Synthesis and Characterization of Ligand-Stabilized Silver Nanoparticles and Comparative Antibacterial Activity against .

Silver is a well-established antimicrobial agent. Conjugation of organic ligands with silver nanoparticles has been shown to create antimicrobial nanoparticles with improved pharmacodynamic properties and reduced toxicity. Twelve novel organic ligand functionalized silver nanoparticles (AgNPs) were prepared via a light-controlled reaction with derivatives of benzothiazole, benzoxazine, quinazolinone, 2-butyne-1,4-diol, 3-butyne-1-ol, and heptane-1,7-dioic.

Cobalt(III)- and rhodium(III)-porphyrin complexes for the effective degradation of fentanyl: Biological inactivation and mechanistic insights.

Cobalt(III) and rhodium(III) complexes containing the water-soluble porphyrin ligand meso-tri(4-sulfonatophenyl)mono(4-carboxyphenyl)porphine (CSTPP), [Rh(CSTPP)]Na•nHO (1) and [Co(CSTPP)]Na•nHO (2) were prepared from the direct reaction of free porphyrin and metal chloride salts in refluxing MeOH/DMF or EtOH/HO. Compounds 1 and 2 were characterized using UV-vis and H NMR spectroscopies, and high-resolution mass spectrometry. Cell culture based assays of opioid receptor activation showed that while the rhodium complex reduced fentanyl opioid activity 113-fold to an IC50 value of 1.

Investigation of copper oxidation states in plasmonic nanomaterials by XAS and Raman spectroscopy.

Plasmonic core-shell-isolated nanoparticles are promising nanoplatforms for photocatalysis and for low detection analysis. This paper describes the characterization of a 2,2'-bipyridine phosphonate functionalized Ag@TiO nanocomposite which complexes copper ions by enhanced Raman spectroscopy and X-ray absorption (XANES and EXAFS). We distinguished Cu(i) from Cu(ii) complexes using shell-isolated nanoparticle enhanced Raman (SHINERS) combined with XAS spectroscopy.

Surface modification of plasmonic noble metal-metal oxide core-shell nanoparticles.

A comprehensive survey on the methods for the surface modification of plasmonic noble metal-metal oxide core-shell nanoparticles is presented. The review highlights various strategies for covalent attachment and electrostatic binding of molecules and molecular ions to core-shell nanoparticles with a focus on plasmonically active silver and gold nanoparticles encapsulated by SiO and TiO shells.

Functionalized core-shell Ag@TiO nanoparticles for enhanced Raman spectroscopy: a sensitive detection method for Cu(ii) ions.

This paper demonstrates the use of surface plasmon resonance of core-shell Ag@TiO2 particles in SHINERS experiments. A copper(ii) complex grafted onto Ag@TiO2 surface was probed by Raman spectroscopy using resonance excitation profiles vs. excitation wavelengths (514, 633 and 785 nm) to tune the Raman signals.

Non-photochemical catalytic hydrolysis of methyl parathion using core-shell Ag@TiO nanoparticles.

Highly water-dispersible core-shell Ag@TiO nanoparticles were prepared and shown to be catalytically active for the rapid degradation of the organothiophosphate pesticide methyl parathion (MeP). Formation of the hydrolysis product, -nitrophenolate was monitored at pH 7.5 and 8.

Synthesis of a Reactive Oxygen Species-Responsive Doxorubicin Derivative.

A heterobifunctional reactive oxygen species (ROS)-responsive linker for directed drug assembly onto and delivery from a quantum dot (QD) nanoparticle carrier was synthesized and coupled to doxorubicin using -(3-dimethylaminopropyl)-'-ethylcarbodiimide hydrochloride (EDC)/sulfo⁻NHS coupling. The doxorubicin conjugate was characterized using ¹H NMR and LC-MS and subsequently reacted under conditions of ROS formation (Cu/H₂O₂) resulting in successful and rapid thioacetal oxidative cleavage, which was monitored using ¹H NMR.

Kinetic analysis of the hydrolysis of methyl parathion using citrate-stabilized 10 nm gold nanoparticles.

"Ligand-free" citrate-stabilized 10 nm gold nanoparticles (AuNPs) promote the hydrolysis of the thiophosphate ester methyl parathion (MeP) on the surface of gold as a function of pH and two temperature values. At 50 °C, the active surface gold atoms show catalytic turnover ∼4 times after 8 h and little turnover of gold surface atoms at 25 °C with only 40% of the total atoms being active. From Michaelis-Menten analysis, k(cat) increases between pH 8 and 9 and decreases above pH 9.

Crystal structure of catena-poly[[chlorido-(4,4'-dimethyl-2,2'-bi-pyridine-κ(2) N,N')copper(II)]-μ-chlorido].

The title compound, [CuCl2(C12H12N2)] n , was obtained via a DMSO-mediated dehydration of Cu(4,4'-dimethyl-2,2'-bi-pyridine)-copper(II)·0.25H2O. The central Cu(II) atom is coordinated in a distorted trigonal-bipyramidal geometry by two N atoms of a chelating 4,4'-dimethyl-2,2'-bi-pyridine ligand [average Cu-N = 2.

Attaching high charge density metal ions to surfaces and biomolecules. Reaction chemistry of hypodentate cobalt diamine complexes.

