Recovery of platinum from leaching solutions by interaction with porphyrins

Two differently substituted base porphyrins, one containing aliphatic unsaturated groups and one functionalized with basic effect at the periphery: 5,10,15,20-tetrakis-(4-allyloxyphenyl)- porphyrin and 5,10,15,20-tetrakis-(4-aminophenyl)-porphyrin, were investigated for their capacity to complex with hexachloroplatinic acid from leaching solutions. Their different nature makes them interact differently with the hexachloroplatinic acid in solution, as aminophenylporphyrin is more capable to form more stable complexes, therefore it is suitable for the recovery of platinum from diluted solutions (removal capacity is large 86.6 %) whereas the amount of platinum that can be recovered by allyloxyphenylporphyrin is lower, only 74.07 %

Complex formation between Co-metalloporphyrin and silver colloid in acidic media

Large flower sized nanoparticles of silver were synthesized and hybrid colloids with porphyrins were obtained. Daisy-like round aggregates generated from triangular-shaped silver nanoparticles can be observed, evenly distributed. The complexation of these particles with organic dyes was the main purpose of this work in order to achieve nanomaterials exhibiting wide absorption bands. The formation of a complex between an acidified Co(II) 5,10,15,20-meso-tetra(3- hydroxyphenyl) porphyrin (Co-3OHPP) solution in THF and the silver colloid negatively charged at the surface was proven by analyzing the UV-vis spectra during the experiment

Detection of phosphine derivates using metalloporphyrins

Starting from the knowledge that phosphine derivatives exhibit medium/high toxicity, in this study we focused on the behavior of Co(II)- 5,10,15,20-tetratolyl-porphyrin (CoTTP) and Mn(III)-5,10,15,20-tetraphenyl-porphyrin chloride (MnTPPCl) as active UV-vis chromophores for the detection of triphenylphosphine oxide (LC50=12.2µg/mL, LC90=29.5µg/mL). The increase of triphenylphosphine oxide concentration generates the hypochromic effect on the Soret bands of the two metalloporphyrins. A comparison regarding the efficiency of the two metalloporphyrins in detecting phosphine derivatives was done

Noble metal colloid and Co-porphyrin hybrid sensitive to 4-aminosalicylic acid

A hybrid organic-inorganic nanomaterial (Co-3OHPP/n-Au) composed of Co(II) 5,10,15,20- meso-tetra(3-hydroxyphenyl)porphyrin (Co-3OHPP) and gold nanoparticles (n-Au) was tested as sensitive material for the optical detection of 4-aminosalicylic acid (PAS). This novel nanomaterial is able to detect 4-aminosalicylic acid in a reasonable concentration domain, covering one order of magnitude: 1.24 x 10-5 – 3.9 x 10-4M. The dependence between the intensity of absorption and the concentration in 4-aminosalicylic acid is linear, with a fair correlation coefficient of 95 %. This hybrid material can be further included in simple devices for the rapid and facile dosage of this antituberculosis drug in body fluids

Mn-tetratolylporphyrin-Nano-Au complex sensitive to 4-aminosalicylic acid

Porphyrins and metalloporphyrins provide recognition sites for amino acids both through their cationic central metal ion and due to various functional groups at the four mesoand the eight β-positions of pyrolles. Immobilized metallo-phenylporphyrins can be used as sensitive and selective sensors for different analytes as they provide two ways of interaction via the metallic center of porphyrin and between the electrons of the macrocycles and the solute [1]. The purpose of this study was to establish an easy way to determine low concentrations of 4-aminosalycilic acid (PAS) using hybrid materials obtained from porphyrins, namely: Mn(III)-tetratolylporphyrin chloride (MnTTPCl) and gold nanoparticles (n-Au). During the adding of 4-aminosalycilic acid to the MnTTPCl-nAu hybrid it can be observed that the intensity of the plasmonic band is continuously decreasing with the increase in 4-aminosalycilic acid concentration. Another notable feature is the bathochromic shift of the major peak to higher wavelengths from 619 nm to 622 nm. Equilibria processes are involved and accompanied by an isosbestic point around 725 nm. The dependence between the absorption intensity of the plasmonic complex and the concentration of 4-aminosalicylic acid is linear, with an excellent corelation coefficient of 99.31% in a wide range of 4- aminosalicylic acid concentrations: 2.88x10-5M - 8.89x10-4M

Influence of CO2 upon UV-Vis spectroscopy of silica-tetra-3,4 dimethoxy-phenylporphyrin hybrid nanomaterial

A symmetrical substituted aryl porphyrin was incorporated by sol-gel method to generate a silica hybrid nanomaterial that preserves the UV-vis absorption properties of bare porphyrin. The novel hybrid demonstrated to be a sensitive material for CO2 detection. The sol-gel synthesis was monitored by UV-vis spectroscopy. Atomic force microscopy was performed for the hybrid before and after CO2 detection and important changes in the aggregation behavior of the nanomaterial were observed

Optical detection of Rhodamine B by Pt(II) tetra-(4-allyloxy-phenyl)-porphyrin

Rhodamine B is a red, water-soluble synthetic dye with multiple uses in cosmetics, textiles, medicines, food, plastics. Nevertheless, the colorant is toxic causing irritation of the skin, eyes, and airways. For this reason, the control of foods and cosmetics is a must. The present study reports a simple and fast UV-vis spectrophotometric method for the detection of rhodamine B by using as sensitive material Pt(II)-tetra-(4-allyloxy-phenyl)-porphyrin. The method is viable in the range of rhodamine B concentrations from 1.94 x10-6M to 4.26 x10- 5M with very good accuracy

Zn-metalloporphyrins containing pyridyl groups and their comparative capacity to coordinate hexachloroplatinic acid

Two Zn-metalloporphyrins, both containing at least one-pyridyl group, were studied regarding their capacity to complex hexachloroplatinic acid comprised in leaching solutions and resulted after hydrometallurgical processes on spent automotive catalysts. The number of pyridyl groups and the steric and electronic influences from surrounding groups determine a different type of coordination with the hexachloroplatinic acid from solution, and surprisingly, although containing only one group of basic pyridyl, the unsymmetrical Zn(II)- 5-pyridyl-10,15,20-tris-(3,4-di-methoxy-phenyl)-porphyrin had a removal capacity of 98% higher than that of Zn(II)-meso-tetrakis-pyridylporphyrin, substituted with four pyridyl groups, but with only a removal capacity of 84 %

Improvement of optical properties by fluorescein complexation with Nano-Pt- and Nano-Ag - porphyrin hybrids

Hybrid organic-inorganic nanomaterials based on Pt and Ag colloids, namely nanoAg-5,10,15,20-tetrakis-(4-aminophenyl)-porphyrin-Zn(II) (ZnTAPP-AgNPs) and nano-Pt5,10,15,20-tetrakis(N-methyl-4-pyridyl)porphyrin-Zn(II) tetrachloride (ZnTMePyP-PtNPs) were obtained and their capacity to form improved optically active complexes with fluorescein was investigated. By interaction with minute quantities of fluorescein the intensity of absorption of the plasmonic bands of the ZnTAPP-AgNPs and ZnTMePyP-PtNPs hybrids increases. ZnTMePyP-PtNPs hybrid will be further tested in clinical trials because it allows for a larger concentration domain of fluorescein complexation and more accurate dosage. All the sensitive materials are easy to prepare and respect the rules of sustainable chemistry