We have examined the catalytic activity of an iron(III) complex bearing the 14,28-[1,3-diiminoisoindolinato]phthalocyaninato (diiPc) ligand in oxidation reactions with three substrates (cyclohexane, cyclooctane, and indan). This modified metallophthalocyaninato complex serves as an efficient and selective catalyst for the oxidation of cyclohexane and cyclooctane, and to a far lesser extent indan. In the oxidations of cyclohexane and cyclooctane, in which hydrogen peroxide is employed as the oxidant under inert atmosphere, we have observed turnover numbers of 100.9 and 122.2 for cyclohexanol and cyclooctanol, respectively. The catalyst shows strong selectivity for alcohol (vs. ketone) formation, with alcohol to ketone (A/K) ratios of 6.7 and 21.0 for the cyclohexane and cyclooctane oxidations, respectively. Overall yields (alcohol + ketone) were 73% for cyclohexane and 92% for cyclooctane, based upon the total hydrogen peroxide added. In the catalytic oxidation of indan under similar conditions, the TON for 1-indanol was 10.1, with a yield of 12% based upon hydrogen peroxide. No 1-indanone was observed in the product mixture.
Purpose
PEG-phospholipid-based micelles have been successfully used for the solubilization of several hydrophobic drugs but generally lack sustained stability in blood. Our novel PEG-Fluorocarbon-DSPE polymers were designed to increase stability and improve time-release properties of drug-loaded micelles.
Methods
Novel ABC fluorous copolymers were synthesized, characterized, and used for encapsulation release of amphotericin B. FRET studies were used to study micelle stability.
Results
The micelles formed by the new polymers showed lower critical micelle concentrations and higher viscosity cores compared with those formed by the polymers lacking the fluorous block. FRET studies indicated that fluorocarbon-containing micelles had increased stability in the presence of human serum. Physicochemical properties and in vitro release profile of the micelles loaded with Amphotericin B (AmB) were studied.
Conclusions
The effect of PEG length and fluorocarbon incorporation were investigated. The shorter hydrophilic PEG-2K induced greater stability than PEG-5K by decreasing the proportion of hydrophilic block of the polymer. The fluorocarbon placed between hydrophilic and hydrophobic block formed a fluorous shell contributing to the enhanced thermodynamic stability of micelles and to the drug sustained release. Polymer mPEG2K-F10-DSPE, bearing both a fluorocarbon block and a shorter mPEG, showed the greatest stability and the longest half-life for AmB release.
We have resolved the enantiomers of a series of chiral modified metallophthalocyaninato complexes of nickel bearing alkoxy groups at the 14 and 28 positions on what would otherwise be a normal phthalocyaninato ligand and conforming to the general formula [14,28-(RO)(2)Pc]Ni(ii), where R = Me, Et, or n-Pr. The complex for which R = n-Pr is reported here for the first time. Resolution of the enantiomers of these complexes was accomplished via HPLC utilizing an immobilized carbohydrate-based stationary phase, resulting in baseline resolution of peaks corresponding to enantiomers of the complexes, with R(s) values in excess of five. Isolation of milligram quantities of the complexes bearing methoxy and n-propoxy groups in high enantiomeric excess has been achieved via semi-preparative-scale HPLC on the same stationary phase. Resolved samples of these compounds do not appear to racemize at an appreciable rate, nor do they readily exchange alkoxy groups with alcohols while stirring in alcoholic solution. The spectroscopic details and the crystallographically-determined solid-state structure for the complex where R = n-Pr are reported, and are highly similar to those that have been observed for the previously reported analogues. It has been shown by NMR that the chirality and C(2) molecular symmetry of the complex bearing n-propoxy groups is maintained in solution.
Linear, dibranched and miktoarm amphiphiles containing both hydrophobic and fluorophilic moieties were synthesized and
characterized in an attempt to elucidate the relationship between semi-fluorinated amphiphile structure and aggregate behaviour in
aqueous solution. For the linear and dibranched amphiphiles, there was an exponential decrease in critical aggregation
concentration (CMC) and a logarithmic increase in core microviscosity with increasing length of the fluorocarbon segments; while
the miktoarm architecture produced no notable trend in microviscosity or CMC. Furthermore, the linear and dibranched surfactants
showed enhanced kinetic stability, dissociating more slowly in the presence of human serum than did either the dibranched or
miktoarm amphiphiles. Finally, encapsulation studies with the hydrophobic drug paclitaxel (PTX) showed that the ability to
solubilize and retain PTX increased with the presence and with the increasing size of the fluorocarbon moiety for both the linear
and dibranched amphiphiles, while no such trend was observed for the miktoarm amphiphiles.
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