Self-Buffering Organocatalysis Tailoring Alternating Polyester

A major success has been made on organocatalytic ring-opening alternating copolymerization (ROAP) of phthalic anhydride and ethylene oxide (EO) by use of a simple phosphazene base (<i>t</i>-BuP₁). Polyesters with perfectly alternating sequence distribution, controlled molar masses, and low dispersities (<i>Đ</i>_M < 1.1) are obtained. The ROAP exhibited a distinct living nature so that block, nonlinear, end-functional structures and postpolymerization modification of the alternating polyesters are readily achieved. Solvent, excess EO, and catalyst can be effortlessly recovered and reused. The ideally suitable basicity of <i>t</i>-BuP₁ is considered crucial for the high selectivity and neatness of the ROAP, which engenders a self-buffering mechanism rendering the carboxy and hydroxy terminals appropriately active to allow chain growth in an strictly alternating manner and complete avoidance of side reactions (epoxide self-propagation, transesterification) even at full conversion of the anhydride

Calcium-Mediated C–H and C–F Bond Cleavage: Synthesis of Indenes and Perfluorodibenzopentalenes from 1,4-Dilithio-1,3-butadienes

The development of Ca-mediated reactions is of great importance and is in great demand in both organometallic and organic chemistry. In this paper, we report that calcium iodide efficiently promotes the transformation of various 1,4-dilithio-1,3-butadienes into indenes or perfluorodibenzopentalenes, via an intramolecular C–H or C–F bond cleavage, respectively. In the reaction process, the Ca-induced s-<i>cis/trans</i> configurational isomerization of 1,4-dilithio-1,3-butadienes is followed by the subsequent nucleophilic C–H or C–F bond activation

Supplementary_Table_of_SSR_marker_for_Halenia_elliptica – Supplemental material for Transcriptome Analysis and Microsatellite Markers Development of a Traditional Chinese Medicinal Herb Halenia elliptica D. Don (Gentianaceae)

<p>Supplemental material, Supplementary_Table_of_SSR_marker_for_Halenia_elliptica for Transcriptome Analysis and Microsatellite Markers Development of a Traditional Chinese Medicinal Herb Halenia elliptica D. Don (Gentianaceae) by Mingliu Yang, Nanyu Han, Heng Li and Lihua Meng in Evolutionary Bioinformatics</p

Calcium-Mediated C–H and C–F Bond Cleavage: Synthesis of Indenes and Perfluorodibenzopentalenes from 1,4-Dilithio-1,3-butadienes

The development of Ca-mediated reactions is of great importance and is in great demand in both organometallic and organic chemistry. In this paper, we report that calcium iodide efficiently promotes the transformation of various 1,4-dilithio-1,3-butadienes into indenes or perfluorodibenzopentalenes, via an intramolecular C–H or C–F bond cleavage, respectively. In the reaction process, the Ca-induced s-<i>cis/trans</i> configurational isomerization of 1,4-dilithio-1,3-butadienes is followed by the subsequent nucleophilic C–H or C–F bond activation

Synthesis, Structural Characterization, and Reactivity of a Fluorene-Based Calcium Oxycyclopentadienide Complex

Direct deprotonation of 9-fluorenol with Ca­[N­(SiMe₃)₂]₂ efficiently generated a fluorene-based calcium oxycyclopentadienide complex, which is the first alkaline earth metal complex containing an oxycyclopentadienyl dianion ligand. The η⁵, η¹, and η² interactions between the oxycyclopentadienyl dianion ligand and the calcium center were observed in the solid state. The calcium oxycyclopentadienide complex displayed reductive character and multiple reactive sites. Its reactivity toward a range of electrophiles, especially acid chlorides, was investigated and discussed in detail. A wide variety of fluorene derivatives were synthesized

Well-Defined and Structurally Diverse Aromatic Alternating Polyesters Synthesized by Simple Phosphazene Catalysis

Alcohol-initiated ring-opening alternating copolymerization (ROAP) of phthalic anhydride (PA) and a variety of mono-, di-, and trisubstituted epoxides has been performed with a weak phosphazene base (<i>t</i>-BuP₁) as the catalyst. Each product exhibits a perfectly alternating sequence distribution, controlled molar mass (<i>M</i>_n up to 124 kg mol^–1), and low dispersity (<i>Đ</i>_M < 1.15, mostly). Full conversion of PA can be reached in 0.5–24 h depending on the substituent of the epoxide, the targeted degree of polymerization, and the amount of <i>t</i>-BuP₁ used (0.2–5 mol % of PA) when the reactions are conducted under solvent-free conditions at 100 °C with a small excess of the epoxide (0.5 equiv of PA). The glass transition temperature of the polyester ranges from −14 to 135 °C. The living nature of the ROAP allows one-pot construction of well-defined block-alternating copolymers through sequential addition of two epoxides. Statistical-alternating copolymers have also been synthesized by copolymerization of PA and two mixed epoxides. Thus, the structural diversity of aromatic alternating polyesters synthesized by this simple organocatalysis has been largely enriched

