Its Zinc Research Articles

Synthesis, characterization, photophysical and photochemical properties of peripherally tetra benzodioxane substituted metal-free phthalocyanine and its zinc(II) and magnesium(II) derivatives

The phthalonitrile (3) including 2-(methoxymethyl)-2,3-dihydro-1,4-benzodioxane substituent and peripherally tetra substituted metal-free (4), zinc(II) (5) and magnesium(II) (6) phthalocyanines were synthesized. The photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen generation and photodegradation) properties of phthalocyanines (4-6) were examined in DMSO solutions. The zinc(II) phthalocyanine (5) showed higher singlet oxygen quantum yield (ΦΔ=0.82) compared to metal-free (4) (ΦΔ=0.13) and magnesium(II) (5) (ΦΔ=0.29) phthalocyanine. Also, the fluorescence quenching behaviors of phthalocyanines (4-6) by 1,4-benzoquinone (BQ) were investigated.

Electrochemical and spectroelectrochemical characterizations of new tetra-substituted metallophthalocyanines bearing 4-(trifluoromethoxy)phenoxy groups on non-peripheral positions

In this study, a series of non-peripherally tetra-substituted phthalocyanines [M = Zn(II), Co(II), and In(III)] was successfully prepared by cyclotetramerization of the phthalonitrile derivative bearing 4-(trifluoromethoxy)phenoxy group at 3-position. All newly synthesized compounds were characterized using spectroscopic methods, such as FT-IR, NMR, and UV–Vis spectroscopy. The effect of concentration on aggregation properties of the resulting phthalocyanines was investigated in different concentrations ranging from 4 × 10−6 to 14 × 10−6 M in THF. In addition, the spectral properties of the metallophthalocyanines were studied in various organic solvents. Besides, redox responses of metallophthalocyanines and their electro-optical responses were determined. Although {1(4),8(11),15(18),22(25)-tetrakis[4-(trifluoromethoxy)phenoxy]phthalocyaninato}cobalt(II) showed well-resolved reversible redox peaks depicting the anticipated electron transfer reactions, electrochemical investigation of its zinc(II) and indium(III) chloride analogs resulted in complex redox waves, and their chemical reversibility decreased with the aggregation of the complexes. The influence of the redox processes on the optical responses of metallophthalocyanines was studied with in situ spectroelectrochemistry measurements and the peak assignments and optical responses of the electrogenerated species were determined.

Picoline Based Fluorescence ‘Turn-On’ Chemosensor for Zinc(II) Ion Recognition, Cell Imaging and Cytotoxicity Study: Synthesis, Crystal Structure, Spectroscopy and DFT

A new picoline based ligand, namely 2-hydroxy-5-methyl-3-[{(6-methylpyridin-2-yl)imino}methyl]benzaldehyde ( L ) and it’s zinc(II) complex, Zn(L) 2 ( 1 ) have been synthesized and structurally characterized. The ligand ( L ) selectively interacts with Zn 2+ ion in presence of series of cations in CH 3 CN-H 2 O (v/v 1:1) in 1 mM HEPES buffer (pH 7.2). The fluorescence intensity of L is significantly enhanced, and it is increased to 52 times on coordination with Zn(II) ion. The fluorescence intensity value of the L does not show any significant change in the pH range 5 to 9, while the extent of emission phenomenon with Zn(II) ions is observed in the said pH range. The detection limit (0.36 µM) and association constant (log K app = 13.25) are evaluated by the fluorescence emission experiment. The probe shows reversibility in addition of dihydrogen phosphate (H 2 PO 4 – ) ion to the 1 . Additionally, the ‘turn-on’ fluorescence probe has sufficient cell permeability and intracellular Zn(II) sensing property as envisaged from the microscopic imaging in HEK293T cells. Both L and ZnL 2 ( 1) are innocuous against PBMC (peripheral blood mononuclear cells) but effective antitumor agents against U-937 cancer cells.

Structural and Photophysical Properties of 2,1,3-Benzothiadiazole-Based Phosph(III)azane and Its Complexes.

