Pnictogen-based vanadacyclobutadiene complexes.

The reactivity of the V[triple bond, length as m-dash]C Bu multiple bonds in the complex (dBDI)V[triple bond, length as m-dash]C Bu(OEt) (C) (dBDI = ArNC(CH)CHC(CH)NAr, Ar = 2,6- PrCH) with unsaturated substrates such as N[triple bond, length as m-dash]CR (R = Ad or Ph) and P[triple bond, length as m-dash]CAd leads to the formation of rare 3d transition metal compounds featuring α-aza-vanadacyclobutadiene, (dBDI)V(κ- , - BuC(R)N) (R = Ad, 1; R = Ph, 2) and β-phospha-vanadacyclobutadiene moieties, (dBDI)V(κ- , - BuPAd) (3). Complexes 1-3 are characterized using multinuclear and multidimensional NMR spectroscopy, including the preparation of the 50% N-enriched isotopologue (dBDI)V(κ- , - BuCC(Ad)N) (1-N). Solid-state structural analysis is used to determine the dominant resonance structures of these unique pnictogen-based vanadacyclobutadienes.

Controlling the Size of Molecular Copper Clusters Supported by a Multinucleating Macrocycle.

The use of a nonrigid, pyridyldialdimine-derived macrocyclic ligand (PDAI) enabled the synthesis of well-defined mono-, di-, tri-, and tetra-nuclear Cu(I) complexes in good yields through rational synthetic means. Starting from mono- and diargentous PDAI complexes, transmetalation to Cu(I) proceeded smoothly with formation of AgX (X = Cl, I) salts to generate mono-, di-, and trinuclear copper complexes. Monodentate supporting ligands (MeCN, xylNC, PMe, PPh) were found to either transmetallate with or bind various di- and trinuclear clusters.

Bifunctional Ligands: Evaluating the Role of Acidic Protons in the Secondary Coordination Sphere.

To evaluate bifunctional ligand reactivity involving NH acidic sites in the secondary coordination sphere, complexes where the proton has been substituted with a methyl group (NMe) are often investigated. An alternative strategy involves substitution of the NH group for an O. This contribution considers and compares the merits of these approaches; the synthesis and characterization of cationic square-planar Rh carbonyl complexes bearing diprotic bispyrazole pyridine ligand L1, and the bis-methylated pyrazole pyridine ligand L1Me are described.

Bushy-Tailed QACs: The Development of Multicationic Quaternary Ammonium Compounds with a High Degree of Alkyl Chain Substitution.

Quaternary ammonium compounds have served as a first line of protection for human health as surface disinfectants and sanitizers for nearly a century. However, increasing levels of bacterial resistance have spurred the development of novel QAC architectures. In light of the observed reduction in eukaryotic cell toxicity when the alkyl chains on QACs are shorter in nature (≤10 C), we prepared 47 QAC architectures that bear multiple short alkyl chains appended to up to three cationic groups, thus rendering them "bushy-tailed" multiQACs.

A Vanadium Methylidene.

Examples of stable 3d transition metal methylidene complexes are extremely rare. Here we report an isolable and stable vanadium methylidene complex, [(PNP)V(=NAr)(=CH)] (PNP = N[2-PPr-4-methylphenyl], Ar = 2,6-PrCH), via H atom transfer (HAT) from [(PNP)V(NHAr)(CH)] or [(PNP)V(=NAr)(CH)] using two or one equivalents of the TEMPO radical (TEMPO = (2,2,6,6-tetramethylpiperidin-1-yl)oxyl), respectively. Alternatively, the vanadium methylidene moiety can also be formed via the treatment of transient [(PNP)V=NAr] with the Wittig reagent, HCPPh.

The current standard of the shoulder trauma series in Ireland - A national audit.

Objectives/aims: The primary aim of this study was to assess the current standard of shoulder radiographs in Ireland. The secondary aim of this study was to determine whether orthopaedic surgeons in Ireland are of the opinion that a national protocol is required, and what this protocol should consist of.

Methods: A national audit of shoulder trauma series x-rays performed in emergency departments was conducted.

Realization of Organocerium-Based Fullerene Molecular Materials Showing Mott Insulator-Type Behavior.

