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The crystal structures of the solid form of solvated 2,6-bis­(1H-imidazol-2-yl)pyridine (H2dimpy) trihydrate, C11H9N5·3H2O·[+solvent], I, and its hydrate hydro­chloride salt 2-[6-(1H-imidazol-2-yl)pyridin-2-yl]-1H-imidazol-3-ium chlo­ride trihydrate, C11H10N5+·Cl·3H2O, II, are reported and analysed in detail, along with potentiometric and spectrophotometric titrations for evaluation of the acid–base equilibria and proton-coupled electron-transfer reactions. Compound I crystallizes in the high-symmetry trigonal space group P3221 with an atypical formation of solvent-accessible voids, as a consequence of the 32 screw axis in the crystallographic c-axis direction, which are probably occupied by uncharacterized disordered solvent mol­ecules. Additionally, the trihydrated chloride salt crystallizes in the conventional monoclinic space group P21/c without the formation of solvent-accessible voids. The acid–base equilibria of H2dimpy were studied by potentiometric and spectrophotometric titrations, and the results suggest the formation of H3dimpy+ (pKa1 = 5.40) and H4dimpy2+ (pKa2 = 3.98), with the electrochemical behaviour of these species showing two consecutive irreversible proton-coupled electron-transfer reactions. Density functional theory (DFT) calculations corroborate the inter­pretation of the experimental results and support the assignment of the electrochemical behaviour.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S2053229619011951/uk3189sup1.cif
Contains datablocks H2dimpyI, II, global

mol

MDL mol file https://doi.org/10.1107/S2053229619011951/uk3189IIsup4.mol
Supplementary material

cml

Chemical Markup Language (CML) file https://doi.org/10.1107/S2053229619011951/uk3189IIsup3.cml
Supplementary material

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S2053229619011951/uk3189IIsup2.hkl
Contains datablock II

pdf

Portable Document Format (PDF) file https://doi.org/10.1107/S2053229619011951/uk3189sup5.pdf
Additional supporting information

CCDC references: 1915852; 1915851

Computing details top

For both structures, data collection: APEX3 (Bruker, 2010); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009) and ORTEP-3 (Farrugia, 2012); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009) and Mercury (Macrae et al., 2008).

2,6-Bis(1H-imidazol-2-yl)pyridine trihydrate (H2dimpyI) top
Crystal data top
C11H9N5·3H2O·[+solvent]Dx = 1.127 Mg m3
Mr = 265.28Cu Kα radiation, λ = 1.54178 Å
Trigonal, P3221Cell parameters from 3604 reflections
a = 18.6043 (5) Åθ = 2.7–68.5°
c = 3.9112 (1) ŵ = 0.71 mm1
V = 1172.38 (7) Å3T = 150 K
Z = 3Needle, colourless
F(000) = 4200.42 × 0.07 × 0.06 mm
Data collection top
Bruker APEX CCD detector
diffractometer
1416 independent reflections
Radiation source: fine-focus sealed tube1375 reflections with I > 2σ(I)
Detector resolution: 8.3333 pixels mm-1Rint = 0.035
φ and ω scansθmax = 68.5°, θmin = 2.7°
Absorption correction: multi-scan
(SADABS; Bruker, 2010)
h = 2222
Tmin = 0.589, Tmax = 0.753k = 2111
4574 measured reflectionsl = 44
Refinement top
Refinement on F2Hydrogen site location: mixed
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.038 w = 1/[σ2(Fo2) + (0.0717P)2 + 0.0039P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.095(Δ/σ)max < 0.001
S = 1.12Δρmax = 0.19 e Å3
1416 reflectionsΔρmin = 0.18 e Å3
107 parametersAbsolute structure: Flack x determined using 610 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
13 restraintsAbsolute structure parameter: 0.06 (13)
Primary atom site location: dual
Special details top

