Chiral one-dimensional hydrogen-bonded architectures constructed from single-enantiomer phosphoric triamides

Molecular Insights into Water-Chloride and Water-Water Interactions in the Supramolecular Architecture of Aconine Hydrochloride Dihydrate

Despite the previous preparation of aconine hydrochloride monohydrate (AHM), accurate determination of the crystal's composition was hindered by severely disordered water molecules within the crystal. In this study, we successfully prepared a new dihydrate form of the aconine hydrochloride [C25H42NO9+Cl-·2(H2O), aconine hydrochloride dihydrate (AHD)] and accurately refined all water molecules within the AHD crystal. Our objective is to elucidate both water-chloride and water-water interactions in the AHD crystal. The crystal structure of AHD was determined at 136 K using X-ray diffraction and a multipolar atom model was constructed by transferring charge-density parameters to explore the topological features of key short contacts. By comparing the crystal structures of dihydrate and monohydrate forms, we have observed that both AHD and AHM exhibit identical aconine cations, except for variations in the number of water molecules present. In the AHD crystal, chloride anions and water molecules serve as pivotal connecting hubs to establish three-dimensional hydrogen bonding networks and one-dimensional hydrogen bonding chain; both water-chloride and water-water interactions assemble supramolecular architectures. The crystal packing of AHD exhibits a complete reversal in the stacking order compared to AHM, thereby emphasizing distinct disparities between them. Hirshfeld surface analysis reveals that H···Cl- and H···O contacts play a significant role in constructing the hydrogen bonding network and chain within these supramolecular architectures. Furthermore, topological analysis and electrostatic interaction energy confirm that both water-chloride and water-water interactions stabilize supramolecular architectures through electrostatic attraction facilitated by H···Cl- and H···O contacts. Importantly, these findings are strongly supported by the existing literature evidence. Consequently, navigating these water-chloride and water-water interactions is imperative for ensuring storage and safe processing of this pharmaceutical compound.

Structural differences/similarities of diastereotopic groups in three new chiral phosphoramides

The crystal structures of two single-enantiomer amidophosphoesters with an (O)₂P(O)(N) skeleton and one single-enantiomer phosphoric triamide with an (N)₂P(O)(N) skeleton were studied. The compounds are diphenyl [(R)-(+)-α-4-dimethylbenzylamido]phosphate, (I), and diphenyl [(S)-(-)-α-4-dimethylbenzylamido]phosphate, (II), both C₂₁H₂₂NO₃P, and N-(2,6-difluorobenzoyl)-N',N''-bis[(R)-(+)-α-ethylbenzyl]phosphoric triamide, C₂₅H₂₈F₂N₃O₂P, (III). The asymmetric units contain two amidophosphoester molecules for (I) and (II), and one phosphoric triamide molecule for (III). In the crystal structures of (I) and (II), molecules are assembled in a similar one-dimensional chiral ribbon architecture, but with almost a mirror-image relationship with respect to each other through N-H...O(P) and C-H...O(P) hydrogen bonds along [010]. In the crystal structure of (III), the chiral tape architecture along [100] is mediated by N-H...O(P) and N-H...O(C) hydrogen bonds, and the tapes are connected into slabs by C-H...O interactions (along the ab plane). The differences/similarities of the two diastereotopic phenoxy groups in (I)/(II) and the two chiral amine fragments in (III) were studied on the grounds of geometry, conformation and contribution to the crystal packing, as well as ¹H and ¹³C signals in a solution NMR study.

Dicyclohexylammonium O,O’-Diphenyl Phosphate, [(C6H11)2NH2][(C6H5O)2P(O)(O)]: Spectroscopic Study, Crystal Structure, and Hirshfeld Surface Analysis

The title salt, [(C6H11)2NH2][(C6H5O)2P(O)(O)], crystallizes in the chiral space group P212121, composed of achiral cation and anion components. The strong charge-assisted N–H…O hydrogen bonds build a linear assembly along the a axis, including a non-centrosymmetric C22(6) chain graph-set motif. The intra and intermolecular C–H…O interactions as well as the C–H…π-electron ring interactions also exist in the crystal structure. Fingerprint plots are used for a detailed investigation of intermolecular interactions participating in the crystal packing. The spectroscopic features (IR, 1H NMR, 13C{1H} NMR, 31P{1H} NMR, and mass) are studied.

Two single-enantiomer amidophosphoesters: a database study on the chirality of (O)2P(O)(N)-based structures

The crystal structures of two single-enantiomer amidophosphoesters with an (O)₂P(O)(N) skeleton, i.e. diphenyl [(R)-(+)-α-methylbenzylamido]phosphate, (I), and diphenyl [(S)-(-)-α-methylbenzylamido]phosphate, (II), both C₂₀H₂₀NO₃P, are reported. In both structures, chiral one-dimensional hydrogen-bonded architectures, along [010], are mediated by N-H...OP interactions. The statistically identical assemblies include the noncentrosymmetric graph-set motif C(4) and the compounds crystallize in the chiral space group P2₁. As a result of synergistic co-operation from C-H...O interactions, a two-dimensional superstructure is built including a noncentrosymmetric R₄⁴(22) hydrogen-bonded motif. A Cambridge Structural Database survey was performed on (O)₂P(O)(N)-based structures in order to review the frequency of space groups observed in this family of compounds; the hydrogen-bond motifs in structures with chiral space groups and the types of groups inducing chirality are discussed. The ^2,3J_X-P (X = H or C) coupling constants from the NMR spectra of (I) and (II) have been studied. In each compound, the two diastereotopic C₆H₅O groups are different, which is reflected in the different chemical shifts and some coupling constants.

The (CF3C(O)NH)(C6H5CH2NH)2P(O) phosphoric triamide as a novel carrier with excellent efficiency for Cu(ii) in a liquid membrane transport system

Transport of Ag(i), Cd(ii), Co(ii), Cu(ii), Ni(ii), Pb(ii) and Zn(ii) cations across a bulk liquid membrane (BLM) containing N,N′-dibenzyl-N′′-(2,2,2-trifluoroacetyl)-phosphoric triamide (PTC) as a new carrier is studied by atomic absorption spectrometry. The results show selective and efficient transport of the copper(ii) cation from aqueous solution in the presence of the other cations. Various factors are optimized in order to obtain maximum transport efficiency. The PTC ligand is characterized by single crystal X-ray diffraction analysis, IR, NMR (¹⁹F, ³¹P, ¹H, ¹³C) and mass spectroscopy. The complex formation reaction between copper(ii) and PTC is studied by a conductometric method, which shows the 1 : 1 stoichiometry for ligand and copper(ii).

Selective transport of Cu(ii) cation in the presence of six other cations across a bulk liquid membrane containing a novel phosphoric triamide carrier is studied.

Decorated single-enantiomer phosphoramide-based silica/magnetic nanocomposites for direct enantioseparation

The nano-composites Fe₃O₄@SiO₂@PTA(+) and Fe₃O₄@SiO₂@PTA(−) (PTA: phosphoric triamide) were prepared and used for the chiral separation of five racemic mixtures.