Reaction of Vinyl Chloride with Cationic Palladium Acyl Complexes

Vinyl chloride (VC) reacts with the cationic Pd complexes [L2Pd(Me)(CO)][B(C6F5)4] (3a−d; L2 = Me2bipy, tBu2bipy, dppp, dmpe) and [L2Pd{C(O)Me}(CO)][B(C6F5)4] (4a−d) by 2,1-insertion of L2Pd{C(O)Me}(VC)+ intermediates to yield the O-chelated products [L2Pd{CHClCH2C(O)Me}][B(C6F5)4] (5a−d). 5a−d were characterized by NMR spectroscopy, and the molecular structures of 5a and 5b·CH2Cl2 were determined by X-ray crystallography. The VC 2,1-insertion regiochemistry is favored in part because the alternative L2Pd{CH2CHClC(O)Me}+ 1,2-insertion products would be destabilized by placement of the electron-withdrawing Cl and acyl substituents on the same carbon. In contrast to analogous nonhalogenated L2Pd{CHRCHR‘C(O)Me}+ species, 5a,c do not further react with CO, due to the stability of the chelate ring and the low migratory aptitude of the −CHClCH2C(O)Me group

Molecular Structure and Vinyl Chloride Insertion of a Cationic Zirconium(IV) Acyl Carbonyl Complex

The reaction of vinyl chloride (VC) with the cationic Zr acyl complex [Cp2Zr{C(O)Me}(CO)][MeB(C6F5)3] (1a/b, O-inside and O-outside isomers) yields an unusual dinuclear dicationic μ-acyl μ-keto-alkoxide complex, [Cp2Zr{μ-C(O)Me}{μ-OCMe(CHCH2)C(O)Me}ZrCp2][MeB(C6F5)3]2 (3), which was characterized by NMR spectroscopy and X-ray crystallography. This reaction proceeds by 1,2 insertion into the Zr−acyl bond of Cp2Zr{C(O)Me}+ to yield Cp2Zr{CH2CHClC(O)Me}+, which undergoes β-Cl elimination to form methyl vinyl ketone (MVK) and Cp2ZrCl+ (8). The MVK is trapped by Cp2Zr{C(O)Me}+ to form [Cp2Zr{η2-C(O)Me}(MVK)][MeB(C6F5)3] (9), which rearranges to [Cp2Zr{κ2-OC(Me)(CHCH2)C(O)Me}][MeB(C6F5)3] (10). Intermediate 10 is trapped by Cp2Zr{C(O)Me}+ to form 3. 3 is also formed by the reaction of 1a/b with 0.5 equiv of MVK. 1,2 VC insertion of Cp2Zr{C(O)Me}+ is favored over 2,1 insertion by steric factors. The molecular structure of 1a was determined by X-ray crystallography

Reaction of Vinyl Chloride with Cationic Palladium Acyl Complexes

Vinyl chloride (VC) reacts with the cationic Pd complexes [L2Pd(Me)(CO)][B(C6F5)4] (3a−d; L2 = Me2bipy, tBu2bipy, dppp, dmpe) and [L2Pd{C(O)Me}(CO)][B(C6F5)4] (4a−d) by 2,1-insertion of L2Pd{C(O)Me}(VC)+ intermediates to yield the O-chelated products [L2Pd{CHClCH2C(O)Me}][B(C6F5)4] (5a−d). 5a−d were characterized by NMR spectroscopy, and the molecular structures of 5a and 5b·CH2Cl2 were determined by X-ray crystallography. The VC 2,1-insertion regiochemistry is favored in part because the alternative L2Pd{CH2CHClC(O)Me}+ 1,2-insertion products would be destabilized by placement of the electron-withdrawing Cl and acyl substituents on the same carbon. In contrast to analogous nonhalogenated L2Pd{CHRCHR‘C(O)Me}+ species, 5a,c do not further react with CO, due to the stability of the chelate ring and the low migratory aptitude of the −CHClCH2C(O)Me group

