Seven structurally similar cationic nickel(II)−alkyl complexes were synthesized by using a series of P, N ligands, and their reactivity was explored in the hydrosilylation of alkenes. More electron-rich phosphines enhanced the overall reactivity of the transformation; in contrast, groups on the imine donor had little impact. Overall, these catalysts displayed reactivity and selectivity that was previously unknown or very rare in nickel-catalyzed hydrosilylation. In reactions with Ph 2 SiH 2 , 1,2-disubstituted vinylarenes showed complete benzylic selectivity for silane addition, whereas terminal selectivity was observed for 1,1-disubstituted alkenes. The related PhSiH 3 led to exclusively Markovnikov selectivity for monosubstituted vinylarenes with no competing double addition observed. Mechanistic investigations supported the hypothesis that a Ni−H functions as the active species in this catalytic hydrosilylation, which in turn also showed catalytic competence for the silane redistribution reaction, especially with sterically unhindered silanes.

A cationic [(iminophosphine)nickel(allyl)] + complex was found to be sufficiently electrophilic to activate aldehydes and N-allylimines to undergo hydroboration with pinacolborane (HBpin) under mild reaction conditions. The catalyst displayed excellent selectivity toward aldehydes in the presence of ketones. A wide variety of functional groups were tolerated, includ- [a] I. 1877 ing halogens, NO 2 , CN, OMe, and alkenes for both aldehydes and imines. Electron-rich substrates were found to be significantly more reactive than their electron poor counterparts, a feature that was correlated to their enhanced ability to coordinate to the Lewis acidic nickel center. [40] Colorless liquid (60 mg, 81 % isolated yield). 1 H NMR (600 MHz, CDCl 3 ): δ = 7. 33-7.30 (m, 4H), 7.25-7.22 (m, 1H), 5.92 (ddt, 3 J HH = 17.2, 3 J HH = 10.2, 3 J HH = 6.0 Hz, 1H), 5.19 (dq, 3 J HH = 17.2, 4 J HH = 2 J HH = 1.5 Hz, 1H), 5.10 (dq, 3 J HH = 10.2, 4 J HH = 2 J HH = 1.5 Hz, 1H), 3.78 (s, 2H), 3.27 (dt, 3 J HH = 6.0, 4 J HH = 1.5 Hz, 2H), 1.47 (br s, 1H). 13 C{ 1 H} NMR (151 MHz, CDCl 3 ): δ = 140. 3, 136.9, 128.5, 128.3, 127.1, 116.1, 53.4, 51.9. [30a] Colorless liquid (74 mg, 92 % isolated yield). 1 H NMR (600 MHz, CDCl 3 ): δ = 7.22 (d, 3 J HH = 7.9 Hz, 2H), 7.15 (d, 3 J HH = 7.9 Hz, 2H), 5.94 (ddt, 3 J HH = 17.2, 3 J HH = 10.2, 3 J HH = 6.0 Hz, 1H), 5.20 (dq, 3 J HH = 17.2, 4 J HH = 2 J HH = 1.6 Hz, 1H), 5.12 (dq, 3 J HH = 10.2, 4 J HH = 2 J HH = 1.6 Hz, 1H), 3.76 (s, 2H), 3.28 (dt, 3 J HH = 6.0, 4 J HH = 1.6 Hz, 2H), 2.35 (s, 3H), 1.52 (br s, [41] Colorless liquid (81 mg, 91 % isolated yield). 1 H NMR (600 MHz, CDCl 3 ): δ = 7.24 (d, 3 J HH = 8.3 Hz, 2H), 6.86 (d, 3 J HH = 8.3 Hz, 2H), 5.93 (ddt, 3 J HH = 17.3, 3 J HH = 10.4, 3 J HH = 6.0 Hz, 1H), 5.19 (dq, 3 J HH = 17.3, 4 J HH = 2 J HH = 1.6 Hz, 1H), 5.11 (dq, 3 J HH = 10.4, 4 J HH = 2 J HH = 1.6 Hz, 1H), 3.79 (s, 3H), 3.73 (s, 2H), 3.26 (dt, 3 J HH = 6.0, 4 J HH = 1.6 Hz, 2H), 1.45 (br s, 1H). 13 C{ 1 H} NMR (151 MHz, CDCl 3 ): δ = 158. 7, 136.9, 132.5, 129.5, 116.1, 113.8, 55.4, 52.8, 51.8. N-Benzylprop-2-en-1-amine (2b): N-(4-Methylbenzyl)prop-2-en-1-amine (2c): N-(4-Methoxybenzyl)prop-2-en-1-amine (2d): N-(4-N,N-Dimethylaminobenzyl)prop-2-en-1-amine(2e): [30a] Pale yellow liquid (87 mg, 91 % isolated yield). 1 H NMR (600 MHz, CDCl 3 ): δ = 7.20 (d, 3 J HH = 8.6 Hz, 2H), 6.72 (d, 3 J HH = 8.6 Hz, 2H), 5.94 (ddt, 3 J HH = 16.8, 3 J HH = 10.1, 3 J HH = 6.1 Hz, 1H), 5.19 (dq, 3 J HH = 16.8, 4 J HH = 2 J HH = 1.6 Hz, 1H), 5.10 (dq, 3 J HH = 10.1, 4 J HH = 2 J HH = 1.6 Hz, 1H), 3.70 (s, 2H), 3.27 (dt, 3 J HH = 6.1, 4 J HH = 1.6 Hz, 2H), 2.94 (s, 6H), 1.38 (br s, 1H). 13 C{ 1 H} NMR (151 MHz, CDCl 3 ): δ = 149.9, 136.9, 129.2, 128.2, 115.9, 112.7, 52.8, 51.7, 40.8. N-(4-Fluorobenzyl)prop-2-en-1-amine (2f):[30a] Colorless liquid (71 mg, 86 % isolated yield). 1 H NMR (600 MHz, CDCl 3 ): δ = 7.32-7.27 (m, 2H), 7.04-6.98 (m, 2H), 5.92 (ddt, 3 J HH = 17.1, 3 J HH = 10.2, 3 J HH = 5.9 Hz, 1H), 5.19 (dq, 3 J HH = 17.1, 4 J HH = 2 J HH = 1.4 Hz, 1H), 5.12 (dq, 3 J HH = 10.2, 4 J HH = 2...

