the results revealed that the compounds were mainly intercalated with calf thymus DNA.

Two butterfly-shaped LnIII2 compounds constructed by a multidentate Schiff base ligand: Structures, fluorescence properties and SMMs behaviors

Two new butterfly-shaped Ln2 compounds, namely, [Ln2(dbm)2(L1)2(CH3O)2] ·6CH3OH (Ln(III) = Tb (1) and Dy (2), Hdbm = dibenzoylmethane, and HL = furan-2-carboxylic acid (2-hydroxy-3-methoxy-benzylidene)-hydrazide), have been successfully synthesized via using solvothermal method, and the structures and magnetic properties further have been studied. Compounds 1 and 2 display the characteristic lanthanum luminescence at room temperature. The magnetic studies reveal that 1 and 2 show single-molecule magnets (SMMs) behaviors under Hdc = 0 Oe (ΔE/kB = 0.63 K and τ0 = 2.69 × 10−5 s for 1; and ΔE/kB = 39.3 K and τ0 = 5.68 × 10−7 s for 2).

Binuclear Pd(II) complexes with multidentate Schiff base ligands: synthesis, catalysis, and antibacterial properties

Binuclear Pd(II) complexes with multidentate Schiff base ligands: synthesis, catalysis, and antibacterial properties

Design, one-pot synthesis, cytotoxic, in vivo anticancer, antioxidant and antimicrobial evaluation of a novel mixed schiff base ligand and its metal complexes

This contribution of work describes the synthesis of a novel mixed Schiff base ligand, 3-((2-((1-(2-hydroxyphenyl)ethylidene)amino)ethyl)imino)-N-(o-tolyl)butanamide derived from 1,2-ethylenediamine, o-hydroxyacetophenone and 2-methylacetoacetanilide and its some transition metal, Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) complexes. The multidentate Schiff base ligand was characterized analytically by elemental analysis and spectroscopically by HRMS, IR-, 1H NMR, 13C NMR- and UV-Vis spectral data in addition to the above, physico-chemical methods like elemental analysis, molar conductance, magnetic susceptibility measurement and various spectral techniques were employed for the characterization of the metal complexes. This study investigated that, the potential applications of metal complexes as cytotoxicity and, in vivo antitumor efficiency against Earlich Ascites Carcinoma cell induced ascites tumor and Dalton’s Lymphoma Ascites cell induced solid tumor in Swiss Albino female mice. Antioxidant radical scavenging activity of complexes have bee evaluated against DPPH, super oxide anion, nitric oxide and H2O2 radicals. Antimicrobial screening by MIC method also performed some selected microbes. The present study proposed that the ligand and its metal complexes behave as potential cytotoxic, anticancer, antioxidant and antibacterial and antifungal agents.

Dinuclear dysprosium(III) complex derived from a multidentate bis-hydrazone Schiff base ligand: Synthesis, crystal structure and magnetic properties

Starting from phloroglucinol, a multidentate Schiff base ligand, H3L [N, N'-((1E, 1′E)-(5-acetyl-2,4,6-trihydroxy-1,3-phenylene)bis(ethan-1-yl-1-ylidene)bis(2-hydroxy-2-phenylacetohydrazide)], decorated with multiple coordination sites has been designed. A dinuclear dysprosium complex, [{Dy(L)(H2O)2}2]·4CH3OH·3H2O (1), was synthesized by employing this ligand and characterized by elemental analysis, spectroscopic and structural investigations. Single crystal X-ray diffraction analysis reveals that 1 is a dinuclear Dy(III) complex with a large Dy…Dy distance. Magnetic investigation shows the absence of slow relaxation of the magnetization in 1 owing to the lack of an axial crystal-field.

