Robersonadamsen9559

Herein, we show that Zn2+ binds to phosphatidylserine (PS) lipids in supported lipid bilayers (SLBs), forming a PS-Zn2+ complex with an equilibrium dissociation constant of ∼100 μM. Significantly, Zn2+ binding to SLBs containing more than 10 mol % PS induces extensive reordering of the bilayer. This reordering is manifest through bright spots of high fluorescence intensity that can be observed when the bilayer contains a dye-labeled lipid. Measurements using atomic force microscopy (AFM) reveal that these spots represent three-dimensional unilamellar blebs. Bleb formation is ion specific, inducible by exposing the bilayer to μM concentrations of Zn2+ but not Mg2+, Cu2+, Co2+, or Mn2+. Moreover, Ca2+ can induce some blebbing at mM concentrations but not nearly as effectively as Zn2+. The interactions of divalent metal cations with PS lipids were further investigated by a combination of vibrational sum frequency spectroscopy (VSFS) and surface pressure-area isotherm measurements. VSFS revealed that Zn2+ and Ca2+ were bound to the phosphate and carboxylate moieties on PS via contact ion pairing, dehydrating the lipid headgroup, whereas Mg2+ and Cu2+ were bound without perturbing the hydration of these functional groups. Lipopolysaccharides nmr Additionally, Zn2+ was found to dramatically reduce the area per lipid in lipid monolayers, while Mg2+ and Cu2+ did not. Ca2+ could also reduce the area per lipid but only when significantly higher surface pressures were applied. These measurements suggest that Zn2+ caused lipid blebbing by decreasing the area per lipid on the side of the bilayer to which the salt was exposed. Such findings have implications for blebbing, fusion, oxidation, and related properties of PS-rich membranes in biological systems where Zn2+ concentrations are asymmetrically distributed.Selective cleavage of the B-O bond or B-H bond in HBpin can be achieved by adjusting the pincer ligand of a phosphorus(III) compound guided by a combination of theoretical prediction and experimental verification. Theoretical calculations reveal that a pincer-type phosphorus compound with an [ONO]3- ligand reacts with HBpin, leading to cleavage of the stronger B-O bonds (ΔG°⧧ = 23.2 kcal mol-1) rather than the weaker B-H bond (ΔG°⧧ = 26.4 kcal mol-1). A pincer-type phosphorus compound with a [NNN]3- ligand reacts with HBpin, leading to the weaker B-H bond cleavage (ΔG°⧧ = 16.2 kcal mol-1) rather than cleavage of the stronger B-O bond (ΔG°⧧ = 33.0 kcal mol-1). The theoretical prediction for B-O bond cleavage was verified experimentally, and the final products were characterized by NMR, HRMS, and single-crystal X-ray diffraction. The chemoselectivity of B-O bond cleavage was also observed in the presence of B-C or B-B bonds in borane substrates.β-Ga2O3 microrods have attracted increasing attention for their integration into solar blind/UV photodetectors and gas sensors. However, their synthesis using a low-temperature chemical route in aqueous solution is still under development, and the physicochemical processes at work have not yet been elucidated. Here, we develop a double-step process involving the growth of α-GaOOH microrods on silicon using chemical bath deposition and their further structural conversion to β-Ga2O3 microrods by postdeposition thermal treatment. It is revealed that the concentration of gallium nitrate has a drastic effect on tuning the morphology, dimensions (i.e., diameter and length), and density of α-GaOOH microrods over a broad range, in turn governing the morphological properties of β-Ga2O3 microrods. The physicochemical processes in aqueous solution are investigated by thermodynamic computations yielding speciation diagrams of Ga(III) species and theoretical solubility plots of GaOOH(s). In particular, the qualitative evolution of the morphological properties of α-GaOOH microrods with the concentration of gallium nitrate is found to be correlated with the supersaturation in the bath and discussed in light of the standard nucleation and growth theory. Interestingly, the structural conversion following the thermal treatment at 900 °C in air results in the formation of pure β-Ga2O3 microrods without any residual minor phases and with tunable morphology and improved structural ordering. These findings reporting a double-step process for forming high-quality pure β-Ga2O3 microrods on silicon open many perspectives for their integration onto a large number of substrates for solar blind/UV photodetection and gas sensing.The synthesis of rare anionic heteroleptic and homoleptic α-diimine iron complexes is described. Heteroleptic BIAN (bis(aryl)iminoacenaphthene) complexes 1-[K([18]c-6)(thf)0.5] and 2-[K([18]c-6)(thf)2] were synthesized by reduction of the [(BIAN)FeBr2] precursor complex using stoichiometric amounts of potassium graphite in the presence of the corresponding olefin. The electronic structure of these paramagnetic species was investigated by numerous spectroscopic analyses (NMR, EPR, 57Fe Mössbauer, UV-vis), magnetic measurements (Evans NMR method, SQUID), and theoretical techniques (DFT, CASSCF). Whereas anion 1 is a low-spin complex, anion 2 consists of an intermediate-spin Fe(III) center. Both complexes are efficient precatalysts for the hydroboration of carbonyl compounds under mild reaction conditions. The reaction of bis(anthracene) ferrate(1-) gave the homoleptic BIAN complex 3-[K([18]c-6)(thf)], which is less catalytically active. The electronic structure was elucidated with the same techniques as described for complexes 1-[K([18]c-6)(thf)0.5] and 2-[K([18]c-6)(thf)2] and revealed an Fe(II) species in a quartet ground state.Randomly oriented vanadium dioxide (VO2) nanowires were produced on a glass substrate by spin coating from a cosolvent. SEM studies reveal that highly dense VO2 nanowires were grown at an annealing temperature of 400 °C. X-ray diffraction (XRD) provides evidence of the high crystallinity of the VO2 nanowires-embedded VO2 thin films on the glass substrate at 400 °C. Characterization by high-resolution transmission electron microscopy (HR-TEM) confirmed the formation of VO2 nanowires. The optical band gap of the nanowires-embedded VO2 thin films was also calculated from the transmittance data to be 2.65-2.70 eV. The growth mechanism of the solution-processed semiconducting VO2 nanowires was proposed based on both solvent selection and annealing temperature. Finally, the solar water splitting ability of the VO2 nanowires-embedded VO2 thin films was demonstrated in a photoelectrochemical cell (PEC).