Hard and soft porphyrins: equilibrium constants for Cd2 and Pb2 with water‐soluble free base porphyrins

2000 ◽  
Vol 4 (3) ◽  
pp. 256-260
Author(s):  
Ray Hall Self ◽  
P. Hambright
Keyword(s):  
Equilibrium Constants ◽  
Water Soluble ◽  
Free Base

Hard and soft porphyrins: equilibrium constants for Cd2+ and Pb2+ with water-soluble free base porphyrins

2000 ◽  
Vol 04 (03) ◽  
pp. 256-260 ◽  
Author(s):  
RAY HALL SELF ◽  
P. HAMBRIGHT
Keyword(s):  
Equilibrium Constants ◽  
Water Soluble ◽  
Free Base

Equilibrium constants (1:1) for the reactions of cadmium(II) and lead(II) with water-soluble free base porphyrins of differing basicities (pK3) are reported. Soft porphyrins with low pK3 values favor the softer Cd (II), while harder porphyrins with higher pK3 values have more affinity for the relatively harder Pb (II) ion.

Free-base corroles: determination of deprotonation constants in non-aqueous media

2007 ◽  
Vol 11 (04) ◽  
pp. 269-276 ◽  
Author(s):  
Jing Shen ◽  
Zhongping Ou ◽  
Jianguo Shao ◽  
Michał Gałęzowski ◽  
Daniel T. Gryko ◽  
...  
Keyword(s):  
Equilibrium Constants ◽  
Aqueous Media ◽  
Free Base ◽  
Organic Base ◽  
Experimental Conditions ◽  
Spectral Changes ◽  
Base Analysis ◽  
Uv Visible ◽  
The Given

A series of free-base corroles with different electron-donating or electron-withdrawing substituents were reacted with piperidine, 4-aminopyridine, 2-methylimidazole, 2-aminopyridine or pyridine in PhCN and the UV-visible spectral changes monitored during conversion of ( Cor ) H 3 to [( Cor ) H 2]- as a function of the concentration and strength of the added organic base. Analysis of the UV-visible spectral changes as a function of the added base concentration enabled calculation of equilibrium constants ( logK ) for deprotonation of each corrole under the given experimental conditions. Relationships are examined between the experimentally measured logK values and previously published spectroscopic and structural properties of the compounds.

Thermochromism of Metal Exchange Reaction between Zinc(II) and Mercury(II) Porphyrins

1995 ◽  
Vol 50 (4) ◽  
pp. 545-550 ◽  
Author(s):  
Masaaki Tabata ◽  
Masahiro Ide ◽  
Kentaro Kaneko
Keyword(s):  
Aqueous Solution ◽  
Exchange Reaction ◽  
Thermodynamic Parameters ◽  
Distribution Curve ◽  
Equilibrium Constants ◽  
Metal Exchange ◽  
Free Base ◽  
Temperature Range ◽  
Base Form ◽  
Metal Exchange Reaction

Thermochromism was observed for an aqueous solution containing zinc(II) and mercury( II) cations and N-p-nitrobenzyl-5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin anion (NO2Bz(Htpps)4-) in the temperature range 10 to 70 °C. The equilibrium constants and the thermodynamic parameters of Zn(NO2Bztpps)3- and Hg(NO2Bztpps)3- have been determined spectrophotometrically to elucidate the thermochromism at 10, 15, 20, 25 and 30 °C in 0.1 mol dm-3 NaNO3. The protonation and metalation constants of NO2Bz(Htpps)4- are defined as K2 = [H2P][H+]-1[HP]-1, K3 = [H3P][H+]-1[H2P]-1 and KMP = [M P][H+][M2+]-1[HP]-1, where HP and MP denote the free base form of the prophyrin and the metalloporphyrins of zinc(II) and mercury(II), respectively. Charges of the prophyrin and metalloporphyrins are omitted for simplicity. The following values were found: logK2 = 7.75 ±0.02 (25 °C), ΔH°/kJmol-1 = -21.2±0.5 and ΔS°/Jmol-1K-1 = 77±1, logK3 = 2.55±0.02 (25 °C), ΔH°/kJmol-1 = -25±0.8 and ΔS°/Jmol-1K-1 = -35±3 and log KZnP = 0.63±0.03 (25 °C), ΔH°/kJmol-1 = 31.0±0.8 and ΔS°/Jmol-1K-1 = 116±3, logKHgP = 6.22±0.03 (25 °C), ΔH°/kJmol-1 = 4.5±0.7 and ΔS°/Jmol-1K-1 = 134±2. The distribution curve calculated from the thermodynamic parameters sufficiently agrees with the observed metal exchange reaction between the metalloporphyrins.

Synthesis and characterization of water-soluble free-base, zinc and copper porphyrin–oligonucleotide conjugates

2008 ◽  
Vol 16 (13) ◽  
pp. 6544-6551 ◽  
Author(s):  
Angela Mammana ◽  
Tomohiro Asakawa ◽  
Klaus Bitsch-Jensen ◽  
Amanda Wolfe ◽  
Saireudee Chaturantabut ◽  
...  
Keyword(s):  
Water Soluble ◽  
Synthesis And Characterization ◽  
Free Base ◽  
Copper Porphyrin ◽  
Oligonucleotide Conjugates

Colorimetric assay for the rapid determination of free-base nicotine in e-liquid

2020 ◽  
Vol 12 (2) ◽  
pp. 193-199
Author(s):  
Yan-Jun Huang ◽  
Qi-Xin Deng ◽  
Hong-Qiao Lan ◽  
Zheng-Zhong Fang ◽  
Hui Chen ◽  
...  
Keyword(s):  
Rapid Determination ◽  
Colorimetric Assay ◽  
Water Soluble ◽  
Free Base ◽  
Base Form

Nicotine exists in e-liquids primarily as the monoprotonated form and free-base form. The free-base form could be evaluated by use of a water-soluble indicator.

