Presence Of Phen Research Articles

Upgrading Major Waste Streams Derived from the Biodiesel Industry and Olive Mills via Microbial Bioprocessing with Non-Conventional Yarrowia lipolytica Strains

This study reports the development of a bioprocess involving the valorization of biodiesel-derived glycerol as the main carbon source for cell proliferation of Yarrowia lipolytica strains and production of metabolic compounds, i.e., citric acid (Cit), polyols, and other bio-metabolites, the substitution of process tap water with olive mill wastewater (OMW) in batch fermentations, and partial detoxification of OMW (up to 31.1% decolorization). Increasing initial phenolics (Phen) of OMW-glycerol blends led to substantial Cit secretion. Maximum Cit values, varying between 64.1–65.1 g/L, combined with high yield (YCit/S = 0.682–0.690 g Cit/g carbon sources) and productivity (0.335–0.344 g/L/h) were achieved in the presence of Phen = 3 g/L. The notable accumulation of endopolysaccharides (EPs) on the produced biomass was determined when Y. lipolytica LMBF Y-46 (51.9%) and ACA-YC 5033 (61.5%) were cultivated on glycerol-based media. Blending with various amounts of OMW negatively affected EPs and polyols biosynthesis. The ratio of mannitol:arabitol:erythritol was significantly affected (p < 0.05) by the fermentation media. Erythritol was the major polyol in the absence of OMW (53.5–62.32%), while blends of OMW-glycerol (with Phen = 1–3 g/L) promoted mannitol production (54.5–76.6%). Nitrogen-limited conditions did not favor the production of cellular lipids (up to 16.6%). This study addressed sustainable management and resource efficiency enabling the bioconversion of high-organic-load and toxic waste streams into valuable products within a circular bioeconomy approach.

Portable solid sensor supported in nylon for silver ion determination: testing its liberation as biocide.

This paper reports the fabrication and utility of a new solid sensor, which allows the quantitation of silver ions acting as catalyst at the low micromolar level. The optical sensor was prepared by incorporating both reagents, pyrogallol red (PGR) and 1,10-phenanthroline (Phen), in a nylon membrane. The effect of parameters in determining silver-catalyzed oxidation of PGR by persulfate in the presence of Phen as an activator was studied and optimized for achieving suitable sensitivity. Semiquantitative analysis can be performed by visual inspection of the color of the sensor by comparing it with standard responses and quantitative analysis can be carried out by its diffuse reflectance (DR) measurement or by a digital image-processing tool (GIMP) using a smartphone. The sensor exhibited a linear relationship toward Ag(I) concentrations ranging from 0.4 to 10μM or 1-25μM and limits of detection of 0.1μM or 0.3μM for incubation times of 50 and 30min, respectively. The relative standard deviation achieved for several batches of sensors was around 2%. The analysis of water samples from tap and refrigerating circuits containing solid biocides, which leach silver ions, prove that this portable and sustainable sensor is successfully operational in real situations. Graphical abstract.

Heterobimetallic Cu(I)/Ru(II) Acetylide Bridged Hybrid Complexes Containing Coordination and Organometallic Sites

AbstractThe heterobimetallic complexes [Cu(phen)(NC5H4HC=NC6H4C≡CC6H4C≡CRu(dppe)2Cl)]X (1 a‐4 a) and [Cu(bipy)(NC5H4H C=NC6H4C≡CC6H4C≡CRu(dppe)2Cl)]X (1 b‐4 b) (where X= I, ClO4, BF4, PF6; phen= 1, 10 phenanthroline, bipy= 2, 2′ bipyridine) have been prepared by the reaction of (NC5H4HC=NC6H4C≡CC6H4C≡CRu(dppe)2Cl) with copper salts in presence of phen or bipy as a coligand. Our synthetic attempts and successes are discussed in combination with spectroscopic and electronic characterization of the compounds. Comparison between phen and bipy complexes were studied by thermal and electrochemical analysis where, thermally robust complexes demonstrate quasireversible redox behaviour analogous to CuI/II/RuII/III couple. SEM of representative complexes 2 a and 2 b clarify the average size and morphology of the complexes. Room temperature luminescence influenced by varying coordinating ability of counter anions along with π‐acidic character in green‐yellow region was observed. Solvent dependant emission displays positive solvatochromism at ambient temperature. The second harmonic generation (SHG) efficiency of the complexes was measured by Kurtz‐powder technique indicating that all complexes display the second harmonic generation (SHG) property.

