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The conformation of the seven-membered ring in the title compound, C18H14N5+·Cl, is close to a boat, and this fragment has an approximate mirror plane of symmetry. The protonation takes place at an N atom of the triazole ring. One strong N—H...Cl and two weak C—H...Cl hydrogen bonds determine the crystal packing.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801000952/na6035sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801000952/na6035Isup2.hkl
Contains datablock I

CCDC reference: 159725

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.003 Å
  • R factor = 0.048
  • wR factor = 0.113
  • Data-to-parameter ratio = 12.3

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry




Comment top

In the course of studies on benzodiazepine derivatives, potential new neurodrugs, we solved the crystal structure of title compound, (I). Similar compounds with the s-triazole ring fused to the benzodiazepine skeleton are used clinically as anxiolytics and hypnotics (for example, alprazolam, marketed as Xanax, and triazolam, marketed as Halcion).

The protonation takes place at one of N atoms of triazole ring, and the resulting N—H group acts as a donor in a strong linear hydrogen bond with the chloride anion.

The overall shape of the cation (see Fig. 1) is mainly determined by the conformation of the seven-membered ring, which is close to the cycloheptatriene-like boat (also the bond-length pattern within this ring indicates a similarity to the cycloheptatriene ring). There is an approximate mirror plane that passes through the C16 atom and the midpoint of the C5—N9 bond; the appropriate asymmetry parameter (Duax & Norton, 1976) Δs = 6.10. The conformation of the diazepine ring can be also described by the dihedral angles between the central plane of the boat (C4/C10/C15/N17) and the planes of its `bow' (C15/C16/N17) and `stern' (C4/C5/N9/C10). The values of the bow and stern angles, of 52.3 (2) and 36.00 (7)°, respectively, compare well with the angles found in similar benzodiazepine derivatives [for example, 55.5 (8) and 36.2 (8)° in 1-methyl-6-phenyl-8-(trifluoromethyl)-4H-s-triazolo[4,3-a]- [1,4]benzodiazepine (Kemmish & Hamor, 1988), and 53.4 (7) and 34.3 (7)° in 8-chloro-6-(2-chlorophenyl)-1-(4-pyridyl)-1,2,4-triazolo[4,3-a][1,4]- benzodiazepine (Kemmish & Hamor, 1989)].

The three rings fused to the central seven-membered ring are planar within experimental error (maximum deviations from the least-squares planes are 0.006 (1) Å for the triazine, 0.012 (2) Å for the benzo and 0.002 (1) Å for the pyrrolo ring). The mutual disposition of these rings is obviously enforced by the conformation of diazepine ring. Relatively free rotation is possible only around the C8—C2' bond; the dihedral angle between the triazinium and pyridine planes is 43.31 (6)°. The crystal packing is determined mainly by van der Waals interactions and hydrogen bonds accepted by the chloride anion; one strong N—H···Cl and two weaker, but structurally important, C—H···Cl bonds. These bonds connect the cations and anions into layers approximately perpendicular to the [010] direction (Fig. 2).

Experimental top

The title compound was provided by Ciba-Geigy. Colourless crystals were grown from an ethanol solution by slow evaporation.

Computing details top

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: ENPROC (Rettig, 1978); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: Stereochemical Workstation (Siemens, 1989).

