Modulating ß-Keto-enamine-Based Covalent Organic Frameworks for Photocatalytic Atom-Transfer Radical Addition Reaction.

The atom-transfer radical addition (ATRA) reaction simultaneously forges carbon-carbon and carbon-halogen bonds. However, frequently-used photosensitizers such as precious transition metal complexes, or organic dyes have limitations in terms of their potential toxicity and recyclability. Three ß-ketoenamine-linked covalent organic frameworks (COFs) from 1,3,5-triformylphloroglucinol and 1,4-phenylenediamines with variable transient photocurrent and photocatalytic activity have been prepared. A COF bearing electron-deficient Cl atoms displayed the highest photocatalytic activity toward the ATRA reaction of polyhalogenated alkanes to give halogenated olefins under visible light at room temperature. This heterogeneous photocatalyst exhibited good functional group tolerance and could be recycled without significant loss of activity.

Aggregation-Induced Emission Phosphorescence Featured Au-Ag Coordination Polymer with a Diphosphine N-Heterocyclic Carbene Ligand for Highly Sensitive Detection of Cr(VI).

Luminescent materials with aggregation-induced emission (AIE) characteristics have been recognized as highly selective and sensitive probes for the detection of toxic metal ions in recent years. In this paper, a Au-Ag cluster-based coordination polymer [Au3Ag3(L)2(CN)6(H2O)2]n [1, L = 1,3-bis((diphenylphosphanyl)methyl)-4,5-dihydro-imidazolylidene] was prepared by in situ generation of the diphosphine N-heterocyclic carbene (PCNHCP)-type ligand L in the presence of the corresponding metal salts. Compound 1 exhibited 530 nm phosphorescence under 380 nm excitation with a QY of 6.30% and a lifetime (τ) of 7.14 µs in the solid state. 1 showed good AIE behavior in the mixture of MeOH/H2O while the best aggregation state (fwater = 90%, QY = 6.79%, τ = 6.70 µs) exhibited selective and sensitive emission quenching toward Cr(VI) ions. Ultralow detection limits of 9.7 ppb (w/w) for Cr2O72- and 17.9 ppb (w/w) for CrO42- were achieved.

One-Dimensional Heterobimetallic Au/Ag Coordination Polymer Showing a Selective, Reversible, and Visible Vapor-Chromic Photoluminescent Response toward Methanol.

A heterobimetallic coordination polymer [Au4(dppmt)4(AgCl)2]n (1) incorporating an in situ generated P-S ligand (dppmtH) was synthesized from the solvothermal reaction of Au(tht)Cl, AgCl, and dpppyatc in CH3CN/CH2Cl2 (dppmtH = (diphenylphosphino)methanethiol, tht = tetrahydrothiophene, dpppyatc = N,N-bis((diphenylphosphaneyl)methyl)-N-(pyridin-2-yl)-amino-thiocarbamide). The structure of 1 contains a one-dimensional helical Au-Au chain in which the unique [Au4Ag2S2] cluster units are connected by [Au2(dppmt)2] dimers. Upon excitation at 343 nm, 1 exhibited cyan (495 nm) phosphorescent emission at quantum yield (QY) = 22.3% and τ = 0.78 µs (λex = 375 nm). Coordination polymer 1 exhibited a rapid, selective, reversible, and visible vapor-chromic response on exposure to methanol (MeOH) vapor with its emission shifting to a more intense green (530 nm, λex = 388 nm) with QY = 46.8% and τ = 1.24 µs (λex = 375 nm). A polymethylmethacrylate film containing 1 served as a reversible chemical sensor for the sensitive detection of MeOH in air.

A Novel Photoluminescent Ag/Cu Cluster Exhibits a Chromic Photoluminescence Response towards Volatile Organic Vapors.