Molecular Structure and Vinyl Chloride Insertion of a Cationic Zirconium(IV) Acyl Carbonyl Complex

The reaction of vinyl chloride (VC) with the cationic Zr acyl complex [Cp2Zr{C(O)Me}(CO)][MeB(C6F5)3] (1a/b, O-inside and O-outside isomers) yields an unusual dinuclear dicationic μ-acyl μ-keto-alkoxide complex, [Cp2Zr{μ-C(O)Me}{μ-OCMe(CHCH2)C(O)Me}ZrCp2][MeB(C6F5)3]2 (3), which was characterized by NMR spectroscopy and X-ray crystallography. This reaction proceeds by 1,2 insertion into the Zr−acyl bond of Cp2Zr{C(O)Me}+ to yield Cp2Zr{CH2CHClC(O)Me}+, which undergoes β-Cl elimination to form methyl vinyl ketone (MVK) and Cp2ZrCl+ (8). The MVK is trapped by Cp2Zr{C(O)Me}+ to form [Cp2Zr{η2-C(O)Me}(MVK)][MeB(C6F5)3] (9), which rearranges to [Cp2Zr{κ2-OC(Me)(CHCH2)C(O)Me}][MeB(C6F5)3] (10). Intermediate 10 is trapped by Cp2Zr{C(O)Me}+ to form 3. 3 is also formed by the reaction of 1a/b with 0.5 equiv of MVK. 1,2 VC insertion of Cp2Zr{C(O)Me}+ is favored over 2,1 insertion by steric factors. The molecular structure of 1a was determined by X-ray crystallography

A Novel Graphdiyne-Based Catalyst for Effective Hydrogenation Reaction

The platinum nanoparticles (Pt NPs) hybrided with nanostructured carbon materials with high stability are important for catalyzing hydrogenation reaction. Here we reported the fabrication of ultrastable Pt NPs anchored on graphdiyne, in which the strong interactions induced by the porous graphdiyne can prevent the thermal migration of Pt nanoparticles on the graphdiyne surface, exploiting the strong charge transfer interactions from Pt NPs to GDY substrate to tune the electron density of Pt NPs. Pt NPs catalyst with size of 2–3 nm showed high performance on hydrogenation of aldehydes and ketones to the corresponding alcohols compared with commercial Pt–C. Our results indicated that graphdiyne is a promising substrate for constructing metal nanoparticle-based heterogeneous catalysts, especially for those requiring strong interactions between metal nanoparticles and reactants

Polymerization of Norbornene and Methyl Acrylate by a Bimetallic Palladium(II) Allyl Complex

The sequential reaction of {(allyl)Pd(μ-Cl)}2 (2) with AgPF6 and PCy3 in CH2Cl2 generates a mixture (1-in situ) of [{(allyl)Pd(PCy3)}2(μ-Cl)][PF6] (1), 2, [(allyl)Pd(PCy3)2][PF6] (3), and (allyl)PdCl(PCy3) (4), which evolves to form pure 1 after 20 h at 23 °C. Complex 1 reacts with PCy3 to generate 3 and 4 and undergoes facile exchange of Pd units with 4. Both 1 and 1-in situ polymerize mixtures of norbornene (NB) and methyl acrylate (MA) to a mixture of poly(NB) and poly(MA) via competing NB insertion polymerization and MA radical polymerization

Polymerization of Norbornene and Methyl Acrylate by a Bimetallic Palladium(II) Allyl Complex

The sequential reaction of {(allyl)Pd(μ-Cl)}2 (2) with AgPF6 and PCy3 in CH2Cl2 generates a mixture (1-in situ) of [{(allyl)Pd(PCy3)}2(μ-Cl)][PF6] (1), 2, [(allyl)Pd(PCy3)2][PF6] (3), and (allyl)PdCl(PCy3) (4), which evolves to form pure 1 after 20 h at 23 °C. Complex 1 reacts with PCy3 to generate 3 and 4 and undergoes facile exchange of Pd units with 4. Both 1 and 1-in situ polymerize mixtures of norbornene (NB) and methyl acrylate (MA) to a mixture of poly(NB) and poly(MA) via competing NB insertion polymerization and MA radical polymerization