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

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
C10.82009 (12)0.40541 (14)0.3290 (4)0.0424 (5)
H10.8101180.4496030.2780800.051*
C20.77089 (11)0.32375 (13)0.2485 (4)0.0439 (5)
H20.7197640.3012610.1283720.053*
C30.87644 (11)0.33371 (12)0.5186 (4)0.0376 (4)
C40.93872 (11)0.31921 (12)0.6842 (4)0.0393 (5)
C50.93498 (13)0.24231 (13)0.6823 (5)0.0488 (5)
H50.8894990.1950000.5810930.059*
C61.0000000.23727 (18)0.8333330.0563 (7)
H61.0000000.1862040.8333310.068*
N10.88686 (9)0.41061 (10)0.4985 (3)0.0371 (4)
H1A0.9292050.4562260.5802140.045*
N20.80616 (10)0.27824 (10)0.3670 (4)0.0434 (4)
N31.0000000.38611 (12)0.8333330.0357 (5)
O11.0000000.56592 (11)0.8333330.0498 (5)
H1B0.9841900.5909420.9775270.075*
O2B0.7265 (2)0.1091 (2)0.420 (4)0.126 (4)0.710 (16)
H2BA0.7539170.0889080.3172710.189*0.710 (16)
H2BB0.7627780.1613430.4505090.189*0.710 (16)
O2A0.7301 (4)0.1159 (4)0.160 (3)0.059 (3)0.290 (16)
H2AA0.7355400.0911510.0186240.089*0.290 (16)
H2AB0.7700140.1670820.1415710.089*0.290 (16)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0340 (9)0.0561 (12)0.0319 (7)0.0187 (9)0.0036 (6)0.0041 (7)
C20.0340 (9)0.0572 (12)0.0333 (8)0.0175 (8)0.0007 (6)0.0024 (7)
C30.0302 (8)0.0444 (9)0.0303 (8)0.0126 (7)0.0070 (6)0.0016 (6)
C40.0334 (9)0.0448 (10)0.0336 (8)0.0150 (8)0.0094 (7)0.0010 (7)
C50.0433 (12)0.0431 (10)0.0536 (11)0.0167 (9)0.0053 (9)0.0019 (8)
C60.0581 (18)0.0482 (11)0.0658 (17)0.0291 (9)0.0001 (14)0.0001 (7)
N10.0275 (7)0.0437 (8)0.0320 (6)0.0117 (6)0.0047 (5)0.0009 (6)
N20.0343 (7)0.0484 (9)0.0364 (7)0.0122 (7)0.0029 (5)0.0061 (6)
N30.0298 (10)0.0420 (9)0.0312 (9)0.0149 (5)0.0072 (7)0.0036 (3)
O10.0377 (10)0.0433 (8)0.0665 (13)0.0189 (5)0.0007 (8)0.0004 (4)
O2B0.0570 (19)0.0463 (17)0.261 (13)0.0153 (14)0.052 (4)0.027 (3)
O2A0.049 (3)0.040 (3)0.084 (6)0.019 (2)0.024 (3)0.014 (3)
Geometric parameters (Å, º) top
C1—H10.9500C5—H50.9500
C1—C21.362 (3)C5—C61.391 (3)
C1—N11.368 (3)C6—H60.9500
C2—H20.9500N1—H1A0.8800
C2—N21.385 (3)O1—H1Bi0.87
C3—C41.465 (3)O1—H1B0.8708
C3—N11.347 (3)O2B—H2BA0.8693
C3—N21.333 (3)O2B—H2BB0.8699
C4—C51.397 (3)O2A—H2AA0.8711
C4—N31.330 (2)O2A—H2AB0.8700