Structural and photoluminescent properties of six chiral coordination compounds based on N-acetyl-L-tyrosine

Six novel chiral coordination compounds, namely [Cd(acty)(phen)2](ClO4)·3H2O 1, {[Cd(acty)(bpp)2(H2O)2](NO3)·2H2O}n2, {[Cd(acty)(bpp)2(H2O)2](ClO4)·2H2O}n3, {[Zn2(acty)2(bpp)2(O)]·3.5H2O}n4, {[Ag4(acty)2(bpp)4](NO3)2·8H2O}n5, {[Ag(acty)(4,4’-bipy)]·2H2O}n6 have been synthesized in the presence of N-donor ligands (Hacty = N-acetyl-L-tyrosine, phen = 1,10-phenanthroline, bpp = 1,3-di(4-pyridyl)propane, 4,4’-bipy = 4,4’-bipyridine). Compound 1 shows a 0D structure in the presence of phen. Compounds 2 and 3 are isostructural 1D right-hand helical chains via flexible bpp ligand. Compound 4 features a 1D double-chain structure and 5 displays a 2D (6,6)-connected grid network also by bpp ligand. Compound 6 displays a 1D single-chain structure by rigid 4,4’-bipy ligand. Compound 1, 2 and 5 are further extended into 3D supramolecular architectures through hydrogen-bonding interactions. Compounds 4 and 6 are further linked by hydrogen-bonding interactions into a 2D supramolecular layer. Circular dichroism and luminescent properties of compounds 1−6 were investigated at room temperature. Our results highlight the frameworks and luminescent properties can be controlled via adjusting ancillary N-donor ligands and metal centers.

Nitrogen-Based Ligands Accelerate Ammonia Borane Dehydrogenation with the Shvo Catalyst

We previously reported that quantitative poisoning, a test for homogeneous catalysis, behaves oddly in the dehydrogenation of ammonia borane (AB) by Shvo’s catalyst, whereas the “poison” 1,10-phenanthroline (phen) accelerates catalysis and apparently prevents catalyst deactivation. Thus, we proposed a protective role for phen in the catalysis. Herein we account for the mechanistic origin of this accelerated AB dehydrogenation in the presence of phen and define the relevance boundaries of our prior proposal. In so doing, we present syntheses for novel amine- and pyridine-ligated homologues of the Shvo catalyst and show their catalytic efficacy in AB dehydrogenation. These catalysts are synthetically easy to access, air stable, and rapidly release over 2 equiv of H2. The mechanisms of these reactions are also discussed.

Sol–gel derived silica thin films immobilized with 1,10-phenanthroline and their binding activity toward iron(II)

Transparent sol–gel thin films immobilized with 1,10-phenanthroline were prepared via the acid-catalyzed sol–gel reaction of tetraethylorthosilicate (TEOS) in the presence of phen. Three surfactants that include cationic cetyl trimethyl ammonium bromide (CTAB), anionic sodium dodecyl sulfate (SDS) and non-ionic Triton X-100 (TX-100) were tested for the improvement of the host material mesostructure, increasing its porosity and good accommodation of the phen within the silica matrix. The immobilized phen thin films showed similar behavior as their free counterpart in aqueous solution. The immobilized phen complex retained its activity toward Fe2+ metal ions by immobilization and produced a stable complex without any shift in the wavelength of Vis absorption spectra comparing with its free counterpart. Different parameters including concentrations of phen, Fe2+ and surfactant, type of surfactant, lifetime and number of measurements were investigated. The phen thin film sensor showed high sensitivity, chemical stability, good reproducibility and long lifetime behavior. The immobilized phen thin films were used for quantification of iron(II) in versatile aqueous samples. The polarized light microscopy indicated that the phen molecules were distributed uniformly within the host silica network.