Electron-rich organocerium complexes (CMeH)Ce and [(CMe)Ce(-oxa)], with redox potentials = -0.82 V and = -0.86 V versus Fc/Fc, respectively, were reacted with fullerene (C) in different stoichiometries to obtain molecular materials.

Vanadium Alkylidyne Initiated Cyclic Polymer Synthesis: The Importance of a Deprotiovanadacyclobutadiene Moiety.

Reported is the catalytic cyclic polymer synthesis by a 3d transition metal complex: a V(V) alkylidyne, [(dBDI)V≡CBu(OEt)] (), supported by the deprotonated β-diketiminate dBDI (dBDI = ArNC(CH)CHC(CH)NAr, Ar = 2,6-PrCH). Complex is a precatalyst for the polymerization of phenylacetylene (PhCCH) to give cyclic poly(phenylacetylene) (-PPA), whereas its precursor, complex [(BDI)V≡CBu(OTf)] (; BDI = [ArNC(CH)]CH, Ar = 2,6-PrCH, OTf = OSOCF), and the zwitterion [((CF)B-dBDI)V≡CBu(OEt)] () exhibit low catalytic activity despite having a neopentylidyne ligand. Cyclic polymer topologies were verified by size-exclusion chromatography (SEC) and intrinsic viscosity studies.

Metallacyclobuta-(2,3)-diene: A Bidentate Ligand for Stream-line Synthesis of First Row Transition Metal Catalysts for Cyclic Polymerization of Phenylacetylene.

Described here is a direct entry to two examples of 3d transition metal catalysts that are active for the cyclic polymerization of phenylacetylene, namely, [(BDI)M{κ -C,C-(Me SiC SiMe )}] (2-M) (BDI=[ArNC(CH )] CH , Ar=2,6- Pr C H ; M=Ti, V). Catalysts are prepared in one step by the treatment of [(BDI)MCl ] (1-M, M=Ti, V) with 1,3-dilithioallene [Li (Me SiC SiMe )]. Complexes 2-M have been spectroscopically and structurally characterized and the polymers that are catalytically formed from phenylacetylene were verified to have a cyclic topology based on a combination of size-exclusion chromatography (SEC) and intrinsic viscosity studies.

Glenohumeral joint osteoarthritis is not associated with clavicle fractures in a large arthroplasty cohort.

Introduction: A recent study based on a large osteological collection reported an association between clavicle fractures and osteoarthritis of the glenohumeral joint. No clinical study has yet addressed this potential association. Other radiographic parameters such as the critical shoulder angle have been associated with the risk of glenohumeral joint osteoarthritis.

Metal-Ligand Redox Cooperativity in Cerium Amine-/Amido-Phenolate-Type Complexes.

The synthesis and characterization of two cerium complexes of redox-active amine/amido-phenolate-type ligands are reported. A tripodal framework comprising the tris(2-(3',5'-di--butyl-2'-hydroxyphenyl)amino-phenyl) amine (HClamp) proligand was synthesized for comparison of its cerium complex with a potassium-cerium heterobimetallic complex of the 4,6-di--butyl-2-[(2,6-diisopropylphenyl)imino]quinone (ap) proligand. Structural studies indicate differences in the cerium(III) cation coordination spheres, where Ce(CHCN)(HClamp) () exhibits shorter Ce-O distances and longer Ce-N bond distances compared to the analogous distances in K(THF)Ce(ap) (), due to the gross structural differences between the systems.

Tellurolate: an effective Te-atom transfer reagent to prepare the triad of group 5 metal bis(tellurides).

We show in this work how lithium tellurolate Li(X)TeCHSiMe (X = THF, = 1, 1; X = 12--4, = 2, 2), can serve as an effective Te-atom transfer reagent to all group 5 transition metal halide precursors irrespective of the oxidation state. Mononuclear and bis(telluride) complexes, namely (PNP)M(Te) (M = V; Nb, 3; Ta, 4; PNP = N[2-PPr-4-methylphenyl]), are reported herein including structural and spectroscopic data. Whereas the known complex (PNP)V(Te) can be readily prepared from the trivalent precursor (PNP)VCl, two equiv.

Observing Similarities and Differences in the Properties of Isostructural Niobium(V)/Tantalum(V) Coordination Compounds with Strong Pi-Donor Ligands.