Construction of an Octanuclear Zn(II)‐Yb(III) Schiff Base Complex for the NIR Luminescent Sensing of Nitrofuran Antibiotics

Main observation and conclusionOne near‐infrared (NIR) luminescent octanuclear Zn(II)‐Yb(III) complex [Zn6Yb2L4(OAc)2(DMF)EtOH] (1) was obtained from a new multidentate Schiff base ligand. It exhibits interesting luminescent sensing activity to antibiotics, in particular to nitrofuran antibiotics (NFAs) with high sensitivity due to the inner filter effect. The NIR luminescence quenching constants and limits of the detection of the complex towards NFAs are 2.9 × 104—5.5 × 104 L/mol and 1.27—2.38 μmol/L, respectively. Its high luminescence sensitivity to NFAs is not changed with the existence of other antibiotics.

The Reactivity of Multidentate Schiff Base Ligands Derived from Bi‐ and Terphenyl Polyamines towards M(II) (M=Ni, Cu, Zn, Cd) and M(III) (M=Co, Y, Lu)

AbstractMultidentate Schiff base ligands derived from a selection of biphenyl‐ and terphenyl polyamines were synthesized, and their reactivity towards divalent (Ni, Cu, Zn, Cd) and trivalent (Co, Y, Lu) metals was studied by single‐crystal X‐ray diffraction analysis, NMR spectroscopy, and UV/Vis spectroscopy for the Cu(II) complexes. Large variations in the resulting complexes were observed based on the relative position of the amine substituents in the parent triamines, as well as the electronic properties of the Schiff base ligand itself. Most notably, Schiff base ligands derived from a m‐terphenyl‐2,2’,2’’‐triamine were found to coordinate in a tetradentate, pentadentate or hexadentate fashion, depending on the size and the valency of the corresponding metal center.

Synthesis and DFT Study of the Complexation of Schiff Base Derived Curcumin and L-Tyrosine with Al(III), Ag(I), and Pb(II) Metal Ions

The multi-dentate Schiff base ligand (H2L), where H2L=2,2'-(((1,3,5,6)-1-(3-((l1-oxidaneyl)-l5-methyl)-4-hydroxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-diylidene)bis(azaneylylidene))bis(3-(4-hydroxyphenyl)propanoic acid), has been prepared from curcumin and L- Tyrosine amino acid. The synthesized Schiff base ligand (H2L) and the second ligand 1,10-phenanthroline (phen) are used to prepare the new complexes [Al(L)(phen)]Cl, K[Ag(L)(phen)] and [Pb(L)(phen)]. The synthesized compounds are characterized by magnetic susceptibility measurements, micro elemental analysis (C.H.N), mass spectrometry, molar conductance, FT-infrared, UV-visible, atomic absorption (AA), 13C-NMR, and 1H-NMR spectral studies. The characterization of the synthesized complexes shows that the environment surrounding the central metal ion in the complexes adopted a distorted octahedral configuration. Moreover, the conductivity measurements show a non-electrolytic character for the [Pb(L)(phen)] complex and an electrolytic character for the [Al(L)(phen)]Cl and K[Ag(L)(phen)] complexes. The experimental infrared data are supported by density functional theory (DFT) calculations using the B3LYP level of theory and LANL2DZ basis set. The vibrational frequencies of the molecules are computed using the optimized geometry obtained from the DFT calculations. The calculated vibrational frequencies have been compared with obtained experimental values. 1H and 13C-NMR chemical shifts were computed for the H2L ligand using the DFT/GIAO method. Additionally, the molecular electronic structures of the complexes have been investigated by DFT calculations.

Transition metal complexes of a multidentate Schiff base ligand containing pyridine: synthesis, characterization, enzyme inhibitions, antioxidant properties, and molecular docking studies.

