Molecular tapes in the structure of isoguaninium chloride

Isoguanine, an analogue of guanine, is of intrinsic interest as a noncanonical nucleobase. The crystal structure of isoguaninium chloride (systematic name: 6-amino-2-oxo-1H,7H-purin-3-ium chloride), C₅H₆N₅O⁺·Cl⁻, has been determined by single-crystal X-ray diffraction. Structure analysis was supported by electrostatic interaction energy (E_es) calculations based on charge density reconstructed with the UBDB databank. In the structure, two kinds of molecular tapes are observed, one parallel to (010) and the other parallel to (50). The tapes are formed by dimers of isoguaninium cations interacting with chloride anions. E_es analysis indicates that cations in one kind of tape are oriented so as to minimize repulsive electrostatic interactions.

Computing details

Data collection: CrysAlis PRO (Agilent, 2014); cell refinement: CrysAlis PRO (Agilent, 2014); data reduction: CrysAlis PRO (Agilent, 2014); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2017 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

6-Amino-2-oxo-1H,7H-purin-3-ium chloride

Crystal data

C5H6N5O^+·Cl^−	F(000) = 768
Mr = 187.60	Dx = 1.685 Mg m^−3
Monoclinic, P21/c	Cu Kα radiation, λ = 1.54184 Å
a = 14.0359 (6) Å	Cell parameters from 11926 reflections
b = 13.6930 (5) Å	θ = 4.5–76.2°
c = 7.7026 (3) Å	µ = 4.25 mm^−1
β = 92.754 (4)°	T = 100 K
V = 1478.68 (10) Å^3	Needle, colourless
Z = 8	0.73 × 0.12 × 0.09 mm

Data collection

Agilent SuperNova Dual Source diffractometer with an Atlas detector	5522 independent reflections
Radiation source: sealed X-ray tube, SuperNova (Cu) X-ray Source	4803 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.132
Detector resolution: 5.2195 pixels mm^-1	θmax = 76.9°, θmin = 3.2°
ω scans	h = −17→17
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014)	k = −17→17
Tmin = 0.465, Tmax = 1.000	l = −9→9
42770 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.062	All H-atom parameters refined
wR(F^2) = 0.192	w = 1/[σ^2(Fo^2) + (0.1497P)^2 + 0.6578P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max < 0.001
5522 reflections	Δρmax = 0.72 e Å^−3
266 parameters	Δρmin = −0.60 e Å^−3
0 restraints

Special details

Experimental. Single crystals of iGHCl were selected and mounted with paratone-N oil on a MiTeGen micro-mount. The crystal was kept at 100.0 (1) K during diffraction data collection on a Rigaku Oxford Diffraction (former Agilent Technologies) SuperNova four-circle diffractometer with a Cu Kα radiation and Atlas detector. The temperature was controlled with an Oxford Cryosystems low-temperature nitrogen gas-flow device (Cryostream Plus). The crystal was positioned 74 mm from the detector. A total of 5060 frames were collected in 49 runs using ω scan with a rotation width of 1.0°. The exposure time was in the range of 1–5 s. The determination of unit-cell parameters, integration of reflection intensities and data reduction, including a multiscan absorption correction, were performed using CrysAlis PRO (Agilent, 2014).

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.