C2—C1—H1127.1C6—C5—C4117.8 (2)
C2—C1—N1105.72 (18)C6—C5—H5121.1
N1—C1—H1127.1C5i—C6—C5119.7 (3)
C1—C2—H2124.9C5i—C6—H6120.2
C1—C2—N2110.18 (16)C5—C6—H6120.2
N2—C2—H2124.9C1—N1—H1A126.0
N1—C3—C4120.95 (17)C3—N1—C1108.06 (16)
N2—C3—C4127.88 (18)C3—N1—H1A126.0
N2—C3—N1111.15 (18)C3—N2—C2104.88 (16)
C5—C4—C3123.15 (18)C4—N3—C4i119.1 (2)
N3—C4—C3114.09 (18)H1B—O1—H1Bi90.6
N3—C4—C5122.75 (18)H2BA—O2B—H2BB104.6
C4—C5—H5121.1H2AA—O2A—H2AB104.4
C1—C2—N2—C30.12 (19)N1—C1—C2—N20.22 (19)
C2—C1—N1—C30.47 (17)N1—C3—C4—C5173.49 (15)
C3—C4—C5—C6176.78 (13)N1—C3—C4—N35.7 (2)
C3—C4—N3—C4i177.97 (15)N1—C3—N2—C20.43 (17)
C4—C3—N1—C1179.33 (14)N2—C3—C4—C55.0 (3)
C4—C3—N2—C2179.08 (15)N2—C3—C4—N3175.81 (13)
C4—C5—C6—C5i1.07 (11)N2—C3—N1—C10.58 (17)
C5—C4—N3—C4i1.18 (12)N3—C4—C5—C62.3 (2)
Symmetry code: (i) x+2, x+y+1, z+5/3.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O10.882.052.900 (2)163
O1—H1B···O2Bii0.872.072.823 (5)144
O1—H1B···O2Aii0.872.192.719 (7)119
O2B—H2BB···N20.871.932.734 (4)153
O2A—H2AB···N20.872.032.740 (7)138
Symmetry code: (ii) y+1, xy, z+2/3.
2-[6-(1H-Imidazol-2-yl)pyridin-2-yl]-1H-imidazol-3-ium chloride trihydrate (II) top
Crystal data top
C11H10N5+·Cl·3H2OF(000) = 632
Mr = 301.74Dx = 1.404 Mg m3
Monoclinic, P21/cCu Kα radiation, λ = 1.54178 Å
a = 6.6577 (5) ÅCell parameters from 51 reflections
b = 22.6308 (16) Åθ = 2.4–19.1°
c = 9.7566 (7) ŵ = 2.53 mm1
β = 103.845 (3)°T = 150 K
V = 1427.31 (18) Å3Needle, colorless
Z = 40.21 × 0.12 × 0.06 mm
Data collection top
Bruker APEX CCD detector
diffractometer
2337 reflections with I > 2σ(I)
Detector resolution: 8.3333 pixels mm-1Rint = 0.037
phi and ω scansθmax = 66.6°, θmin = 3.9°
Absorption correction: multi-scan
(SADABS; Bruker, 2010)
h = 77
Tmin = 0.541, Tmax = 0.753k = 2626
12948 measured reflectionsl = 1011
2501 independent reflections
Refinement top
Refinement on F2Primary atom site location: dual
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.030H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.083 w = 1/[σ2(Fo2) + (0.0446P)2 + 0.3908P]
where P = (Fo2 + 2Fc2)/3
S = 1.08(Δ/σ)max < 0.001
2501 reflectionsΔρmax = 0.19 e Å3
208 parametersΔρmin = 0.25 e Å3
0 restraints
Special details top

