4-Amino-5-(2-ethoxyphenyl)-2,4-dihydro-2H-1,2,4-triazole-3-thione–triphenylphosphine oxide (1/1)

Abstract

Key indicators: single-crystal X-ray study; T = 298 K; mean (C-C) = 0.004 Å; R factor = 0.053; wR factor = 0.135; data-to-parameter ratio = 14.5.In the title compound, C 18 H 15 OPÁC 10 H 12 N 4 OS, the triazole ring makes a dihedral angle of 51.24 (7) with the attached benzene ring. The triazole ring and its thione substituent are delocalized. There are intermolecular N-HÁ Á ÁO and N-HÁ Á ÁS hydrogen bonds, which also involve the cocrystallized triphenylphosphine oxide molecule. ExperimentalCrystal data C 18 H 15 OPÁC 10 H 12 N 4 OS M r = 514.57 Monoclinic, P2 1 =c a = 10.0514 (7) Å b = 18.3008 (12) Å c = 15.285 (1) Å = 105.726 (1) V = 2706.4 (3) Å 3 Z = 4 Mo K radiation = 0.21 mm À1 T = 298 (2) K 0.42 Â 0.31 Â 0.27 mm Data collection Bruker APEX area-detector diffractometer Absorption correction: multi-scan (SADABS; Bruker, 2002) T min = 0.917, T max = 0.942 14188 measured reflections 4857 independent reflections 4255 reflections with I > 2(I) R int = 0.022 Refinement R[F 2 > 2(F 2 )] = 0.053 wR(F 2 ) = 0.135 S = 1.08 4857 reflections 335 parameters 3 restraints H atoms treated by a mixture of independent and constrained refinement Á max = 0.27 e Å À3 Á min = À0.27 e Å À3 References Comment Recently, iminophosphoranes have attracted increasing attention as useful building blocks for nitrogen-containing heterocycles (Fresneda & Molina, 2004). Many interesting crystal structures involving iminophosphorane groups have been published, including some recent reports from our laboratory (Ding et al., 2005; Huang et al., 2005). As an extension of our research, we report the synthesis and crystal structure of the title compound (I), in which an iminophosphorane is not formed.The molecular structure of (I) is shown in Fig. 1. The triazole ring (C20, C19, N1-N3) is planar with an r.m.s. deviation of 0.0066 Å, and makes a dihedral angle of 51.24 (7)° with the attached benzene group. The C-N bond lengths, in the range 1.305 (3) Å-1.370 (3) Å, are longer than a typical C=N bond [ca 1.269 (2) Å], but short than a typical C-N bond length [ca 1.443 (4) Å], indicating electron delocalization in the triazole ring (Jin et al., 2004).The crystal packing (Fig. 2) is stabilized by an intramolecular N-H···O hydrogen bond, an intermolecular N-H···O