Refinement. Refined as a 2-component twin

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cl1	0.32116 (6)	0.36689 (7)	0.13649 (13)	0.0208 (3)
Cl2	−0.20744 (6)	0.17005 (6)	−0.53743 (13)	0.0202 (3)
O1	0.28818 (18)	0.3810 (2)	−0.3447 (4)	0.0224 (6)
N1	0.4323 (2)	0.3775 (2)	−0.1963 (4)	0.0151 (6)
N3	0.4224 (2)	0.3789 (2)	−0.5007 (4)	0.0167 (7)
N7	0.6673 (2)	0.3796 (2)	−0.3906 (5)	0.0163 (7)
N9	0.5746 (2)	0.3807 (2)	−0.6363 (4)	0.0174 (6)
N10	0.5733 (2)	0.3759 (2)	−0.0266 (5)	0.0183 (7)
C2	0.3741 (2)	0.3795 (3)	−0.3490 (5)	0.0172 (7)
C4	0.5196 (2)	0.3785 (3)	−0.4958 (5)	0.0145 (7)
C5	0.5741 (2)	0.3775 (3)	−0.3414 (5)	0.0162 (7)
C6	0.5293 (2)	0.3771 (3)	−0.1807 (5)	0.0157 (8)
C8	0.6635 (2)	0.3806 (3)	−0.5653 (6)	0.0170 (7)
H1	0.403 (4)	0.376 (4)	−0.096 (8)	0.028 (13)*
H3	0.388 (3)	0.377 (3)	−0.610 (7)	0.022 (12)*
H7	0.715 (4)	0.383 (4)	−0.330 (8)	0.040 (16)*
H8	0.721 (4)	0.385 (4)	−0.634 (7)	0.038 (15)*
H10A	0.637 (3)	0.367 (3)	−0.024 (7)	0.021 (12)*
H10B	0.539 (4)	0.371 (4)	0.064 (7)	0.026 (13)*
O2	−0.12492 (17)	0.42561 (19)	−0.4301 (4)	0.0217 (6)
N11	0.0093 (2)	0.4414 (2)	−0.2529 (4)	0.0159 (6)
N13	−0.0473 (2)	0.2868 (2)	−0.3411 (4)	0.0156 (6)
N17	0.15561 (19)	0.2389 (2)	−0.0712 (4)	0.0149 (6)
N19	0.0456 (2)	0.1495 (2)	−0.2204 (4)	0.0148 (6)
N20	0.1439 (2)	0.4653 (2)	−0.0703 (5)	0.0196 (7)
C12	−0.0590 (2)	0.3861 (3)	−0.3468 (5)	0.0169 (7)
C14	0.0260 (2)	0.2465 (3)	−0.2420 (5)	0.0142 (7)
C15	0.0924 (2)	0.3033 (3)	−0.1533 (5)	0.0157 (7)
C16	0.0853 (2)	0.4063 (3)	−0.1548 (5)	0.0156 (7)
C18	0.1249 (2)	0.1489 (3)	−0.1165 (5)	0.0166 (7)
H11	0.002 (3)	0.506 (4)	−0.267 (6)	0.026 (12)*
H13	−0.090 (3)	0.252 (3)	−0.392 (6)	0.013 (10)*
H17	0.206 (3)	0.253 (3)	−0.009 (6)	0.012 (9)*
H18	0.153 (3)	0.088 (3)	−0.075 (6)	0.016 (10)*
H20A	0.196 (3)	0.443 (4)	−0.015 (6)	0.024 (12)*
H20B	0.139 (4)	0.531 (5)	−0.075 (8)	0.053 (18)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0167 (4)	0.0303 (5)	0.0150 (5)	−0.0023 (3)	−0.0016 (3)	0.0001 (4)
Cl2	0.0193 (4)	0.0157 (4)	0.0249 (5)	0.0000 (3)	−0.0060 (3)	−0.0008 (3)
O1	0.0158 (12)	0.0296 (15)	0.0216 (17)	−0.0011 (10)	−0.0012 (11)	−0.0014 (12)
N1	0.0137 (13)	0.0227 (16)	0.0089 (16)	−0.0003 (11)	−0.0013 (12)	−0.0004 (12)
N3	0.0157 (14)	0.0240 (16)	0.0102 (17)	−0.0017 (11)	−0.0026 (12)	−0.0008 (12)
N7	0.0144 (14)	0.0213 (16)	0.0131 (17)	0.0007 (11)	0.0003 (12)	−0.0007 (13)
N9	0.0173 (13)	0.0202 (15)	0.0147 (17)	0.0017 (11)	0.0006 (12)	0.0018 (13)
N10	0.0173 (14)	0.0253 (17)	0.0120 (17)	−0.0002 (11)	−0.0021 (12)	−0.0003 (13)
C2	0.0184 (16)	0.0193 (17)	0.014 (2)	−0.0003 (13)	0.0030 (14)	−0.0012 (15)
C4	0.0162 (15)	0.0139 (16)	0.0133 (19)	−0.0011 (12)	−0.0008 (13)	0.0003 (13)
C5	0.0140 (15)	0.0177 (17)	0.017 (2)	0.0005 (12)	−0.0008 (14)	−0.0004 (14)
C6	0.0157 (15)	0.0126 (16)	0.019 (2)	−0.0002 (12)	−0.0004 (14)	0.0016 (14)
C8	0.0168 (15)	0.0173 (17)	0.017 (2)	0.0004 (12)	0.0026 (14)	−0.0006 (14)
O2	0.0193 (11)	0.0153 (12)	0.0295 (17)	0.0016 (9)	−0.0085 (11)	0.0013 (11)
N11	0.0186 (13)	0.0103 (14)	0.0185 (17)	0.0000 (10)	−0.0022 (12)	0.0008 (11)
N13	0.0154 (12)	0.0131 (14)	0.0177 (17)	−0.0010 (11)	−0.0042 (11)	−0.0012 (12)
N17	0.0129 (12)	0.0156 (15)	0.0159 (17)	−0.0004 (10)	−0.0027 (11)	−0.0012 (12)
N19	0.0156 (13)	0.0132 (14)	0.0155 (17)	0.0008 (10)	−0.0005 (11)	−0.0014 (12)
N20	0.0189 (14)	0.0154 (15)	0.0239 (19)	−0.0003 (11)	−0.0054 (13)	−0.0024 (13)
C12	0.0171 (15)	0.0158 (17)	0.017 (2)	0.0002 (12)	−0.0016 (13)	0.0013 (14)
C14	0.0153 (14)	0.0159 (16)	0.0113 (18)	0.0016 (13)	0.0008 (12)	−0.0001 (13)
C15	0.0153 (14)	0.0142 (17)	0.018 (2)	0.0002 (12)	0.0010 (13)	0.0002 (14)
C16	0.0146 (14)	0.0135 (16)	0.019 (2)	0.0003 (12)	0.0027 (13)	0.0006 (14)
C18	0.0181 (15)	0.0131 (16)	0.019 (2)	0.0020 (12)	0.0055 (14)	−0.0012 (14)