A series of Fe(II), Ni(II), and Pd(II) complexes were prepared with a novel Schiff base ligand containing pyridine moiety. The prepared compounds were characterized using FT-IR, 1H and 13C NMR, UV-Vis, powder XRD, thermogravimetric analysis, mass spectra, magnetic susceptibility, and elemental analysis. The coordination geometry of Fe(II) and Ni(II) complexes were octahedral, where Fe(II) and Ni(II) metal ions were coordinated by an oxygen atom of the carbonyl group, a nitrogen atom of the azomethine moiety, and a phenolic oxygen atom. The Pd(II) complex had square planar geometry. All of the synthesized compounds were tested for their biochemical properties, including enzyme inhibition and antioxidant activities. According to the in vitro DPPH and FRAP antioxidant methods, the Schiff base ligand and its Fe(II)/Pd(II) complexes showed close antioxidant activities against the standards (BHA, BHT, ascorbic acid, and α-tocopherol). Enzyme inhibitions of the metal complexes were investigated against glutathione S-transferase (GST), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzymes. The best inhibition value (Ki) was observed for the Ni(II) complex against GST (2.63 ± 0.04µM). Also, the Pd(II) complex showed the best inhibition value (10.17 ± 1.88µM) against AChE. Molecular docking specified significant interactions at the active pockets of respective target enzymes. The Ni(II) complex exhibited good binding affinity against both BChE (- 9.0kcal/mol and 9.36 ± 2.03µM) and GST (- 7.0kcal/mol and 2.63 ± 0.04µM) enzymes.

In Situ Ligand Formation in the Synthetic Processes from Mononuclear Dy(III) Compounds to Binuclear Dy(III) Compounds: Synthesis, Structure, Magnetic Behavior, and Theoretical Analysis.

Guided by the self-assembled process and mechanism, the strategy of in situ Schiff base reaction would be capable of bringing a feasible method to construct and synthesize lanthanide compounds with distinct structures and magnetic properties. A mononuclear Dy(III) compound was synthesized through a multidentate Schiff base ligand and a chelating β-diketonate ligand, which was named as [Dy(L)(bppd)]·CH3OH [1; H2L = N,N'-bis(2-hydroxy-5-methyl-3-formylbenzyl)-N,N'-bis(pyridin-2-ylmethyl)ethylenediamine and bppd = 3-bis(pyridin-2-yl)propane-1,3-dione]. Furthermore, a new binuclear Dy(III) compound, [Dy2(H2Lox)(bppd)3]·8CH3OH [2; H4Lox = N,N'-bis[2-hydroxy-5-methyl-3-(hydroxyiminomethyl)benzyl]-N,N'-bis(pyridin-2-ylmethyl)ethylenediamine], was obtained via an in situ synthetic process. Under similar synthetic conditions, [Dy(L)(ctbd)] [3; ctbd = 1-(4-chlorophenyl)-4,4,4-trifluoro-1,3-butanedione] and [Dy2(H2Lox)(ctbd)3]·CH3OH·C4H10O (4) were synthesized by modifying the β-diketonate ligand and in situ Schiff base reaction. Compound 3 is a mononuclear configuration, while compound 4 exhibits a binuclear Dy(III) unit. Therein, formylbenzyl groups of H2L in 1 and 3 were changed to (hydroxyiminomethyl)benzyl groups in 2 and 4, respectively. In isomorphous 2 and 4, two Dy(III) centers are connected through two phenol O- atoms of the H2Lox2- ligand to form a binuclear structure. Eight-coordinated Dy(III) ions with different distortions can be observed in 1-4. The crystals of 1 and 3 suffered dissolution/precipitation to obtain 2 and 4, respectively. The relationship between the structure and magnetism in compounds 1-4 was discussed through the combination of structural, experimental, and theoretical investigations. Especially, the rates of quantum tunneling of magnetization of 1-4 were theoretically predicted and are consistent with the experimental results. For 2 and 4, the theoretically calculated dipolar parameters Jdip are consistent with the experimental observation of weak ferromagnetic coupling.

