A naphthylamide based fluorescent probe for detection of Al3+, Fe3+, and CN- with high sensitivity and selectivity.

A naphthylamide based fluorescent chemosensor, N,N'-(1,2-phenylene)bis(1-hydroxy-2-naphthamide) (H4L), for detection of Fe3+ and Al3+ cations as well as CN- anion is reported. This compound has been synthesized by a novel and facile synthetic method with high yield and characterized by FT-IR, 1H NMR, elemental analysis, and UV-Vis spectroscopy. It could detect Fe3+ and Al3+ ions in different media with different excitation and emission wavelengths. In DMSO solution, H4L showed selective ON-OFF quenching of its 451 nm emission in the presence of Fe3+. On the other hand, in DMF solution, H4L exhibited selective OFF-ON fluorescence upon the addition of Al3+, the intensity at 429 nm increases drastically by 24-fold. Also, among the anions, the probe can selectively distinguish CN- by deprotonation of OH and NH groups, as proved by 1H NMR titration. TD-DFT calculation supports the UV-Vis and fluorescence measurements of the chemosensor.

A new fluorene derived Schiff-base as a dual selective fluorescent probe for Cu2+ and CN.

A new fluorene based fluorogenic chemosensor, 2-[(9H-Fluoren-2-ylmethylene)-amino]-phenol (L), has been designed, synthesized, and characterized by CHN analyses and different spectroscopic methods. This turn-on fluorogenic chemosensor shows high selectivity and sensitivity toward Cu2+ and CN- with low detection limits of 1.54 × 10-9 M and 1.83 × 10-7 M, respectively. The stoichiometry ratio of L-Cu2+ in solution is 1:1, by the method of Job's plot and ESI-MS. The microcrystalline solid product of the chemosensor reaction with copper is characterized as CuL2. The χT value for CuL2 is temperature independent at a value of 0.403 cm3 K mol-1, which is in agreement with a mononuclear copper(II) complex with an isotropic g-value of 2.075. The fluorescence turn-on recognition process for detection of Cu2+ is attributed to the restricted imine isomerization and blocking of intramolecular charge transfer (ICT) quenching process in the analyte-bound sensor. The selectivity of L for Cu2+ is based on the chelation-enhanced fluorescence effect (CHEF) mechanism. Other interfering ions such as Na+, K+, Ca2+, Mg2+, Ag+, Fe2+, Fe3+, Co2+, Ni2+, Zn2+, Cd2+, Hg2+, Mn2+, Pb2+ and Al3+, show no change in the fluorescence intensity of L in the presence of Cu2+. Furthermore, the compound L can be used as a fluorescence and colorimetric sensor for selective detection of CN- over a number of other anions based on the nucleophilic addition to the imine CN bond, with consequent hydrogen bond formation and electrostatic interaction of the resulting product with K+. The sensing mechanism for CN- was theoretically supported by DFT calculations.

Applications of Nanomaterials Based on Magnetite and Mesoporous Silica on the Selective Detection of Zinc Ion in Live Cell Imaging.

Functionalized magnetite nanoparticles (FMNPs) and functionalized mesoporous silica nanoparticles (FMSNs) were synthesized by the conjugation of magnetite and mesoporous silica with the small and fluorogenic benzothiazole ligand, that is, 2(2-hydroxyphenyl)benzothiazole (hpbtz). The synthesized fluorescent nanoparticles were characterized by FTIR, XRD, XRF, 13C CP MAS NMR, BET, and TEM. The photophysical behavior of FMNPs and FMSNs in ethanol was studied using fluorescence spectroscopy. The modification of magnetite and silica scaffolds with the highly fluorescent benzothiazole ligand enabled the nanoparticles to be used as selective and sensitive optical probes for zinc ion detection. Moreover, the presence of hpbtz in FMNPs and FMSNs induced efficient cell viability and zinc ion uptake, with desirable signaling in the normal human kidney epithelial (Hek293) cell line. The significant viability of FMNPs and FMSNs (80% and 92%, respectively) indicates a potential applicability of these nanoparticles as in vitro imaging agents. The calculated limit of detections (LODs) were found to be 2.53 × 10−6 and 2.55 × 10−6 M for Fe3O4-H@hpbtz and MSN-Et3N-IPTMS-hpbtz-f1, respectively. FMSNs showed more pronounced zinc signaling relative to FMNPs, as a result of the more efficient penetration into the cells.

A Ho(III) potentiometric polymeric membrane sensor based on a new four dentate neutral ion carrier.

