Ethynylphenyl-Derivatized Free Base Porphyrins: Anodic Oxidation Processes and Covalent Grafting onto Glassy Carbon Electrodes.

In six of seven cases, direct anodic oxidation of the ethynyl group of an ethynylphenyl-derivatized free-base porphyrin gave modified glassy carbon electrodes in which the porphyrin was strongly surface-bound, most likely in a perpendicular geometry through covalent attachment of the ethynyl group to a surface carbon atom. The porphyrins each contained an ethynylphenyl group in one meso position and varied in the groups present in the other three meso positions. Electrografted 5,10,15,20-tetrakis(ethynylphenyl)porphyrin, H, which has ethynyl moieties in all four meso positions, has well-defined surface voltammetry and grows to multilayer levels upon repeated cyclic voltammetry (CV) deposition scans.

Novel organometallic chloroquine derivative inhibits tumor growth.

Autophagy has emerged as a mechanism critical to both tumorigenesis and development of resistance to multiple lines of anti-cancer therapy. Therefore, targeting autophagy and alternative cell death pathways has arisen as a viable strategy for refractory tumors. The anti-malarial 4-aminoquinoline compounds chloroquine and hydroxychloroquine are currently being considered for re-purposing as anti-cancer therapies intended to sensitize different tumors by targeting the lysosomal cell death pathway.

Effect of Large Electrolyte Anions on the Sequential Oxidations of Bis(fulvalene)diiron Attached to Glassy Carbon by an Ethynyl Linkage.

Two ethynyl-derivatized isomers of bis(fulvalene)diiron (BFD, 1,1'-biferrocenylene) were prepared and covalently attached to glassy carbon electrodes through their ethynyl group by three different electrode modification methods. Cyclic voltammetry and square wave (SW) voltammetry were used to characterize surface coverages of 1.4-5.

Quality assessment and improvement of post graduate family medicine training in the USA.

Background: In 2013, the World Organisation of Family Doctors published training standards for post-graduate medical education (GME) in Family Medicine/General Practice (FP/GP). GME quality has not been well-defined, other than meeting accreditation standards. In 2009, the Association of Family Medicine Residency Directors (AFMRD) developed a tool that would aid in raising the quality of family medicine residency training in the USA.

Anodic Methods for Covalent Attachment of Ethynylferrocenes to Electrode Surfaces: Comparison of Ethynyl Activation Processes.

The electrochemical oxidation of ferrocenes having an H- or Li-terminated ethynyl group has been studied, especially as it relates to their covalent anchoring to carbon surfaces. The anodic oxidation of lithioethynylferrocene (1-Li) results in rapid loss of Li(+) and formation of the ethynyl-based radical FeCp(η(5)-C5H4)(C≡C), (1, Cp = η(5)-C5H5), which reacts with the electrode. Chemically modified electrodes (CMEs) were thereby produced containing strongly bonded, ethynyl-linked monolayers and electrochemically controlled multilayers.

Facilitated carbon dioxide reduction using a Zn(II) complex.

Two new Zn(II) complexes have been prepared and evaluated for their capacity to activate and reduce CO2. The electrochemical properties of dichlorobis[diphenyl-(2-pyridyl)phosphine-κ(1)-N]zinc(II) [corrected]. and dichloro[diphenyl-(2-pyridyl)phosphine-κ(1)-N]zinc(II) 2 are compared using cyclic voltammetry.

Unexpected formal insertion of CO2 into the C-Si bonds of a zinc compound.

Reaction of [κ2-PR2C(SiMe3)Py]2Zn (R = Ph, 2a; iPr, 2b) with CO2 affords the products of formal insertion at the C–Si bond, [κ2-PR2CC(O)O(SiMe3)Py]2Zn (R = Ph, 3a; iPr, 3b). Insertion product 3b was structurally characterized. The reaction appears to be a stepwise insertion and rearrangement of CO2 based on kinetic data.

The Residency Performance Index: An Effort at Residency Quality Assessment and Improvement in Family Medicine.

Background: Residency programs are increasingly being asked to defend their quality, and that of the residents they produce. Yet "residency quality" is a construct that has not been well defined, with no accepted standards other than meeting accreditation standards. In 2009, the Association of Family Medicine Residency Directors developed a strategic plan that included the goal of raising the quality of family medicine training.

Influence of cyclopentadienyl ring-tilt on electron-transfer reactions: redox-induced reactivity of strained [2] and [3]ruthenocenophanes.

