Crystal structure of bis­(3-carb­oxy-1-methyl­pyrid­inium) octa­bromide

The structure of the title compound is composed of rare Z-shaped octa­bromide anions embedded within N-methyl­nicotinic acid cations.

Key indicators

Structure: I

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.007 Å
• R factor = 0.047
• wR factor = 0.075
• Data-to-parameter ratio = 22.8

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT434_ALERT_2_B Short Inter HL..HL Contact Br1      ..Br1      .       3.18 Ang.
                                                1-x,1-y,1-z  =      2_666 Check
PLAT434_ALERT_2_B Short Inter HL..HL Contact Br3      ..Br4      .       3.06 Ang.
                                                      x,y,z  =      1_555 Check

Alert level C
PLAT042_ALERT_1_C Calc. and Reported MoietyFormula Strings  Differ     Please Check
PLAT341_ALERT_3_C Low Bond Precision on  C-C Bonds ...............      0.007 Ang.
PLAT906_ALERT_3_C Large K Value in the Analysis of Variance ......     10.861 Check
PLAT906_ALERT_3_C Large K Value in the Analysis of Variance ......      2.332 Check
PLAT923_ALERT_1_C S    Values in the CIF and FCF Differ by .......      0.011 Check

Alert level G
PLAT002_ALERT_2_G Number of Distance or Angle Restraints on AtSite          2 Note
PLAT045_ALERT_1_G Calculated and Reported Z Differ by a Factor ...          2 Check
PLAT068_ALERT_1_G Reported F000 Differs from Calcd (or Missing)...     Please Check
PLAT172_ALERT_4_G The CIF-Embedded .res File Contains DFIX Records          1 Report
PLAT199_ALERT_1_G Reported _cell_measurement_temperature ..... (K)        293 Check
PLAT200_ALERT_1_G Reported   _diffrn_ambient_temperature ..... (K)        293 Check
PLAT480_ALERT_4_G Long H...A H-Bond Reported H1A      ..BR3      .       2.96 Ang.
PLAT480_ALERT_4_G Long H...A H-Bond Reported H5       ..BR4      .       2.99 Ang.
PLAT764_ALERT_4_G Overcomplete CIF Bond List Detected (Rep/Expd) .       1.15 Ratio
PLAT769_ALERT_4_G CIF Embedded Explicitly Supplied Scattering Data     Please Note
PLAT802_ALERT_4_G CIF Input Record(s) with more than 80 Characters          1 Info
PLAT860_ALERT_3_G Number of Least-Squares Restraints .............          1 Note
PLAT883_ALERT_1_G No Info/Value for _atom_sites_solution_primary .     Please Do !
PLAT910_ALERT_3_G Missing # of FCF Reflection(s) Below Theta(Min).          1 Note
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600        474 Note
PLAT941_ALERT_3_G Average HKL Measurement Multiplicity ...........        3.1 Low
PLAT978_ALERT_2_G Number C-C Bonds with Positive Residual Density.          0 Info
PLAT982_ALERT_1_G The Br-f'=   -0.3819 Deviates from  IT-value =      -0.2901 Check
PLAT983_ALERT_1_G The Br-f"=    2.4662 Deviates from  IT-Value =       2.4595 Check

   0 ALERT level A = Most likely a serious problem - resolve or explain
   2 ALERT level B = A potentially serious problem, consider carefully
   5 ALERT level C = Check. Ensure it is not caused by an omission or oversight
  19 ALERT level G = General information/check it is not something unexpected

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

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Computing details

Data collection: CrysAlis PRO (Rigaku OD, 2021); cell refinement: CrysAlis PRO (Rigaku OD, 2021); data reduction: CrysAlis PRO (Rigaku OD, 2021); program(s) used to solve structure: SHELXT (Sheldrick, 2015); program(s) used to refine structure: olex2.refine (Bourhis et al., 2015); molecular graphics: Olex2 (Dolomanov et al., 2009); software used to prepare material for publication: Olex2 (Dolomanov et al., 2009).

