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The quantification of cannabinoids is an essential part of cannabis profiling and testing, whether for medical or recreational use. As regulatory bodies continue to increase testing requirements for these products, it is crucial that alternative and effective analytical methods be developed. Herein, we describe the use of benchtop NMR instruments for the quantification of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in a variety of cannabis concentrates and compare the values to those obtained using HPLC, the most common approach for the quantification of cannabinoids. Based on the discrepancies observed in test values from different laboratories using only HPLC, the value of orthogonal testing methods has been identified and is increasingly desired.

Real‐time polymerase chain reaction (PCR) for SARS‐CoV‐2 is the mainstay of COVID‐19 diagnosis, yet there are conflicting reports on its diagnostic performance. Wide ranges of false‐negative PCR tests have been reported depending on clinical presentation, the timing of testing, specimens tested, testing method, and reference standard used. We aimed to estimate the frequency of discordance between initial nasopharyngeal (NP) PCR and repeat NP sampling PCR and serology in acutely ill patients admitted to the hospital. Panel diagnosis of COVID‐19 infection is further utilized in discordance analysis. Included in the study were 160 patients initially tested by NP PCR with repeat NP sampling PCR and/or serology performed. The percent agreement between initial and repeat PCR was 96.7%, while the percent agreement between initial PCR and serology was 98.9%. There were 5 (3.1%) cases with discordance on repeat testing. After discordance analysis, 2 (1.4%) true cases tested negative on initial PCR. Using available diagnostic methods, discordance on repeat NP sampling PCR and/or serology is a rare occurrence.

The use of nickel complexes utilizing non-innocent ligands based on picolinamide to function as redox carriers in flow batteries was explored. The picolinamide moiety was linked together with -CH2 CH2 - (bpen), -CH2 CH2 CH2 - (bppn), and -C6 H4 - (bpb) moieties, resulting in two, three, and four quasi-reversible waves, respectively, for the nickel complexes and >3 V difference between the outermost positive and negative waves. The redox events were theoretically modelled for each complex, showing excellent agreement (

Redox flow batteries (RFBs) have recently been recognized as a potentially viable technology for scalable energy storage. To take full advantage of RFBs, one possible approach for achieving high energy densities is to maximize a number of redox events by utilizing charge carriers capable of multiple one-electron transfers within the electrochemical window of solvent. However, past efforts to develop more efficient electrolytes for nonaqueous RFBs have mostly been empirical. In this manuscript, we shed light on design principles by theoretically investigating the effects of systematically substituting pyridyl moieties with imine ligands within a series of Fe complexes with some experimental validation. We found that such replacement is an effective strategy for reducing the molecular weight-to-charge ratios of these complexes. Simultaneously, calculations suggest that the reduction potentials and ligand-based redox activity of such substituted N-heterocyclic Fe compounds might be maintained within their +4 → -1 charge states. Additionally, by theoretically examining the role of coordination geometry, vis-à-vis reducing the number of redox noninnocent ligands within the first coordination sphere, we have demonstrated that Fe complexes with one such ligand were also capable of supporting multielectron reduction events and exhibited reduction potentials similar to their parent analogs supported by two or three of the same multidentate ligands. However, some differences in redox nature within the lower (+2 → -1) charge states were also noticed. Specifically, complexes containing two bidentate ligands, or one tridentate ligand, exhibited ligand-based reductions, whereas compounds with one bidentate ligand exhibited metal-centered reductions. The current results pave the way toward the design of the next-generation of Fe complexes with lower molecular weights and greater stored energy for redox flow batteries.