Here we describe the synthesis of a novel N,N’-bis(2,1,3-benzothiadiazol-4-yl)-1-phenylphosphanediamine (H2L) and its zinc (II) and copper (I) coordination compounds [Zn2L2]·nC7H8 (1·nC7H8), [Zn2(H2L)2Cl4]·nC7H8 (2·nC7H8), and [Cu(H2L)Cl]n·nTHF (3·THF). According to single crystal X-ray diffraction analysis, H2L ligand and its deprotonated species exhibit different coordination modes. An interesting isomerism is observed for the complexes [Zn2(H2L)2Cl4] (2a and 2b) that differ by the arrangement of H2L. Both complexes possess internal cavities capable of incorporating toluene molecules. Upon toluene release, the geometry of 2b changes substantially, while that of 2a changes slightly. Due to the diverse structures, the compounds 1–3 reveal different photophysical properties. These results are discussed based on previously reported studies and DFT (density functional theory) calculations.

Novel peripherally tetra substituted phthalocyanines: Synthesis, characterization, photophysical and photochemical properties

In this paper, phthalonitrile (3) and it’s zinc(II) (4) and magnessium (II) phthalocyanine (5) derivatives were prepared. The novel compounds (3–5) were characterized spectroscopically. The photochemical and photophysical properties compounds (4 and 5) were examined to determine whether they are suitable photosensitizers for PDT applications. The magnessium (II) phthalocyanine (5) produced low amount of singlet oxygen and high fluorescence quantum yield. However, the zinc(II) phthalocyanine (4) had potential to be used in PDT applications with it’s high singlet oxygen production and high photostability.

Synthesis, Characterization and Fluorescence Property of a New Zinc(II) Complex Based on 2,6-Bis(imino)pyridyl Ligand

A new zinc(II) complex [Zn(L1)Cl2]‧CH3CN‧1/2H2O (complex 1), where L1 stands for 2,6-Bis{[(2-ethylphenyl)imino]ethyl}pyridine, has been synthesized and characterized. Both the crystal structures of complex 1 and L1 have been determined by single-crystal X-ray diffraction. L1 crystallizes in monoclinic system P21/n space group, with a = 7.7165(5) A, b = 9.1139(7) A, c = 30.535(2) A, β = 96.037(2)° and Z = 4. Complex 1 crystallizes in the orthorhombic system, space group Pbca, and its crystallographic data are a = 14.0520(9) A, b = 14.5780(11) A, c = 26.3450(17) A, α = β = γ = 90°, and Z = 8. In complex 1, Zn1 atom is five-coordinated with a trigonal bipyramidal geometry. L1 acts as a tridentate ligand and coordinated to Zn1 with three nitrogen atoms. A two-dimensional supermolecular network is formed by hydrogen bonds, in which acetonitrile and water solvent molecules play an important role. The luminescent properties of L1 and complex 1 were investigated in the solid state. The results indicate that when coordinated with Zn atom, the fluorescence intensity of complex 1 increases accompanied by a blue-shift, which can be attributed to metal perturbed π–π* intraligand fluorescence. The single crystals of 2,6-Bis{[(2-ethylphenyl)imino]ethyl}pyridine (L1) and it’s Zinc(II) complex [Zn(L1)Cl2]‧CH3CN‧1/2H2O (1) were determined. In the crystal structure of complex 1, the acetonitrile and water solvent molecules play great role in the formation of hydrogen bonds, forming a two-dimensional supermolecular network structure.

Photomechanical Molecular Crystals of an Azopyridine Derivative and Its Zinc(II) Complex: Synthesis, Crystallization and Photoinduced Motion

In this work, photomechanical molecular crystals of 4-(4-(6-Hydroxyhexyloxy) phenylazo) pyridine (6cazpy) and its zinc(II) organic complex (complex-I) were synthesized and crystallized. DSC and TGA were used to characterize and compare properties of 6cazpy and its complex-I crystals. Photoinduced motions of 6cazpy crystals and its complex-I crystals were investigated and compared by UV/Vis irradiation. Bending away motions from the light source were observed from both 6cazpy crystals and its complex-I crystals. The bending away motion was attributed to the trans-to-cis photoisomerization of azopyridine derivatives in the crystalline phase. It is worth noting that the photomechanical properties of complex-I were enhanced by the formation of the ligand, which might be caused by the looser packing of molecules inside complex-I crystal. In addition, because of the existence of ligand, which combined two photoactive groups in each complex-I molecule, the isomerization reactions of these two photoactive groups in the molecules can increase the photomechanical movement ability of the crystal. It was also found that the crystal size and shape will affect the photoinduced movement of the crystals. PXRD and AFM were used to investigate the molecular mechanism and the surface topological change upon photoisomerization. The corresponding mechanism was proposed.

