2,6-Di­amino­pyridinium bromide monohydrate

In the title compound, [C₅H₆N₃]Br·H₂O, the 2,6-di­amino­pyridine is protonated on the ring N atom. The cation is planar. The moieties are held together by extensive hydrogen bonding and by π–π interactions. The bromide ion is hydrogen bonded, as acceptor, to two H₂O mol­ecules, with an average Br...H—O(H₂O) distance of 3.322 (11) Å, to the ring N atom Br...N—H(NH) 3.353 (3) Å, and to four amino N atoms, with an average Br...H—N(NH₂) 3.63 (14) Å. The water mol­ecule bonds, as acceptor, to the pyridine N atom O...H—N(NH₂) 2.583 (5) Å. The closest π–π interaction is between pyridine ring planes, with an interplanar spacing 3.358 Å apart.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.038
• wR factor = 0.100
• Data-to-parameter ratio = 14.3

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT027_ALERT_3_A _diffrn_reflns_theta_full too Low ..............      24.97 Deg.

Alert level B
PLAT415_ALERT_2_B Short Inter D-H..H-X       H2A    ..  H5A      =       1.98 Ang.

Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.99
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT230_ALERT_2_C Hirshfeld Test Diff for    N2     -   C2       =       5.41 su
PLAT420_ALERT_2_C D-H Without Acceptor       N2     -   H2A    ...          ?
PLAT731_ALERT_1_C Bond    Calc     0.88(4), Rep   0.882(19) ......       2.11 su-Rat
              O    -H1      1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.88(5), Rep   0.881(19) ......       2.63 su-Rat
              O    -H2      1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.88(4), Rep   0.882(19) ......       2.11 su-Rat
              O    -H1      1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.88(5), Rep   0.881(19) ......       2.63 su-Rat
              O    -H2      1.555   1.555

   1 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   8 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   5 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: XSCANS (Bruker, 1996b); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: XS in SHELXTL (Bruker, 1996); program(s) used to refine structure: XL in SHELXTL; molecular graphics: XP in SHELXTL; software used to prepare material for publication: XCIF in SHELXTL.

'2,6-Diaminopyridinium Bromide Hydrate'

Crystal data

C5H8N3^+·Br^−·H2O	Z = 2
Mr = 208.07	F(000) = 208
Triclinic, P1	Dx = 1.722 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.1225 (12) Å	Cell parameters from 28 reflections
b = 7.2333 (8) Å	θ = 5.9–18.1°
c = 8.7082 (13) Å	µ = 5.06 mm^−1
α = 91.557 (11)°	T = 295 K
β = 102.518 (17)°	Parallelpiped, pink
γ = 112.627 (11)°	0.40 × 0.35 × 0.28 mm
V = 401.21 (10) Å^3

