Syntheses, Characterizations and Crystal Structures of Two New Racemic Amidophosphoesters: rac -(C 6 H 5 O)( cyclo -C 6
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TRUCTURE OF ORGANIC COMPOUNDS
Syntheses, Characterizations and Crystal Structures of Two New Racemic Amidophosphoesters: rac-(C6H5O)(cyclo-C6H11NH)P(O)N(C4H8)NP(O)(NH-cycloC6H11)(OC6H5) and rac-(p-CH3-C6H4NH)P(O)(OC6H4-p-CH3)(OC6H5) F. Karimi Ahmadabada, M. Pourayoubia,*, and M. Nečasb a
Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran of Chemistry, Faculty of Science, Masaryk University, Brno, 61137 Czech Republic *e-mail: [email protected]
b Department
Received December 12, 2019; revised March 13, 2020; accepted April 20, 2020
Abstract—The new racemic compounds, rac-diphenyl bis(cyclo-hexylamido)(piperazine)-1,4-diyldiphosphinate, C28H42N4O4P2 (I), and rac-phenyl(p-methylphenyl)(p-tolylamido)-phosphonate, C20H20NO3P (II), were synthesized and characterized by elemental analysis, 31P, 13C, 1H nuclear magnetic resonance, infrared spectroscopy and single-crystal X-ray diffraction analysis. The phosphorus atoms exhibit distorted tetrahedral environment [O]P=O[N][N] in I and [N]P=O[O][O] in II. In compound I, two (C6H5O)P(O)(NHcyclo-C6H11) fragments are bridged via a NC4H8N linker that accepts chair conformation. In structure II, the environment of the P atom is a result of the linking of one amido and two different phenoxy groups bonded to the P atom. In crystal structure I, adjacent molecules are linked to each other through hydrogen bonds N–H⋅⋅⋅OP in a two-dimensional network along the ab plane, including R44(26) ring motifs, while in structure II, pairs of intermolecular hydrogen bonds N–H⋅⋅⋅OP lead to the formation of centrosymmetric dimers with the R22 (8) graph-set motif. DOI: 10.1134/S1063774520070020
INTRODUCTION Phosphoramides containing P(O)(N)n(O)3 – n (n = 1, 2, 3) and P(O)(N)m(O)2 – mX (m = 1, 2; X = halogen) skeletons are among the well-studied inorganic compounds, numerous structures of which are deposited in the Cambridge Structural Database (CSD) [1]. Interest in phosphoramides is due to their application in different research fields; typical examples are the usage in biological sciences [2], as stereo selective catalysts [3, 4], the preparation of flame retardants [5] and the use as ligands in luminescent metal complexes [6]. Recently, the synthesis and crystallography experiments have been developed for some racemate mixed amidophosphinates with the P(O)[O][N][N] skeleton [7–9]. Examination of CSD shows only a few structures of diphosphorus racemate mixed amidophosphinate [10]. Moreover, there are several racemic P(O)[O][O][N]-based structures in the CSD [11–15]. The study of the racemate amidophosphoesters is interesting owing to the challenging task of the synthe-
sis procedure, which needs multi-step reaction conditions and a purification process [7–9]. Racemic compounds are also interesting because of probability to separate enantiomer components [16]. In terms of structural studies and crystal engineering concepts, it is possible to use different segments with different structural properties (such as flexibility/rigidity, volume, bridging) for b
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