Puckering behavior in six new phosphoric triamides containing aliphatic six- and seven-membered ring groups and a database survey of analogous ring-containing structures

Abstract

The influence of a N heteroatom on the ring conformations of six-and seven-membered aliphatic rings in six new C(O)NHP(O)-based phosphoric triamide structures (analysed by X-ray crystallography) is investigated. Additionally the influence of steric and crystal packing effects is also studied by the analysis of Hirshfeld surfaces. The results are compared to analogous structures with three-to seven-aliphatic membered rings deposited in the Cambridge Structural Database. In the newly determined structures, the six-membered rings only show the near-chair conformation with a maximum deviation of the q puckering parameter of 4.4 from the ideal chair value of 0 /180 , while the seven-membered rings are found in different conformations such as near-chair, twist chair and twist sofa.

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

“…H atoms are drawn as spheres of arbitrary radii. and C O bond lengths are all within the ranges observed in analogous structures(Keikha et al, 2016;Vahdani Alviri et al, 2018). The P-N bond of the C(O)NHP(O) segment is longer than the other two P-N bonds.…”

Conformational flexibility in amidophosphoesters: a CSD analysis completed with two new crystal structures of (C6H5O)2P(O)X [X = NHC7H13 and N(CH2C6H5)2]

“…The relationship between conformational behaviour and molecular packing has been extensively studied, and there are many examples of conformations imposed by intra-and intermolecular interactions and conformational preferences, typically in organotin systems (Buntine et al, 1998), amides and acids (Dauber & Hagler, 1980) and polypeptide chains (Gregoret & Cohen, 1991). The effect of conformational flexibility on the existence of two (or more) symmetry-independent molecules in the crystal, disordered structures and the formation of polymorphs were also ISSN 2053ISSN -2296 # 2020 International Union of Crystallography studied (Toghraee et al, 2011;Keikha et al, 2017;Vahdani Alviri et al, 2018;Bernstein & Hagler, 1978).…”

“…The Cambridge Structural Database (CSD; Version 5.40, updated to November 2018; Groom et al, 2016) provides the opportunity to study conformational behaviour in analogous structures; in some recently published articles, we investigated conformational changes, typically in P(O)NHC(O)-based structures (Toghraee et al, 2011;Vahdani Alviri et al, 2018) and phosphate salts (Moghaddam et al, 2019), where, for example, the orientation of P(O) versus C(O) groups, the ring conformations of four-, five-, six-and seven-membered aliphatic rings, and the conformational flexibility of aliphatic and aromatic rings with respect to the other segments in the molecule/salt were considered.…”

A combined X-ray crystallography and theoretical study of N—H...OX (X is =P and —C) hydrogen bonds in two new structures with a (C—O)2(N)P(=Y) (Y is O and S) skeleton

“…In the hydrogen bonds formed, the P O group has a better acceptor capability than the other acceptor groups that usually exist in the structures, typically C O (Vahdani Alviri et al, 2018), S O (Pourayoubi et al, 2011) and N O/N-O (Gholivand et al, 2009), and a much better capability than ISSN 2053ISSN -2296 # 2018 International Union of Crystallography acceptors such as P S (Cupertino et al, 1998), C S (Omrani et al, 2015) and OAr (Ar = aryl) (Sabbaghi et al, 2016) groups. Thus, the P O group usually dictates the hydrogen-bond pattern as the best hydrogen-bond acceptor in the molecule.…”