Characteristics of multidentate schiff base ligand and its complexes using cyclic voltammetry, fluorescence, antimicrobial behavior and DFT-calculations

The electrochemical behavior of a series of the metal complexes [Fe(III), Ni(II), Ru(III),Pd(II) and Hf(IV)]derived from the Schiff base ligand(E)-5-((phenyl(-pyridin-2-yl) methylene) amino) pyrimidine-2,4(1H, 3H)‑dione(H2L) which was previously prepared from condensation of 5-aminouracil and 2-benzoylpyridine was studied by using cyclic voltammetric technique. The Schiff base ligand H2L and its metal complexes exhibited quasi- reversible oxidation- reduction with three electron transfer and it was suggested that their reactions on the platinum surface electrode are not purely diffusion controlled but also under adsorption control. The redox reactive sites of the H2L and its complexes were located via the geometry optimization and frequency calculations using density functional theory (DFT) at the B3LYP/LanL2DZ level of theory. In addition, the Schiff base ligand and its metal complexes exhibit fluorescent properties. The antimicrobial activity of the Schiff base ligand H2L and its metal complexes was tested against Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus(, Gram-negative bacteria (E. coli and Pseudomonas aeruginosa) and fungal strain (Aspergillus niger) by using agar well-diffusion method. The microbial testes of the ligand (H2L) and its metal complexes exhibited good inhibition efficiency to prevent growth of bacteria.

A new polymeric thin film by using electropolymerization: thin film of poly(phenazine-salen) obtained from 2,2'-[1,2-ethanediylbis(nitrilomethylidyne)] -bis[4-amino-phenol

Abstract In the last years, the study of the formation of a polymer containing multidentate Schiff-base ligand as subunits has been performed. In general, the electropolymerization occurs through the interaction between the phenyl rings and metallic centers. However, in this paper, we proposed a new polymeric thin film formation from 2,2'-[1,2-ethanediylbis(nitrilomethylidyne)]bis[4-amino-phenol] obtained by electropolymerization. The electropolymerization mechanism for poly(phenazine-salen) formation was based on the carbon-nitrogen coupling. The effect of experimental parameters such as scan rate, applied potential range, supporting electrolyte, and solvent type on the electropolymerization process was also evaluated. The poly(phenazine-salen) film was characterized by cyclic voltammetry and electrochemical impedance spectroscopy in an inert supporting electrolyte showing a redox couple ascribed to pyrazine moieties. The Mott-Schottky plot of the electropolymerized material indicated that the polymer is an n-type semiconductor. The results indicate a polymeric formation controlled by the electropolymerization parameters and the electrochemical behavior tuned by the ions insertion/extraction from supporting electrolyte.

Hg(II) coordination compounds containing tridentate NNO Schiff-base ligand: synthesis, characterization, and crystal structure analysis

Hg(II) coordination complexes containing the tridentate N-(2-methoxyphenyl)-1-(pyridin-2-yl)methanimine ligand were synthesized by using template synthesis approach and characterized using spectroscopic techniques and single crystal X-ray crystallography. The molecular structure and supramolecular features of these compounds were investigated using geometrical, Hirshfeld surface analyses, and theoretical calculations. The supramolecular architecture of these coordination complexes is governed by a combination of π–π, C–H⋯π, and C–H⋯X–M hydrogen bonding interactions. This study may provide further insight into the understanding of the coordination chemistry of Hg(II) containing multidentate Schiff-base ligand and the role of weak non-covalent interactions in the solid-state structure of coordination compounds.

Construction of a family of Ln3 clusters using multidentate Schiff base and β-diketonate ligands: fluorescence properties, magnetocaloric effect and slow magnetic relaxation

Seven μ-Oacylhydrazone-bridged Ln3 clusters were synthesized. Cluster 3 displayed magnetic refrigeration properties, whereas cluster 5 showed slow magnetic relaxation. The solid-state fluorescence properties of 2, 4 and 5 were also studied.