Figures top
[Figure 1] Fig. 1. A view of the salt (Siemens, 1989) with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level, the H atoms are depicted as spheres of arbitrary radii, and the strong N—H···Cl hydrogen bond is drawn as a dashed line.
[Figure 2] Fig. 2. The crystal packing as seen along the y direction (Siemens, 1989). Displacement ellipsoids are drawn at the 50% probability level and the H atoms are depicted as spheres of arbitrary radii. Hydrogen bonds are drawn as dashed lines. [Symmetry codes: (i) x, 1.5 - y, -0.5 + z; (ii) 1 + x, 1.5 - y, -0.5 + z; (iii) 1 + x, y, z; (iv) x, 1.5 - y, 0.5 + z; (v) 1 + x, 1.5 - y, 0.5 + z.]
1-(2-Pyridyl)-8H-pyrrolo[2,1-c]-s-triazolo[4,3-a][1,4]benzodiazepinium chloride top
Crystal data top
C18H14N5+·ClF(000) = 696
Mr = 335.79Dx = 1.352 Mg m3
Monoclinic, P21/cCu Kα radiation, λ = 1.54178 Å
a = 8.7856 (5) ÅCell parameters from 25 reflections
b = 8.2058 (5) Åθ = 5–35°
c = 22.990 (2) ŵ = 2.12 mm1
β = 95.513 (6)°T = 293 K
V = 1649.8 (2) Å3Block, colourless
Z = 40.2 × 0.2 × 0.15 mm
Data collection top
CAD-4F four-circle
diffractometer
Rint = 0.048
Radiation source: fine-focus sealed tubeθmax = 74.8°, θmin = 5.1°
Ni-filter monochromatorh = 010
ω/2θ scansk = 100
3604 measured reflectionsl = 2828
3380 independent reflections2 standard reflections every 33 min
3315 reflections with I > 2σ(I) intensity decay: 2%
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.048All H-atom parameters refined
wR(F2) = 0.113 w = 1/[σ2(Fo2) + (0.01P)2 + 0.7P]
where P = (Fo2 + 2Fc2)/3
S = 1.26(Δ/σ)max = 0.001
3380 reflectionsΔρmax = 0.42 e Å3
274 parametersΔρmin = 0.55 e Å3
0 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0098 (6)
Crystal data top
C18H14N5+·ClV = 1649.8 (2) Å3
Mr = 335.79Z = 4
Monoclinic, P21/cCu Kα radiation
a = 8.7856 (5) ŵ = 2.12 mm1
b = 8.2058 (5) ÅT = 293 K
c = 22.990 (2) Å0.2 × 0.2 × 0.15 mm
β = 95.513 (6)°
Data collection top
CAD-4F four-circle
diffractometer
Rint = 0.048
3604 measured reflections2 standard reflections every 33 min
3380 independent reflections intensity decay: 2%
3315 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.113All H-atom parameters refined
S = 1.26Δρmax = 0.42 e Å3
3380 reflectionsΔρmin = 0.55 e Å3
274 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cl10.57862 (5)0.82294 (7)0.166179 (19)0.05235 (18)
C10.0478 (2)0.5787 (2)0.15720 (8)0.0428 (4)
H10.158 (3)0.587 (3)0.1477 (10)0.056 (6)*
C20.0678 (2)0.5067 (2)0.13014 (8)0.0471 (4)
H20.057 (3)0.455 (3)0.0961 (10)0.057 (6)*