Geometric parameters (Å, º)

O1—C2	1.208 (4)	O2—C12	1.226 (4)
N1—C2	1.399 (5)	N11—C12	1.397 (5)
N1—C6	1.361 (4)	N11—C16	1.365 (4)
N1—H1	0.89 (6)	N11—H11	0.90 (6)
N3—C2	1.378 (5)	N13—C12	1.369 (5)
N3—C4	1.363 (4)	N13—C14	1.368 (4)
N3—H3	0.95 (5)	N13—H13	0.85 (4)
N7—C5	1.379 (4)	N17—C15	1.383 (4)
N7—C8	1.344 (5)	N17—C18	1.346 (5)
N7—H7	0.80 (6)	N17—H17	0.86 (4)
N9—C4	1.359 (5)	N19—C14	1.365 (5)
N9—C8	1.338 (4)	N19—C18	1.339 (5)
N10—C6	1.312 (5)	N20—C16	1.304 (5)
N10—H10A	0.91 (5)	N20—H20A	0.88 (5)
N10—H10B	0.87 (5)	N20—H20B	0.91 (7)
C4—C5	1.383 (5)	C14—C15	1.370 (5)
C5—C6	1.415 (5)	C15—C16	1.413 (5)
C8—H8	0.98 (6)	C18—H18	0.97 (5)
C2—N1—H1	117 (3)	C12—N11—H11	114 (3)
C6—N1—C2	127.9 (3)	C16—N11—C12	126.5 (3)
C6—N1—H1	115 (3)	C16—N11—H11	120 (3)
C2—N3—H3	120 (3)	C12—N13—H13	117 (3)
C4—N3—C2	120.6 (3)	C14—N13—C12	120.3 (3)
C4—N3—H3	119 (3)	C14—N13—H13	122 (3)
C5—N7—H7	128 (4)	C15—N17—H17	127 (3)
C8—N7—C5	106.4 (3)	C18—N17—C15	106.0 (3)
C8—N7—H7	125 (4)	C18—N17—H17	126 (3)
C8—N9—C4	103.2 (3)	C18—N19—C14	103.7 (3)
C6—N10—H10A	116 (3)	C16—N20—H20A	120 (3)
C6—N10—H10B	118 (3)	C16—N20—H20B	123 (4)
H10A—N10—H10B	124 (4)	H20A—N20—H20B	116 (5)
O1—C2—N1	121.3 (4)	O2—C12—N11	120.9 (3)
O1—C2—N3	123.7 (4)	O2—C12—N13	122.8 (3)
N3—C2—N1	114.9 (3)	N13—C12—N11	116.3 (3)
N3—C4—C5	122.3 (3)	N13—C14—C15	121.6 (3)
N9—C4—N3	125.7 (3)	N19—C14—N13	127.1 (3)
N9—C4—C5	111.9 (3)	N19—C14—C15	111.3 (3)
N7—C5—C4	104.8 (3)	N17—C15—C16	133.1 (3)
N7—C5—C6	135.1 (4)	C14—C15—N17	105.8 (3)
C4—C5—C6	120.1 (3)	C14—C15—C16	121.1 (3)
N1—C6—C5	114.1 (3)	N11—C16—C15	114.1 (3)
N10—C6—N1	120.4 (4)	N20—C16—N11	121.0 (3)
N10—C6—C5	125.5 (3)	N20—C16—C15	124.9 (3)
N7—C8—H8	123 (3)	N17—C18—H18	125 (3)
N9—C8—N7	113.6 (3)	N19—C18—N17	113.3 (3)
N9—C8—H8	123 (3)	N19—C18—H18	121 (3)
N3—C4—C5—N7	−178.7 (3)	N13—C14—C15—N17	−179.0 (3)
N3—C4—C5—C6	−0.1 (5)	N13—C14—C15—C16	2.7 (5)