<i>In Situ</i> Microscope Measurements of the Formation of Nanometer-Sized Gold Particles at the Dodecane/Water Interface through the Direct Reduction of Aqueous Tetrachloroaurate(III) by Hydrophobic <i>dl</i>-α-Tocopherol in the Presence of 1,10-Phenanthroline

The contact of a dodecane solution of hydrophobic dl-α-tocopherol with an aqueous solution of tetrachloroaurate(III) resulted in the direct reduction of tetrachloroaurate(III) and the formation of gold particles at the dodecane/water interface. Without other additives, the gold particles were unfavorably aggregated with each other and chains of gold particles were formed. In the present study, a chemical preventing the aggregation was sought. Fourteen types of chemicals were individually added to the two-phase system, and then the size, shape, and movements of the gold particles formed at the dodecane/water interface were observed through an optical microscope using bright-field illumination, using dark-field illumination, or with scattered laser light under total internal reflection conditions. Of the 14 chemicals, 1,10-phenanthroline (phen) effectively prevented the aggregation of gold particles at the interface. The gold particles formed in the presence of phen under the optimized conditions were recovered on a coverslip, and their size and shape were recorded using an atomic force microscope. Almost all of the recovered gold particles were not higher than 50 nm and this meant that nanometer-sized gold particles were formed.

A novel photoluminescent nanohybrid of poly(ε-caprolactone) grafted Mg/Al layered double hydroxides and Tb3+ ions: Synthesis and characterization

This paper demonstrates a systematic study of the synthesis and characterization of the hybrid of Mg–Al layer double hydroxides (LDHs), poly(ε-caprolactone) (PCL), and terbium ions (Tb3+). The hybrid LDH-g-PCL-Tb3+-1,10-phenanthroline (Phen) was prepared by the combination of ring opening polymerization (ROP), click chemistry, and coordination chemistry. First, LDHs with a molar ratio of Mg/Al = 2 were prepared by the co-precipitation method, which was subsequently functionalized with (3-chloropropyl) trimethoxysilane in order to introduce azide groups through the reaction of chlorine with sodium azide. Meanwhile, the acetylene functionalized PCL was prepared by ROP of ε-CL, followed by esterification of the hydroxyl groups using succinic anhydride. The click reaction of alkyne-PCL and N3-LDHs successfully afforded LDH-g-PCL, which was coordinated with Tb3+ ions in the presence of Phen. The structure and properties of the nanohybrids were investigated by FT-IR, XPS, EDS, SEM, and TGA analyses. The data indicate the coordination of Tb3+ ions with LDH-g-PCL nanohybrids. The content of Tb3+ ions in the LDH-g-PCL-Tb3+-Phen complex was calculated to be 8.7% (w/w). The LDH-g-PCL-Tb3+-Phen complexes showed four emission bands with high fluorescence intensity centered at 489 nm (5D4 → 7F6), 546 nm (5D4 → 7F5), 586 nm (5D4 → 7F4) and 623 nm (5D4 → 7F3) with excitation at 328 nm (3F6 → 5G6). The stability of LDH-g-PCL-Tb3+-Phen complexes under UV irradiation was high, and no leaching effect was observed.

Combination of Best Promoter and Micellar Catalyst for Chromic Acid Oxidation of D-Mannitol to Mannose in Aqueous Media

Abstract Chromic acid oxidation of D-mannitol to mannose has been studied in aqueous media. The effect of promoter (PA, phen and bpy), micellar catalyst (SDS, TX-100 and CPC) and their combination is studied. All the reactions were performed under the condition [D-mannitol]T ≫ [Cr(VI)]T. All the promoters accelerate the reaction rate and the rate is highest in presence of phen. In absence of a promoter the anionic surfactant SDS increases the rate followed by Triton TX-100. The cationic surfactant CPC retards the reaction in comparison to the reaction in aqueous media. Although phen is the best promoter in absence of any surfactant the catalyst combination of bpy and SDS produce a maximum rate enhancement.

