Synthesis and characterizations of N,N-bis(diphenylphosphino)ethylaniline derivatives and X-ray crystal structure of palladium (II), platinum (II) complexes

N,N-Bis(diphenylphosphino)ethylaniline compounds, [Ph₂P]₂N-C₆H₄-C₂H₅, with ethyl groups at the ortho- and para-positions have been synthesized. Oxidation of the aminophosphines with hydrogen peroxide, elemental sulfur and selenium gave the corresponding oxides, sulfides and selenides [Ph₂P(E)]₂N-C₆H₄-C₂H₅ (E = O, S, Se). Complexes [MCl₂{(Ph₂P)₂N-C₆H₄-(C₂H₅)}] (M = Pd, Pt) and [Cu{(Ph₂P)₂N-C₆H₄-C₂H₅}₂]PF₆ were obtained by the reaction of N,N-bis(diphenylphosphino)ethylaniline with [MCl₂(COD)] (M = Pd, Pt) and [Cu(MeCN)₄]PF₆. The new compounds were characterized by NMR, IR spectroscopy and microanalysis. In addition, representative solid-state structures of the palladium and platinum complexes were determined using single crystal X-ray diffraction analyses.     

Cross‐coupling reactions in water using ionic liquid‐based palladium(II)–phosphinite complexes as outstanding catalysts

Two new phosphinite ligands based on ionic liquids [(Ph₂PO)C₇H₁₄N₂Cl]Cl ( 1 ) and [(Cy₂PO)C₇H₁₄N₂Cl]Cl ( 2 ) were synthesized by reaction of 1‐(3‐chloro‐2‐hydoxypropyl)‐3‐methylimidazolium chloride, [C₇H₁₅N₂OCl]Cl, with one equivalent of chlorodiphenylphosphine or chlorodicyclohexylphosphine, respectively, in anhydrous CH₂Cl₂ and under argon atmosphere. The reactions of 1 and 2 with MCl₂(cod) (M = Pd, Pt; cod = 1,5‐cyclooctadiene) yield complexes cis‐[M([(Ph₂PO)C₇H₁₄N₂Cl]Cl)₂Cl₂] and cis‐[M(Cy₂PO)C₇H₁₄N₂Cl]Cl)₂Cl₂], respectively. All complexes were isolated as analytically pure substances and characterized using multi‐nuclear NMR and infrared spectroscopies and elemental analysis. The catalytic activity of palladium complexes based on ionic liquid phosphinite ligands 1 and 2 was investigated in Suzuki cross‐coupling. They show outstanding catalytic activity in coupling of a series of aryl bromides or aryl iodides with phenylboronic acid under the optimized reaction conditions in water. The complexes provide turnover frequencies of 57 600 and 232 800 h^?1 in Suzuki coupling reactions of phenylboronic acid with p‐bromoacetophenone or p‐iodoacetophenone, respectively, which are the highest values ever reported among similar complexes for Suzuki coupling reactions in water as sole solvent in homogeneous catalysis. Furthermore, the palladium complexes were also found to be highly active catalysts in the Heck reaction affording trans‐stilbenes. Copyright © 2014 John Wiley & Sons, Ltd.     

Synthesis of new aminophosphine complexes and their catalytic activities in C-C coupling reactions

Two new aminophosphines, benzyl-N(Ph₂P)₂ and 2-picolyl-N(Ph₂P)₂, have been synthesized. Oxidation of the aminophosphines with either hydrogen peroxide, elemental sulfur and selenium gave the corresponding oxides, sulfides and selenides benzyl-N(Ph₂PE)₂ and 2-picolyl-N(Ph₂PE)₂, where E = O, S, or Se. Complexes [benzyl-N(Ph₂P)₂]MCl₂ and [2-picolyl-N(Ph₂P)₂]MCl₂, where M = Pd, Pt, were obtained by the reaction of the aminophosphines with MCl₂(cod). The new compounds were characterised by NMR, IR spectroscopy and microanalysis. Furthermore, representative solid-state structures of the palladium and platinum complexes were determined using single crystal X-ray diffraction analysis. The palladium complexes were further investigated as potential catalysts in C-C coupling reactions.     

Synthesis,Characterization, Crystal and Molecular Structure of 1,5‐Dihydro‐2H‐cyclopenta[1,2‐b:5,4‐b′]dipyridin‐2‐imine

The reaction of 1,5‐dihydro‐2H‐cyclopenta[1,2‐b:5,4‐b′]dipyridin‐2‐one ( 3 ) with an alkylamine (butylamine, hexylamine or ethylenediamine) yields, quite unexpectedly and in the absence of catalyst, the novel compound 1,5‐dihydro‐2H‐cyclopenta[1,2‐b:5,4‐b′]dipyridin‐2‐imine ( 4 ) as the sole, analytically pure, solid product, which was fully characterized. The structure of 4 was unequivocally solved by single‐crystal X‐ray‐diffraction analysis. The compound crystallizes in a monoclinic cell (space group P 2₁/c), with two molecules in the asymmetric unit, held together by intermolecular H‐bonds. Compound 4 could be interesting as a bi‐ or even tridentate ligand, and exhibits a strong fluorescence upon excitation at 310 nm. A mechanism, based on the observed C? N bond cleavage, is proposed.     