In this research, we report a new Ho(3+)-PVC membrane electrode based on N-(4,5-dimethyl-2-(picolinamido)phenyl)picolinamide (H(2)Me(2)bpb) as a suitable ion carrier. Poly vinylchloride (PVC)-based membrane composed of H(2)Me(2)bpb with oleic acid (OA) as anionic additives, and o-nitrophenyloctyl ether (NPOE) as plasticized solvent mediator. The sensor exhibits a Nernstian slope of 20.1 ± 0.2 mV decade(-1) over the concentration range of 1.0 × 10(-6) to 1.0 × 1(-2) mol L(-1), and a detection limit of 5.0 × 10(-7) mol L(-1) of Ho(3+) ions. The potentiometric response of the sensor is independent of the solution pH in the range of 3.5-9.4. It has a very short response time, in the whole concentration range (<10s), and can be used for at least eight weeks. The proposed electrode shows a good selectivity towards Ho(3+) ions over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. To assess its analytical applicability the proposed Ho(3+) sensor was successfully applied as an indicator electrode in the titration of Ho(3+) ion solutions in certified reference materials, alloy samples and for the determination of the fluoride ion in two mouthwash preparations.

{N,N'-[2,2'-(Ethane-1,2-diyldisulfanediyl)di-o-phenyl-ene]bis-(quinoline-2-carboxamidato)}copper(II).

In the title compound, [Cu(C(34)H(24)N(4)O(2)S(2))] or [Cu(bqdapte)], where H(2)bqdapte is 1,2-{bis-[2-(quinoline-2-carboxamido)-phen-yl]sulfan-yl}ethane, the Cu(II) ion is coordinated to the dianionic hexa-dentate bqdapte(2-) ligand by two amide and two quinoline N atoms and two thio-ether S atoms. In the observed conformation of the hexa-dentate ligand, the quinoline rings attain positions related by a twofold axis. The Cu atom displays a Jahn-Teller-distorted octa-hedral CuN(4)S(2) geometry axially compressed along the two trans-configured Cu-N(amidate) bonds.

{2,2'-[3-Aza-pentane-1,5-diylbis(nitrilo-methyl-idyne)]dipyrrol-1-yl}(4-methyl-pyridine)cobalt(III) tetra-phenyl-borate.

The title compound, [Co(C(14)H(17)N(5))(C(6)H(7)N)](C(24)H(20)B) or [Co{(pyrrole)(2)dien}(4-Mepy)]BPh(4) where (pyrrole)(2)dien is 2,2'-[(3-aza-pentane-1,5-diylbis(nitrilo-methyl-idyne)]dipyrrole and 4-Mepy is 4-methyl-pyridine, contains a penta-dentate (pyrrole)(2)dien ligand furnishing an N(5) set, such that two of the pyrrole N atoms and two of the dien N atoms occupy the equatorial positions while one of the imine N atoms of the (pyrrole)(2)dien ligand occupies the axial position. The 4-methyl-pyridine ligand occupies an axial position trans to one of the imine N atoms of the penta-dentate ligand. In the observed conformation of the penta-dentate ligand, the pyrrole rings attain asymmetrical positions owing to the structural demands. The geometry of the resulting CoN(6) coordination can be described as distorted octa-hedral.

Nano-level determination of copper with atomic absorption spectrometry after pre-concentration on N,N-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide-naphthalene.

A novel, simple, sensitive and effective method has been developed for selective extraction and pre-concentration of copper on N,N-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide-naphthalene. After pre-concentration, copper was eluted from sorbent with hydrochloric acid, and then flame atomic absorption spectrometry (FAAS) was used for its determination. The effect of pH, sample flow rate and the volume and concentration of eluent on the recovery of the analyte was investigated and the optimum conditions were established. A pre-concentration factor of 400, and an adsorption capacity of 6.9 mg g(-1) of the solid-phase sorbent or 82.8 mg g(-1) of ligand was achieved using the optimum conditions. The calibration graph was linear in the range of 1.0-4000 ng mL(-1) with the detection limit of 1.0 ng mL(-1). A R.S.D. value of 2.4% was obtained by this method for 400 ng mL(-1) of Cu(2+) solution. This procedure has been successfully applied to separate and determine the ultra trace levels of copper in the environmental samples, free from the interference of some diverse ions.

[1,1'-Diphenyl-3,3'-(propane-1,3-diyldinitrilo)dibut-1-enolato]copper(II).

The title compound, [Cu(C(23)H(24)N(2)O(2))] or [Cu{(BA)(2)pn}], where (BA)(2)pn is 1,1'-diphenyl-3,3'-(propane-1,3-diyldinitrilo)dibut-1-enolate, is a mononuclear copper(II) complex, located on a twofold axis. The four-coordinate Cu(II) atom is in a tetra-hedrally distorted square plane defined by the N and O atoms of the Schiff base ligand. In the tetra-dentate ligand, the two chelate rings are twisted relative to each other, making a dihedral angle of 36.57 (3)°.