A one-step selective fluorescence turn-on detection of cysteine and homocysteine based on a facile CdTe/CdS quantum dots–phenanthroline system

In this paper, we report a simple, selective, sensitive and low-cost turn-on photoluminescent sensor for cysteine and homocysteine based on the fluorescence recovery of the CdTe/CdS quantum dots (QDs)–phenanthroline (Phen) system. In the presence of Phen, the fluorescence of QDs could be quenched effectively due to the formation of the non-fluorescent complexes between water-soluble thioglycolic acid (TGA)-capped QDs and Phen. Subsequently, upon addition of cysteine and homocysteine, the strong affinity of cysteine and homocysteine to QDs enables Phen to be dissociated from the surface of QDs and to form stable and luminescent complexes with cysteine and homocysteine in solution. Thus, the fluorescence of CdTe/CdS QDs was recovered gradually. A good linear relationship was obtained from 1.0 to 70.0μM for cysteine and from 1.0 to 90.0μM for homocysteine, respectively. The detection limits of cysteine and homocysteine were 0.78 and 0.67μM, respectively. In addition, the method exhibited a high selectivity for cysteine and homocysteine over the other substances, such as amino acids, thiols, proteins, carbohydrates, etc. More importantly, the sensing system can not only achieve quantitative detection of cysteine and homocysteine but also could be applied in semiquantitative cysteine and homocysteine determination by digital visualization. Therefore, as a proof-of-concept, the proposed method has potential application for the selective detection of cysteine and homocysteine in biological fluids.

1,10-Phenanthroline Modulated Redox Potentials Explored for Benign Iron Speciation Analysis

The objective of this study is to develop a simple, environmentally benign alternate analytical method for simultaneous estimation of iron oxidation states. This proposed method of iron speciation is based on 1,10-phenanthroline (phen) modified redox potential of transition metal ions. In a pre-step ex- cess cerium(IV) oxidizes iron(II) in sample to iron(III). Initial back titration of un-reacted cerium(IV) with cobalt(II) in presence of phen gives amount of iron(II) in sample, reduction of iron(III) with cobalt(II) is then used to estimate total iron as iron(III). The potentiometric titration method has been successfully test- ed for determinations of iron(II) and total iron in synthetic and natural samples and represents a distinc- tively green alternative to other reported protocols of iron speciation analysis. (doi: 10.5562/cca2167)

Combination of best promoter and catalyst for hypervalent chromium oxidation of l-sorbose to lactone of C5 aldonic acid in aqueous media at room temperature

Chromic acid oxidation of l-sorbose to lactone of C5 aldonic acid has been studied in aqueous media. The effect of promoter (PA, phen and bpy), micellar catalyst (SDS, TX-100 and CPC) and their combination is studied. All the reactions were performed under the condition [l-sorbose]T≫[Cr(VI)]T. All the promoters accelerate the reaction rate. But the rate is highest in the presence of phen. In absence of promoter anionic surfactant SDS increases the rate followed by TX-100 whereas cationic surfactant CPC retards the reaction in comparison to aqueous media. Although phen is the best promoter in the absence of catalyst combination of bpy and SDS produces maximum rate enhancement.

Synthesis and characterization of Pb(II) compounds constructed from N-tosyl-L-glutamic acid

{[Pb(tsgluo)] · H2O} n (1), [Pb2(tsgluo)2(phen)2] (2), and [Pb2(tsgluo)2(bipy)2] (3) (H2tsgluo = N-p-tolylsulfonyl-L-glutamate, phen = 1,10-phenanthroline, bipy = 2,2′-pyridine) have been synthesized in the absence or presence of phen or 2,2′-bipy and structurally characterized by elemental analysis, IR, and X-ray crystallography. Single-crystal X-ray analyses reveal that tsgluo exhibits two coordination modes to link lead ions. Complex 1 gives a 2-D layer structure while 2 and 3 exhibit monomolecular structures; 3 is further connected into a double-chain structure by hydrogen bonds. Phen and 2,2′-bipy are very important for the crystal structure. Fluorescence of the compounds is also discussed.