Bis(3-carboxy-1-methylpyridinium) octabromide

Crystal data

2C7H8NO2^+·Br8^2^−	Z = 1
Mr = 915.52	F(000) = 424.594
Triclinic, P1	Dx = 2.397 Mg m^−3
a = 6.8537 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.0873 (6) Å	Cell parameters from 2335 reflections
c = 14.5145 (6) Å	θ = 3.2–23.7°
α = 95.746 (5)°	µ = 12.67 mm^−1
β = 91.156 (4)°	T = 293 K
γ = 115.002 (7)°	Block, light red
V = 634.23 (8) Å^3	0.17 × 0.11 × 0.06 mm

Data collection

Xcalibur, Eos diffractometer	1848 reflections with I ≥ 2u(I)
Detector resolution: 16.1593 pixels mm^-1	Rint = 0.048
ω scans	θmax = 29.3°, θmin = 2.8°
Absorption correction: multi-scan (CrysAlisPro; Rigaku OD, 2021)	h = −8→9
Tmin = 0.458, Tmax = 1.000	k = −9→9
9457 measured reflections	l = −19→19
3008 independent reflections

Refinement

Refinement on F^2	13 constraints
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.047	w = 1/[σ^2(Fo^2) + (0.0186P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.075	(Δ/σ)max = −0.001
S = 1.02	Δρmax = 1.38 e Å^−3
3008 reflections	Δρmin = −1.32 e Å^−3
132 parameters	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
1 restraint	Extinction coefficient: 0.0112 (5)

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

	x	y	z	Uiso*/Ueq
Br2	0.06745 (8)	0.45917 (8)	0.30515 (3)	0.05120 (19)
Br3	−0.18168 (9)	0.43980 (10)	0.15210 (3)	0.0628 (2)
Br1	0.29688 (10)	0.47662 (9)	0.43679 (4)	0.0673 (2)
Br4	−0.04755 (10)	0.12253 (10)	0.04613 (3)	0.0781 (3)
O1	0.9137 (6)	0.8874 (6)	0.3821 (2)	0.0564 (10)
O2	0.7895 (5)	1.0613 (5)	0.4839 (2)	0.0540 (10)
N1	0.4595 (6)	0.8218 (6)	0.1811 (2)	0.0420 (10)
C2	0.6297 (7)	0.9597 (7)	0.3314 (3)	0.0348 (12)
C6	0.7873 (8)	0.9736 (8)	0.4062 (3)	0.0430 (13)
C1	0.6035 (7)	0.8341 (7)	0.2488 (3)	0.0423 (13)
H1a	0.6851 (7)	0.7580 (7)	0.2398 (3)	0.0507 (15)*
C4	0.3646 (8)	1.0582 (8)	0.2730 (3)	0.0477 (13)
H4	0.2828 (8)	1.1345 (8)	0.2802 (3)	0.0572 (16)*
C5	0.3421 (8)	0.9306 (8)	0.1928 (3)	0.0497 (14)
H5	0.2430 (8)	0.9193 (8)	0.1454 (3)	0.0597 (17)*
C3	0.5093 (8)	1.0726 (8)	0.3430 (3)	0.0444 (13)
H3	0.5259 (8)	1.1585 (8)	0.3981 (3)	0.0533 (16)*
C7	0.4279 (8)	0.6816 (8)	0.0942 (3)	0.0660 (17)
H7a	0.508 (4)	0.600 (4)	0.1002 (9)	0.099 (3)*
H7b	0.2774 (10)	0.589 (4)	0.0823 (13)	0.099 (3)*
H7c	0.477 (5)	0.7640 (9)	0.0437 (5)	0.099 (3)*
H1	0.992 (7)	0.879 (9)	0.426 (3)	0.099 (3)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br2	0.0515 (4)	0.0417 (3)	0.0592 (3)	0.0185 (3)	0.0015 (2)	0.0076 (2)
Br3	0.0686 (4)	0.0771 (5)	0.0512 (3)	0.0412 (3)	−0.0081 (3)	0.0013 (3)
Br1	0.0787 (5)	0.0529 (4)	0.0661 (4)	0.0265 (3)	−0.0223 (3)	0.0019 (3)
Br4	0.0779 (5)	0.0717 (5)	0.0592 (4)	0.0069 (4)	−0.0200 (3)	0.0140 (3)
O1	0.057 (3)	0.077 (3)	0.047 (2)	0.042 (2)	−0.0104 (17)	−0.0010 (19)
O2	0.057 (2)	0.072 (3)	0.0359 (18)	0.036 (2)	−0.0069 (15)	−0.0123 (17)
N1	0.039 (3)	0.046 (3)	0.036 (2)	0.015 (2)	−0.0041 (18)	−0.0001 (19)
C2	0.029 (3)	0.040 (3)	0.032 (2)	0.012 (2)	−0.0030 (19)	0.006 (2)
C6	0.038 (3)	0.045 (3)	0.049 (3)	0.021 (3)	−0.002 (2)	0.005 (3)
C1	0.035 (3)	0.045 (3)	0.043 (3)	0.014 (2)	−0.002 (2)	0.004 (2)
C4	0.049 (3)	0.053 (3)	0.051 (3)	0.032 (3)	−0.002 (2)	0.004 (3)
C5	0.045 (3)	0.063 (4)	0.041 (3)	0.024 (3)	−0.007 (2)	0.009 (3)
C3	0.048 (3)	0.044 (3)	0.039 (3)	0.019 (3)	0.001 (2)	0.002 (2)
C7	0.074 (4)	0.078 (4)	0.041 (3)	0.034 (3)	−0.018 (3)	−0.020 (3)