In contrast to ruthenocene [Ru(η(5) -C5 H5 )2 ] and dimethylruthenocene [Ru(η(5) -C5 H4 Me)2 ] (7), chemical oxidation of highly strained, ring-tilted [2]ruthenocenophane [Ru(η(5) -C5 H4 )2 (CH2 )2 ] (5) and slightly strained [3]ruthenocenophane [Ru(η(5) -C5 H4 )2 (CH2 )3 ] (6) with cationic oxidants containing the non-coordinating [B(C6 F5 )4 ](-) anion was found to afford stable and isolable metalmetal bonded dicationic dimer salts [Ru(η(5) -C5 H4 )2 (CH2 )2 ]2 [B(C6 F5 )4 ]2 (8) and [Ru(η(5) -C5 H4 )2 (CH2 )3 ]2 [B(C6 F5 )4 ]2 (17), respectively. Cyclic voltammetry and DFT studies indicated that the oxidation potential, propensity for dimerization, and strength of the resulting RuRu bond is strongly dependent on the degree of tilt present in 5 and 6 and thereby degree of exposure of the Ru center. Cleavage of the RuRu bond in 8 was achieved through reaction with the radical source [(CH3 )2 NC(S)SSC(S)N(CH3 )2 ] (thiram), affording unusual dimer [(CH3 )2 NCS2 Ru(η(5) -C5 H4 )(η(3) -C5 H4 )C2 H4 ]2 [B(C6 F5 )4 ]2 (9) through a haptotropic η(5) -η(3) ring-slippage followed by an apparent [2+2] cyclodimerization of the cyclopentadienyl ligand.

Covalent attachment of porphyrins and ferrocenes to electrode surfaces through direct anodic oxidation of terminal ethynyl groups.

One with the surface: A method is presented for electrode modification with terminal alkynes and alkenes. Direct oxidation of these moieties leads to efficient grafting onto glassy carbon, gold, platinum, and indium tin oxide surfaces. Various ferrocenes and 5,10,15,20-(4-ethynylphenyl)porphyrin were attached in this way.

Metal complexes (M = Zn, Sn, and Pb) of 2-phosphinobenzenethiolates: insights into ligand folding and hemilability.

The divalent metal complexes M(II){(SC6H4-2-PR2)-κ(2)S,P}2 (3-7, and 9-11) (M = Zn, Sn, or Pb; R = (i)Pr, (t)Bu, or Ph), the Sn(IV) complexes Sn{(SC6H4-2-PR2)-κ(2)-S,P}Ph2Cl (12 and 13) (R = (i)Pr and (t)Bu), and the ionic Sn(IV) complexes [Sn{(SC6H4-2-PR2)-κ(2)-S,P}Ph2][BPh4] (14 and 15) (R = (i)Pr and (t)Bu) have been prepared and characterized by multinuclear NMR spectroscopy and single crystal X-ray diffraction when suitable crystals were afforded. The Sn(II) and Pb(II) complexes with R = Ph, (i)Pr, or (t)Bu (5, 6, 9, and 10) demonstrated ligand "folding" hinging on the P,S vector-a behavior driven by the repulsions of the metal/phosphorus and metal/sulfur lone pairs and increased M-S sigma bonding strength. This phenomenon was examined by density functional theory (DFT) calculations for the compounds in both folded and unfolded states.

An anodic method for covalent attachment of molecules to electrodes through an ethynyl linkage.

Electroactive organometallic molecules have been covalently attached to electrode surfaces through an ethynyl linkage. The process takes advantage of ethynyl-based radicals generated by anodic oxidation of a lithio-activated terminal ethynyl group. Electrophores containing redox-active ferrocene, cymantrene, or cobaltocenium moieties have been deposited at the one-to-three monolayer level.

Metal-metal bond formation between [n]metallocenophanes: synthesis and characterisation of a dicarba[2]ruthenocenophanium dimer.

Feeling the strain: The first example of metal-metal bonding between strained [n]metallocenophanes is reported. A dicarba[2]ruthenocenophanium dimer has been synthesised through the oxidation of a dicarba[2]ruthenocenophane (see figure). The structural and electrochemical characterisation of the dimer is also discussed.

Anodic properties of diarylethene derivatives having organometallic piano-stool tags.

The half-sandwich tamoxifen derivative, Mn(CO)(3)(η(5)-C(5)H(4)(Et)C=C(C(6)H(5))(2)), gives a radical cation which is charge-delocalized between the "cymantrenyl" and diphenylethene moieties and undergoes facile metal-carbonyl substitution reactions. Mn and Re complexes with finely tuned redox potentials can be obtained for cancer cell inhibition studies.

Organometallic electrodes: modification of electrode surfaces through cathodic reduction of cyclopentadienyldiazonium complexes of cobalt and manganese.