Data collection

Siemens P21 upgraded to P4 diffractometer	1292 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.031
Graphite monochromator	θmax = 25.0°, θmin = 2.4°
ω scans	h = −8→1
Absorption correction: psi-scan (XPREP in SHELXTL; Bruker, 1996)	k = −8→8
Tmin = 0.146, Tmax = 0.242	l = −10→10
1781 measured reflections	3 standard reflections every 97 reflections
1412 independent reflections	intensity decay: <0.01%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.100	H atoms treated by a mixture of independent and constrained refinement
S = 1.09	w = 1/[σ^2(Fo^2) + (0.0593P)^2 + 0.2936P] where P = (Fo^2 + 2Fc^2)/3
1412 reflections	(Δ/σ)max < 0.001
99 parameters	Δρmax = 0.44 e Å^−3
3 restraints	Δρmin = −0.63 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
C5	0.6409 (6)	0.7561 (6)	−0.0186 (5)	0.0486 (9)
H5A	0.7567	0.7581	−0.0526	0.058*
Br	0.88031 (6)	0.66391 (6)	0.63033 (4)	0.0519 (2)
N2	0.1227 (4)	0.7448 (5)	0.1128 (4)	0.0430 (7)
H2A	0.0117	0.7102	0.0366	0.052*
H2B	0.1184	0.7742	0.2079	0.052*
N1	0.2839 (5)	0.7032 (5)	−0.0697 (4)	0.0431 (7)
H1A	0.1642	0.6709	−0.1358	0.052*
C2	0.2996 (6)	0.7528 (6)	0.0837 (5)	0.0455 (9)
N6	0.4118 (6)	0.6507 (6)	−0.2809 (4)	0.0597 (9)
H6A	0.2892	0.6204	−0.3423	0.072*
H6B	0.5123	0.6484	−0.3196	0.072*
C3	0.4874 (6)	0.8053 (6)	0.1924 (5)	0.0501 (9)
H3A	0.5009	0.8389	0.2993	0.060*
C6	0.4459 (6)	0.7013 (6)	−0.1262 (5)	0.0443 (8)
C4	0.6576 (6)	0.8066 (6)	0.1377 (5)	0.0531 (10)
H4A	0.7868	0.8430	0.2097	0.064*
O	0.1830 (6)	0.9045 (6)	0.3976 (4)	0.0673 (8)
H1	0.177 (8)	1.024 (4)	0.404 (6)	0.075 (17)*
H2	0.130 (9)	0.834 (7)	0.470 (6)	0.088 (19)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C5	0.039 (2)	0.049 (2)	0.061 (3)	0.0188 (17)	0.0152 (17)	0.0046 (18)
Br	0.0481 (3)	0.0676 (3)	0.0451 (3)	0.0279 (2)	0.01310 (18)	0.00455 (18)
N2	0.0290 (15)	0.0647 (19)	0.0409 (17)	0.0226 (14)	0.0123 (12)	0.0068 (14)
N1	0.0327 (15)	0.0492 (17)	0.0483 (18)	0.0184 (13)	0.0080 (13)	0.0059 (14)
C2	0.043 (2)	0.0476 (19)	0.051 (2)	0.0209 (17)	0.0173 (17)	0.0097 (17)
N6	0.055 (2)	0.084 (3)	0.047 (2)	0.036 (2)	0.0118 (16)	0.0010 (18)
C3	0.048 (2)	0.058 (2)	0.045 (2)	0.0234 (19)	0.0086 (17)	0.0026 (17)
C6	0.044 (2)	0.0431 (18)	0.051 (2)	0.0212 (16)	0.0156 (17)	0.0088 (16)
C4	0.039 (2)	0.056 (2)	0.059 (3)	0.0187 (18)	0.0032 (18)	0.0000 (19)
O	0.078 (2)	0.077 (2)	0.064 (2)	0.0399 (19)	0.0344 (17)	0.0142 (17)

Geometric parameters (Å, º)

C5—C4	1.367 (6)	C2—C3	1.368 (6)
C5—C6	1.399 (6)	N6—C6	1.331 (5)
C5—H5A	0.9300	N6—H6A	0.8600
N2—C2	1.319 (5)	N6—H6B	0.8600
N2—H2A	0.8600	C3—C4	1.392 (6)
N2—H2B	0.8600	C3—H3A	0.9300
N1—C2	1.343 (5)	C4—H4A	0.9300
N1—C6	1.353 (5)	O—H1	0.882 (19)
N1—H1A	0.8600	O—H2	0.881 (19)
C4—C5—C6	118.6 (4)	C6—N6—H6B	120.0
C4—C5—H5A	120.7	H6A—N6—H6B	120.0
C6—C5—H5A	120.7	C2—C3—C4	117.7 (4)
C2—N2—H2A	120.0	C2—C3—H3A	121.2
C2—N2—H2B	120.0	C4—C3—H3A	121.2
H2A—N2—H2B	120.0	N6—C6—N1	118.3 (4)
C2—N1—C6	123.7 (3)	N6—C6—C5	123.7 (4)
C2—N1—H1A	118.2	N1—C6—C5	117.9 (4)
C6—N1—H1A	118.2	C5—C4—C3	122.2 (4)
N2—C2—N1	113.7 (3)	C5—C4—H4A	118.9
N2—C2—C3	126.4 (4)	C3—C4—H4A	118.9
N1—C2—C3	120.0 (4)	H1—O—H2	110 (3)
C6—N6—H6A	120.0
C6—N1—C2—N2	180.0 (3)	C2—N1—C6—C5	−0.7 (6)
C6—N1—C2—C3	0.1 (6)	C4—C5—C6—N6	179.5 (4)
N2—C2—C3—C4	−179.3 (4)	C4—C5—C6—N1	0.7 (6)
N1—C2—C3—C4	0.6 (6)	C6—C5—C4—C3	−0.1 (6)
C2—N1—C6—N6	−179.6 (4)	C2—C3—C4—C5	−0.6 (6)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2B···O	0.86	1.76	2.583 (5)	161
N1—H1A···Br^i	0.86	2.52	3.353 (3)	162
N6—H6A···Br^ii	0.86	2.91	3.464 (4)	124
N6—H6A···Br^i	0.86	3.01	3.735 (4)	144
N6—H6B···Br^iii	0.86	2.71	3.553 (4)	167
O—H1···Br^iv	0.88 (2)	2.46 (2)	3.329 (4)	169 (5)
O—H2···Br^v	0.88 (2)	2.47 (3)	3.314 (4)	161 (5)
N2—H2B···Br^vi	0.86	3.51	3.752 (3)	100

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