Hydrophilic interior between hydrophobic regions in inverse bilayer structures of cation–1,1′-binaphthalene-2,2′-diyl phosphate salts

Abstract

A series of 1,1 0 -binaphthalene-2,2 0 -diyl phosphate (BNPPA À ) salts have been synthesized. Their crystal packings show a separation of the hydrophobic naphthyl and hydrophilic (RO) 2 PO 2 À phosphate/cation/solvate regions. Hydrogen bonding in the latter is the driving force for ''inverse bilayer'' formation, with a hydrophilic interior exposing the hydrophobic binaphthyl groups to the exterior. Stacking of the inverse bilayers occurs less through p-p and more through CHÁ Á Áp interactions between the naphthyl groups, which correlates with the formation of thin crystal plates along the stacking direction. Cations used with R-or rac-BNPPA À are protonated isonicotin-1-ium amide (1), isonicotin-1-ium acid (2), guanidinium (3), the metal complexes transtetraammine-dimethanol-copper(II) (4), trans-diaqua-tetramethanol-copper(II) (5) and cis-diaquabis(ethylene diamine)-nickel(II) (6). Crystallization occurs with inclusion of water and methanol solvent molecules, except in 2. Starting from R-BNPPA, inversion takes place with calcium acetate to give 1 as the racemate. 2 is crystallized as the R-BNPPA salt. The inversionsymmetrical complex trans-[Cu(H 2 O) 2 (CH 3 OH) 4 ] 21 in 5 has Cu-OH 2 bond lengths of 1.937(4) A ˚, and Cu-O(methanol) of 2.112(4) and 2.167(4) A ˚, corresponding to a compressed tetragonal geometry.Scheme 1 Molecules with a polar head (J) and a non-polar tail (Q) can spontaneously form (a) monolayers, (b) micelles, (c) bilayers and (d) liposome vesicles.

Mechanistic Investigation of Chiral Phosphoric Acid Catalyzed Asymmetric Baeyer–Villiger Reaction of 3‐Substituted Cyclobutanones with H2O2 as the Oxidant

“…This pre-equilibrium should be a fast and kinetically indistinguishable process. It is worth noting that chiral organophosphoric acids are known to be amphiphilic, [56] with a hydrophilic acidic interior being sandwiched between the hydrophobic binaphthalene skeleton and the 3-and 3'-substituent groups. Although the effective concentration of H 2 O 2 in dichloromethane is expected to be very small compared with that of cyclobutanone due to mutual immiscibility, [44,54] a hydrogen-bonding complex cat.-H 2 O 2 is preferentially formed probably at the interface between the aqueous and organic phases.…”

Synthesis and Spectral Characterization of Hydrazone Schiff Bases Derived from 2,4-Dinitrophenylhydrazine. Crystal Structure of Salicylaldehyde-2,4-Dinitrophenylhydrazone

“…There is a single classical intermolecular, albeit rather weak N-H··· O hydrogen bond (Table 1, not shown in Fig. 3) [17,18]. Adjacent molecules stacked on top of each other along the b axis exhibit some medium to weak π-π interactions between their exactly parallel (by symmetry) aryl planes.…”

“…Centroid-centroid contacts are 4.35Å, interplanar distances 3.34 and 3.31Å, slip angles (angle between centroid-centroid vector and normal to plane) 50.2 and 49.6 • , and vertical displacements (between ring centroids) 2.79 and 2.82Å for the interactions of ring C11-C16 and C21-C26, respectively, with their symmetry related counterparts with operation x, 1±y, z [19 -21]. The program PLATON, which was used for calculating the supramolecular interactions, did neither indicate the presence of strong intermolecular C-H··· O hydrogen bonds [22,23] nor the existence of C-H··· π interactions [17,20,24,25]. Instead, a spacefilling presentation of adjacent molecules, shown in Fig.…”

A Cadmium Anionic 1-D Coordination Polymer {[Cd(H2O)6][Cd2(atr)2(μ2-btc)2(H2O)4] 2H2O}n within a 3-D Supramolecular Charge-Assisted Hydrogen-Bonded and π-Stacking Network

“…The carboxylate groups of btc 3´a s hydrogen bond acceptors carry negative ionic charges. Such charge-assisted H-bonds are usually stronger and shorter than neutral H-bonds [37][38][39][40][41][42]. (5) 2.785 (7) 167 (8) vi = −x + 1, y + 1/2, −z + 3/2 O9-H9B···N2 ii 0.89 (9) 2.02 (9) 2.897 (8) 171 (8) ii = −x + 1, −y + 1, −z + 1 O10-H10A···O6 0.95 (9) 1.84 (9) 2.742 (7) 158 (7) -O10-H10B···N4 vii 0.98 (5) 1.91 (6) 2.803 (8) 151 (7) vii = −x + 2, −y + 1, −z + 2 O11-H11A···O6…”