Two complexes of CuBr₂ with 5-tert-butyl­pyrazole

trans-Di­bromo­bis(5-tert-butyl­pyrazole-N²)copper(II), trans-[CuBr₂(Hpz^tBu)₂] (Hpz^tBu is 5-tert-butyl­pyrazole, C₇H₁₂N₂), ex­hibits a distorted square-planar geometry with a significant tetrahedral twist, while trans-di­bromo­tetrakis(5-tert-butyl­pyrazole-N²)copper(II), trans-[CuBr₂(Hpz^tBu)₄], adopts a distorted octahedral geometry across a crystallographic inversion centre. Both compounds exhibit intramolecular N—H...Br hydrogen-bonding interactions.

S1. Comment

We have recently discovered that complexation of CuCl₂ or CuBr₂ by Hpz^tBu [Hpz^tBu is 3(5)-tertbutylpyrazole] in basic MeOH leads to a novel heptacopper aggregate structure, which appears to be templated by N—H···X (X^- = Cl^-, Br^-) hydrogen-bonding interactions to non-coordinated anions (Liu et al., 2001). As a result of a more in-depth study of this system, we have isolated two more adducts of CuBr₂ and Hpz^tBu, namely trans-dibromobis(5-tert-butylpyrazole-N²)copper(II), [CuBr₂(Hpz^tBu)₂], (I), and trans-dibromotetrakis(5-tert-butylpyrazole-N²)copper(II), [CuBr₂(Hpz^tBu)₄], (II). The Trofimenko nomenclature for substituted pyrazoles is employed throughout this discussion (Trofimenko, 1999).

The asymmetric unit of (I) contains one molecule of the complex lying on a general position. The Cu^II centre in (I) is four-coordinate, with trans-disposed Br^- and Hpz^tBu ligands; the latter are coordinated as the less sterically hindered 5-tert-butylpyrazole tautomer. The two Cu—N bond lengths in the molecule are crystallographically identical. However, the Cu1—Br20 bond is 0.0713 (6) Å longer than Cu1—Br21, which presumably reflects the presence of two hydrogen bonds to Br20 (see below). Although clearly derived from a square plane, the coordination sphere at Cu1 has a significant tetrahedral twist, which can be expressed by the dihedral angle of 45.71 (6)° between the Cu1/N2/Br20 and Cu1/N11/Br21 planes. This angle would be 0° for an ideal square-planar geometry and 90° for a tetrahedron. The N—H groups on each pyrazole ligand form an intramolecular hydrogen bond to Br20, leading to a distorted pyramidal geometry for this atom defined by the angles H3···Br20—Cu1 = 70.0, H12···Br20—Cu1 = 73.4 and H3···Br20···H12 = 108.2°.

Several 2:1 adducts of pyrazole derivatives with copper dihalides have been crystallographically characterized by others. Bis-pyrazole complexes of CuF₂ and CuCl₂ most commonly adopt dimeric structures in the solid state of general formula [{CuX(µ-X)L₂}₂] (X^- = F^-, Cl^-; L is a pyrazole derivative: ten Hoedt et al., 1981; Reitmeijer et al., 1984; Keij et al., 1991; Malecka et al., 1998; Chandrasekhar et al., 2000). Two coordination polymers with this stoichiometry (Keij et al., 1988; Malecka et al., 1998) and a number of monomeric [CuCl₂L₂] structures (Francisco et al., 1980; Watson et al., 1989; Hergold-Brundic et al., 1991; Valle, et al., 1995; Malecka et al., 1998) have also been reported. The only CuBr₂ bis-pyrazole adduct whose crystal structure has been previously determined is the mononuclear complex [CuBr₂(Hpz^Ph2)₂] (Hpz^Ph2 is 3,5-diphenylpyrazole; Murray et al., 1988). Interestingly, this compound exhibits cis-disposed Br^- and Hpz^Ph2 ligands in the solid, but otherwise adopts an almost identical coordination geometry to (I).