N7—C5—C6—N1	178.1 (4)	N17—C15—C16—N11	−178.8 (4)
N7—C5—C6—N10	−2.2 (7)	N17—C15—C16—N20	0.3 (7)
N9—C4—C5—N7	0.3 (4)	N19—C14—C15—N17	−0.6 (4)
N9—C4—C5—C6	178.8 (3)	N19—C14—C15—C16	−179.0 (3)
C2—N1—C6—N10	179.4 (3)	C12—N11—C16—N20	−178.9 (4)
C2—N1—C6—C5	−0.8 (5)	C12—N11—C16—C15	0.3 (5)
C2—N3—C4—N9	−178.0 (3)	C12—N13—C14—N19	178.5 (3)
C2—N3—C4—C5	0.8 (5)	C12—N13—C14—C15	−3.4 (5)
C4—N3—C2—O1	179.2 (4)	C14—N13—C12—O2	−178.1 (4)
C4—N3—C2—N1	−1.4 (5)	C14—N13—C12—N11	2.4 (5)
C4—N9—C8—N7	−0.7 (4)	C14—N19—C18—N17	0.3 (4)
C4—C5—C6—N1	0.1 (5)	C14—C15—C16—N11	−1.1 (5)
C4—C5—C6—N10	179.8 (4)	C14—C15—C16—N20	178.0 (4)
C5—N7—C8—N9	0.9 (4)	C15—N17—C18—N19	−0.7 (4)
C6—N1—C2—O1	−179.0 (4)	C16—N11—C12—O2	179.6 (4)
C6—N1—C2—N3	1.5 (5)	C16—N11—C12—N13	−0.9 (5)
C8—N7—C5—C4	−0.7 (4)	C18—N17—C15—C14	0.8 (4)
C8—N7—C5—C6	−178.9 (4)	C18—N17—C15—C16	178.8 (4)
C8—N9—C4—N3	179.1 (3)	C18—N19—C14—N13	178.5 (4)
C8—N9—C4—C5	0.2 (4)	C18—N19—C14—C15	0.2 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Cl1	0.89 (6)	2.18 (6)	3.067 (3)	175 (5)
N3—H3···Cl1^i	0.95 (5)	2.13 (5)	3.078 (3)	175 (4)
N7—H7···Cl2^ii	0.80 (6)	2.56 (6)	3.240 (4)	144 (5)
N7—H7···O2^iii	0.80 (6)	2.48 (6)	3.014 (4)	125 (5)
N10—H10A···Cl2^ii	0.91 (5)	2.24 (5)	3.146 (3)	174 (4)
N10—H10B···N9^iv	0.87 (5)	2.34 (5)	3.006 (5)	134 (4)
N11—H11···N19^v	0.90 (6)	2.07 (6)	2.957 (4)	167 (4)
N13—H13···Cl2	0.85 (4)	2.25 (5)	3.093 (3)	176 (4)
N17—H17···Cl1	0.86 (4)	2.47 (4)	3.267 (3)	154 (4)
N17—H17···O1^vi	0.86 (4)	2.48 (4)	2.981 (4)	118 (4)
C18—H18···O1^vi	0.97 (5)	2.57 (4)	3.057 (5)	111 (3)
C18—H18···O2^vii	0.97 (5)	2.26 (5)	3.078 (4)	141 (3)
N20—H20A···Cl1	0.88 (5)	2.31 (5)	3.188 (3)	173 (4)
N20—H20B···Cl2^v	0.91 (7)	2.28 (6)	3.045 (3)	141 (5)

Symmetry codes: (i) x, y, z−1; (ii) x+1, −y+1/2, z+1/2; (iii) x+1, y, z; (iv) x, y, z+1; (v) −x, y+1/2, −z−1/2; (vi) x, −y+1/2, z+1/2; (vii) −x, y−1/2, −z−1/2.