The intramicellar mass heterogeneity of a series of sequence-defined ionic peptoid block copolymers carrying a single charged monomer has been determined through contrast variation small-angle neutron scattering analysis. We observe that the internal micellar structure, namely, the number density radial distributions of invasive water and peptoid polymer, is significantly impacted by the location of the ionic monomer. By positioning the ionic monomer progressively closer to the hydrophilic/hydrophobic block junction, the micelles become less compact with increasing levels of chain folding and invasive water to accommodate electrostatic repulsion among the ionic monomers via solvation. This results in increasingly smaller micellar aggregates with aggregation numbers (N agg) ranging from 15.6 to 44 and micellar radii (R b) ranging from 61 to 94 Å. This study highlights the potential of using ionic monomer position as a design parameter to control the internal structures of nanoscale micellar assemblies.

Cellular functions of membrane proteins are strongly coupled to their structures and aggregation states in the cellular membrane. Molecular agents that can induce the fragmentation of lipid membranes are highly sought after as they are potentially useful for extracting membrane proteins in their native lipid environment. Toward this goal, we investigated the fragmentation of synthetic liposome using hydrophobe-containing polypeptoids (HCPs), a class of facially amphiphilic pseudo-peptidic polymers. A series of HCPs with varying chain lengths and hydrophobicities have been designed and synthesized. The effects of polymer molecular characteristics on liposome fragmentation are systemically investigated by a combination of light scattering (SLS/DLS) and transmission electron microscopy (cryo-TEM and negative stained TEM) methods. We demonstrate that HCPs with a sufficient chain length (DP n ≈ 100) and intermediate hydrophobicity (PNDG mol % = 27%) can most effectively induce the fragmentation of liposomes into colloidally stable nanoscale HCP−lipid complexes owing to the high density of local hydrophobic contact between the HCP polymers and lipid membranes. The HCPs can also effectively induce the fragmentation of bacterial lipid-derived liposomes and erythrocyte ghost cells (i.e., empty erythrocytes) to form nanostructures, highlighting the potential of HCPs as novel macromolecular surfactants toward the application of membrane protein extraction.

Attempts were taken to synthesize vanadium doped rubidium and cesium hexagonal tungsten bronze samples with nominal composition MxW1-yVyO3 (x =0.30, 0.25 and 0.0 ≤ y ≤ x). The samples were synthesized by solid state synthesis method at 700˚C in an evacuated silica glass tube. X-ray diffraction data of MxW1-yVyO3 reveal that pure hexagonal tungsten bronze (HTB) phase could be formed up to y = 0.18 and y = 0.15 for x = 0.30 and x = 0.25 series, respectively revealing 60% of replacement of W5+ by V5+. Rietveld structure refinement of XRD data also reveal the systematic incorporation of vanadium in the HTB lattice and shortening of the V/W-O bond distances within the xy plane and elongation in the crystallographic c direction. FTIR absorption spectra of the oxidized phases also support the XRD results. Moreover, there develop an absorption feature as a function of y and shows a significant increase of its intensity with gradual replacement of W5+ by V5+, indicating a significant decrease in the metallic like contribution and reveals nonmetallic nature of the compounds. Elemental analysis show excellent agreement with their nominal ones indicating that a systematic incorporation of vanadium in MxW1-yVyO3 system. ------#Present address of Altaf Hussain: Bangabandhu Sheikh Mujibur Rahman Maritime University, Bangladesh.