Hypodentate diamine cobalt(III) pentammine complexes [Co(NH3)5(NH2(CH2)(n)NH3)](ClO4)4 (8: a: n = 3; b: n = 4; c: n = 6; d: n = 8) have been synthesized via the reaction of [Co(NH3)5(OTf)](OTf)2 (TfOH = CF3SO3H) with the corresponding diamines. The analogous t-boc protected diamine complexes [Co(NH3)5(NH2(CH2)(n)NHt-boc)](ClO4)3 (7a-d) were prepared in 4-26% yield. Low yields for the formation of 7a-d are due to competing side reactions which also gave [Co(NH3)6](3+).

Synthesis of a 2,2'-bipyridyl functionalized oligovinylene-phenylene using Heck and Horner-Wadsworth-Emmons reactions and X-ray crystal structure of E-(4-(4-bromostyryl)phenyl)(methyl)sulfane.

The synthesis of a new 2,2'-bipyridyl functionalized oligovinylenephenylene (OVP-5) containing a methyl protected thiol using Heck coupling and the Horner-Wadsworth-Emmons reaction and is described. A key step involving a diisopropylcarbodiimide promoted dehydration of a stable β-hydroxyphosphonate intermediate was identified. The structure of precursor E-(4-(4-bromostyryl)phenyl)(methyl)sulfane was determined using X-ray crystallography.

Accelerating the initial rate of hydrolysis of methyl parathion with laser excitation using monolayer protected 10 nm Au nanoparticles capped with a Cu(bpy) catalyst.

Using a low power green laser, we have demonstrated a rate acceleration of ~2-fold for the hydrolysis of methyl parathion by irradiating the plasmon absorption band of Au nanoparticles capped with a Cu(bpy) catalyst.

Oxidation of trimethoprim by ferrate(VI): kinetics, products, and antibacterial activity.

Kinetics, stoichiometry, and products of the oxidation of trimethoprim (TMP), one of the most commonly detected antibacterial agents in surface waters and municipal wastewaters, by ferrate(VI) (Fe(VI)) were determined. The pH dependent second-order rate constants of the reactions of Fe(VI) with TMP were examined using acid-base properties of Fe(VI) and TMP. The kinetics of reactions of diaminopyrimidine (DAP) and trimethoxytoluene (TMT) with Fe(VI) were also determined to understand the reactivity of Fe(VI) with TMP.

Poly[aqua(μ-vinyl-phospho-nato)cadmium].

The title compound, [Cd(C(2)H(3)O(3)P)(H(2)O)](n), was obtained from vinyl-phospho-nic acid and cadmium nitrate. The vinyl groups project into the inter-lamellar space and the structure is held together via van der Waals forces. The Cd(2+) ion is six-coordinate and the geometry is best described as distorted octa-hedral, with O-Cd-O angles falling within the range 61.

Cobalt Complexes as Antiviral and Antibacterial Agents.

Metal ion complexes are playing an increasing role in the development of antimicrobials. We review here the antimicrobial properties of cobalt coordination complexes in oxidation state 3+. In addition to reviewing the cobalt complexes containing polydentate donor ligands, we also focus on the antimicrobial activity of the homoleptic [Co(NH₃)₆] ion.

Antiviral properties of cobalt(III)-complexes.

We have investigated the potential antiviral activity of three cobalt(III) compounds. Two compounds, Co(III)-cyclen-methylbenzoic acid and its methyl ester derivative, are based on the macrocyclic chelator, cyclen, and were synthesized in our laboratory. Both compounds have been shown to bind tightly to nucleic acids and to hydrolyze phosphodiester bonds.

RNA hydrolysis and inhibition of translation by a Co(III)-cyclen complex.

Metal ion-chelator catalysts based on main-group, lanthanide, or transition metal complexes have been developed as nonenzymatic alternatives for the hydrolysis of the phosphodiester bonds in DNA and RNA. Cobalt (III), with its high-charge density, is known for its ability to hydrolyze phosphodiesters with rate constants as high as 2 x 10(-4) s(-1). We have developed a kinetically inert Co(III)-cyclen-based complex, Co(III)-cycmmb that is very potent in inhibiting the translation of RNA into protein.

Carboxylic acid functionalized cobalt(III) cyclen complexes for catalytic hydrolysis of phosphodiester bonds.

4-(1,4,7,10-Tetraazacyclotetradec-1-yl)methylbenzoic acid (cycmba, 1) has been synthesized, as a step towards the eventual development of sequence-specific hydrolytic complexes. A cobalt(III) complex of 1, [Co(cycmba)Cl2]Cl.1.

Coordination chemistry of the water-soluble ligand TPPTP and formation of a [Mo(CO)5(m-TPPTP)] monolayer on an alumina surface.

Phosphonate and phosphonic acid functionalized phosphine complexes of platinum(II) were prepared via direct reaction of the ligands with K2PtCl4 in water. Either cis or trans geometries were found depending on the nature of the ligand. The crystal structure of P(3-C6H4PO3H2)3.

Synthesis and Characterization of Palladium(II) and Platinum(II) Complexes Containing Water-Soluble Hybrid Phosphine-Phosphonate Ligands.

Water-soluble phosphonate-functionalized triaryl phosphine ligands Na(2)[Ph(2)P(4-C(6)H(4)PO(3))].1.5H(2)O (4a), Na(2)[Ph(2)P(3-C(6)H(4)PO(3))].