Synthesis, Characterization, Spectroelectrochemical, Photophysical and HSA‑Binding Properties of Novel and Versatile meso-Tetra(4-pyridylvinylphenyl)porphyrins Coordinated to Ruthenium(II)-Polypyridyl Derivatives

The free-base meso-tetra(4-pyridylvinylphenyl)porphyrin (1a) and its zinc(II) complex were synthesized and then functionalized with [Ru(bpy)2Cl]+ units (2a and 2b) via conventional methods and evaluated in terms of photophysical, electrochemical and biological aspects. All porphyrins present moderate singlet oxygen production and fluorescence quantum yield, and did not show any aggregation process. The photo-oxidation ability of those porphyrins decreased in the order 2b > 1a > 2a. The electrochemical behavior of 2a and 2b modified electrodes was evaluated by electroanalytical methods. Also the 2b electrode showed a smaller charge transfer resistance (36.70 Ω) when compared to 2a electrode (45.17 Ω). In addition, even after 30 consecutive injections of nitrite solution (1.0 × 10−4 mol L−1) using the flow injection analysis (FIA) system, the modified 2b electrode showed an relative standard deviation (RSD, n = 30) of 1.36% exhibiting a great potential as amperometric sensor for nitrite. Moreover, the biological evaluation towards human serum albumin (HSA) indicated spontaneous, weak and ground-state association in the IB subdomain (site III) and possibily a second site, changing the conventional interaction mode of porphyrins with biomolecules as consequence of the longer arms (porphyrin ring substituents at meso-positions) ending with a ruthenium polypyridyl complex, that may enhance the photodynamic therapy (PDT) efficiency of photogenerated reactive oxygen species (ROS) species.

Synthesis, modeling and biological activity of new zinc(II) hydroxamates against streptococcus pneumoniae

Abstract In this paper we report the synthesis and characterization of the following aromatic hydroxamates: potassium(I) benzohydroxamate (BZH), potassium(I) nitrobenzohydroxamate (N-BZH), potassium(I) dinitrobenzohydroxamate (DN-BZH) and the complexes derived containing zinc(II): BZH-Zn, N-BZH-Zn and DN-BZH-Zn. The compounds were characterized and their probable structures proposed using infrared spectroscopy, nuclear magnetic resonance spectroscopy, thermogravimetry and elemental analysis. Calculations of HOMO and LUMO pointed out that DN-BZH anion is the most reactive specie, once it presented the lowest value of energy gap, ca. of 7.65 eV. The compounds were evaluated against Streptococcus pneumoniae, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. It was possible to observe that DN-BZH demonstrated a minimum inhibitory concentration (MIC) of 25 µg/mL, while its zinc(II) complex presented a MIC of 12.5 µg/mL for S. pneumoniae. Molecular docking studies performed with an urease model suggested coordination between the hydroxamic fraction of DN-BZH and nickel(II) ions located in the active site, showing a bond length of approximately 2.3 A and a variety of interactions with specific amino acids residues.

Sensitization of TiO2 by halogenated porphyrin derivatives for visible light biomedical and environmental photocatalysis

New hybrid TiO2-based materials were obtained by impregnation of semiconductor with 5,10,15,20-tetrakis(2,6-difluorosulfonylophenyl)porphyrin (F2POH) and its zinc(II) complex (ZnF2POH). The efficient immobilization of the porphyrins on the surface of titanium dioxide was obtained due to the presence of -SO3H functional groups, which interact with the surface of TiO2. All prepared materials were thoroughly characterized in terms of their morphological, spectroscopic, electrochemical, photochemical and functional properties by diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry, photoelectrochemistry as well as biological and photocatalytic tests. The modification of TiO2 with halogenated (metallo)porphyrins allows to improve overall properties of the studied materials and assess their activity upon visible part of the electromagnetic radiation (>400 nm). Nevertheless, due to their limited stability, observed photochemical effects are quite short lived. It is shown that the fluorine atoms present in porphyrin structure modulate not only physicochemical properties of the hybrid materials but also their photoactivity in the generation of reactive oxygen species (ROS). The materials based on fluorinated porphyrins have shown photocatalytic activity in the degradation of model pollutants: 4-chlorophenol and opioid drug – tramadol. Moreover, they exhibit quite significant antibacterial activity against Gram-positive (S. aureus), notably higher than TiO2 modified with commercial tetraphenyl porphyrin (TPPS). The role of singlet oxygen, hydroxyl and iodide radicals in the performed photoinactivation processes is elucidated for all studied systems. Finally, TiO2 alone is not active against bacteria upon visible light irradiation, what implies that materials containing fluorinated and sulfonated porphyrins have improved photochemical activity and efficiency of the ROS generation. Thus, they are interesting materials especially for photodynamic inactivation of microorganisms.