A new Ag/Cu bimetallic cluster [Ag10Cu6(bdppthi)2(C≡CPh)12(EtOH)2](ClO4)4 (1, bdppthi = N,N'-bis(diphenylphosphanylmethyl)-tetrahydroimidazole) exhibited strong phosphorescent (PL) emission at 644 nm upon excitation at 400 nm. Removal of the coordinated EtOH molecules in 1 resulted in derivative 1a, which exhibited significant red-shifted emission at 678 nm. The structure and PL of 1 was restored on exposure to EtOH vapor. Cluster 1a also exhibited a vapor-chromic PL response towards other common organic solvent vapors including acetone, MeOH and MeCN. A PMMA film of 1a was developed as a reusable visible sensor for MeCN.

A Multiple Stimuli-Responsive Ag/P/S Complex Showing Solvochromic and Mechanochromic Photoluminescence.

The reaction of CF3COOAg, 3-bdppmapy (N,N-bis(diphenylphosphanylmethyl)-3-aminopyridine) and HTZ (1,2,4-triazole-3-thiol) in CH2Cl2/MeOH resulted in a dinuclear Ag/P/S complex [Ag2(TZ)2(3-bdppmapy)2]·xSol (1·xSol). Crystals of 1·xSol converted to 1·2MeOH in air at room temperature and further to 1 under vacuum upon heating. The solid-state, room-temperature photoluminescent emission of 1·xSol (510 nm) shifted to 494 nm (1·2MeOH) and 486 nm (1). Grinding solids of 1·2MeOH in air resulted in amorphous 1G characterized by solid-state emission at 468 nm, which converted to 1GR with 513 nm emission upon MeOH treatment. Grinding 1GR in air returned 1G, and this interconversion was reproducible over five cycles. The solid-state photoluminescence of 1G changed in response to vapors containing low-molecular weight alcohols but remained unchanged after exposure to other volatile organic compounds (VOCs) or to water vapor. Test papers impregnated with 1G could detect methanol in vapors from aqueous solutions at concentrations above 50%. Complex 1G is, therefore, an example of a stimuli-responsive molecular sensor for the detection of alcohols.

Hantzsch Ester as a Visible-Light Photoredox Catalyst for Transition-Metal-Free Coupling of Arylhalides and Arylsulfinates.

Diethyl 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (HEH) has been utilized as a visible-light photoredox catalyst for the cross coupling of arylhalides and arylsulfinates without transition metal, sacrificial agent, and mediator. This method is compatible with various functional groups and provides diaryl sulfones in good to high yields. Mechanistic studies indicate that this reaction undergoes the stepwise light irradiation of HE- , single electron transfer (SET) in donor-acceptor complex (DAC) from *HE- to arylhalide, trapping of aryl radical with sulfinate, and SET oxidation of sulfone radical anion by HE. to sulfone by the DAC method.

Nickel-Catalyzed Sonogashira C(sp)-C(sp2) Coupling through Visible-Light Sensitization.

An efficient method for visible-light-initiated, nickel-catalyzed Sonogashira C(sp)-C(sp2) coupling has been developed via an energy-transfer mode. Thioxanthen-9-one as a photosensitizer could significantly accelerate the arylation of alkynes with a wide range of (hetero)aryl halides in high yields. The cross-coupling reaction undergoes the stepwise oxidative addition of an arylhalide to nickel(0), transmetalation of the resulting aryl-Ni(II) halide species with Zn(II) acetylide into aryl-Ni(II) acetylide species, energy transfer from the excited state of thioxanthen-9-one to aryl-Ni(II) acetylide, and reductive elimination to the aryl alkyne.

A comparative study of clinical effect of total knee arthroplasty in the treatment of primary osteoarthritis and osteoarthritis of Kashin-Beck disease.