C30.2052 (2)0.5325 (2)0.16482 (8)0.0428 (4)
H30.304 (2)0.494 (3)0.1596 (9)0.046 (6)*
C40.16905 (19)0.6198 (2)0.21296 (7)0.0359 (4)
C50.26225 (19)0.6754 (2)0.26350 (7)0.0354 (4)
N60.40341 (17)0.7306 (2)0.26449 (7)0.0424 (4)
H60.459 (3)0.759 (3)0.2313 (10)0.054 (6)*
N70.46255 (18)0.7704 (2)0.31949 (7)0.0459 (4)
C80.3530 (2)0.7391 (2)0.35263 (8)0.0393 (4)
N1'0.2539 (2)0.8371 (2)0.43927 (7)0.0546 (4)
C2'0.3703 (2)0.7668 (2)0.41603 (8)0.0419 (4)
C3'0.5043 (3)0.7222 (3)0.44829 (10)0.0607 (6)
H3'0.584 (3)0.672 (3)0.4275 (12)0.071 (8)*
C4'0.5173 (3)0.7502 (4)0.50771 (11)0.0715 (7)
H4'0.615 (4)0.730 (4)0.5307 (14)0.096 (10)*
C5'0.3987 (3)0.8224 (3)0.53224 (10)0.0648 (6)
H5'0.408 (3)0.843 (3)0.5744 (12)0.073 (8)*
C6'0.2716 (3)0.8627 (4)0.49654 (10)0.0654 (6)
H6'0.191 (3)0.908 (4)0.5103 (12)0.077 (8)*
N90.22472 (15)0.68080 (17)0.31946 (6)0.0340 (3)
C100.08906 (19)0.6093 (2)0.33966 (7)0.0350 (4)
C110.1031 (2)0.5132 (2)0.38937 (8)0.0440 (4)
H110.201 (3)0.497 (3)0.4101 (9)0.050 (6)*
C120.0272 (3)0.4441 (3)0.40865 (10)0.0543 (5)
H120.020 (3)0.383 (4)0.4469 (13)0.081 (8)*
C130.1677 (3)0.4676 (3)0.37776 (10)0.0560 (5)
H130.256 (3)0.417 (4)0.3920 (11)0.073 (8)*
C140.1796 (2)0.5601 (3)0.32752 (10)0.0487 (5)
H140.279 (3)0.573 (3)0.3040 (10)0.057 (6)*
C150.05162 (19)0.6339 (2)0.30754 (8)0.0378 (4)
C160.0641 (2)0.7316 (2)0.25220 (8)0.0405 (4)
H16B0.169 (3)0.744 (3)0.2376 (10)0.053 (6)*
H16A0.015 (2)0.840 (3)0.2590 (9)0.043 (5)*
N170.01414 (16)0.64735 (17)0.20759 (6)0.0369 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0415 (3)0.0770 (4)0.0395 (3)0.0112 (2)0.00837 (18)0.0050 (2)
C10.0470 (10)0.0405 (9)0.0396 (9)0.0050 (8)0.0028 (8)0.0024 (7)
C20.0620 (12)0.0454 (10)0.0339 (9)0.0069 (9)0.0055 (8)0.0029 (8)
C30.0495 (10)0.0435 (10)0.0368 (9)0.0010 (8)0.0115 (8)0.0014 (7)
C40.0365 (8)0.0360 (8)0.0355 (8)0.0017 (7)0.0059 (6)0.0039 (7)
C50.0348 (8)0.0365 (8)0.0355 (8)0.0007 (7)0.0064 (6)0.0032 (6)
N60.0361 (8)0.0561 (9)0.0360 (7)0.0082 (7)0.0079 (6)0.0024 (7)
N70.0374 (8)0.0602 (10)0.0403 (8)0.0085 (7)0.0040 (6)0.0008 (7)
C80.0336 (8)0.0449 (9)0.0396 (9)0.0017 (7)0.0043 (7)0.0013 (7)
N1'0.0538 (10)0.0672 (11)0.0430 (9)0.0073 (8)0.0064 (7)0.0032 (8)
C2'0.0416 (9)0.0451 (10)0.0384 (9)0.0030 (8)0.0016 (7)0.0028 (7)
C3'0.0545 (12)0.0741 (15)0.0512 (12)0.0128 (11)0.0062 (10)0.0018 (11)
C4'0.0767 (17)0.0825 (18)0.0506 (13)0.0082 (14)0.0182 (12)0.0048 (12)
C5'0.0911 (18)0.0666 (14)0.0360 (10)0.0074 (13)0.0022 (11)0.0004 (10)
C6'0.0750 (16)0.0777 (16)0.0451 (11)0.0055 (13)0.0140 (11)0.0065 (11)
N90.0316 (7)0.0371 (7)0.0338 (7)0.0012 (5)0.0053 (5)0.0018 (5)