BackgroundCOVID-19 caused by the novel coronavirus SARS-CoV-2 has caused the greatest public health emergency of our time. Accurate laboratory detection of the virus is critical in order to contain the spread. Although real-time polymerase chain reaction (PCR) has been the cornerstone of laboratory diagnosis, there have been conflicting reports on the diagnostic accuracy of this method.MethodsA retrospective review was performed on all hospitalized patients tested for SARS-CoV-2 (at St. Pauls Hospital in Vancouver, BC) from March 13 – April 12, 2020. Diagnostic accuracy of initial PCR on nasopharyngeal (NP) swabs was determined against a composite reference standard which included a clinical assessment of the likelihood of COVID-19 by medical experts, initial and repeat PCR, and post-hoc serological testing.ResultsA total of 323 patients were included in the study, 33 (10.2%) tested positive and 290 (89.8%) tested negative by initial PCR. Patients testing positive were more likely to exhibit features of cough (66.7% vs 39.3%), shortness of breath (63.6% vs 35.9%), fever (72.7% vs 27.6%), radiographic findings (83.3% vs 39.6%) and severe outcomes including ICU admission (24.2% vs 9.7%) and mortality (21.2% vs 6.2%) compared to patients testing negative. Serology was performed on 90 patients and correlation between serology and PCR was 98.9%. There were 90 patients included in the composite reference standard. Compared to the composite reference standard, initial PCR had sensitivity of 94.7% (95% CI 74.0 to 99.9%), specificity of 100% (95% CI 94.9 to 100%), positive predictive value of 100% (95% CI 81.5 to 100%) and a negative predictive value of 98.6% (95% CI 92.5 to 100%).DiscussionOur study showed high sensitivity of PCR on NP swab specimens when compared to composite reference standard in hospitalized patients. High correlation of PCR with serological testing further increased confidence in the diagnostic reliability of properly collected NP swabs.

Oxidative addition and reductive elimination are key steps in a wide variety of catalytic reactions mediated by transition-metal complexes. Historically, this reactivity has been considered to be the exclusive domain of d-block elements. However, this paradigm has changed in recent years with the demonstration of transition-metal-like reactivity by main-group compounds. This Review highlights the substantial progress achieved in the past decade for the activation of robust single bonds by main-group compounds and the more recently realized activation of multiple bonds by these elements. We also discuss the significant discovery of reversible activation of single bonds and distinct examples of reductive elimination at main-group element centers. The review consists of three major parts, starting with oxidative addition of single bonds, proceeding to cleavage of multiple bonds, and culminated by the discussion of reversible bond activation and reductive elimination. Within each subsection, the discussion is arranged according to the type of bond being cleaved or formed and considers elements from the left to the right of each period and down each group of the periodic table. The majority of results discussed in this Review come from the past decade; however, earlier reports are also included to ensure completeness.

The reaction of cyclic urea 1,3-dimethyl-2-imidazolidinone with the aluminum(I) compound NacNacAl (1) gives an unexpected adduct of urea with the isomerized aluminum(III) hydride NacNac′AlH(O═SIMe) (3). A related reaction of 1 with phosphine oxides results in cleavage of the P═O bond and formation of hydroxyl derivatives NacNac′Al(OH)(O═PR3) [R = Ph (5) and Et (6)]. Density functional theory calculations revealed that these reactions proceed via a bimolecular mechanism in which either the basic aluminum(I) center or the transient Al═O species deprotonate the methyl group of the NacNac ligand.

The cationic aluminum complex [NacNacAlH]+ (2; NacNac = CH{C(Me)N(2,6-Pri2C6H3)}2) can be easily generated from NacNacAlH2 by hydride abstraction and functions as a catalyst for the hydrosilylation of olefins and alkynes. Mechanistic studies suggest that, although olefin insertion into the Al–H bond is very facile, the catalysis does not proceed by an insertion/metathesis mechanism but likely by Lewis acid activation. Stoichiometric reactions of 2 with alkynes furnished unexpected products of C≡C addition across the NacNacAl moiety to give tripodal aluminum cations, which are also potent catalysts for the hydrosilylation of alkynes.