Transition metal complexes of a multidentate Schiff base ligand containing guanidine moiety: Synthesis, characterization, anti-cancer effect, and anti-microbial activity

Abstract Guanidine Schiff bases are famous for their distinctive features and medicinal benefits with potential applications for the control of bacterial infections and cancer development. The current study was performed with a prospect to the dinuclear series of Cu(II), Ni(II), Co(II), Mn(II), Fe(III), Cr(III), Bi(III), and Zn(II) complexes of new guanidine Schiff base ligand. These complexes have been arranged and examined by 1H NMR, mass spectra, IR, UV–Vis, ESR spectra, magnetic moments, and conductance measurements, as well as, elemental and thermal analyses (DTA and TGA). The cytotoxicity, the anti-cancer effect, and the anti-microbial activity of these complexes were assessed. The IR spectral data showed that the Schiff base behaved as a neutral bidentate or monobasic bidentate ligand bonded to the metal particles through the azomethine nitrogen atom and the hydroxyl oxygen atom in protonated or deprotonated form embracing tetragonally distorted octahedral geometries. The new complexes were non-hygroscopic dissolvable in DMSO but insoluble in common natural solvents. A molar conductance, in DMF arrangement, demonstrated that the complexes were non-electrolytes. There was a variation in the cytotoxic activity of the complexes on murine spleen cells. Also, cytotoxic and apoptotic effects, indicative of the anti-cancer activity, of the twelve complexes, were noticed against the human hepatoma (HepG2) cell line. Additionally, the newly synthesized complexes showed enhanced anti-tumor and anti-microbial effects in comparison to the parent ligand and to the standard drug.

Heterometallic Zn(II)-K(I) complex with salen-type Schiff-base ligand: Synthesis, crystal structure, solid-state photoluminescent property and theoretical study

A novel tetranuclear heterometallic complex, [KZn(3-MeOsalpn) (μ1,1-NCS)]2(1) [3-MeOsalpn2- = N, N′-propylene bis(3-methoxysalicylideneiminate)] has been synthesized by the reaction of Zn(OAc)2・2H2O with the multidentate Schiff-base ligand, N, N’-bis(2-hydroxy-3-methoxybenzylidene)-propane-1,2-diamine (H2LOMe) in the presence of KSCN. 1 is characterized by elemental analysis, powder X-ray diffraction and different spectroscopic techniques along with single crystal X-ray crystallography. Crystal structure of 1 completely divulges a very intricate heterometallic environment of Zn(II) which is a centrosymmetric penta-coordinated distorted square pyramidal molecule possessing a basic tetranuclear structural core [KZn(OAr)2(μ1,1-NCS)]2 that consisting mainly two Zn atoms and two K atoms bridged by four μ2-OAr- (O1, O1*, O2 and O2*), and two [μ1,1-NCS]- groups. In the asymmetric unit of the binding action μ2-OAr- from one fully deprotonated [LOMe]2- enable to construct the four membered heterometallic ZnK(O)2 core. Complex 1 structure was optimized with the aid of density functional theory at B3LYP level hybrid functional and GAUSSIAN 16 programming package in presence of 6–31 + g(d, p) basis set. ESP study of Schiff base ligand further supported that polymerization is more favorable with potential border line Zn(II) metal ion. Hirshfeld surface and 2D fingerprint plots have been explored in 1 to find out different types of non-covalent supramolecular interactions. The solution and solid-state luminescent property of the title complex 1 was reported. Fluorescence life time study further indicates that excited state stabilities of 1 are smaller than Schiff base ligand. Finally, experimental UV–Vis electronic transitions of 1 were compared with those obtained theoretically from TD-DFT level of calculations.

Co-existence of ferro- and antiferromagnetic interactions in a hexanuclear mixed-valence CoMnMn cluster sustained by a multidentate Schiff base ligand.