OBJECTIVE: To evaluate the clinical efficacy of total knee arthroplasty (TKA) in the treatment of primary osteoarthritis (OA) and osteoarthritis of Kashin-Beck disease (KBD). METHODS: This study enrolled 77 KBD patients (77 knees, KBD-TKA) and 75 OA patients (75 knees, OA-TKA) who underwent TKA from September 2008 to June 2018. Clinical assessments for each patient were performed pre-operatively and last follow-up. The efficacy measures included the visual analogue scale (VAS) pain score, range of motion (ROM), Hospital for Special Surgery (HSS) score, and short form 36 Health Survey (SF-36) as well as related influencing factors between the two groups. RESULTS: All patients were followed up; the follow-up time of KBD-TKA was 14-132 months, with an average of 72.68 ± 37.55 months; OA-TKA was 15-120 months, with an average of 49.2 ± 28.91 months. There was no difference in pre-operative VAS score (7.29 vs. 7.24) and SF-36 (PCS) score (4.87 vs. 5.49) between KBD-TKA and OA-TKA (P > 0.05), while compared with OA, KBD-TKA had significantly worse pre-operative ROM (75.48° vs. 82.87°), HSS score (36.40 vs. 41.84), and SF-36 (MCS) score (26.28 vs. 28.73) (P < 0.05). At the final follow-up, there was no significant difference in VAS score (1.13 vs. 1.16), ROM (105.79 vs. 105.79), and HSS score (92.06 vs. 92.25) between KBD-TKA and OA-TKA (P > 0.05), while compared with OA, KBD-TKA had significantly worse SF-36 (PCS) score (36.90 vs. 42.00) and SF-36 (MCS) score (55.16 vs. 59.70) (P < 0.05). In a multivariate regression, controlling for multiple potential confounders, diagnosis of KBD was associated with poor quality of life after surgery, whereas pre-operative pain was specifically associated with post-operative pain. However, preoperative gender, age, BMI, and the angles of knee prosthesis (before and after surgery) were not associated with post-operative outcome. CONCLUSION: Patients with KBD undergoing primary TKA have excellent outcomes, comparable with OA at the final follow-up, in spite of worse pre-operative ROM, HSS score, and SF-36(MCS) score. However, KBD patients are worse than OA in terms of general health. Pre-operative age, gender, BMI, and the angles of knee prosthesis were not the factors influencing the clinical efficacy of TKA. The diagnosis of KBD was an independent risk factor for poor quality of life after TKA. Pre-operative pain was a clinically important predictor of outcome.

Reaction condition controlled nickel(ii)-catalyzed C-C cross-coupling of alcohols.

The challenge in the C-C cross-coupling of secondary and primary alcohols using acceptorless dehydrogenation coupling (ADC) is the difficulty in accurately controlling product selectivities. Herein, we report a controlled approach to a diverse range of ß-alkylated secondary alcohols, α-alkylated ketones and α,ß-unsaturated ketones using the ADC methodology employing a Ni(ii) 4,6-dimethylpyrimidine-2-thiolate cluster catalyst under different reaction conditions. This catalyst could tolerate a wide range of substrates and exhibited a high activity for the annulation reaction of secondary alcohols with 2-aminobenzyl alcohols to yield quinolines. This work is an example of precise chemoselectivity control by careful choice of reaction conditions.

Switchable Chemoselective Transfer Hydrogenations of Unsaturated Carbonyls Using Copper(I) N-Donor Thiolate Clusters.

Unsaturated alcohols and saturated carbonyls are important chemical, pharmaceutical, and biochemical intermediates. We herein report an efficient transfer hydrogenation protocol in which conversion of unsaturated carbonyl compounds to either unsaturated alcohols or saturated carbonyls was catalyzed by Cu(I) N-donor thiolate clusters along with changing hydrogen source (isopropanol or butanol) and base (NaOH or K2CO3). Mechanistic studies supported by DFT transition state modeling indicate that such a chemoselectivity can be explained by the relative concentrations of Cu(I) monohydride and protonated Cu(I) hydride complexes in each catalytic system.

Capturing the Organic Species Derived from the C-C Cleavage and in Situ Oxidation of 1,2,3,4-Tetra(pyridin-4-yl)cyclobutane by [CuCN] n-Based MOFs.