C100.0342 (8)0.0335 (8)0.0391 (8)0.0014 (6)0.0122 (6)0.0018 (7)
C110.0473 (10)0.0432 (10)0.0431 (9)0.0008 (8)0.0129 (8)0.0041 (8)
C120.0665 (13)0.0458 (11)0.0546 (12)0.0044 (10)0.0270 (10)0.0065 (9)
C130.0501 (11)0.0516 (12)0.0713 (14)0.0105 (9)0.0310 (10)0.0044 (10)
C140.0361 (9)0.0469 (10)0.0651 (12)0.0025 (8)0.0156 (9)0.0110 (9)
C150.0354 (8)0.0334 (8)0.0458 (9)0.0008 (7)0.0105 (7)0.0071 (7)
C160.0354 (9)0.0383 (9)0.0473 (10)0.0054 (7)0.0011 (7)0.0037 (8)
N170.0373 (7)0.0347 (7)0.0383 (7)0.0006 (6)0.0018 (6)0.0001 (6)
Geometric parameters (Å, º) top
C1—N171.354 (2)C4'—C5'1.367 (4)
C1—C21.374 (3)C4'—H4'0.98 (3)
C1—H10.97 (2)C5'—C6'1.362 (4)
C2—C31.398 (3)C5'—H5'0.98 (3)
C2—H20.89 (2)C6'—H6'0.88 (3)
C3—C41.381 (2)N9—C101.445 (2)
C3—H30.94 (2)C10—C111.384 (2)
C4—N171.373 (2)C10—C151.392 (2)
C4—C51.430 (2)C11—C121.388 (3)
C5—N61.319 (2)C11—H110.95 (2)
C5—N91.359 (2)C12—C131.377 (3)
N6—N71.360 (2)C12—H121.01 (3)
N6—H60.97 (2)C13—C141.378 (3)
N7—C81.309 (2)C13—H130.97 (3)
C8—N91.384 (2)C14—C151.394 (3)
C8—C2'1.469 (2)C14—H140.98 (2)
N1'—C6'1.328 (3)C15—C161.499 (3)
N1'—C2'1.330 (3)C16—N171.463 (2)
C2'—C3'1.379 (3)C16—H16B0.95 (2)
C3'—C4'1.379 (3)C16—H16A0.99 (2)
C3'—H3'0.98 (3)
N17—C1—C2108.2 (2)C4'—C5'—H5'119 (2)
N17—C1—H1118 (1)N1'—C6'—C5'124.8 (3)
C2—C1—H1134 (1)N1'—C6'—H6'114 (2)
C1—C2—C3108.2 (2)C5'—C6'—H6'122 (2)
C1—C2—H2126 (2)C5—N9—C8105.9 (1)
C3—C2—H2126 (2)C5—N9—C10125.0 (1)
C4—C3—C2106.4 (2)C8—N9—C10128.1 (1)
C4—C3—H3124 (1)C11—C10—C15121.7 (2)
C2—C3—H3129 (1)C11—C10—N9119.1 (2)
N17—C4—C3108.4 (2)C15—C10—N9119.2 (2)
N17—C4—C5120.4 (2)C10—C11—C12119.0 (2)
C3—C4—C5131.2 (2)C10—C11—H11120 (1)
N6—C5—N9106.6 (2)C12—C11—H11121 (1)
N6—C5—C4126.0 (2)C13—C12—C11120.3 (2)
N9—C5—C4127.4 (2)C13—C12—H12120 (2)
C5—N6—N7111.9 (1)C11—C12—H12120 (2)
C5—N6—H6128 (1)C12—C13—C14120.1 (2)
N7—N6—H6120 (1)C12—C13—H13119 (2)
C8—N7—N6104.9 (2)C14—C13—H13121 (2)
N7—C8—N9110.6 (2)C13—C14—C15121.1 (2)
N7—C8—C2'122.4 (2)C13—C14—H14121 (1)
N9—C8—C2'127.0 (2)C15—C14—H14118 (1)
C6'—N1'—C2'116.5 (2)C10—C15—C14117.7 (2)
N1'—C2'—C3'123.3 (2)C10—C15—C16121.1 (2)
N1'—C2'—C8117.1 (2)C14—C15—C16121.1 (2)
C3'—C2'—C8119.6 (2)N17—C16—C15110.0 (1)
C4'—C3'—C2'118.3 (2)N17—C16—H16B108 (1)
C4'—C3'—H3'124 (2)C15—C16—H16B110 (1)
C2'—C3'—H3'118 (2)N17—C16—H16A108 (1)
C5'—C4'—C3'119.1 (2)C15—C16—H16A111 (1)
C5'—C4'—H4'121 (2)H16B—C16—H16A110 (2)
C3'—C4'—H4'120 (2)C1—N17—C4108.8 (2)
C6'—C5'—C4'118.1 (2)C1—N17—C16128.3 (2)
C6'—C5'—H5'123 (2)C4—N17—C16122.9 (2)
N17—C1—C2—C30.3 (2)N7—C8—N9—C51.0 (2)