The successful utilization of the "direct synthesis" approach yielded the unprecedented hexanuclear complex of formula [Co2MnMn(L1)4Cl2(μ3-O)2(dmf)4]·2dmf (1) (H3L is the Schiff base derived from the condensation of salicylaldehyde and 3-aminopropane-1,2-diol). Single crystal X-ray analysis revealed that 1 crystallizes in the monoclinic system P21/c and it contains a rare mixed-valence {CoMnMn(μ2-O)8(μ3-O)2} core where all metal ions are linked through the phenolato and alkoxo groups of the L3- ligand. Besides the charge balance resulting from the X-ray structure, the oxidation state of the metal ions has been confirmed by XPS spectroscopy. Cryomagnetic studies indicate the coexistence of ferro- (MnIV-MnII, J2 = +1.10(3) cm-1, J3 = +2.19(3) cm-1; MnII-MnII, j = +0.283(3) cm-1) and antiferromagnetic interactions (MnIV-MnIV, J1 = -17.31(4) cm-1), with the six-coordinate CoIII ions being diamagnetic. DFT type calculations were carried out to substantiate these values. The energy diagram for the different spin states using the best-fit parameters shows the occurrence of six low-lying spin states (S = 0-5) which are close in energy but clearly separated from the remaining ones, with the ground spin state being S = 5. Complex 1 is found to be the first example where weak ferromagnetic exchange between MnII ions through the long -O-MnIV-O- pathway takes place.

Homodinuclear {LnIII2} (LnIII = GdIII, TbIII, HoIII, and DyIII) Complexes: Field‐Induced SMM Behavior of the DyIII and TbIII Analogues

A family of four dinuclear complexes, [NHEt3]2[Ln2(µ‐NO3)2(NO3)2(HL)2] [Ln = GdIII (1), TbIII (2), HoIII (3), DyIII (4)], were synthesized by the reaction of an enolizable multidentate Schiff base ligand H3L (H3L = N′‐(2‐hydroxy‐3‐methoxy‐5‐nitrobenzylidene)‐2‐(hydroxyimino)propanehydrazide) with hydrated lanthanide nitrates in the presence of NEt3. The molecular structure of complexes 1–4 was confirmed by single‐crystal XRD analysis. All of the centrosymmetric complexes are dianionic, isostructural and each of the LnIII centers is nine‐coordinate and adopts a muffin like coordination geometry as indicated by SHAPE analysis. The dynamic magnetization studies revealed that the compounds 2 and 4 are field‐induced single‐molecule magnets with effective energy barriers,Ueff = 34(2) K (for 2) and 80(3) K (for 4) and pre‐exponential factors, τo = 1.1 × 10–8 s (for 2) and 1.15 × 10–7 s (for 4).

Exploitation of the Flexidentate Nature of a Ligand To Synthesize Zn(II) Complexes of Diverse Nuclearity and Their Use in Solid-State Naked Eye Detection and Aqueous Phase Sensing of 2,4,6-Trinitrophenol.

Three Zn(II) complexes, [Zn2(HL)2(NO3)2]·H2O (1), [(Zn4L2)(μ3-OH)2](NO3)2·0.5H2O (2), and [(Zn6L2)( o-van)2(μ3-OCH3)2(μ3-OH)2](NO3)2 (3), have been synthesized by exploiting the flexidentate nature of a multidentate Schiff base ligand, H2L ( N, N'-bis(3-methoxysalicylidene)diethylenetriamine), by changing the reaction conditions and stoichiometry of the reactants. All three complexes are highly fluorescent in solution as well as in solid and have been used as luminescence sensors toward nitrophenol explosives in both the media. In aqueous/methanol medium, these complexes show very high selectivity and sensitivity with detection limit in ppb (2.03) or nM level (8.89 nM) for picric acid. The yellow color of all three Zn(II) complexes changes to red on mixing with small amount (∼5%) of picric acid in solid state, revealing the potential of these complexes for practical use in naked eye detection of 2,4,6-trinitrophenol (TNP) or picric acid in ambient light. In order to identify the host-guest interactions between Zn(II) complex and TNP, single crystals of the adduct of TNP with Zn(II) complex, [Zn2(HL)2(H2O)2][C6H2N3O7]2 (4), were grown. Its X-ray crystal structure reveals that two picrate ions are attached to a dinuclear host with the help of H-bonding and π···π interactions, throwing light into the quenching mechanism and selectivity of detection.