The solvothermal cycloreversion and in situ oxidation of 1,2,3,4-tetra(pyridin-4-yl)cyclobutane (tpcb) within [CuCN] n-based MOFs were investigated. The radical mechanism for the cycloreversion of tpcb ligands was supported by capturing a 1,3-butadiene species 1,2,3,4-tetra(4-pyridyl)-1,3-butadiene (tpyb) into {[Cu18(µ-CN)18(tpcb)4(tpyb)2]·H2O} n in the presence of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). Without TEMPO, a furan-based ligand 2,3,4,5-tetra(4-pyridyl)furan (tpyf) was generated within {[Cu4(µ-CN)4(tpyf)]·4MeCN} n via the C-C cleavage, followed by in situ oxidation in acidic condition.

Post-synthetic Modification of a Two-Dimensional Metal-Organic Framework via Photodimerization Enables Highly Selective Luminescent Sensing of Aluminum(III).

Reaction of Cd(NO3)2·4H2O with 5-fluoro-1,3-bis[2-(4-pyridyl)ethenyl]benzene (5-F-1,3-bpeb) and 1,3-benzenedicarboxylic acid (1,3-H2BDC) under the solvothermal conditions gave rise to a two-dimensional metal-organic framework (MOF) [{Cd2(5-F-1,3-bpeb)2(1,3-BDC)2}·0.5DMF·2H2O] n (1). Compound 1 was postmodified by a photodimerization reaction between 5-F-1,3-bpeb ligands to yield [{Cd2( syn-dftpmcp)(1,3-BDC)2}·0.5DMF·H2O] n ( syn-dftpmcp = syn-3,4,12,13-tetrakis(4-pyridyl)-8,17-bisfluoro-1,2,9,10-diethano[2.2]metacyclophane) (2). Compounds 1 and 2 have 2D networks built from linking one-dimensional [Cd2(1,3-BDC)2] n chains via 5-F-1,3-bpeb or syn-dftpmcp bridges. After such a post-synthetic modification, compound 2, relative to 1, can probe Al3+ by using a luminescent quenching approach with much higher selectivity and sensitivity.

Ligand-Free RuCl3-Catalyzed Alkylation of Methylazaarenes with Alcohols.

RuCl3 efficiently catalyzes the alkylation of methylquinolines, methylpyridines, 2-methyl-benzooxazoles, and 2-methyl-quinoxalines with alkyl- or aryl-alcohols as alkylating agents. This synthetically useful and atom economical transformation does not require additional ligands. The mechanistic study indicated the alkylation reaction underwent a stepwise transfer hydrogenation, aldol condensation, and hydrogenation reaction pathway.

Palladium(II) Chloride Complexes of N,N'-Disubstituted Imidazole-2-thiones: Syntheses, Structures, and Catalytic Performances in Suzuki-Miyaura and Sonogashira Coupling Reactions.

Reactions of PdCl2 with 2 equiv of N,N'-disubstituted-imidazole-2-thiones R1R2C3N2S (R1 = R2 = Me (1a), iPr (1b), Cy (1c), C6Me3H2 (1d); R1 = Me, R2 = Ph (1e)) under the different conditions afford five mononuclear complexes trans-[(R1R2C3N2S)2PdCl2] (R1 = R2 = Me (2a), iPr (2b), Cy (2c), C6Me3H2 (2d); R1 = Me, R2 = Ph (2e)) and five binuclear Pd(II) complexes [(PdCl2){µ-(R1R2C3N2S)}]2 (R1 = R2 = Me (3a), iPr (3b), Cy (3c), C6Me3H2 (3d); R1 = Me, R2 = Ph (3e)), respectively. Complexes 2a-2e are easily converted into the corresponding 3a-3e by adding equimolar PdCl2 in refluxing MeOH, while the reverse reaction is achieved at room temperature by addition of 2 equiv of 1a-1e. In 2b, 2d, and 2e, each Pd(II) holds a distorted square planar geometry completed by two trans Cl atoms and two trans S atoms. Complexes 3a-3e have a dimeric [Pd2S2] structure in which two {PdCl2} units are interlinked by two N,N'-disubstituted-imidazole-2-thiones. Each Pd(II) adopts a distorted square planar geometry accomplished by two cis Cl atoms and two cis bridging S atoms. Among them, complex 3d has the two largest C6Me3H2 groups on the 2 and 5 positions of imidazole-2-thione, the longest Pd-µ-S bond, the largest S-Pd-S angle, and displays the highest catalytic activity toward Suzuki-Miyaura and copper-free Sonogashira cross-coupling reactions, which are confirmed by density functional theory calculations. The results provide an interesting insight into the introduction of various substituent groups into the periphery ligands of coordination complex-based catalysts, which could tune their geometric structures to acquire the best catalytic activity toward organic reactions.

