Bis[4-(dimethyl­amino)pyridinium] tetra­bromidocuprate(II)

The metal atom in the anion of the title salt, (C₇H₁₁N₂)₂[CuBr₄], shows a distorted tetra­hedral coordination. The primary contacts between the ions are of the N—H...Br type.

Key indicators

• Single-crystal X-ray study
• T = 233 K
• Mean [sigma](C-C) = 0.009 Å
• R factor = 0.043
• wR factor = 0.123
• Data-to-parameter ratio = 21.6

checkCIF/PLATON results

No syntax errors found



Alert level A
ABSTM02_ALERT_3_A  The ratio of expected to reported Tmax/Tmin(RR) is > 2.00
            Tmin and Tmax reported:      0.321     0.746
            Tmin and Tmax expected:      0.060     0.418
            RR =      2.975
            Please check that your absorption correction is appropriate.

Author Response: The ranges are given in a SADABS run; the molecule have several heavy bromine atoms. The correction for absorption is probably adequate.

PLAT060_ALERT_4_A Ratio Tmax/Tmin (Exp-to-Rep) (too) Large .......       3.06

Author Response: The ranges are given in a SADABS run; the molecule have several heavy bromine atoms. The correction for absorption is probably adequate.

Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.96
PLAT341_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          9

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.560
            Tmax scaled      0.418 Tmin scaled      0.180

Author Response: The ranges are given in a SADABS run; the molecule have several heavy bromine atoms. The correction for absorption is probably adequate.

PLAT062_ALERT_4_G Rescale T(min) & T(max) by .....................       0.56
PLAT154_ALERT_1_G The su's on the Cell Angles are Equal  (x 10000)        200 Deg.

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

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

---

Related literature

For other pyridinium tetrabromidocuprates, see: Coffey et al. (1996); Haddad & Al-Far (2008); Luque et al. (2001); Willet et al. (2000, 2003).

S1. Experimental

Copper sulfate pentahydrate (2.1 g, 8.3 mmol) dissolved in water (5 ml) was mixed with 4-dimethylaminopyridine hydrobromide perbromide (3 g, 8.3 mmol) dissolved in ethanol (10 ml). The mixture was heated for 30 min. The filtered green solution when allowed to evaporate yielded black crystals.

S2. Refinement

Hydrogen atoms were placed at calculated positions (C–H 0.94–0.97 Å; N–H 0.88 Å) and were treated as riding on their parent atoms, with U(H) set to 1.2–1.5U_eq(C, N).

Computing details

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2009).

Figures

Fig. 1. Thermal ellipsoid plot (Barbour, 2001) of 2[C7H11N2][CuBr4] at the 50% probability level. Hydrogen atoms are drawn as spheres of arbitrary radius.

Bis[4-(dimethylamino)pyridinium] tetrabromidocuprate(II)

Crystal data

(C7H11N2)2[CuBr4]	Z = 2
Mr = 629.54	F(000) = 606
Triclinic, P1	Dx = 2.010 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.1768 (2) Å	Cell parameters from 2442 reflections
b = 9.2406 (3) Å	θ = 2.3–27.5°
c = 14.3686 (4) Å	µ = 8.73 mm^−1
α = 93.689 (2)°	T = 233 K
β = 94.814 (2)°	Block, black
γ = 105.073 (2)°	0.35 × 0.30 × 0.10 mm
V = 1040.42 (5) Å^3

Data collection

Bruker SMART APEX diffractometer	4595 independent reflections
Radiation source: fine-focus sealed tube	3168 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.042
ω scans	θmax = 27.5°, θmin = 1.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→10
Tmin = 0.321, Tmax = 0.746	k = −10→12
7224 measured reflections	l = −18→18

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.043	H-atom parameters constrained
wR(F^2) = 0.123	w = 1/[σ^2(Fo^2) + (0.0566P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.00	(Δ/σ)max = 0.001
4595 reflections	Δρmax = 0.84 e Å^−3
213 parameters	Δρmin = −0.82 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0078 (8)