SERS‐based assays for sensitive detection of modafinil

In this paper, we proposed two sensitive surface‐enhanced Raman spectroscopy assays for the determination of modafinil in urine matrix. In the first assay, modafinil was extracted by solid phase extraction and determined after sandwiching with silver nanoparticles. In the second assay, modafinil was extracted by non‐specific interaction with magnetic gold nanoparticles and determined by sandwiching with magnetic gold and silver nanoparticles. The non‐specific magnetic extraction does not require any analyte specific agent like antibody, aptamer, or molecularly imprinted polymer, therefore, the cost and complexity of the assay is very low. Both assays are capable for application to urine samples with the detection limits under the minimum required performance limit of modafinil. The assays were validated in terms of accuracy, precision, detection limits, and ranges. Copyright © 2015 John Wiley & Sons, Ltd.     

Liquid chromatographic and spectrophotometric determination of diflucortolone valerate and isoconazole nitrate in creams

A new RP-LC method and two new spectrophotometric methods, principal component regression (PCR) and first derivative spectrophotometry, are proposed for simultaneous determination of diflucortolone valerate (DIF) and isoconazole nitrate (ISO) in cream formulations. An isocratic system consisting of an ACE C18 column and a mobile phase composed of methanol-water (95 + 5, v/v) was used for the optimal chromatographic separation. In PCR, the concentration data matrix was prepared by using synthetic mixtures containing these drugs in methanol-water (3 + 1, v/v). The absorbance data matrix corresponding to the concentration data matrix was obtained by measuring the absorbances at 29 wavelengths in the range of 242-298 nm for DIF and ISO in the zero-order spectra of their combinations. In first derivative spectrophotometry, dA/dlambda values were measured at 247.8 nm for DIF and at 240.2 nm for ISO in first derivative spectra of the solution of DIF and ISO in methanol-water (3 + 1, v/v). The linear ranges were 4.00-48.0 microg/mL for DIF and 50.0-400 microg/mL for ISO in the LC method, and 2.40-40.0 microg/mL for DIF and 60.0-260 microg/mL for ISO in the PCR and first derivative spectrophotometric methods. These methods were validated by analyzing synthetic mixtures. These three methods were successfully applied to two pharmaceutical cream preparations.     

Silver Nanoparticle Based Analysis of Aminoglycosides

Colorimetric silver nanoparticle sensor was developed for determination of aminoglycosides in milk. Silver nanoparticles were synthesized by using sodium borohydride as reducing agent and sodium dodecyl sulfate as stabilizer. Yellow color of silver turned into orange and red in proportion to the concentrations of analytes. Quantitative analyses were performed by using decrease in absorbance of silver nanoparticles at 394 nm. Linear ranges were 20–60 ng mL^?1, 23–60 ng mL^?1, and 60–100 ng mL^?1 for gentamicin, tobramycin, and amikacin, respectively. The method was optimized in terms of pH, ionic strength, and time. This simple and validated method was applied to milk samples and pharmaceutical preparations.     

Ruthenium(II) complexes derived from C2‐symmetric ferrocene‐based chiral bis(phosphinite) ligands: synthesis and catalytic activity towards the asymmetric reduction of acetophenones

Chiral secondary alcohols are very important building blocks and valuable synthetic intermediates both in organic synthesis and in the pharmaceutical industry for producing biologically active complex molecules. A series of new chiral Ru–phosphinite complexes ( 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ) were prepared from chiral C₂‐symmetric ferrocenyl phosphinites and corresponding chloro complex, [Ru(η⁶‐p‐cymene)(μ‐Cl)Cl]₂. The complexes were characterized using conventional spectroscopic methods. The binuclear complexes were tested as pre‐catalysts and were found to be good pre‐catalysts for the asymmetric transfer hydrogenation of substituted acetophenones in basic 2‐propanol at 82°C, providing the corresponding optically active alcohols with almost quantitative conversion and modest to high enantioselectivities (46–97%). Amongst the all complexes, complex 6 gave the highest ee of 97% in the reduction of 2‐methoxyacetophenone to (S)‐1‐(2‐methoxyphenyl)ethanol at 82°C. Copyright © 2015 John Wiley & Sons, Ltd.     

The application of tunable tridendate P‐based ligands for the Ru(II)‐catalysed transfer hydrogenation of various ketones

Two novel versatile tridendate aminophosphine–phosphinite and phosphinite ligands were prepared and their trinuclear neutral ruthenium(II) dichloro complexes were found to be effective catalysts for the transfer hydrogenation of various ketones in excellent conversions up to 99% in the presence of 2‐propanol/NaOH in 0.1 M isopropanol solution. Particularly, [Ru₃(PPh₂OC₂H₄)₂ N–PPh₂(η⁶‐p‐cymene)₃Cl₆] acts as an excellent catalyst giving the corresponding alcohols in excellent conversion up to 99% (turnover frequency ≤ 1176 h^?1). A comparison of the catalytic properties of the complexes is also discussed briefly. Furthermore, the structures of these ligands and their corresponding complexes have also been clarified using a combination of multinuclear NMR spectroscopy, infrared spectroscopy and elemental analysis. ¹H–¹³C HETCOR or ¹H–¹H COSY correlation experiments were used to confirm the spectral assignments. Copyright © 2014 John Wiley & Sons, Ltd.     

New bis(diphenylphosphino)aniline derivatives: Synthesis and spectroscopic characterization

Six new multidentate bis(diphenyl‐phosphino)amine [R–N(PPh₂)₂] ligands have been prepared from the reaction of aniline derivatives, R–NH₂, with Ph₂PCl in the presence of triethylamine. All of the compounds were obtained in good yields and were characterized by NMR, IR, and microanalysis. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:613–616, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20362