Association of Non‐covalent Interactions C−H… X ( X =O, F, Cl, π) and Cl…π with Hydrogen Bond Interactions N−H…O in Molecular Assembly of New Phosphoramides: A Combined X‐Ray Crystallography and Topology (AIM and Hirshfeld) Analysis

Synthesis and structural study of five new phosphoric triamides: interplay between classical and non-classical intermolecular interactions

Phosphoric triamides are attractive to investigate because of their extensive applications in various fields, especially in medicine. Five new phosphoric triamides with the main parts [N]P(O)[NH]2 and [C(O)NH]P(O)[N]2 have been structurally analyzed by single crystal MoKα/synchrotron-based X-ray diffraction and characterized by spectroscopic methods (FT-IR and 1H, 13C, 31P NMR). Compounds crystallize in orthorhombic (1 with space group Pnma) and monoclinic (2 (P21/a), 3 (C2/c), 4 (P21/n) and 5 (P21/c)) crystal systems. The asymmetric unit of all structures consists of one phosphoric triamide molecule, except for 1 with one half of molecule. X-ray crystallography data reveal that the molecular architectures constructed by classical N—H … O hydrogen bonds are as 1D linear (building the R 2 1 ( 6 ) ${R}_{2}^{1}\left(6\right)$ , C(4) and R 2 2 ( 10 ) / R 2 1 ( 6 ) ${R}_{2}^{2}\left(10\right)/{R}_{2}^{1}\left(6\right)$ motifs, respectively, for 1–3) or dimeric (the R 2 2 ( 8 ) ${R}_{2}^{2}\left(8\right)$ ring motif for 4 and 5). A detailed investigation of the intermolecular interactions using Hirshfeld surface (HS) analysis illustrates that the H … H, O … H/H … O and C … H/H … C contacts for all compounds, and Cl … H/H … Cl and F … H/H … F contacts for 3–5, are the most significant contributors to the crystal packing. Moreover, based on the calculated enrichment ratios (E), the O … H/H … O contacts including the classical N—H … O hydrogen bonds for all structures are considered as favoured contacts.

Diaminomethylenemalononitrile as a Chiral Single Hydrogen Bond Catalyst: Application to Enantioselective Conjugate Addition of α-Branched Aldehydes

An improved diaminomethylenemalononitrile organocatalyst, bearing a N,N-disubstituted structure, promoted enantioselective conjugate addition reaction of α-branched aldehydes with vinyl sulfone, affording adducts with excellent enantioselectivities (up to 96% ee). Mechanistic studies revealed that the diaminomethylenemalononitrile motif holds the vinyl sulfone substrate using a single hydrogen bond accompanied by multiple weak interactions, including electrostatic C-H⋅⋅⋅O interactions.

Coordination versus hydrogen bonds in the structures of different tris(pyridin-2-yl)phosphoric triamide derivatives

The crystalline forms of tris(pyridin-2-yl)phosphoric triamide, OP[NH-2Py]3 were investigated using single crystal X-ray diffraction, both as a metal complex [Co{(O)P[NH-2Py]2[NH-2PyH]}2]Cl3, compound 1, and as the purely organic pseudopolymorphs, the pure/anhydrate OP[NH-2Py]3, 2, monohydrate 2OP[NH-2Py]3·H2O, 3 and solvate 2OP[NH-2Py]3·2DMF·H2O, 4, respectively. An improved model of the metal organic framework (MOF) structure of Cu(ii)O6 {[Cu(OCHO)3][(CH3)2NH2]} n , 5 is also reported. Compound 1 is the first example of a discrete chelate phosphoric triamide (PT) complex with an [N]3P(O)-based backbone which in the PT compound acts as a flexible tridentate ligand. The structures 1, 3 and 4 crystallize in the monoclinic space group P21/n, while the anhydrous form 2 crystallizes in the R3̄ trigonal space group. 5 which was obtained as a byproduct of the synthesis process of coordination compounds of OP[NH-2Py]3, crystallizes in the monoclinic space group I2/c. Hydrogen bonding pattern analysis for the different solid state forms of OP[NH-2Py]3 (2-4) shows a 2D sheet of the N-H⋯N linked molecules for 2, and a 1D chain and a ten-membered ring motif, both formed via the hydrogen bonds N-H⋯O, N-H⋯N and O-H⋯O, for 3 and 4, respectively. Of note is the unusual absence of the expected hydrogen bond interaction N-H⋯O[double bond, length as m-dash]P of PT compounds and also a lack of any significant π interactions in structure 2. The role of the solvent/hydrate and substituent (aminopyridine) in the formation of the expected hydrogen bond interactions in the studied solid state forms is also investigated. For these structures, crystal packing analysis using 3D Hirshfeld surface (HS), 2D fingerprint plot (FP) and enrichment ratio (E) calculations confirm a competition between the pyridinyl nitrogen and phosphoryl oxygen atoms as H-bond acceptors to construct the N-H⋯N or N-H⋯O contacts. Moreover, the significant differences between the anhydrous form of OP[NH-2Py]3, 2, and the monohydrate and solvate forms, 3 and 4, can be correlated to the pseudo-infinite (in 2) versus finite values (in 3 and 4) for the upper values of d e and d i on the related full FPs.