Cadmium(II) Complexes with Mixed cis‐Epoxysuccinate and 2,2′‐Bipyridyl‐Like Ligands: Syntheses, Crystal Structures, and Luminescent Properties

AbstractTwo new CdII complexes, [Cd(ces)(phen)]∞ (1) and {[Cd(ces)(bpy)(H2O)](H2O)}2 (2), were prepared by slow solvent evaporation methods from mixtures of cis‐epoxysuccinic acid and Cd(ClO4)2·6H2O in the presence of phen or bpy co‐ligand (ces = cis‐epoxysuccinate, phen = 1,10‐phenanthroline, and bpy = 2,2′‐bipyridine). Single‐crystal X‐ray diffraction analyses show that complex 1 has a one‐dimensional (1D) helical chain that is further assembled into a two‐dimensional (2D) sheet, and then an overall three‐dimensional (3D) network by the interchain C–H···O hydrogen bonds. Complex 2 features a dinuclear structure, which is further interlinked into a 3D supramolecular network by the co‐effects of intermolecular C–H···O and C–H···π hydrogen bonds as well as π···π stacking interactions. The structural differences between 1 and 2 are attributable to the intervention of different 2,2′‐bipyridyl‐like co‐ligands. Moreover, 1 and 2 exhibit intense solid‐state luminescence at room temperature, which mainly originates from the intraligand π→π* transitions of aromatic co‐ligands.

Structural, Thermal, and Fluorescence Properties of Eu(DBM)3Phenx Complex Doped in PMMA

Tris (dibenzoylmethanido) (o-phenanthroline)-europium(III) complexes [Eu(DBM)(3)(Phen)(x)] have been synthesized, and their structural, thermal, and fluorescence properties have been investigated both as an independent complex and also after embedding it in poly(methyl methacrylate) (PMMA) polymer matrix. X-ray analysis reveals an unusual crystalline to amorphous transformation in structure of the Eu(DBM)(3)Phen(x) complexes when x exceeds 1.0 (mole %). Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) analysis depict the interaction between the Eu(DBM)(3)Phen(x) complex and the PMMA matrix. The fluorescence intensity of Eu(3+) ion in the Eu(DBM)(3)Phen(1·5) complex is an order of magnitude larger compared to the Eu(DBM)(3)·2H(2)O complex. In addition to the transition (5)D(0) → (7)F(2,) which has a rise time of 83 μs, transitions from the (5)D(1) and (5)D(2) levels are also observed, along with several ligand field splittings in the Eu(DBM)(3)Phen(1·5) complex. Appearance of a rise time (∼0.76 ns) in the decay of the fluorescence from DBM in the presence of Phen and a simultaneous large decrease in the fluorescence intensity (both the singlet and triplet emission) of DBM along with a decrease in fluorescence decay time, in the presence of Eu(3+), indicates a cascading excitation energy transfer from Phen to DBM and finally to the (5)D(0) state of Eu(3+) ion in Eu(DBM)(3)Phen(1.5) through short-range excitation energy transfer. A systematic and significant improvement in the thermal and fluorescence properties of the complex is observed with an increase in the mole concentration of Phen. The maximum fluorescence is observed for Eu(DBM)(3)Phen(1·5), which is a new composition as compared with the usual composition reported earlier. This finding indicates the possibility for the development of brighter luminescent lanthanide photonic materials.

Micellization and luminescence of PEG-b-P4VP/Europium(III)/1,10-phenanthroline complex

Luminescent micelles were prepared through the self-assembly of poly(ethylene glycol)-block-poly(4-vinylpyridine) (PEG114-b-P4VP61) and Europium(III) (Eu(III)), with P4VP/Eu(III) as the core, and PEG as the corona. 1,10-phenanthroline (Phen) was assembled into the core of the micelles to sensitize the luminescence. The presence of Phen results into the increasing of apparent average hydrodynamic diameters (\( {\hbox{D}}_{\rm{h}}^{\rm{app}} \)) of the micelles. All Eu(III)-containing micelles emitted the characteristic fluorescence of Eu(III). The intensity of luminescence increased with the presence and the increasing quantity of Phen in the complex micelles due to the effective energy transferring of Phen in the “antenna effect”.