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

	x	y	z	Uiso*/Ueq
Br1	0.46757 (8)	0.23274 (7)	0.31534 (5)	0.04383 (19)
Br2	0.44673 (8)	0.69937 (7)	0.29470 (5)	0.0458 (2)
Br3	0.11950 (8)	0.35808 (7)	0.20247 (4)	0.03895 (18)
Br4	0.65667 (8)	0.48740 (7)	0.15029 (4)	0.04107 (19)
Cu1	0.41731 (9)	0.44301 (7)	0.23676 (5)	0.0323 (2)
N1	0.8043 (9)	0.5220 (8)	0.4011 (5)	0.067 (2)
H1	0.7335	0.4434	0.3685	0.081*
N2	1.1304 (7)	0.8919 (6)	0.5502 (4)	0.0466 (13)
N3	0.6251 (7)	0.8455 (6)	0.1004 (4)	0.0478 (13)
H3	0.5794	0.7776	0.1376	0.057*
N4	0.8436 (7)	1.1604 (6)	−0.0731 (3)	0.0415 (12)
C1	0.9472 (12)	0.5930 (9)	0.3673 (5)	0.063 (2)
H1A	0.9709	0.5576	0.3085	0.075*
C2	1.0582 (9)	0.7127 (9)	0.4141 (5)	0.0521 (18)
H2	1.1589	0.7596	0.3887	0.062*
C3	1.0231 (7)	0.7695 (7)	0.5032 (4)	0.0343 (13)
C4	0.8711 (8)	0.6903 (8)	0.5360 (5)	0.0465 (16)
H4	0.8409	0.7213	0.5942	0.056*
C5	0.7692 (9)	0.5702 (9)	0.4836 (5)	0.064 (2)
H5	0.6683	0.5179	0.5067	0.077*
C6	1.2928 (10)	0.9673 (9)	0.5180 (6)	0.067 (2)
H6A	1.2723	1.0101	0.4597	0.100*
H6B	1.3585	0.8951	0.5080	0.100*
H6C	1.3556	1.0469	0.5650	0.100*
C7	1.0967 (10)	0.9465 (9)	0.6426 (5)	0.062 (2)
H7A	0.9814	0.9571	0.6393	0.093*
H7B	1.1767	1.0433	0.6623	0.093*
H7C	1.1095	0.8752	0.6875	0.093*
C8	0.6803 (9)	0.8036 (7)	0.0201 (5)	0.0472 (17)
H8	0.6688	0.7008	0.0045	0.057*
C9	0.7497 (8)	0.9012 (7)	−0.0374 (4)	0.0409 (15)
H9	0.7858	0.8671	−0.0931	0.049*
C10	0.7710 (7)	1.0591 (6)	−0.0161 (4)	0.0328 (13)
C11	0.7118 (7)	1.1009 (7)	0.0682 (4)	0.0374 (14)
H11	0.7217	1.2026	0.0863	0.045*
C12	0.6401 (8)	0.9918 (8)	0.1234 (4)	0.0462 (17)
H12	0.5999	1.0200	0.1793	0.055*
C13	0.9027 (9)	1.1174 (9)	−0.1615 (5)	0.0558 (18)
H13A	0.9415	1.0274	−0.1553	0.084*
H13B	0.9960	1.1986	−0.1764	0.084*