Stepwise reduction of the diiminopyridine (dimpyr) complex, dimpyrZnCl2, by KC8 leads to molecular zinc compounds dimpyrZnCl (2) and dimpyrZnCl(DMAP) (3, DMAP = 4-dimethylaminopyridine), which were characterized by X-ray diffraction and EPR spectroscopy. Compound 2 shows an unusual nearly square planar geometry of the zinc atom equally ligated by two imine groups. X-ray crystallographic and EPR data suggest significant delocalization of the zinc 4p electron onto the non-innocent dimpyr ligand. The chloride in 2 can also be substituted by a methyl group upon addition of methyl lithium to generate compound 4, dimpyrZnMe. The novel alkylzinc compound displayed approximate square planar geometry around the zinc centre and significant delocalization of electron density onto the dimpyr ligand, as revealed by X-ray crystallographic studies and EPR spectroscopy, akin to 2. Further reduction of 3 leads to compound 5, dimpyrZn(DMAP)2. X-ray diffraction study of 5 revealed an unprecedented see-saw geometry around the four-coordinate zinc center with significant electron density transfer to the dimpyr ligand, supported by DFT calculations.

Oxidative addition of very robust C–F and C–O bonds has been accomplished in reactions of the aluminum(I) compound NacNacAl (1, NacNac = [ArNC(Me)CHC(Me)NAr]− and Ar = 2,6-Pri2C6H3) with fluoroarenes, fluoroalkanes, and ethers. Similar to the transition metals, the ease of aryl C–F oxidative addition decreases as the degree of fluorination diminishes on the aromatic substrate. As well, kinetic studies on the addition of 1,2,3,4-tetrafluorobenzene to compound 1 revealed a second-order reaction characterized by a very negative entropy of activation (ΔS⧧ = −113.6(3) J/K·mol), consistent with a transition metal-like oxidative addition process.

Reaction of the cyclic guanidine TolN═SIMe with the aluminum(I) compound NacNacAl (1) results in the unprecedented cleavage of the C–N multiple bond to give, after rearrangement, the carbene-ligated Al(III) amide, NacNac′Al(NHTol)(SIMe) (6). DFT calculations revealed that these reactions proceed via a bimolecular mechanism in which either the basic Al(I) center or the transient Al═NTol species deprotonates the methyl group of the NacNac ligand.

Reduction of the cationic Ge(II) complex [dimpyrGeCl][GeCl3] (dimpyr=2,6-(ArN=CMe)2NC5H3, Ar=2,6-iPr2C6H3) with potassium graphite in benzene affords an air sensitive, dark green compound of Ge(0), [dimpyrGe], which is stabilized by a bis(imino)pyridine platform. This compound is the first example of a complex of a zero-valent Group 14 element that does not contain a carbene or carbenoid ligand. This species has a singlet ground state. DFT studies revealed partial delocalization of one of the Ge lone pairs over the π*(C=N) orbitals of the imines. This delocalization results in a partial multiple-bond character between the Ge atom and imine nitrogen atoms, a fact supported by the X-ray crystallography and IR spectroscopy data.

Preparation of a terminal scandium imido complex, 2·DMAP, was accomplished through thermolysis of an arylamido methyl complex, 1, stabilized by a bulky β-diketiminato ligand in the presence of 4-N,N-dimethylaminopyridine (DMAP). Mechanistic studies revealed that the reaction proceeds by initial metalation of 1, followed by rapid DMAP-promoted alkane elimination to generate the scandium imido complex. Kinetic studies of the reaction between separately synthesized metalate 3 and DMAP under pseudo-first-order conditions yielded activation parameters of ΔH⧧ = 73.5(2) kJ mol–1 and ΔS⧧ = −70.4(5) J K–1 mol–1. The reaction of 2·DMAP with tert-butyl amine or phenylacetylene resulted in addition of the N–H or C–H bond across the scandium imide linkage, respectively, to furnish complexes endo-/exo-4 and endo-5. These compounds were fully characterized, including via structural analysis, providing further evidence for the terminal scandium imido derivative 2·DMAP.

The aluminum(I) compound NacNacAl (1) reacts with diphenyl disulfide and diethyl sulfide to form the respective four-coordinate bis(phenyl sulfide) complex NacNacAl(SPh)2 (2) and alkyl thiolate aluminum complex NacNacAlEt(SEt) (3). As well, reaction of 1 with tetraphenyl diphosphine furnishes the bis(diphenyl phosphido) complex NacNacAl(PPh2)2 (4). Production of 3 and 4 are the first examples of C(sp(3))-S and R2P-PR2 activation by a main-group element complex. All three complexes were characterized by multinuclear NMR spectroscopy and X-ray crystal structure analysis. Furthermore, a variable-temperature NMR spectroscopic study was undertaken on 4 to study its dynamic behavior in solution.