While niobium and tantalum are found together in their mineral ores, their respective applications in technology require chemical separation. Nb/Ta separations are challenging due to the similar reactivities displayed by these metals in the solution phase. Coordination complexes of these metals have been studied in the contexts of catalysis, small-molecule activation, and functional group insertion reactivity; relatively few studies exist directly comparing the properties of isostructural Nb/Ta complexes.

Iron-Catalyzed Intermolecular C-H Amination Assisted by an Isolated Iron-Imido Radical Intermediate.

Here we report the use of a base metal complex [( pyrpyrr )Fe(OEt )] (1-OEt ) ( pyrpyrr =3,5-tBu -bis(pyrrolyl)pyridine) as a catalyst for intermolecular amination of C -H bonds of 9,10-dihydroanthracene (2 a) using 2,4,6-trimethyl phenyl azide (3 a) as the nitrene source. The reaction is complete within one hour at 80 °C using as low as 2 mol % 1-OEt with control in selectivity for single C-H amination versus double C-H amination. Catalytic C-H amination reactions can be extended to other substrates such as cyclohexadiene and xanthene derivatives and can tolerate a variety of aryl azides having methyl groups in both ortho positions.

Mediating Photochemical Reaction Rates at Lewis Acidic Rare Earths by Selective Energy Loss to 4f-Electron States.

Manifesting chemical differences in individual rare earth (RE) element complexes is challenging due to the similar sizes of the tripositive cations and the corelike 4f shell. We disclose a new strategy for differentiating between similarly sized Dy and Y ions through a tailored photochemical reaction of their isostructural complexes in which the f-electron states of Dy act as an energy sink. Complexes RE(hfac)(NMMO) (RE = Dy () and Y (), hfac = hexafluoroacetylacetonate, and NMMO = -methylmorpholine--oxide) showed variable rates of oxygen atom transfer (OAT) to triphenylphosphine under ultraviolet (UV) irradiation, as monitored by H and F NMR spectroscopies.

Investigating Metal-Metal Bond Polarization in a Heteroleptic Tris-Ylide Diiron System.

This article describes the synthesis, characterization, and S-atom transfer reactivity of a series of -symmetric diiron complexes. The iron centers in each complex are coordinated in distinct ligand environments, with one (Fe) bound in a pseudo-trigonal bipyramidal geometry by three phosphinimine nitrogens in the equatorial plane, a tertiary amine, and the second metal center (Fe). Fe is coordinated, in turn, by Fe, three ylidic carbons in a trigonal plane, and, in certain cases, by an axial oxygen donor.

A mononuclear, terminal titanium(III) imido.

We report the first mononuclear Ti complex possessing a terminal imido ligand. Complex [TpTi{NSi(CH)}(THF)] (2) (Tp = hydridotris(3--butyl-5-methylpyrazol-1-yl)borate) is prepared by reduction of [TpTi{NSi(CH)}(Cl)] (1) with KC in high yield. The connectivity and metalloradical nature of 2 were confirmed by single crystal X-ray diffraction studies, Q- and X-band EPR, UV-Vis and H NMR spectroscopies.

Isostructural bridging diferrous chalcogenide cores [Fe(μ-E)Fe] (E = O, S, Se, Te) with decreasing antiferromagnetic coupling down the chalcogenide series.

Iron compounds containing a bridging oxo or sulfido moiety are ubiquitous in biological systems, but substitution with the heavier chalcogenides selenium and tellurium, however, is much rarer, with only a few examples reported to date. Here we show that treatment of the ferrous starting material [(pyrpyrr)Fe(OEt)] (1-OEt) (pyrpyrr = 3,5-Bu-bis(pyrrolyl)pyridine) with phosphine chalcogenide reagents E = PR results in the neutral phosphine chalcogenide adduct series [(pyrpyrr)Fe(EPR)] (E = O, S, Se; R = Ph; E = Te; R = Bu) (1-E) without any electron transfer, whereas treatment of the anionic starting material [K][(pyrpyrr)Fe(μ-N)] (2-N) with the appropriate chalcogenide transfer source yields cleanly the isostructural ferrous bridging mono-chalcogenide ate complexes [K][(pyrpyrr)Fe(μ-E)] (2-E) (E = O, S, Se, and Te) having significant deviation in the Fe-E-Fe bridge from linear in the case of E = O to more acute for the heaviest chalcogenide. All bridging chalcogenide complexes were analyzed using a variety of spectroscopic techniques, including H NMR, UV-Vis electronic absorbtion, and Fe Mössbauer.