Compound (II) contains discrete six-coordinate Cu^II centres, with Cu1 lying on a crystallographic inversion centre. As for (I), the Hpz^tBu ligands in (II) are coordinated in the 5-tert-butylpyrazole tautomer. The four pyrazole N-donor atoms are strictly coplanar and form an almost perfect square plane, although the two unique Cu1—N bond lengths differ by 0.006 (2) Å, which is of borderline crystallographic significance. The axial Cu1—Br20 distance of 3.02801 (16) Å is substantially longer than the sum of the covalent radii of Cu (1.38 Å) and Br (1.14 Å) (Gordon & Ford, 1972), so that this `bond' is probably better considered as a weak electrostatic interaction between the Br<sup>-</sup> anion and the positively charged void perpendicular to the molecular tetragonal plane. This suggestion is supported by the fact that the Cu1—Br20 `bond' fails the Hirschfeld rigid-bond test (Hirshfeld, 1976) by almost 80 s.u.'s, which implies that there is negligible covalent interaction between these two atoms. Each Br^- ligand accepts two hydrogen bonds from cis-disposed pyrazole ligands, forming an approximately pyramidal geometry with the angles H3···Br20—Cu1 = 64.1 (5)°, H12···Br20—Cu1 = 63.0 (5)° and H3···Br20···H12 = and 76.1 (7)°. The crystal structures of two other 4:1 pyrazole–Cu^II dihalide adducts have been reported previously, namely [CuCl₂(Hpz)₄] (Mighell et al., 1975; Casellato et al., 2000) and catena-[{CuCl₂(µ-dpm)₂}_n] [dpm is bis(pyrazol-4-yl)methane; Broomhead et al., 1998]. Both of these exhibit an essentially identical coordination geometry to (II) and show the same pattern of N—H···Cl intramolecular hydrogen bonding.

Related literature

For related literature, see: Broomhead et al. (1998); Casellato et al. (2000); Chandrasekhar et al. (2000); Flack (1983); Francisco et al. (1980); Gordon & Ford (1972); Hergold-Brundic, Kaitner, Kamenar, Leovac, Iveges & Juranic (1991); Hirshfeld (1976); Hoedt et al. (1981); Keij et al. (1988, 1991); Liu et al. (2001); Malecka et al. (1998); Mighell et al. (1975); Murray et al. (1988); Reitmeijer et al. (1984); Trofimenko (1999); Valle et al. (1995); Watson et al. (1989).

S2. Experimental

For the preparation of compound (I), anhydrous CuBr₂ (0.22 g, 1.0 mmol) and Hpz^tBu (0.18 g, 1.5 mmol) were stirred into a 4:1 CH₂Cl₂–acetone mixture (50 ml) at room temperature for 2 h. The solvent was then removed in vacuo and the residue redissolved in a minimum volume of CH₂Cl₂, yielding a dark-green solution and some insoluble material which was removed by filtration. Slow diffusion of pentane into the filtrate gave a brown microcrystalline product which was removed by filtration. Slow evaporation of the remaining solution yielded green crystals of (I). Analysis, found: C 35.7, H 5.1, N 12.0%; calculated for C₁₄H₂₄Br₂CuN₄: C 35.6, H 5.1, N 11.9%. For the preparation of compound (I), anhydrous CuBr₂ (0.22 g, 1.0 mmol) and Hpz^tBu (0.37 g, 3.0 mmol) were reacted in CH₃OH (50 ml) at room temperature for 30 min. The solvent was then removed in vacuo and the residue redissolved in a minimum volume of CH₂Cl₂, yielding a dark-green solution and some insoluble material which was removed by filtration. Slow diffusion of pentane into the solution gave a mixture of deep-blue well formed crystals of (II), together with a turquoise by-product which was removed manually. Analysis, found: C 46.8, H 6.7, N 15.7%; calculated for C₂₈H₄₈Br₂CuN₈: C 46.7, H 6.7, N 15.6%.

S3. Refinement

The Flack parameter (Flack, 1983) for (I) was determined using Friedel 2070 pairs. One tert-butyl group in (I) was found to be disordered during refinement. Three equally occupied disorder orientations were modelled: C16A–C19A, C16B–C19B and C16C–C19C. All C—C bonds within the disordered group were restrained to 1.53 (2) Å, and non-bonded 1,3-C···C contacts within a given disorder orientation to 2.50 (2) Å. All wholly occupied non-H atoms were refined anisotropically. All H atoms were placed in calculated positions and refined using a riding model, with fixed C—H distances of 0.95 Å for Csp²—H bonds and 0.98 Å for methyl C—H bonds and an N—H distance of 0.88 Å. No disorder was detected in (II). All C-bound H atoms were placed in calculated positions and refined using a riding model, with fixed C—H distances of 0.95 Å for Csp²—H bonds and 0.98 Å for methyl C—H bonds. The N-bound H atoms H3 and H12 were located in a difference Fourier map and were allowed to refine freely.

Computing details

For both compounds, data collection: COLLECT (Nonius, 1999); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEX (McArdle, 1995); software used to prepare material for publication: local program.