The treatment of cyclic thioureas with the aluminum(I) compound NacNacAl (1; NacNac=[ArNC(Me)CHC(Me)NAr]

Aquest mateix article està publicat a l'edició alemanya d''Angewandte Chemie' (ISSN 0044-8249, EISSN 1521-3757), 2016, vol.128, núm. 42, p. 13500–13505. DOI http://dx.doi.org/10.1002/ange.201607735 The treatment of cyclic thioureas with the aluminum(I) compound NacNacAl (1; NacNac=[ArNC(Me)CHC(Me)NAr]−, Ar=2,6-Pri2C6H3) resulted in oxidative cleavage of the C=S bond and the formation of 3 and 5, the first monomeric aluminum complexes with an Al=S double bond stabilized by N-heterocyclic carbenes. Compound 1 also reacted with triphenylphosphine sulfide in a similar manner, which resulted in cleavage of the P=S bond and production of the adduct [NacNacAl=S(S=PPh3)] (8). The Al=S double bond in 3 can react with phenyl isothiocyanate to furnish the cycloaddition product 9 and zwitterion 10 as a result of coupling between the liberated carbene and PhN=C=S. All novel complexes were characterized by multinuclear NMR spectroscopy, and the structures of 5, 9, and 10 were confirmed by X-ray diffraction analysis. The nature of the Al=S bond in 5 was also probed by DFT calculation Financial support from the Spanish Ministerio de Economía y Competitividad in the form of grant CTQ2014-54306-P to S.F.V. is appreciated

Reaction of [(BDPP)ThCl 2 (dme)] ( 1 ) with 2 equivalents of MeMgBr in OEt 2 , followed by filtration and layering a toluene solution with hexanes at −30 °C yielded a single large crystal of [{(BDPP)ThX(μ-X) 2 Mg(OEt 2 )(μ-Me)} 2 ]·2 toluene (X = Br 0.73–0.87 /Cl 0.13–0.27 ; 3 ·2 toluene). This product is the result of halide exchange to form a partially brominated neutral thorium species, which is adducted with MeMgX(OEt 2 ). The complex is then tetrametallic as a result of Mg–Me–Mg bridges. The structure of complex 3 provides direct insight into the process by which halide exchange takes place between electrophilic metal halide complexes and Grignard reagents. This reactivity stands in stark contrast to the reactions of 1 and [(XA 2 )ThCl 2 (dme)] ( 2 ) with PhCH 2 MgCl. In these cases the expected dialkyl products, [LTh(CH 2 Ph) 2 ] [L = BDPP ( 4 ) and XA 2 ( 5 )], were formed under most conditions. However, addition of a PhCH 2 MgCl solution to 2 at −78 °C and warming to room temperature after 5 minutes gave [(XA 2 )Mg(dme)] ( 6 ), the product of ancillary ligand transfer from thorium to magnesium, in 30–50% yield.