{2,2'-[o-Phenyl-enebis(nitrilo-methyl-idyne)]diphenolato}dipyridinecobalt(III) perchlorate.

The title compound, [Co(C(20)H(14)N(2)O(2))(C(5)H(5)N)(2)]ClO(4) or [Co(salophen)(py)(2)]ClO(4), where salophen is o-phenyl-enebis(nitrilo-methyl-idyne)]diphenolate and py is pyridine, contains a six-coordinate mononuclear cobalt(III) atom. The two phenolic O atoms and the two imine N atoms are located in cis positions. There are two pyridine mol-ecules attached to the metal atom, filling the axial sites with a mutually perpendicular disposition of the pyridine planes [86.11 (5)°]. The Co complexes are stacked in layers parallel to (100). Coherence of the structure is provided by a variety of C-H⋯O interactions between the complexes and the perchlor-ate counter anion.

Perchlorate-selective polymeric membrane electrode based on bis(dibenzoylmethanato)cobalt(II) complex as a neutral carrier.

A synthesized bis(dibenzoylmethanato)Co(II) complex (Co(DBM)(2)), has been used as a ionophore for the preparation of a new perchlorate ion-selective electrode. The electrode exhibits a Nernstian response over the perchlorate concentration range of 8.0x10(-7)-1.0x10(-1)M with a slope of 60.3+/-0.5 mV per decade of concentration. The limit of detection as determined from the intersection of the extrapolated linear segments of the calibration plot is 5.6x10(-7)M. The electrode shows good selectivity towards perchlorate with respect to many common anions. The response time of the sensor is very fast (< or = 5s), and can be used for at least 2 months in the pH range of 2.0-9.0. The electrode was used to determine perchlorate in water and human urine. The interaction of the ionophore with perchlorate ions was demonstrated by UV-vis spectroscopy.

N,N'-Bis(8-quinol-yl)pyridine-2,6-dicarboxamide.

In the mol-ecule of the title compound, C(25)H(17)N(5)O(2), the pyridyl ring is oriented at dihedral angles of 8.90 (3) and 28.67 (4)° with respect to the two planar quinolyl ring systems. Intra-molecular N-H⋯N hydrogen bonds result in the formation of four planar five-membered rings, two of which are nearly coplanar with the adjacent quinolyl ring systems.

{2,2'-[1,1'-(3-Aza-pentane-1,5-diyl-dinitrilo)diethyl-idyne]diphenolato}(piperidine)cobalt(III) tetra-phenyl-borate.

The title compound, [Co(C(20)H(23)N(3)O(2))(C(5)H(11)N)](C(24)H(20)B) or [Co{(Me-sal)(2)dien}(pprdn)]BPh(4), where (Me-sal)(2)dien is 2,2'-[1,1'-(3-aza-pentane-1,5-diyldinitrilo)diethyl-idyne]diphenolate and pprdn is piperidine, contains a penta-dentate (Me-sal)(2)dien ligand furnishing an N(3)O(2) set, such that two of the N and one of the O atoms of the salicyl-idene rings define three positions of an equatorial plane, whereas the secondary amine N atom and the other O atom of the salicyl-idene lie in axial positions. The piperidine ligand occupies an equatorial position trans to one of the imine N atoms of the salicyl-idene. In the observed conformation of the penta-dentate ligand, the salicyl-idene rings attain asymmetrical positions owing to the structural demands. The geometry of the resulting CoN(4)O(2) coordination can be described as distorted octa-hedral. The asymetric unit contains two formula units.

{2,2'-[1,1'-(4-Azaheptane-1,7-diyldinitrilo)diethylidyne]diphenolato}copper(II).

The quinquedentate ligand 2,2'-[1,1'-(4-azaheptane-1,7-diyldinitrilo)diethylidyne]diphenol in the title compound, [Cu(C22H27N3O2)], furnishes an N3O2 donor set, which results in a distorted square-pyramidal coordination; the two O and two imine N atoms lie in the basal plane, while the secondary amine N atom of the ligand occupies the axial position. The axial Cu-N bond is 0.33 A longer than the average of the equatorial bonds, and the O atoms are trans. The symmetry of the molecule is lowered by the twist-boat and chair conformations adopted by the two CuNN chelate rings. The complex contains two intramolecular C-H...O interactions, and two molecules of the complex are linked into a dimer by means of moderate N-H...O hydrogen bonds. Spectroscopic evidence supports the presence of hydrogen bonds.