Novel Hexadeca-Substituted Metal Free and Zinc(II) Phthalocyanines; Design, Synthesis and Photophysicochemical Properties.

The syntheses of a novel 1,4,8,11,15,18,22,25-octahexyloxy-2,3,9,10,16,17,23,24-octa-(4-trifluoromethoxyphenyl) phthalocyanine (3a) and its zinc(II) phthalocyanine derivative (3b) have been described and characterized by elemental analysis,1H NMR, 13C NMR, 19F NMR, mass, UV-Vis and FT-IR. The newly prepared metal-free phthalocyanine and its zinc(II) counterpart are soluble in most organic solvents. The photophysical and photochemical properties such as aggregation, fluorescence, singlet oxygen generation and photodegradation under light irradiation of these phthalocyanines have been investigated in DMF. The hexadeca-substituted phthalocyanines (3a and 3b) showed longer absorption and emission wavelength values when compared to that of reported phthalocyanine derivatives due to substitution of the all possible positions in the phthalocyanine framework. The zinc(II) phthalocyanine derivative does not only have a good singlet oxygen generation but also has other photophysicochemical properties that enables this phthalocyanine to be useful as a photosensitizer for cancer treatment using photodynamic therapy.

Piperazinium Bis(hydrogen-3,5-pyrazoledicarboxylate) Proton Transfer Compound and Its Zinc(II) Complex: Synthesis, Characterization and Crystal Structure

Two compounds including a proton transfer ion pair, (pipzH2)(pdcH)2·2H2O (1) (where pipz: piperazine and pdcH2: pyrazole-3,5-dicarboxylic acid) and its Zn(II) complex (2), (pipzH2)[Zn(pdc)2(H2O)2]·6H2O, were synthesized and characterized using elemental analysis, IR spectroscopy and single crystal X-ray diffraction methods. The compound 1 crystallizes in the triclinic space group P $$\bar {1}$$ with Z = 2. The unit cell dimensions are: a = 6.886(3) A, b = 8.132(3) A, c = 8.902(3) A, α = 94.707(9)°, β = 99.632(9)°, γ = 111.508(8)°. The crystal system of 2 is monoclinic with space group P21/c and has two molecules per unit cell. The unit cell dimensions are: a = 12.050(2) A, b = 13.163(2) A, c = 7.610(1) A, β = 97.610(4)°. The zinc(II) atom has a distorted octahedral coordination geometry. The two pdc2− units are almost coplanar to each other. In both crystal structures, a wide range of noncovalent interactions including hydrogen bonding (types of O–H⋯O, N–H⋯O and C–H⋯O), π–π stacking and ion pairing connect the various components into supramolecular structures. X-ray crystal structure of the novel 1:2 proton transfer compound, (pipzH2)(pdcH)2·2H2O (where pipz: piperazine and pdcH2: pyrazole-3,5-dicarboxylic acid) and its Zn(II) complex, (pipzH2)[Zn(pdc)2(H2O)2]·6H2O, show intermolecular N–H⋯O, O–H⋯O and C–H⋯O hydrogen bonds and π–π stacking, together with ion pairing, are responsible for extending the structure in three dimensions, resulting in a supramolecular network.