Cyclic β-hydroxy-α-nitrosulfone isomers readily interconvert open-chain aldehyde forms.

Two structurally diverse cyclic β-hydroxy-α-nitrosulfones have been prepared and their isomerisation reactions studied. These cyclic β-hydroxy-α-nitrosulfones undergo isomer equilibration open-chain aldehyde forms under a variety of mild conditions. Michael condensation of 1,1'-[(1,3-dinitro-1,3-propanediyl)bis(sulfonyl)]bis(benzene) with propenal and subsequent cyclisation afforded 2,4-dinitro-2,4-bis(phenylsulfonyl)cyclohexanol in 98% yield as a mixture of four diastereomers.

Electronic Structure Studies and Photophysics of Luminescent Th(IV) Anilido and Imido Complexes.

A series of thorium anilide compounds [ThNHAr(TriNOx)] (R = -OCH (), -H (), -Cl (), -CF (), TriNOx = (2--butylhydroxylaminato)benzylamine), and their corresponding imido compounds [Li(DME)][Th═NAr(TriNOx)] () as well as the alkyl congeners [ThNHAd(TriNOx)] () and [Li(DME)][Th═NAd(TriNOx)] (), have been prepared. The -substituents on the arylimido moiety were introduced for systematic variation of their electron-donating and withdrawing abilities, changes that were evident in measurements of the C{H} NMR chemical shifts of the -C atom of the Ar moiety. Room temperature, solution-state luminescence of the four new thorium imido compounds, along with the previously reported [Li(THF)][Th═NAr(TriNOx)] () and [Li(THF)(EtO)][Ce═NAr(TriNOx)] () have been described.

Silica Supported Organometallic Ir Complexes Enable Efficient Catalytic Methane Borylation.

Catalytic C-H borylation is an attractive method for the conversion of the most abundant hydrocarbon, methane (CH), to a mild nucleophilic building block. However, existing CH borylation catalysts often suffer from low turnover numbers and conversions, which is hypothesized to result from inactive metal hydride agglomerates. Herein we report that the heterogenization of a bisphosphine molecular precatalyst, [(dmpe)Ir(cod)CH], onto amorphous silica dramatically enhances its performance, yielding a catalyst that is 12-times more efficient than the current standard for CH borylation.

A Systematic Review of Shoulder Arthroplasty in Parkinson's Disease.

Background: Parkinson's disease is a degenerative neurological disorder that can cause both motor and nonmotor symptoms. Motor symptoms are associated with increasing the patient's falls risk. Shoulder arthroplasty surgery in this patient cohort is associated with more complications than non-Parkinsonian patients.

Arthroscopic Rotator Cuff Repair Results in Improved Clinical Outcomes and Low Revision Rates at 10-Year Follow-Up: A Systematic Review.

Purpose: To study the literature to evaluate the functional outcomes, radiologic outcomes, and revision rates following arthroscopic rotator cuff repair (ARCR) at a minimum of 10-years follow-up.

Methods: Two independent reviewers performed a literature search of PubMed, Embase, and Scopus using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Only studies reporting on outcomes of ARCR with a minimum 10-year follow-up were considered for inclusion.

Synthesis and Characterization of a Bridging Cerium(IV) Nitride Complex.

Complexes featuring lanthanide-ligand multiple bonds are rare and highly reactive. They are important synthetic targets to understand 4f/5d-bonding in comparison to d-block and actinide congeners. Herein, the isolation and characterization of a bridging cerium(IV)-nitride complex: [(TriNOx)Ce(Liμ-N)Ce(TriNOx)][BAr] is reported, the first example of a molecular cerium-nitride.

Metalating 5-Methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (ROY): Understanding the Denticity and Speciation of Complexes of the ROY Anion.

5-Methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (ROY) is considered to be the most crystalline polymorphic organic molecule discovered to date with 12 fully characterized crystal structures present in the Cambridge Structural Database (CSD). However, metal complexes of ROY have not previously been described. Here, we explore the synthetic chemistry of ROY (denoted as hereafter for the purpose of our study) and demonstrate that it can be deprotonated using either NaH or KH and that the resulting sodium and potassium salts of can be cleanly isolated.