Analysis of N—H...O hydrogen bonds in new C(O)—NH—P(O)-based phosphoric triamides and analogous structures deposited in the Cambridge Structural Database

Abstract

Five new compounds belonging to the phosphoric triamide family have been synthesized: two of them with the formula XC(O)NHP(O)Y [X = CF3 (1) and CClF2 (2), Y = NHCH2C(CH3)2CH2NH] involving a 1,3-diazaphosphorinane ring part, and three 2,6-Cl2C6H3C(O)NHP(O)Z2 phosphoric triamides [Z = NHC(CH3)3 (3), N(CH3)(C6H11) (4) and N(CH3)(CH2C6H5) (5)]. The characterization was performed by (31)P{(1)H}, (1)H, (13)C NMR, IR spectroscopy besides (19)F NMR for fluorine containing compounds (1) and (2), and X-ray single-crystal structure analysis for (1), (3), (4) and (5). In each molecule the P atom has a distorted tetrahedral environment. The N atoms bonded to P atom have mainly sp(2) character with a very slight tendency to a pyramidal coordination for some amido groups. Different types of N-H···O hydrogen bonds have been analyzed for (1), (3), (4) and (5) and 118 other structures (including 194 hydrogen bonds) deposited in the Cambridge Structural Database, containing either C(O)-NH-P(O)[N(C)(C)]2 or C(O)-NH-P(O)[NH(C)]2. The participation of N(CP)-H···O=P [N(CP) = the nitrogen atom of the C(O)-NH-P(O) fragment], N-H···O=P, N-H···O=C and N(CP)-H···O=C hydrogen bonds in different hydrogen-bonded motifs are discussed. Moreover, the involvement of the O atoms of C=O or P=O in the [N(CP)-H][N-H]···O=P, [N-H]2···O=P, [N-H]2···O=C and [N-H]3···O=C groups are considered. A histogram of N···O distances, the distribution of N-H···O angles and the scatterplot of N-H···O angles versus N···O distances are studied.