Two organometallic complexes having cyclopentadienyldiazonium ligands have been isolated and characterized by spectroscopy, X-ray crystallography, and electrochemistry. Both CoCp(η(5)-C(5)H(4)N(2))(2+) (2(2+)) and Mn(CO)(3)(η(5)-C(5)H(4)N(2))(+) (3(+)) undergo facile cyclopentadienyldiazonium ligand-based one-electron reductions which liberate dinitrogen and result in strong binding of the cyclopentadienyl ligand to a glassy carbon surface, similar to the processes well established for organic aryldiazonium salts. The organometallic-modified electrodes are robust and have a thickness of approximately one monolayer (Γ = (2-4) × 10(-10) mol cm(-2)).

Organometallic electrochemistry based on electrolytes containing weakly-coordinating fluoroarylborate anions.

Electrochemistry is a powerful tool for the study of oxidative electron-transfer reactions (anodic processes). Since the 1960s, the electrolytes of choice for nonaqueous electrochemistry were relatively small (heptaatomic or smaller) inorganic anions, such as perchlorate, tetrafluoroborate, or hexafluorophosphate. Owing to the similar size-to-charge ratios of these "traditional" anions, structural alterations of the electrolyte anion are not particularly valuable in effecting changes in the corresponding redox reactions.

Ligand-solvent interactions in a highly reduced metal chelate complex: medium dependence of the one-electron reduction of the bis(maleonitriledithiolato)gold dianion.

The one-electron reduction of [Au(mnt)(2)](2-) (mnt = [S(2)C(2)(CN)(2)](2-), maleonitriledithiolate), 1(2-), stands out in the rich redox chemistry of metal-mnt complexes as a chemically reversible but electrochemically irreversible process. Although the E(1/2) value of the primary redox reaction 1(2-)/1(3-) is only slightly medium dependent (ca. -1.

Cycloaddition reactions of unactivated olefins catalyzed by an organorhenium electron-transfer mediator.

An electrochemical process is described for the rapid and efficient conversion of unsubstituted cyclic olefins into cycloaddition products. When a potential of 1.25 V vs ferrocene was applied to a solution of cis-cyclooctene (COE) in dichloromethane/[NBu(4)][B(C(6)F(5))(4)] containing a catalytic amount (4 mol %) of ReCp(CO)(3), 1, the olefin was converted to a diastereomeric mixture of the C(8)-dimer tricyclohexadecane, with the major isomer having a cis-anti-cis geometry.

One-electron oxidation of ruthenocene: reactions of the ruthenocenium ion in gentle electrolyte media.

The electrochemical oxidation of ruthenocene, RuCp(2) (Cp = eta(5)-C(5)H(5)), 1, has been studied in dichloromethane using a supporting electrolyte containing either the [B(C(6)F(5))(4)](-) (TFAB) or the [B(C(6)H(3)(CF(3))(2))(4)](-) (BArF(24)) counteranion. A quasi-Nernstian process was observed in both cases, with E(1/2) values of 0.41 and 0.

Conjugated organometallic polymer containing a redox-active center.

The new conjugated organometallic polymer (-spacer-C[triple bond]C-Pt(PBu3)2-C[triple bond]C-)n (3; spacer = para-bis(diphenyl(tetramethyl)quinone diimine) and the cyclic mononuclear model complex, spacer'-C[triple bond]C-Pt(PEt3)2-C[triple bond]C x CuCl (4; spacer' = ortho-diphenyl-2,3,5,6-tetramethyl-1,4-benzoquinone diimine) were synthesized from the 1:1 condensation of the corresponding diethynyl ligands (2-para and 2-ortho (para- and ortho-diethynyl-diphenyl-2,3,5,6-tetramethylquinone diimine), respectively), with the trans-Pt(PBu3)2Cl2 for polymer 3 and cis-Pt(PEt3)2Cl2 for 4. The materials were characterized by GPC, DSC, ATG, and electrochemistry for polymer 3, and by X-ray diffraction for 4. Polymer 3 exhibits a M(n) of 18500, M(w) of 25000 with a PD of 1.

Cymantrene radical cation family: spectral and structural characterization of the half-sandwich analogues of ferrocenium ion.

The anodic one-electron oxidation of three members of the half-sandwich family of piano-stool compounds MnCp (gamma)(CO) 3, where Cp (gamma) is a generic cyclopentadienyl ligand, has been studied in a CH 2Cl 2/[NBu 4][TFAB] electrolyte (TFAB = [B(C6F5) 4] (-)). The long-sought 17 e (-) radical cation of the parent complex MnCp(CO) 3 (cymantrene, 1, E 1/2 = 0.92 V vs ferrocene) has been shown to be persistent in solutions that use weakly coordinating anions in place of more nucleophilic traditional electrolyte anions.