Additional file 1: of Associations of LBX1 gene and adolescent idiopathic scoliosis susceptibility: a meta-analysis based on 34,626 subjects

Table S1. Genotype and allele distribution of LBX1 polymorphisms in AIS cases and controls. Figure S1. X-ray of an AIS patient. Figure S2. Flow chart of data selection. Figure S3. Begg’s funnel plot for publication bias in the dominant model for rs111090870 polymorphism. Figure S4. Begg’s funnel plot for publication bias in the dominant model for rs678741 polymorphism. Figure S5. Begg’s funnel plot for publication bias in the dominant model for rs11598564 polymorphism. Figure S6. Begg’s funnel plot for publication bias in the dominant model for rs625039 polymorphism. (DOCX 144 kb

Cu(II)-Based Metal–Organic Framework Loaded with Silver Nanoparticles as a Catalyst for the A³‑Coupling Reaction

The embedding of metal nanoparticles (NPs) in metal–organic frameworks (MOFs) has attracted a wide range of attention in the field of catalysis due to the high agglomeration resistance of NPs in MOFs. In this work, a Cu(II)-based MOF with the formula {[Cu1.5(TPA)(BIBT)]·4DMF·6H2O]}n (1) (H3TPA = tris(4′-carboxybiphenyl)amine; BIBT = 4,7-di(1H-imidazol-1-yl)benzo[c][1,2,5]thiadiazole; and DMF = N,N-dimethylformamide) was synthesized under solvothermal condition. Structural analysis revealed that Cu-MOF 1 possessed 3-fold interpenetrated three-dimensional (3D) coordination frameworks with large one-dimensional (1D) channels along the a-axis. Due to the interaction between Ag and S/N, Ag NPs could be encapsulated into the pores of Cu-MOF 1 to generate Ag NPs and MOF composites, xAg/1 (x = 0.3, 0.5, 0.8, and x was the molar ratios of AgNO3 with Cu-MOF 1 in the synthesis), which was further demonstrated by powder X-ray diffraction, Fourier transform infrared, scanning electron microscopy, transmission electron microscope, energy dispersive spectrometer, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller (BET) analysis. In addition, synthesized 0.5Ag/1 exhibited outstanding catalytic activity for the A3-coupling reaction of aldehyde, alkyne, and amine with high recyclability. This work presents a viable strategy for using Cu(II)-based MOF loading with Ag NPs as heterogeneous catalysts for the A3-coupling reaction

Admixture dates for Europeans.

<p>The table gives the admixture dates for Europeans. For East Asians we obtain λ = 1,253–1,287, although no valid conversion to <i>t_GF</i> is possible without an East Asian pedigree map and hence we focus on the results for Europeans in this study.</p

Cu(II)-Based Metal–Organic Framework Loaded with Silver Nanoparticles as a Catalyst for the A³‑Coupling Reaction

The embedding of metal nanoparticles (NPs) in metal–organic frameworks (MOFs) has attracted a wide range of attention in the field of catalysis due to the high agglomeration resistance of NPs in MOFs. In this work, a Cu(II)-based MOF with the formula {[Cu1.5(TPA)(BIBT)]·4DMF·6H2O]}n (1) (H3TPA = tris(4′-carboxybiphenyl)amine; BIBT = 4,7-di(1H-imidazol-1-yl)benzo[c][1,2,5]thiadiazole; and DMF = N,N-dimethylformamide) was synthesized under solvothermal condition. Structural analysis revealed that Cu-MOF 1 possessed 3-fold interpenetrated three-dimensional (3D) coordination frameworks with large one-dimensional (1D) channels along the a-axis. Due to the interaction between Ag and S/N, Ag NPs could be encapsulated into the pores of Cu-MOF 1 to generate Ag NPs and MOF composites, xAg/1 (x = 0.3, 0.5, 0.8, and x was the molar ratios of AgNO3 with Cu-MOF 1 in the synthesis), which was further demonstrated by powder X-ray diffraction, Fourier transform infrared, scanning electron microscopy, transmission electron microscope, energy dispersive spectrometer, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller (BET) analysis. In addition, synthesized 0.5Ag/1 exhibited outstanding catalytic activity for the A3-coupling reaction of aldehyde, alkyne, and amine with high recyclability. This work presents a viable strategy for using Cu(II)-based MOF loading with Ag NPs as heterogeneous catalysts for the A3-coupling reaction