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

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cl10.12492 (5)0.11289 (2)0.19035 (3)0.02985 (13)
N10.23324 (18)0.15345 (5)0.50852 (13)0.0242 (3)
H10.209 (3)0.1367 (8)0.4320 (19)0.029*
N20.32601 (18)0.16788 (5)0.73294 (13)0.0238 (3)
H20.363 (2)0.1621 (8)0.8221 (19)0.029*
N30.25814 (16)0.03224 (5)0.52905 (12)0.0207 (2)
N40.16978 (18)0.02797 (6)0.27592 (13)0.0264 (3)
H40.164 (3)0.0095 (8)0.2606 (19)0.032*
N50.21873 (18)0.11532 (5)0.38022 (14)0.0284 (3)
C10.2362 (2)0.21322 (6)0.52931 (16)0.0301 (3)
H1A0.2029590.2427040.4581580.036*
C20.2952 (2)0.22247 (6)0.66969 (16)0.0292 (3)
H2A0.3123230.2596790.7161160.035*
C30.28748 (19)0.12627 (6)0.63302 (14)0.0211 (3)
C40.29992 (18)0.06222 (6)0.65134 (14)0.0203 (3)
C50.3499 (2)0.03559 (6)0.78353 (15)0.0253 (3)
H50.3778690.0584870.8675630.030*
C60.3575 (2)0.02556 (6)0.78827 (16)0.0293 (3)
H60.3900610.0454760.8765420.035*
C70.3175 (2)0.05737 (6)0.66416 (15)0.0271 (3)
H70.3241460.0993070.6656270.032*
C80.26720 (19)0.02676 (6)0.53637 (15)0.0217 (3)
C90.21986 (19)0.05725 (6)0.40025 (15)0.0231 (3)
C100.1339 (2)0.06927 (7)0.17056 (16)0.0316 (3)
H100.0954120.0621500.0717660.038*
C110.1645 (2)0.12247 (7)0.23613 (17)0.0326 (4)
H110.1505350.1595320.1890610.039*
O10.70136 (19)0.21532 (5)0.43975 (13)0.0386 (3)
H1B0.726 (3)0.2432 (10)0.503 (2)0.058*
H1C0.728 (3)0.1862 (10)0.494 (2)0.058*
O20.4310 (2)0.14867 (5)0.01164 (11)0.0345 (3)
H2B0.344 (3)0.1399 (9)0.064 (2)0.052*
H2C0.531 (3)0.1656 (10)0.063 (2)0.052*
O30.76769 (18)0.20389 (5)0.17490 (12)0.0348 (3)
H3A0.868 (3)0.1834 (10)0.182 (2)0.052*
H3B0.756 (3)0.2116 (9)0.259 (2)0.052*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0355 (2)0.0303 (2)0.0229 (2)0.00122 (13)0.00543 (15)0.00105 (13)
N10.0294 (6)0.0225 (6)0.0205 (6)0.0018 (5)0.0054 (5)0.0005 (5)
N20.0294 (6)0.0204 (6)0.0220 (6)0.0016 (4)0.0067 (5)0.0017 (5)
N30.0171 (5)0.0209 (6)0.0236 (6)0.0005 (4)0.0040 (4)0.0009 (4)
N40.0261 (6)0.0254 (6)0.0267 (6)0.0006 (5)0.0042 (5)0.0039 (5)
N50.0262 (6)0.0233 (6)0.0360 (7)0.0026 (4)0.0076 (5)0.0072 (5)
C10.0390 (8)0.0205 (7)0.0318 (8)0.0010 (6)0.0107 (6)0.0046 (6)
C20.0387 (8)0.0181 (7)0.0329 (8)0.0027 (6)0.0128 (6)0.0016 (6)
C30.0180 (6)0.0233 (7)0.0224 (7)0.0008 (5)0.0055 (5)0.0009 (5)
C40.0155 (6)0.0215 (7)0.0235 (7)0.0002 (5)0.0041 (5)0.0016 (5)
C50.0258 (7)0.0257 (7)0.0227 (7)0.0008 (5)0.0026 (5)0.0009 (6)
C60.0341 (8)0.0262 (7)0.0258 (7)0.0018 (6)0.0035 (6)0.0054 (6)
C70.0286 (7)0.0198 (6)0.0312 (8)0.0008 (5)0.0042 (6)0.0012 (6)
C80.0151 (6)0.0219 (7)0.0280 (7)0.0009 (5)0.0050 (5)0.0022 (5)
C90.0177 (6)0.0228 (6)0.0284 (7)0.0015 (5)0.0049 (5)0.0025 (6)
C100.0289 (8)0.0388 (9)0.0264 (8)0.0030 (6)0.0051 (6)0.0106 (6)
C110.0284 (7)0.0308 (8)0.0381 (9)0.0041 (6)0.0071 (7)0.0148 (7)
O10.0539 (7)0.0298 (6)0.0310 (6)0.0030 (5)0.0083 (5)0.0031 (5)