Effect of chelating agent (1,10-phenanthroline) on potassium hydrogen phthalate crystals

The influence of a new organic additive, chelating agent 1,10-phenanthroline (Phen) (∼5.0·10−3 M L−1) on potassium hydrogen phthalate (KHP) single crystals at 30° is investigated. The crystals were grown from the aqueous solutions of pH ∼4.5 at constant temperature by solvent evaporation technique. The chelating agent leads to an increase in metastable zone width and assists the bulk growth process. The growth rate of crystals in the presence of Phen decreases considerably with an increase in impurity concentration. Not much variation is observed in FTIR and cell parameter values, determined by XRD analysis. It appears that the growth promoting effect (GPE) of Phen is caused by the adsorption of the organic additive on the prism of KHP crystals. Differential scanning calorimetry (DSC) and TG-DTA studies reveal the purity of the sample and no decomposition is observed up to the melting point. Scanning electron microscope (SEM) photographs exhibit the effectiveness of the impurity in changing the surface morphology of KHP crystals. Contrary to expectations, Phen depresses the NLO efficiency of KHP, suggesting that the molecular alignments in the presence of Phen results in cancellation effects disturbing the non-linearity.

Polymeric Capsules and Honeycomb Aggregates Formed by p-Sulfonatocalix[6]arene with Phenanthrolinium Compounds

Two crystalline complexes were prepared by the inclusion complexation of p-sulfonatocalix [6]arene (C6AS) with 1,10-phenanthrolinium (Phen+) (1) and 6,7-dihydro-5H- [1,4]diazepino[1,2,3,4-lmn] [1,10]phenanthroline-4,8-diium (PPQ2+) (2). p-Sulfonatocalix [6]arene, in complex 1, maintains the conventional centrosymmetric “up-down” double partial cone conformation, whereas it assumes a novel unsymmetric up−down double partial cone conformation induced by PPQ2+ guest in complex 2. Furthermore, p-sulfonatocalix [6]arene aggregates to the overall structure of multipillars in the presence of Phen+ guest and presents the honeycomb-type packing structure upon complexation with PPQ2+.

Puckered-boat conformation (H 2O) 14 cluster on the self-assembly of an inorganic-metal-architecture

BDC (phthalic acid) reacts with EuCl 3 to form 1D coordination polymer, in the presence of phen (1,10-phenanthroline) under hydrothermal conditions. Puckered-boat-shaped (H 2O) 14 water clusters resulted from four free water molecules and six coordinated water molecules, which join these chains to make a sheet. Of further interesting, the water clusters associate into an inorganic (carbon-free) sheet with chlorine anions by hydrogen bonds. This hybrid water–chlorine configuration acts as a “host” supporting the metal-organic “guest”.

Neutral and cationic mononuclear copper(II) complexes with enrofloxacin: Structure and biological activity

The mononuclear copper complexes with the quinolone antibacterial drug enrofloxacin (=Herx) in the presence or not of a nitrogen donor heterocyclic ligand 1,10-phenanthroline (=phen) and 2,2′-bipyridine (=bipy) have been prepared and characterized. Interaction of copper(II) with deprotonated enrofloxacin leads to the formation of the neutral complex Cu(erx) 2(H 2O), 1, while the presence of phen or bipy leads to the formation of a neutral or a cationic mononuclear complex, respectively. The crystal structures of (chloro)(1,10-phenanthroline)(enrofloxacinato)copper(II), 2, and (aqua)(2,2′-bipyridine)(enrofloxacinato)copper(II) chloride, 3, have been determined with X-ray crystallography. The complexes have been studied with X-band electron paramagnetic resonance in aqueous solutions at liquid helium temperature. The study of the interaction of the complexes with calf-thymus DNA has been performed with diverse spectroscopic techniques and has showed that all complexes are bound to DNA by the intercalative mode. The antimicrobial efficiency of the complexes has been tested on three different microorganisms and the available evidence supports that the best inhibition is provided by Cu(erx) 2(H 2O) (minimum inhibitory concentration = 0.125 μg mL −1) against Escherichia coli and Pseudomonas aeruginosa.