Figures

	Fig. 1. The molecular structure of (I) showing 50% probability displacement ellipsoids and the atom-numbering scheme employed. H atoms have arbitrary radii. For clarity, only one orientation of the disordered tert-butyl group (C16A—C19A) is shown, while all C-bound H atoms have been omitted.
	Fig. 2. The molecular structure of (II) showing 50% probability displacement ellipsoids and the atom-numbering scheme employed. H atoms have arbitrary radii. For clarity, all C-bound H atoms have been omitted. [Symmetry code: (i) -x + 0.5, -y + 0.5, -z.]

(I) trans-dibromobis(5-tert-butylpyrazole-N²)copper(II)

Crystal data

[CuBr2(C7H12N2)2]	Dx = 1.632 Mg m^−3
Mr = 471.73	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pca21	Cell parameters from 37366 reflections
a = 17.4947 (2) Å	θ = 4.1–27.5°
b = 9.8730 (1) Å	µ = 5.30 mm^−1
c = 11.1165 (1) Å	T = 150 K
V = 1920.10 (3) Å^3	Column, green
Z = 4	0.48 × 0.18 × 0.14 mm
F(000) = 940

Data collection

Nonius KappaCCD diffractometer	4373 independent reflections
Radiation source: fine-focus sealed tube	4268 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.056
Detector resolution: 9.091 pixels mm^-1	θmax = 27.5°, θmin = 4.1°
area–detector scans	h = −22→22
Absorption correction: multi-scan (SORTAV; Blessing, 1995)	k = −12→12
Tmin = 0.185, Tmax = 0.524	l = −14→14
37366 measured reflections

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)] = 0.024	H-atom parameters constrained
wR(F^2) = 0.060	w = 1/[σ^2(Fo^2) + (0.0351P)^2 + 0.6531P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max = 0.001
4373 reflections	Δρmax = 0.25 e Å^−3
203 parameters	Δρmin = −0.47 e Å^−3
31 restraints	Absolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.006 (8)

Special details

Experimental. Detector set at 30 mm from sample with different 2theta offsets 1 degree phi exposures for chi=0 degree settings 1 degree omega exposures for chi=90 degree settings

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. For both compounds, structure solution was achieved by direct methods using SHELXS97 (Sheldrick, 1990), while least squares refinement used SHELXL97 (Sheldrick, 1997).