Bioconjugatable synthetic chlorins rendered water-soluble with three PEG-12 groups via click chemistry

2020 ◽  
Vol 24 (01n03) ◽  
pp. 362-378 ◽  
Author(s):  
Nobuyuki Matsumoto ◽  
Masahiko Taniguchi ◽  
Jonathan S. Lindsey
Keyword(s):  
Aqueous Solution ◽  
Quantum Yield ◽  
Click Chemistry ◽  
Fluorescence Quantum Yield ◽  
Molecular Design ◽  
Water Soluble ◽  
Propanoic Acid ◽  
Free Base ◽  
Yield Formula ◽  
Water Solubilization

Chlorins provide many ideal features for use as red-region fluorophores but require molecular tailoring for solubilization in aqueous solution. A chlorin building-block bearing 18,18-dimethyl, 15-bromo and 10-[2,4,6-tris(propargyloxy)phenyl] substituents has been transformed via click chemistry with CH3(OCH2CH[Formula: see text]-N3 followed by Suzuki coupling with 3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)propanoic acid, thereby installing a water-solubilization motif and a bioconjugatable handle, respectively. In toluene, [Formula: see text]-dimethylformamide (DMF) or water, the resulting facially encumbered free base chlorin exhibits characteristic chlorin absorption ([Formula: see text] [Formula: see text]412, 643 nm) and fluorescence ([Formula: see text] [Formula: see text]645 nm) spectra with only modest variation in fluorescence quantum yield ([Formula: see text] values (0.24, 0.25 and 0.19, respectively). The zinc chlorin derived therefrom exhibits similar spectral constancy ([Formula: see text] [Formula: see text]414 and 613 nm, [Formula: see text] [Formula: see text]616 nm) and [Formula: see text] 0.094, 0.10 and 0.086 in the three solvents. The results together indicate the viability of the molecular design and synthetic methodology to create red-region fluorophores for use in diverse applications.

Solvent and acidity effects on the UV-visible spectra and protonation-deprotonation of free-base octaethylcorrole

2008 ◽  
Vol 12 (01) ◽  
pp. 1-10 ◽  
Author(s):  
Zhongping Ou ◽  
Hongxia Sun ◽  
Weihua Zhu ◽  
Zulin Da ◽  
Karl M. Kadish
Keyword(s):  
Equilibrium Constants ◽  
Visible Spectrum ◽  
Soret Band ◽  
Free Base ◽  
Tetrabutylammonium Hydroxide ◽  
Experimental Conditions ◽  
Visible Spectra ◽  
Meso Position ◽  
Uv Visible ◽  
Strong Acids

The UV-visible spectrum of free-base octaethylcorrole, (OECor) H 3, was recorded in thirteen different nonaqueous solvents as well as in a mixed acetonitrile/acid solvent containing one of seven different acids. Spectra were also measured in seven different solutions of neat concentrated acid and in CH 3 CN containing piperidine or tetrabutylammonium hydroxide as an added base. The overall data was analyzed as a function of solvent acidity or basicity parameters and the number of protons on the central nitrogens of the macrocycle, the predominant form of the corrole in these solutions being respresented as (OECor)H 3, [ (OECor)H 4]+, [ (OECor)H 2]− or [ (OECor)H ]2− where OECor = trianion of octaethylcorrole. The mono-protonated corrole, [ (OECor)H 4]+, is formed in concentrated acetic acid or in CH 3 CN containing 0.10 M trifluoroacetic acid, H 2 SO 4, HCl , H 3 PO 4 or HClO 4. The mono-deprotonated corrole, [ (OECor)H 2]−, is generated in piperidine while doubly deprotonated [ (OECor)H ]2− exists in solutions of tetrabutylammonium hydroxide. An addition of protons to the macrocycle of [ (OECor)H 4]+ also occurs in the presence of concentrated strong acids and this results in a loss of the characteristic Soret band of the corrole leading presumably to [ (OECor)H 5]2+ where the second proton has been added to a meso-position of the macrocycle. The UV-visible spectral changes upon formation of [ (OECor)H 4]+, [ (OECor)H 2]− or [ (OECor)H ]2− in CH 3 CN were monitored during a titration with the relevent acid or base and equilibrium constants for protonation or deprotonation of (OECor)H 3 were determined using standard equations. The measured logK values are compared to protonation and deprotonation constants obtained for two related corroles and two related porphyrins under the same experimental conditions.

High pH sensing with water-soluble porpholactone derivatives and their incorporation into a Nafion® optode membrane

The Analyst ◽  
2015 ◽  
Vol 140 (1) ◽  
pp. 190-196 ◽  
Author(s):  
Jill L. Worlinsky ◽  
Steven Halepas ◽  
Masoud Ghandehari ◽  
Gamal Khalil ◽  
Christian Brückner
Keyword(s):  
Metal Complexes ◽  
Water Soluble ◽  
Ph Sensing ◽  
Free Base ◽  
Aryl Group ◽  
High Ph ◽  
Optode Membrane

The known optical high pH sensing chromophores, free base and metal complexes (M = 2H, Zn(ii), Pt(ii)) of meso-tetrakis(pentafluorophenyl)porpholactone, and the as yet untested Ga(iii) complex, were made freely water-soluble by derivatization at the aryl group with PEG chains.

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