Redox flow batteries (RFBs) are emerging as the preferred choice for Mega-watt scale energy storage for the future grids in large part to the decoupled energy/power outputs from the storage system [1]. However, narrow electrochemical stability window of water limits the operating voltage of aqueous flow batteries to < 1.6 V and poses an obstacle to achieving high capacity aqueous RFBs. A higher capacity (energy density) can be obtained if water is replaced with organic solvents such as acetonitrile processing a broader electrochemical stability window (>5 V). While organic solvents increase the cost per kilowatt-hour of the electrolyte this can be offset by the greater energy storage capacity of the RFBs [2]. This tradeoff can be beneficial if less-expensive metal-ligand redox couples are used in non-aqueous RFBs, especially those based on Fe on both the anolyte and catholyte [3]. The other significant cost factor of RFBs is expensive perfluorinated Nafion® membranes. Therefore, the combination of less-expensive redox couples and hydrocarbon membranes could lead to the DOE long term target of 100 USD per kWh for RFBs. To achieve these strict economic targets, we have combined the expertise of inorganic synthesis and fuel cell capabilities at the Los Alamos National Laboratory’s towards non-aqueous flow battery development. We are systematically studying the structure-property relationship of Iron and Nickel-containing inorganic redox-active couples as anolyte and catholyte in RFBs. Design aspects of these redox couples and electrochemical characterization will be discussed in this presentation. Besides, results will be presented on specifically tailored anion exchange membrane with high compatibility with organic solvents and the active redox couples. In addition to the component work, results of flow battery testing using these novel membranes and electrolytes will be presented. A voltage window >3 V has been achieved in preliminary results using the Ni and Fe systems. The reversibility of these redox couples and their potential for long-term operation in RFBs will be discussed. Acknowledgement This work is supported by Laboratory Directed Research & Development, Los Alamos National Laboratory. References: [1] S.H. Shin, S.H. Yun, S.H. Moon, RSC Advances, 3 (2013) 9095-9116. [2] R.M. Darling, K.G. Gallagher, J.A. Kowalski, S. Ha, F.R. Brushett, Energy & Environmental Science, 7 (2014) 3459-3477. [3] J. Friedl, M.A. Lebedeva, K. Porfyrakis, U. Stimming, T.W. Chamberlain, Journal of the American Chemical Society, 140 (2018) 401-405.

Redox flow batteries are an attractive solution to the problem of grid-level energy storage however low energy densities and high costs are preventing them from becoming commercially viable on a large-scale. A promising approach to address low energy density is the utilization of non-aqueous solvents, assuming well designed charge carriers can utilize the wider potential window and be sufficiently soluble. In this presentation, we will detail the preparation, characterization, and electrochemical performance of metal complexes with polypyridyl ligands along with preliminary results from a bench-scale flow battery system.

Los Alamos National Laboratory is leveraging its resources in theoretical modeling, inorganic synthesis, and fuel cell expertise to transform the grid scale energy storage with flow cells. This talk will discuss our initial efforts at charge carrier design and flow testing, with a particular focus on multi-coordinate pyridine-amido ligands incorporating Fe and Ni.

The Al(I) compound NacNacAl (1, NacNac = [ArNC(Me)CHC(Me)NAr](-) and Ar = 2,6-Pr(i)2C6H3) reacts with H-X (X = H, Si, B, Al, C, N, P, O) σ bonds of H2, silanes, borane (HBpin, pin = pinacolate), allane (NacNacAlH2), phosphine (HPPh2), amines, alcohol (Pr(i)OH), and Cp*H (Cp* = pentamethylcyclopentadiene) to give a series of hydride derivatives of the four-coordinate aluminum NacNacAlH(X), which are characterized herein by spectroscopic methods (NMR and IR) and X-ray diffraction. This method allows for the syntheses of the first boryl hydride of aluminum and novel silyl hydride and phosphido hydride derivatives. In the case of the addition of NacNacAlH2, the reaction is reversible, proving the possibility of reductive elimination from the species NacNacAlH(X).