Novel tetradentate Schiff base zinc(II) complex as a potential antioxidant and cancer chemotherapeutic agent: Insights from the photophysical and computational approach

In this study a new N4 Schiff base ligand (SB) was synthesized via condensation reaction of 3,4-diaminobenzophenone with diacetyl monoxime in 1:2 M ratio. Moreover, the synthesization and characterization of its zinc (II) complex was carried out through elemental analysis, FT-IR, 1H NMR, UV–Vis spectroscopies and molar conductance. Afterwards we scrutinized the above obtained complex to determine its potential anticancer activity against MCF-7 cell line through MTT test, reducing the viable cell numbers to 11% of the control samples after exposure for 72 h. In order to specify its in vitro antioxidant activity, the Zn(II) complex was evaluated, as a radical scavenger, versus 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH). Data obtained from the above assay revealed that Zn(II) complex demonstrated limited (IC50 = 239.5 mg L−1) antioxidant activity in comparison with ascorbic acid. For the purpose of investigating the complex-model proteins binding, human serum albumin (HSA) and β-lactoglobulin (β-LG), we used biophysical methods and molecular modeling. Experimental results showed that the two systems demonstrated identical interactions (hydrogen bonding and Van der Waals forces). But the β-LG demonstrated a much firmer binding affinity to Zn(II) complex than HSA (Kb ∼ 0.67 (±0.10) × 104 M−1 for HSA-Zn complex and 6.45 (±0.15) × 104 M−1 for β-LG-Zn complex). According to the molecular modeling analysis, the Zn(II) complex develops bonds to the remnants that exist in the subdomain IIA of HSA and site A of β-LG.

Supramolecular Adducts of Anionic Porphyrins and a Biocompatible Polyamine: Effect of Photodamage-on Human Red Blood Cells.

Supramolecular adducts obtained by interaction between the anionic porphyrin meso-tetrakis(4-carboxyphenyl)porphyrin (TPPC) or its zinc(II) derivative (ZnTPPC) with a biocompatible amino-terminated polypropylene or poly(ethylene oxide)s (Jeffamines) has been investigated. The interaction with the polymer allows the stabilization of the porphyrins in their monomeric form under physiological conditions. The photodynamic properties of the supramolecular adducts were explored by typical 1O2 indirect detection. Their photodynamic action were evaluated in vitro using human red blood cells (HRBCs) under different experimental conditions. The morphology of erythrocytes was investigated by optical microscopy after incubation with porphyrin compounds and light irradiation. The images show loss of their normal biconcave profile and an incoming spiny configuration with blebs evident on their surfaces.

An Azoaromatic Ligand as Four Electron Four Proton Reservoir: Catalytic Dehydrogenation of Alcohols by Its Zinc(II) Complex.

Electroprotic storage materials, though invaluable in energy-related research, are scanty among non-natural compounds. Herein, we report a zinc(II) complex of the ligand 2,6-bis(phenylazo)pyridine (L), which acts as a multiple electron and proton reservoir during catalytic dehydrogenation of alcohols to aldehydes/ketones. The redox-inactive metal ion Zn(II) serves as an oxophilic Lewis acid, while the ligand behaves as efficient storage of electron and proton. Synthesis, X-ray structure, and spectral characterizations of the catalyst, ZnLCl2 (1a) along with the two hydrogenated complexes of 1a, ZnH2LCl2 (1b), and ZnH4LCl2 (1c) are reported. It has been argued that the reversible azo-hydrazo redox couple of 1a controls aerobic dehydrogenation of alcohols. Hydrogenated complexes are hyper-reactive and quantitatively reduce O2 and para-benzoquinone to H2O2 and para-hydroquinone, respectively. Plausible mechanistic pathways for alcohol oxidation are discussed based on controlled experiments, isotope labeling, and spectral analysis of intermediates.

Computational Investigation of the Influence of Halogen Atoms on the Photophysical Properties of Tetraphenylporphyrin and Its Zinc(II) Complexes.

How the tetraphenylporphyrin (TPP) and its zinc(II) complexes (ZnTPP) photophysical properties (absorption energies, singlet-triplet energy gap and spin-orbit coupling contributions) can change due to the presence of an increasing number of heavy atoms in their molecular structures has been investigated by means of density functional theory and its time-dependent formulation. Results show that the increase of the atomic mass of the substituted halogen strongly enhances the spin-orbit coupling values, allowing a more efficient singlet-triplet intersystem crossing. Different deactivation channels have been considered and rationalized on the basis of El-Sayed and Kasha rules. Most of the studied compounds possess the appropriate properties to generate cytotoxic singlet molecular oxygen (1Δg) and, consequently, they can be proposed as photosensitizers in photodynamic therapy.