C1—C2—C3—C40.4 (2)C2'—C8—N9—C5179.9 (2)
C2—C3—C4—N170.4 (2)N7—C8—N9—C10169.7 (2)
C2—C3—C4—C5177.6 (2)C2'—C8—N9—C1011.1 (3)
N17—C4—C5—N6144.8 (2)C5—N9—C10—C11131.4 (2)
C3—C4—C5—N637.4 (3)C8—N9—C10—C1135.4 (3)
N17—C4—C5—N935.8 (3)C5—N9—C10—C1546.3 (2)
C3—C4—C5—N9142.0 (2)C8—N9—C10—C15146.9 (2)
N9—C5—N6—N71.0 (2)C15—C10—C11—C122.1 (3)
C4—C5—N6—N7178.6 (2)N9—C10—C11—C12179.8 (2)
C5—N6—N7—C80.4 (2)C10—C11—C12—C131.7 (3)
N6—N7—C8—N90.4 (2)C11—C12—C13—C140.0 (3)
N6—N7—C8—C2'179.6 (2)C12—C13—C14—C151.2 (3)
C6'—N1'—C2'—C3'0.5 (3)C11—C10—C15—C140.8 (3)
C6'—N1'—C2'—C8179.4 (2)N9—C10—C15—C14178.5 (2)
N7—C8—C2'—N1'136.0 (2)C11—C10—C15—C16177.0 (2)
N9—C8—C2'—N1'43.1 (3)N9—C10—C15—C160.7 (2)
N7—C8—C2'—C3'43.0 (3)C13—C14—C15—C100.8 (3)
N9—C8—C2'—C3'137.9 (2)C13—C14—C15—C16178.7 (2)
N1'—C2'—C3'—C4'0.9 (4)C10—C15—C16—N1766.1 (2)
C8—C2'—C3'—C4'179.8 (2)C14—C15—C16—N17111.7 (2)
C2'—C3'—C4'—C5'0.8 (4)C2—C1—N17—C40.0 (2)
C3'—C4'—C5'—C6'0.4 (4)C2—C1—N17—C16177.3 (2)
C2'—N1'—C6'—C5'0.1 (4)C3—C4—N17—C10.2 (2)
C4'—C5'—C6'—N1'0.0 (4)C5—C4—N17—C1178.0 (2)
N6—C5—N9—C81.1 (2)C3—C4—N17—C16177.7 (2)
C4—C5—N9—C8178.4 (2)C5—C4—N17—C160.6 (2)
N6—C5—N9—C10170.4 (2)C15—C16—N17—C1112.5 (2)
C4—C5—N9—C109.2 (3)C15—C16—N17—C464.4 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N6—H6···Cl10.97 (2)1.98 (2)2.953 (2)177 (2)
C16—H16B···Cl1i0.95 (2)2.71 (2)3.624 (2)161 (2)
C5—H5···Cl1ii0.98 (3)2.82 (3)3.531 (2)130 (2)
Symmetry codes: (i) x1, y, z; (ii) x, y+3/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC18H14N5+·Cl
Mr335.79
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)8.7856 (5), 8.2058 (5), 22.990 (2)
β (°) 95.513 (6)
V3)1649.8 (2)
Z4
Radiation typeCu Kα
µ (mm1)2.12
Crystal size (mm)0.2 × 0.2 × 0.15
Data collection
DiffractometerCAD-4F four-circle
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
3604, 3380, 3315
Rint0.048
(sin θ/λ)max1)0.626
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.113, 1.26
No. of reflections3380
No. of parameters274
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.42, 0.55

Computer programs: CAD-4 Software (Enraf-Nonius, 1989), CAD-4 Software, ENPROC (Rettig, 1978), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), Stereochemical Workstation (Siemens, 1989).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N6—H6···Cl10.97 (2)1.98 (2)2.953 (2)177 (2)
C16—H16B···Cl1i0.95 (2)2.71 (2)3.624 (2)161 (2)
C5'—H5'···Cl1ii0.98 (3)2.82 (3)3.531 (2)130 (2)
Symmetry codes: (i) x1, y, z; (ii) x, y+3/2, z+1/2.
 

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