One tert-butyl group is disordered over three equally occupied orientations, C16A—C19A, C16B—C19B and C16C—C19C. All C—C bonds within the disordered moiety were restrained to 1.53 (2) Å, and non-bonded 1,3-C···C contacts within a given disorder orientation to 2.50 (2) Å. All wholly occuped non-H atoms were refined anisotropically. All H atoms were placed in calculated positions and refined using a riding model, at fixed C—H distances of 0.95 Å for the sp² C—H bonds and 0.98 Å for the methyl C—H bonds, or N—H = 0.88 Å.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Cu1	0.291298 (15)	0.78148 (3)	0.69315 (3)	0.02836 (7)
N2	0.21062 (12)	0.6480 (2)	0.7179 (2)	0.0318 (5)
N3	0.21436 (12)	0.5639 (2)	0.8136 (2)	0.0360 (5)
H3	0.2530	0.5625	0.8643	0.043*
C4	0.15308 (14)	0.4826 (2)	0.8236 (3)	0.0330 (5)
C5	0.10668 (14)	0.5156 (3)	0.7265 (3)	0.0374 (6)
H5	0.0588	0.4761	0.7067	0.045*
C6	0.14435 (15)	0.6187 (3)	0.6638 (3)	0.0354 (5)
H6	0.1256	0.6616	0.5932	0.042*
C7	0.14560 (16)	0.3788 (3)	0.9217 (3)	0.0389 (6)
C8	0.21347 (18)	0.3871 (4)	1.0082 (4)	0.0515 (8)
H8A	0.2079	0.3183	1.0711	0.062*
H8B	0.2150	0.4772	1.0452	0.062*
H8C	0.2610	0.3712	0.9638	0.062*
C9	0.07223 (17)	0.4072 (4)	0.9930 (3)	0.0517 (7)
H9A	0.0668	0.3399	1.0572	0.062*
H9B	0.0281	0.4017	0.9390	0.062*
H9C	0.0749	0.4980	1.0283	0.062*
C10	0.1408 (3)	0.2378 (3)	0.8645 (4)	0.0612 (10)
H10A	0.1363	0.1692	0.9278	0.073*
H10B	0.1871	0.2208	0.8172	0.073*
H10C	0.0960	0.2332	0.8118	0.073*
N11	0.34337 (11)	0.9503 (2)	0.73202 (18)	0.0292 (4)
N12	0.39656 (11)	0.9593 (2)	0.82064 (19)	0.0283 (4)
H12	0.4177	0.8884	0.8553	0.034*
C13	0.41341 (14)	1.0869 (2)	0.8495 (2)	0.0302 (5)
C14	0.36924 (18)	1.1676 (3)	0.7743 (3)	0.0407 (6)
H14	0.3680	1.2637	0.7716	0.049*
C15	0.32725 (16)	1.0785 (3)	0.7038 (3)	0.0382 (6)
H15	0.2918	1.1053	0.6437	0.046*
C16A	0.4689 (9)	1.1279 (16)	0.9470 (14)	0.037 (8)*	0.33333
C17A	0.4928 (7)	0.9985 (11)	1.0186 (10)	0.041 (3)*	0.33333
H17A	0.4483	0.9622	1.0612	0.061*	0.33333
H17B	0.5327	1.0221	1.0768	0.061*	0.33333
H17C	0.5124	0.9302	0.9626	0.061*	0.33333
C18A	0.5414 (6)	1.1814 (13)	0.8817 (12)	0.052 (3)*	0.33333
H18A	0.5643	1.1080	0.8344	0.079*	0.33333
H18B	0.5784	1.2137	0.9413	0.079*	0.33333
H18C	0.5273	1.2561	0.8281	0.079*	0.33333
C19A	0.4339 (9)	1.2289 (14)	1.0317 (13)	0.065 (6)*	0.33333
H19A	0.4183	1.3096	0.9867	0.097*	0.33333
H19B	0.4714	1.2544	1.0930	0.097*	0.33333
H19C	0.3891	1.1885	1.0706	0.097*	0.33333
C16B	0.4765 (7)	1.1257 (12)	0.9346 (11)	0.032 (4)*	0.33333
C17B	0.4739 (8)	1.0297 (12)	1.0426 (10)	0.044 (3)*	0.33333
H17D	0.4216	1.0252	1.0738	0.066*	0.33333
H17E	0.5083	1.0632	1.1056	0.066*	0.33333
H17F	0.4903	0.9390	1.0174	0.066*	0.33333
C18B	0.5525 (5)	1.1297 (11)	0.8700 (11)	0.037 (3)*	0.33333
H18D	0.5629	1.0409	0.8341	0.055*	0.33333
H18E	0.5931	1.1522	0.9273	0.055*	0.33333
H18F	0.5508	1.1985	0.8065	0.055*	0.33333
C19B	0.4580 (6)	1.2696 (10)	0.9858 (11)	0.049 (3)*	0.33333
H19D	0.4590	1.3360	0.9203	0.074*	0.33333
H19E	0.4962	1.2941	1.0465	0.074*	0.33333
H19F	0.4071	1.2688	1.0227	0.074*	0.33333
C16C	0.4693 (7)	1.1147 (13)	0.9533 (11)	0.030 (5)*	0.33333
C17C	0.4749 (8)	0.9973 (12)	1.0404 (10)	0.033 (3)*	0.33333
H17G	0.5106	1.0204	1.1053	0.050*	0.33333
H17H	0.4935	0.9168	0.9978	0.050*	0.33333
H17I	0.4244	0.9785	1.0745	0.050*	0.33333
C18C	0.5494 (6)	1.1437 (13)	0.9003 (12)	0.039 (3)*	0.33333
H18G	0.5475	1.2269	0.8522	0.059*	0.33333
H18H	0.5651	1.0678	0.8492	0.059*	0.33333
H18I	0.5862	1.1549	0.9659	0.059*	0.33333
C19C	0.4435 (7)	1.2486 (11)	1.0142 (11)	0.028 (2)*	0.33333
H19G	0.4373	1.3191	0.9529	0.042*	0.33333
H19H	0.4822	1.2771	1.0727	0.042*	0.33333
H19I	0.3947	1.2341	1.0554	0.042*	0.33333
Br20	0.391135 (14)	0.63896 (2)	0.78137 (3)	0.03398 (7)
Br21	0.243097 (17)	0.85958 (3)	0.50569 (3)	0.04032 (8)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.02511 (13)	0.03068 (13)	0.02930 (13)	−0.00248 (10)	−0.00408 (12)	0.00108 (12)
N2	0.0290 (10)	0.0337 (10)	0.0327 (12)	−0.0030 (7)	−0.0058 (9)	0.0012 (8)
N3	0.0312 (10)	0.0373 (11)	0.0395 (12)	−0.0091 (8)	−0.0092 (9)	0.0045 (9)
C4	0.0285 (11)	0.0291 (11)	0.0415 (14)	−0.0050 (9)	−0.0015 (10)	−0.0036 (10)
C5	0.0288 (12)	0.0382 (13)	0.0451 (15)	−0.0064 (10)	−0.0080 (10)	−0.0040 (12)
C6	0.0289 (12)	0.0375 (12)	0.0399 (14)	−0.0019 (10)	−0.0066 (10)	−0.0032 (11)
C7	0.0354 (13)	0.0357 (13)	0.0457 (15)	−0.0095 (10)	−0.0050 (13)	0.0014 (12)
C8	0.0435 (16)	0.0523 (17)	0.059 (2)	−0.0136 (13)	−0.0127 (16)	0.0166 (17)
C9	0.0412 (15)	0.073 (2)	0.0408 (16)	−0.0105 (15)	−0.0026 (13)	0.0050 (16)
C10	0.086 (3)	0.0321 (14)	0.066 (2)	−0.0157 (16)	0.0002 (19)	0.0008 (14)
N11	0.0276 (9)	0.0349 (10)	0.0252 (9)	−0.0023 (8)	−0.0046 (8)	0.0027 (8)
N12	0.0259 (9)	0.0314 (10)	0.0277 (10)	−0.0027 (7)	−0.0024 (8)	0.0019 (8)
C13	0.0297 (11)	0.0326 (11)	0.0281 (11)	−0.0045 (9)	0.0011 (10)	−0.0005 (10)
C14	0.0510 (15)	0.0292 (11)	0.0420 (15)	−0.0020 (11)	−0.0066 (14)	0.0040 (12)
C15	0.0452 (14)	0.0327 (12)	0.0368 (13)	0.0000 (10)	−0.0107 (12)	0.0055 (11)
Br20	0.02716 (12)	0.03378 (12)	0.04101 (15)	0.00362 (8)	−0.00407 (10)	−0.00189 (11)
Br21	0.03937 (14)	0.04965 (15)	0.03193 (14)	−0.00396 (10)	−0.01137 (12)	0.00457 (11)