A rigid NSN-donor proligand, 4,5-bis(2,6-diisopropylanilino)-2,7-di-tert-butyl-9,9-dimethylthioxanthene (H(2)[TXA(2)], 1) was prepared by palladium-catalyzed coupling of 2,6-diisopropylaniline with 4,5-dibromo-2,7-di-tert-butyl-9,9-dimethylthioxanthene. Deprotonation of 1 using (n)BuLi provided Li(2)(DME)(2)[TXA(2)] (2), and subsequent reaction with UCl(4) afforded [Li(DME)(3)][(TXA(2))UCl(3)] (4). The analogous NON-donor ligated complex [(XA(2))UCl(3)K(DME)(3)] [3; XA(2) = 4,5-bis(2,6-diisopropylanilino)-2,7-di-tert-butyl-9,9-dimethylxanthene] was prepared by the reaction of K(2)(DME)(x)[XA(2)] with UCl(4). A cyclic voltammogram (CV) of 3 in THF/[NBu(4)][B(C(6)F(5))(4)] at 200 mV s(-1) showed an irreversible reduction to uranium(III) at E(pc) = -2.46 V versus FeCp(2)(0/+1), followed by a product wave at E(1/2) = -1.83 V. Complex 4 also underwent irreversible reduction to uranium(iii) [E(pc) = -2.56 V], resulting in an irreversible product peak at E(pa) = -1.83 V. One-electron reduction of complexes 3 and 4 using K(naphthalenide) under an argon atmosphere in DME yielded 6-coordinate [(XA(2))UCl(DME)] (5) and the thermally unstable 7-coordinate [(TXA(2))U(DME)Cl(2)Li(DME)(2)] (6), respectively. The U-S distances in 4 and 6 are uncommonly short, the C-S-U angles are unusually acute, and the thioxanthene backbone of the TXA(2) ligand is significantly bent. By contrast, the xanthene backbone in XA(2) complexes 3 and 5 is planar. However, κ(3)-coordination and an approximately meridional arrangement of the ancillary ligand donor atoms is maintained in all complexes. DFT and Atoms in Molecules (AIM) calculations were carried out on 3, 4, 5, 6, [(XA(2))UCl(3)](-) (3B), [(TXA(2))UCl(2)(DME)](-) (6B) and [(TXA(2))UCl(DME)] (6C) to probe the extent of covalency in U-SAr(2) bonding relative to U-OAr(2) bonding.

Polyanions based on poly(methyl vinyl ether-alt-maleic acid) were investigated as materials for cell encapsulation. These water-soluble polyanions having molecular masses ranging from 20 to 1980 kDa were prepared by functionalization of poly(methyl vinyl ether-alt-maleic anhydride) with 5-aminofluorescein and/or α-methoxy-ω-amino-poly(ethylene glycol), followed by base hydrolysis of the residual anhydride groups to form the corresponding poly(methyl vinyl ether-alt-sodium maleate). Their potential to replace alginate both in the core and, in particular, the outer shell of calcium alginate-poly(L-lysine)-alginate (APA) capsules was determined using confocal fluorescence microscopy, osmotic pressure tests, permeability studies, protein binding and cell viability assays. These polymers were shown to be able to replace the outer layer of alginate, forming more resilient capsule shells. The resulting capsules showed similar permeability and resistance to bovine serum albumin binding, as well as superior viability for encapsulated cells, when compared to standard APA capsules. In addition, these polymers showed promise for use as functional additives to the capsule cores.

Traditionally, the measuring or monitoring system of manufacturing industries uses sensors, computers and screens for their quality control (Q.C.). The acquired information is fed back to the control room by wires, which - for obvious reason - are not suitable in many environments. This paper describes a method to solve this problem by employing the new Bluetooth technology to set up a complete new system, where a total wireless solution is made feasible. This new Q.C. system allows several line scan cameras to be connected at once to a graphical user interface (GUI) that can monitor the production process. There are many Bluetooth devices available on the market such as cell-phones, headsets, printers, PDA etc. However, the detailed application is a novel implementation in the industrial Q.C. area. This paper will contain more details about the Bluetooth standard and why it is used (nework topologies, host controller interface, data rates, etc.), the Bluetooth implemetation in the microcontroller of the line scan camera, and the GUI and its features.

A Siemens Virtual Wedge has recently been installed and commissioned at the Northeastern Ontario Regional Cancer Centre. Measurements reported below show that 1) Virtual Wedge factors are within 1.5% of 1; 2) percentage depth doses down to 15 cm for open and virtually wedged fields are identical to within 0.7%; 3) relative cross beam profiles for 60 degrees virtual and physical wedges are very similar except at the toe end where a 5% difference in relative dose has been observed and 4) the peripheral dose from the 60 degrees Virtual Wedge is about half of that from the 60 degrees physical wedge. A clinical protocol requiring combined open and 60 degrees wedged fields has been developed and validated. This protocol, which does not impair the utility of the Virtual Wedge, facilitates the use of on-line portal imaging and significantly reduces the effort required to commission the system.