Geometric parameters (Å, º)

Br2—Br3	2.7307 (7)	C2—C1	1.380 (6)
Br2—Br1	2.4095 (7)	C2—C3	1.373 (6)
Br3—Br4	3.0625 (10)	C1—H1a	0.9300
Br1—Br1^i	3.1813 (12)	C4—H4	0.9300
Br4—Br4^ii	2.4002 (15)	C4—C5	1.365 (6)
O1—C6	1.290 (6)	C4—C3	1.370 (6)
O1—H1	0.845 (19)	C5—H5	0.9300
O2—C6	1.228 (5)	C3—H3	0.9300
N1—C1	1.348 (5)	C7—H7a	0.9600
N1—C5	1.332 (6)	C7—H7b	0.9600
N1—C7	1.476 (5)	C7—H7c	0.9600
C2—C6	1.483 (6)
Br1—Br2—Br3	178.04 (3)	H1a—C1—C2	120.0 (3)
Br4—Br3—Br2	90.37 (2)	C5—C4—H4	120.4 (3)
Br1^i—Br1—Br2	162.42 (4)	C3—C4—H4	120.4 (3)
Br4^ii—Br4—Br3	176.22 (3)	C3—C4—C5	119.2 (5)
H1—O1—C6	116 (4)	C4—C5—N1	121.2 (4)
C5—N1—C1	120.7 (4)	H5—C5—N1	119.4 (3)
C7—N1—C1	119.4 (4)	H5—C5—C4	119.4 (3)
C7—N1—C5	119.8 (4)	C4—C3—C2	119.8 (4)
C1—C2—C6	120.3 (5)	H3—C3—C2	120.1 (3)
C3—C2—C6	120.6 (4)	H3—C3—C4	120.1 (3)
C3—C2—C1	119.2 (4)	H7a—C7—N1	109.5
O2—C6—O1	125.2 (4)	H7b—C7—N1	109.5
C2—C6—O1	114.6 (4)	H7b—C7—H7a	109.5
C2—C6—O2	120.1 (5)	H7c—C7—N1	109.5
C2—C1—N1	120.0 (5)	H7c—C7—H7a	109.5
H1a—C1—N1	120.0 (3)	H7c—C7—H7b	109.5
O1—C6—C2—C1	9.9 (5)	N1—C1—C2—C6	179.8 (4)
O1—C6—C2—C3	−169.6 (4)	N1—C1—C2—C3	−0.6 (5)
O2—C6—C2—C1	−169.9 (4)	N1—C5—C4—C3	−0.7 (6)
O2—C6—C2—C3	10.6 (5)	C2—C3—C4—C5	0.3 (5)

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O2^iii	0.80 (7)	1.89 (7)	2.668 (5)	164 (7)
C1—H1A···Br3^iv	0.93	2.96	3.838 (5)	158
C5—H5···Br4^v	0.93	2.99	3.881 (5)	160
C7—H7A···Br3^iv	0.96	2.92	3.857 (6)	166

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