H13C	0.8099	1.0977	−0.2112	0.084*
C14	0.8708 (10)	1.3216 (6)	−0.0511 (5)	0.059 (2)
H14A	0.9513	1.3551	0.0044	0.088*
H14B	0.7635	1.3424	−0.0398	0.088*
H14C	0.9158	1.3747	−0.1035	0.088*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0494 (4)	0.0387 (4)	0.0482 (4)	0.0151 (3)	0.0101 (3)	0.0186 (3)
Br2	0.0496 (4)	0.0355 (3)	0.0513 (4)	0.0073 (3)	0.0199 (3)	−0.0051 (3)
Br3	0.0337 (3)	0.0415 (3)	0.0407 (3)	0.0089 (3)	0.0043 (2)	0.0009 (3)
Br4	0.0450 (4)	0.0397 (3)	0.0446 (4)	0.0155 (3)	0.0205 (3)	0.0109 (3)
Cu1	0.0331 (4)	0.0319 (4)	0.0336 (4)	0.0095 (3)	0.0084 (3)	0.0061 (3)
N1	0.062 (5)	0.074 (5)	0.060 (4)	0.022 (4)	−0.024 (4)	−0.017 (4)
N2	0.034 (3)	0.058 (3)	0.042 (3)	0.002 (3)	0.004 (2)	0.003 (3)
N3	0.053 (4)	0.045 (3)	0.040 (3)	0.002 (3)	0.003 (3)	0.009 (3)
N4	0.050 (3)	0.035 (3)	0.036 (3)	0.005 (2)	0.005 (2)	0.005 (2)
C1	0.078 (6)	0.075 (5)	0.050 (4)	0.052 (5)	0.000 (4)	−0.010 (4)
C2	0.041 (4)	0.077 (5)	0.048 (4)	0.031 (4)	0.014 (3)	0.001 (4)
C3	0.028 (3)	0.046 (3)	0.034 (3)	0.019 (3)	0.005 (2)	0.006 (3)
C4	0.040 (4)	0.060 (4)	0.036 (3)	0.005 (3)	0.010 (3)	0.007 (3)
C5	0.043 (5)	0.083 (6)	0.059 (5)	0.004 (4)	−0.005 (4)	0.014 (5)
C6	0.054 (5)	0.063 (5)	0.074 (5)	−0.005 (4)	0.001 (4)	0.029 (4)
C7	0.058 (5)	0.068 (5)	0.052 (4)	0.009 (4)	−0.003 (4)	−0.011 (4)
C8	0.060 (5)	0.030 (3)	0.048 (4)	0.008 (3)	−0.003 (3)	0.003 (3)
C9	0.050 (4)	0.041 (3)	0.031 (3)	0.014 (3)	0.000 (3)	−0.003 (3)
C10	0.028 (3)	0.036 (3)	0.030 (3)	0.004 (2)	−0.007 (2)	0.001 (3)
C11	0.037 (3)	0.037 (3)	0.034 (3)	0.005 (3)	0.000 (3)	−0.003 (3)
C12	0.038 (4)	0.069 (5)	0.031 (3)	0.015 (3)	0.002 (3)	0.000 (3)
C13	0.060 (5)	0.070 (5)	0.037 (4)	0.009 (4)	0.016 (3)	0.016 (4)
C14	0.091 (6)	0.022 (3)	0.061 (5)	0.007 (3)	0.000 (4)	0.017 (3)