O20.0469 (7)0.0338 (6)0.0238 (5)0.0080 (5)0.0101 (5)0.0031 (4)
O30.0395 (6)0.0338 (6)0.0305 (6)0.0071 (5)0.0073 (5)0.0053 (5)
Geometric parameters (Å, º) top
N1—H10.818 (18)C4—C51.3899 (19)
N1—C11.3672 (18)C5—H50.9500
N1—C31.3321 (18)C5—C61.385 (2)
N2—H20.856 (18)C6—H60.9500
N2—C21.3742 (19)C6—C71.379 (2)
N2—C31.3354 (18)C7—H70.9500
N3—C41.3426 (17)C7—C81.395 (2)
N3—C81.3376 (17)C8—C91.4625 (19)
N4—H40.861 (19)C10—H100.9500
N4—C91.3521 (19)C10—C111.356 (2)
N4—C101.3674 (19)C11—H110.9500
N5—C91.3286 (18)O1—H1B0.87 (2)
N5—C111.375 (2)O1—H1C0.84 (2)
C1—H1A0.9500O2—H2B0.88 (2)
C1—C21.348 (2)O2—H2C0.82 (2)
C2—H2A0.9500O3—H3A0.80 (2)
C3—C41.4604 (18)O3—H3B0.86 (2)
C1—N1—H1125.9 (12)C6—C5—C4117.58 (13)
C3—N1—H1124.8 (12)C6—C5—H5121.2
C3—N1—C1109.29 (12)C5—C6—H6120.2
C2—N2—H2124.7 (12)C7—C6—C5119.63 (13)
C3—N2—H2126.3 (12)C7—C6—H6120.2
C3—N2—C2108.91 (12)C6—C7—H7120.7
C8—N3—C4117.38 (12)C6—C7—C8118.69 (13)
C9—N4—H4129.1 (12)C8—C7—H7120.7
C9—N4—C10107.50 (13)N3—C8—C7122.78 (13)
C10—N4—H4123.4 (12)N3—C8—C9115.17 (12)
C9—N5—C11104.94 (12)C7—C8—C9122.05 (12)
N1—C1—H1A126.4N4—C9—C8122.47 (12)
C2—C1—N1107.14 (13)N5—C9—N4111.18 (12)
C2—C1—H1A126.4N5—C9—C8126.35 (13)
N2—C2—H2A126.5N4—C10—H10127.1
C1—C2—N2107.02 (12)C11—C10—N4105.83 (14)
C1—C2—H2A126.5C11—C10—H10127.1
N1—C3—N2107.63 (12)N5—C11—H11124.7
N1—C3—C4124.40 (12)C10—C11—N5110.55 (13)
N2—C3—C4127.97 (12)C10—C11—H11124.7
N3—C4—C3113.53 (12)H1B—O1—H1C99 (2)
N3—C4—C5123.93 (12)H2B—O2—H2C107 (2)
C5—C4—C3122.54 (12)H3A—O3—H3B107 (2)
C4—C5—H5121.2
N1—C1—C2—N20.46 (17)C4—N3—C8—C70.00 (19)
N1—C3—C4—N32.26 (18)C4—N3—C8—C9179.85 (11)
N1—C3—C4—C5177.58 (12)C4—C5—C6—C70.5 (2)
N2—C3—C4—N3177.85 (12)C5—C6—C7—C80.9 (2)
N2—C3—C4—C52.3 (2)C6—C7—C8—N30.7 (2)
N3—C4—C5—C60.3 (2)C6—C7—C8—C9179.12 (12)
N3—C8—C9—N40.23 (18)C7—C8—C9—N4179.61 (13)
N3—C8—C9—N5179.97 (12)C7—C8—C9—N50.2 (2)
N4—C10—C11—N50.03 (16)C8—N3—C4—C3179.65 (11)
C1—N1—C3—N20.29 (15)C8—N3—C4—C50.51 (18)
C1—N1—C3—C4179.62 (12)C9—N4—C10—C110.15 (15)
C2—N2—C3—N10.00 (15)C9—N5—C11—C100.10 (16)
C2—N2—C3—C4179.91 (13)C10—N4—C9—N50.22 (15)
C3—N1—C1—C20.48 (17)C10—N4—C9—C8179.60 (12)
C3—N2—C2—C10.29 (16)C11—N5—C9—N40.20 (15)
C3—C4—C5—C6179.91 (12)C11—N5—C9—C8179.62 (13)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···Cl10.82 (2)2.35 (2)3.1508 (13)166 (2)
N2—H2···O2i0.86 (2)1.82 (2)2.6762 (17)178 (2)
N4—H4···Cl10.86 (2)2.43 (2)3.2907 (13)174 (2)
O1—H1B···O3ii0.87 (2)2.03 (2)2.8839 (16)169 (2)
O1—H1C···N5iii0.84 (2)2.00 (2)2.8359 (18)178 (2)
O2—H2B···Cl10.88 (2)2.21 (2)3.0900 (13)177 (2)
O2—H2C···O30.82 (2)1.90 (2)2.7230 (17)177 (2)
O3—H3A···Cl1iv0.80 (2)2.33 (2)3.1223 (12)171 (2)
O3—H3B···O10.86 (2)1.89 (2)2.7359 (17)169 (2)
Symmetry codes: (i) x, y, z+1; (ii) x, y+1/2, z+1/2; (iii) x+1, y, z+1; (iv) x+1, y, z.
 

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