Chemical fixation of carbon dioxide to cyclic carbonates catalyzed by zinc(II) complex bearing 1,2-disubstituted benzimidazole ligand

A new zinc(II) complex of formula [ZnCl2(L1)2] (1) [L1 = 2-(2-thienyl)-1-(2-thienylmethyl)-1H- benzimidazole] was synthesized and fully characterized by nuclear magnetic resonance and infrared spectroscopy, elemental analysis, electrospray ionization high-resolution mass spectrometry, and thermogravimetric analysis. The molecular structure was confirmed by single-crystal X-ray diffraction. Complex 1 consists of mononuclear tetrahedral zinc(II) units with a locked geometry resulting from weak intramolecular S…π and π–π interligand interactions. The benzimidazole ligand and its zinc(II) complex were readily obtained through a simple synthetic route. The catalytic activity of 1 was investigated in the coupling of carbon dioxide with epoxides to produce cyclic carbonates, and a series of parameters were evaluated. The complex efficiently catalyzed the transformation of various epoxides under solvent-free conditions, with good conversions, turnover numbers, and turnover frequencies.

2-Acetylpyrydine-aminoguanidine Schiff base – Novel ligand salt and zinc(II) complex containing thiocyanate

A new salt of Schiff base of aminoguanidine and 2-acetylpyridine, and its zinc(II) complex were obtained and their physicochemical and structural properties studied. The reaction of an aqueous solution of the chloride ligand salt and NH4NCS resulted in formation of the dithiocyanate ligand salt, L?2HNCS, while the reaction of the obtained salt with zinc(II) acetate gave a neutral complex of the formula [ZnL(NCS)2]. In this complex, chelate ligand is coordinated in its neutral form, in a common tridentate NNN manner, via pyridine, azomethine and imino nitrogen atoms of the aminoguanidine fragment. This coordination mode results in formation of two strained five-membered metallocycles. Zinc(II) is situated in a distorted square-pyramidal environment of the tridentate ligand and one thiocyanate ion in the equatorial and the other thiocyanate ion in the apical position. The crystal structure of the ligand salt is stabilized by N?H?N and N?H?S interactions formed between the cationic and anionic species, while the three-dimensional crystal packing of the complex units is based on weak N?H?S interactions which involve the S acceptors from both NCS ligands.

A New Trinuclear Zn(II) Complex {[Zn(μ-ONN)(μ2-O)(μ-OO)]2Zn}: Synthesis, Characterization, Thermal Decomposition and Antibacterial Activity

New centrosymmetric trinuclear zinc(II) complex {[Zn(μ-ONN)(μ2-O)(μ-OO)]2Zn} has been synthesized by the reaction of a potentially ONN tridentate Schiff base ligand, and N,N-dimethylethylendiamin, with Zn(OAc)2·2H2O in methanol, in the refluxed conditions and characterized by elemental analysis, FT-IR and UV–Vis spectroscopy. Single crystal X-ray structure analysis reveals a trinuclear complex {[Zn(μ-ONN)(μ2-O)(μ-OO)]2Zn} with zinc(II) ions connected by three different bridges, (μ-ONN) of the Schiff base ligand, μ2-O and μ-OO of the acetate. The complex is centrosymmetric, with one of the Zn atoms located at the inversion center. While the central Zn(II) ion is six-coordinated, the coordination number of the other Zn(II) ions is five. Finally, the {[Zn(μ-ONN)(μ2-O)(μ-OO)]2Zn} complex was thermally decomposed in air at 700 °C resulted in ZnO nano crystalites with the average size of 42 nm. The antibacterial activity of ligand and its zinc(II) complex were tested against gram-positive and gram-negative bacteria. The ligand showed higher activity than its zinc(II) complex.

Synthesis, spectroscopic properties and DFT calculations of a novel multipolar azo dye and its zinc(II) complex

The synthesis and photophysical properties of 5-(diethylamino)-4-[(E)-(4-nitrophenyl)diazenyl]-2-(1,3-benzoxazol-2-yl)phenol (AB-HBO) and its zinc complex were examined. The organic molecule acts as a pH sensitive chromophore and as mononegative ligand for zinc(II) ion. Structural features and photophysical properties of AB-HBO were studied. The solvatochromic blue shift, shown by the ligand in its neutral form, is widely enhanced in its deprotonated form. The color solution ranges from red-orange to violet and blue-green as function of the electronic density deformation. Fluorescence spectra were recorded on both ligand and zinc complex solutions. (TD)DFT calculations have been performed to rationalize the absorbance of chromophore and complex.