Geometric parameters (Å, º)

Br1—Cu1	2.4164 (9)	C4—H4	0.9400
Br2—Cu1	2.4039 (9)	C5—H5	0.9400
Br3—Cu1	2.3544 (9)	C6—H6A	0.9700
Br4—Cu1	2.3662 (9)	C6—H6B	0.9700
N1—C5	1.320 (10)	C6—H6C	0.9700
N1—C1	1.330 (11)	C7—H7A	0.9700
N1—H1	0.8800	C7—H7B	0.9700
N2—C3	1.339 (7)	C7—H7C	0.9700
N2—C6	1.458 (9)	C8—C9	1.314 (9)
N2—C7	1.463 (8)	C8—H8	0.9400
N3—C12	1.342 (8)	C9—C10	1.433 (8)
N3—C8	1.343 (9)	C9—H9	0.9400
N3—H3	0.8800	C10—C11	1.410 (8)
N4—C10	1.338 (7)	C11—C12	1.364 (9)
N4—C14	1.457 (7)	C11—H11	0.9400
N4—C13	1.464 (8)	C12—H12	0.9400
C1—C2	1.334 (10)	C13—H13A	0.9700
C1—H1A	0.9400	C13—H13B	0.9700
C2—C3	1.431 (8)	C13—H13C	0.9700
C2—H2	0.9400	C14—H14A	0.9700
C3—C4	1.404 (8)	C14—H14B	0.9700
C4—C5	1.341 (9)	C14—H14C	0.9700
Br1—Cu1—Br2	131.05 (4)	N2—C6—H6C	109.5
Br1—Cu1—Br3	99.47 (3)	H6A—C6—H6C	109.5
Br1—Cu1—Br4	97.82 (3)	H6B—C6—H6C	109.5
Br2—Cu1—Br3	100.27 (3)	N2—C7—H7A	109.5
Br2—Cu1—Br4	97.76 (3)	N2—C7—H7B	109.5
Br3—Cu1—Br4	136.48 (4)	H7A—C7—H7B	109.5
C5—N1—C1	119.7 (7)	N2—C7—H7C	109.5
C5—N1—H1	120.2	H7A—C7—H7C	109.5
C1—N1—H1	120.2	H7B—C7—H7C	109.5
C3—N2—C6	122.6 (6)	C9—C8—N3	122.3 (6)
C3—N2—C7	120.4 (6)	C9—C8—H8	118.9
C6—N2—C7	116.7 (6)	N3—C8—H8	118.9
C12—N3—C8	119.5 (6)	C8—C9—C10	120.8 (6)
C12—N3—H3	120.2	C8—C9—H9	119.6
C8—N3—H3	120.2	C10—C9—H9	119.6
C10—N4—C14	122.4 (5)	N4—C10—C11	122.2 (5)
C10—N4—C13	122.4 (5)	N4—C10—C9	121.7 (5)
C14—N4—C13	115.2 (6)	C11—C10—C9	116.1 (6)
C2—C1—N1	122.3 (7)	C12—C11—C10	119.2 (5)
C2—C1—H1A	118.9	C12—C11—H11	120.4
N1—C1—H1A	118.9	C10—C11—H11	120.4
C1—C2—C3	119.6 (7)	N3—C12—C11	122.1 (6)
C1—C2—H2	120.2	N3—C12—H12	118.9
C3—C2—H2	120.2	C11—C12—H12	118.9
N2—C3—C4	123.4 (5)	N4—C13—H13A	109.5
N2—C3—C2	120.7 (6)	N4—C13—H13B	109.5
C4—C3—C2	116.0 (6)	H13A—C13—H13B	109.5
C5—C4—C3	119.5 (6)	N4—C13—H13C	109.5
C5—C4—H4	120.2	H13A—C13—H13C	109.5
C3—C4—H4	120.2	H13B—C13—H13C	109.5
N1—C5—C4	122.9 (8)	N4—C14—H14A	109.5
N1—C5—H5	118.5	N4—C14—H14B	109.5
C4—C5—H5	118.5	H14A—C14—H14B	109.5
N2—C6—H6A	109.5	N4—C14—H14C	109.5
N2—C6—H6B	109.5	H14A—C14—H14C	109.5
H6A—C6—H6B	109.5	H14B—C14—H14C	109.5
C5—N1—C1—C2	−0.1 (12)	C12—N3—C8—C9	0.2 (10)
N1—C1—C2—C3	−0.9 (11)	N3—C8—C9—C10	0.5 (10)
C6—N2—C3—C4	176.1 (7)	C14—N4—C10—C11	1.6 (9)
C7—N2—C3—C4	2.7 (9)	C13—N4—C10—C11	−179.0 (5)
C6—N2—C3—C2	−4.6 (9)	C14—N4—C10—C9	−178.1 (6)
C7—N2—C3—C2	−178.0 (6)	C13—N4—C10—C9	1.3 (8)
C1—C2—C3—N2	−178.2 (6)	C8—C9—C10—N4	179.0 (6)
C1—C2—C3—C4	1.2 (9)	C8—C9—C10—C11	−0.7 (8)
N2—C3—C4—C5	178.9 (6)	N4—C10—C11—C12	−179.6 (5)
C2—C3—C4—C5	−0.5 (9)	C9—C10—C11—C12	0.2 (8)
C1—N1—C5—C4	0.8 (12)	C8—N3—C12—C11	−0.8 (9)
C3—C4—C5—N1	−0.4 (11)	C10—C11—C12—N3	0.6 (9)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Br1	0.88	2.54	3.380 (7)	162
N3—H3···Br2	0.88	2.65	3.449 (6)	152