Schiff-base Polymer Immobilized Ruthenium for Efficient Catalytic Cross-coupling of Secondary Alcohols with 2-amino- and γ-aminobenzyl Alcohols to Give Quinolines and Pyridines.

A Schiff-base porous polymer has been impregnated with ruthenium trichloride for acceptor-free dehydrogenation coupling (ADC) of secondary alcohols with γ-amino- and 2-aminobenzyl alcohols to give pyridines and quinolines. This heterogenous catalyst exhibited high catalytic efficiency over repeated cycles with wide functional group tolerance.

METTL14-mediated upregulation of lncRNA HOTAIR represses PP1α expression by promoting H3K4me1 demethylation in oxycodone-treated mice.

N6-methyladenosine (m6A) methylation is a vital epigenetic mechanism associated with drug addiction. However, the relationship between m6A modification and oxycodone rewarding is less well explored. Based on an open field test, the present study evaluated oxycodone rewarding using chromatin immunoprecipitation PCR, immunofluorescence, and RNA sequencing. A marked increase in METTL14 protein and a decrease in PP1α protein due to oxycodone abundance in the striatal neurons were observed in a dose- and time-dependent manner. Oxycodone markedly increased LSD1 expression, and decreased H3K4me1 expression in the striatum. In the open field test, intra-striatal injection of METTL14 siRNA, HOTAIR siRNA, or LSD1 shRNA blocked oxycodone-induced increase in locomotor activity. The downregulation of PP1α was also inhibited after treatment with METTL14/HOTAIR siRNA and LSD1 shRNA. Enhanced binding of LSD1 with CoRest and of CoRest with the PP1α gene induced by oxycodone was also reversed by LSD1 shRNA. In addition, H3K4me1 demethylation was also blocked by the treatment. In summary, the investigation confirmed that METTL14-mediated upregulation of HOTAIR resulted in the repression of PP1α, which in turn facilitated the recruitment of LSD1, thus catalyzing H3K4me1 demethylation and promoting oxycodone addiction.

The epigenetically regulated PP1α expression by KDM1A may contribute to oxycodone conditioned place preference in mice.

The lysine-specific demethylase 1 (KDM1A) is reported to be a regulator in learning and memory. However, the effect of KDM1A in oxycodone rewarding memory has yet to be studied. In our study, rewarding memory was assessed by using conditioned place preference (CPP) in male mice. Next generation sequencing and chromatin immunoprecipitation-PCR were used to explore the molecular mechanisms. Oxycodone significantly decreased PP1α mRNA and protein levels in hippocampal neurons. Oxycodone significantly increased KDM1A and H3K4me1 levels, while significantly decreased H3K4me2 levels in a time- and dose-dependent manner. Behavioral data demonstrated that intraperitoneal injection of ORY-1001 (KDM1A inhibitor) or intra-hippocampal injection of KDM1A siRNA/shRNA blocked the acquisition and expression of oxycodone CPP and facilitated the extinction of oxycodone CPP. The decrease of PP1α was markedly blocked by the injection of ORY-1001 or KDM1A siRNA/shRNA. Oxycodone-induced enhanced binding of CoRest with KDM1A and binding of CoRest with the PP1α promoter was blocked by ORY-1001. The level of H3K4me2 demethylation was also decreased by the treatment. The results suggest that oxycodone-induced upregulation of KDM1A via demethylation of H3K4me2 promotes the binding of CoRest with the PP1α promoter, and the subsequent decrease in PP1α expression in hippocampal neurons may contribute to oxycodone reward.