Reaction of Vinyl Chloride with Late Transition Metal Olefin Polymerization Catalysts

The reactions of vinyl chloride (VC) with representative late metal, single-site olefin dimerization and polymerization catalysts have been investigated. VC coordinates more weakly than ethylene or propylene to the simple catalyst (Me2bipy)PdMe+ (Me2bipy = 4,4‘-Me2-2,2‘-bipyridine). Insertion rates of (Me2bipy)Pd(Me)(olefin)+ species vary in the order VC > ethylene > propylene. The VC complexes (Me2bipy)Pd(Me)(VC)+ and (α-diimine)Pd(Me)(VC)+ (α-diimine = (2,6-iPr2−C6H3)NCMeCMeN(2,6-iPr2−C6H3)) undergo net 1,2 VC insertion and β-Cl elimination to yield Pd−Cl species and propylene. Analogous chemistry occurs for (pyridine-bisimine)MCl2/MAO catalysts (M = Fe, Co; pyridine-bisimine = 2,6-{(2,6-iPr2−C6H3)NCMe}2-pyridine) and for neutral (sal)Ni(Ph)PPh3 and (P−O)Ni(Ph)PPh3 catalysts (sal = 2-{C(H)N(2,6-iPr2−C6H3)}-6-Ph-phenoxide; P−O = {Ph2PC(SO3Na)C(p-tol)O}), although the initial metal alkyl VC adducts were not detected in these cases. These results show that the LnMCH2CHClR species formed by VC insertion into the active species of late metal olefin polymerization catalysts undergo rapid β-Cl elimination which precludes VC polymerization. Termination of chain growth by β-Cl elimination is the most significant obstacle to metal-catalyzed insertion polymerization of VC

Tiny Grains Give Huge Gains: Nanocrystal-Based Signal Amplification for Biomolecule Detection

Nanocrystals, despite their tiny sizes, contain thousands to millions of atoms. Here we show that the large number of atoms packed in each metallic nanocrystal can provide a huge gain in signal amplification for biomolecule detection. We have devised a highly sensitive, linear amplification scheme by integrating the dissolution of bound nanocrystals and metal-induced stoichiometric chromogenesis, and demonstrated that signal amplification is fully defined by the size and atom density of nanocrystals, which can be optimized through well-controlled nanocrystal synthesis. Further, the rich library of chromogenic reactions allows implementation of this scheme in various assay formats, as demonstrated by the iron oxide nanoparticle linked immunosorbent assay (ILISA) and blotting assay developed in this study. Our results indicate that, owing to the inherent simplicity, high sensitivity and repeatability, the nanocrystal based amplification scheme can significantly improve biomolecule quantification in both laboratory research and clinical diagnostics. This novel method adds a new dimension to current nanoparticle-based bioassays

Video4_A bio-fabricated tesla valves and ultrasound waves-powered blood plasma viscometer.MP4

Introduction: There is clinical evidence that the fresh blood viscosity is an important indicator in the development of vascular disorder and coagulation. However, existing clinical viscosity measurement techniques lack the ability to measure blood viscosity and replicate the in-vivo hemodynamics simultaneously.Methods: Here, we fabricate a novel digital device, called Tesla valves and ultrasound waves-powered blood plasma viscometer (TUBPV) which shows capacities in both viscosity measurement and coagulation monitoring.Results: Based on the Hagen-Poiseuille equation, viscosity analysis can be faithfully performed by a video microscopy. Tesla-like channel ensured unidirectional liquid motion with stable pressure driven that was triggered by the interaction of Tesla valve structure and ultrasound waves. In few seconds the TUBPV can generate an accurate viscosity profile on clinic fresh blood samples from the flow time evaluation. Besides, Tesla-inspired microchannels can be used in the real-time coagulation monitoring.Discussion: These results indicate that the TUBVP can serve as a point-of-care device in the ICU to evaluate the blood’s viscosity and the anticoagulation treatment.</p