A Phosphorescent P/N/S Hybrid Ligand Stabilized Au2Cu Complex Selectively Senses Ammonia and Amines.

Reaction of a P/N/S hybrid ligand dpppyatc (N,N-bis((diphenylphosphaneyl)methyl)-N-(pyridin-2-yl)-amino-thiocarbamide) with Au(tht)Cl (tht=tetrahydrothiophene) and [Cu(MeCN)4]BF4 afforded cluster complex [Au2Cu(dpppyatc)2](BF4)2Cl (1). Upon excitation at 480 nm, 1 emitted orange phosphorescence at 646 nm, which was red-shifted to ~698 nm selectively in the presence of ammonia or amine vapor. This chromic photoluminescent response toward ammonia was sensitive and reversible. Complex1 could detect ammonia in aqueous solution down to concentrations of 2 ppm (w/w).

Covalent Grafting of a Nickel Thiolate Catalyst onto Covalent Organic Frameworks for Increased Photocatalytic Activity.

Covalent organic frameworks (COFs) have recently emerged as prospective photoactive materials with noble Pt as a cocatalyst for photocatalytic hydrogen evolution. In this work, a series of SH-group-functionalized covalent organic frameworks, TpPa-1-SH-X, is prepared by reaction of p-phenylenediamine (Pa) and 1,3,5-triformylphloroglucinol (Tp) with p-NH2 C6 H4 SH as a modulating agent. The reaction of TpPa-1-SH-X with NiII acetylacetonate Ni(acac)2 gave nickel thiolate-immobilized TpPa-1 (TpPa-1-SNi-X). The highest hydrogen evolution rate was 10.87 mmol h-1 g-1 , which was an enhancement of 16.47, 3.83, and 1.84 times than that of the parent TpPa-1, covalent-bond-free [(p-NH2 C6 H4 S)2 Ni]n /TpPa-1-SH-10, and 3 wt % Pt-deposited TpPa-1, respectively. This enhanced photocatalytic hydrogen evolution is ascribed to enhanced crystallinity, the use of NiII thiolate as a cocatalyst and covalent bonding between the cocatalyst and TpPa-1.

Heteroleptic copper(I) complexes [Cu(dmp)(N

Earth-abundant copper(I) coordination complexes of an imine-phosphine and a diimine have been developed as visible-light photocatalysts. Reaction of [Cu(MeCN)4]BF4 with hetero-bidentate phosphinopyrazole (phpz) ligand R1R2C3HN2PPh3 (R1 = R2 = H (1a); R1 = H, R2 = Me (1b); R1 = H, R2 = Ph (1c); R1 = R2 = Me (1d)) and 2,9-dimethyl-1,10-phenanthroline (dmp) gave four heteroleptic bis-chelate Cu(I) complexes [Cu(dmp)(R1R2C3HN2PPh3)]BF4 (R1 = R2 = H (2a); R1 = H, R2 = Me (2b); R1 = H, R2 = Ph (2c); R1 = R2 = Me (2d)) with distorted tetrahedral geometries. Complexes 2a-2d exhibited broad absorption in the visible spectrum and could facilitate photochemical intermolecular atom-transfer radical addition reactions of CBr4, or CCl3Br, CHI3 to styrenes in yields up to 91% and with a broad substrate scope. The absorption, emission, redox potential and photocatalytic activity were dependent on the substituents on the phpz ligand. Mechanistic studies supported an atom-transfer radical addition (ATRA) mechanism.