Geometric parameters (Å, º)

Cu1—N2	1.951 (2)	C16A—C19A	1.502 (15)
Cu1—N11	1.948 (2)	C16A—C18A	1.554 (15)
Cu1—Br20	2.4479 (4)	C16A—C17A	1.562 (15)
Cu1—Br21	2.3766 (4)	C17A—H17A	0.9800
N2—C6	1.338 (3)	C17A—H17B	0.9800
N2—N3	1.351 (3)	C17A—H17C	0.9800
N3—C4	1.344 (3)	C18A—H18A	0.9800
N3—H3	0.8800	C18A—H18B	0.9800
C4—C5	1.389 (4)	C18A—H18C	0.9800
C4—C7	1.503 (4)	C19A—H19A	0.9800
C5—C6	1.398 (4)	C19A—H19B	0.9800
C5—H5	0.9500	C19A—H19C	0.9800
C6—H6	0.9500	C16B—C18B	1.512 (13)
C7—C8	1.530 (4)	C16B—C17B	1.530 (13)
C7—C10	1.533 (4)	C16B—C19B	1.565 (13)
C7—C9	1.534 (4)	C17B—H17D	0.9800
C8—H8A	0.9800	C17B—H17E	0.9800
C8—H8B	0.9800	C17B—H17F	0.9800
C8—H8C	0.9800	C18B—H18D	0.9800
C9—H9A	0.9800	C18B—H18E	0.9800
C9—H9B	0.9800	C18B—H18F	0.9800
C9—H9C	0.9800	C19B—H19D	0.9800
C10—H10A	0.9800	C19B—H19E	0.9800
C10—H10B	0.9800	C19B—H19F	0.9800
C10—H10C	0.9800	C16C—C17C	1.514 (14)
N11—C15	1.334 (3)	C16C—C18C	1.547 (13)
N11—N12	1.358 (3)	C16C—C19C	1.552 (13)
N12—C13	1.333 (3)	C17C—H17G	0.9800
N12—H12	0.8800	C17C—H17H	0.9800
C13—C14	1.390 (4)	C17C—H17I	0.9800
C13—C16B	1.503 (11)	C18C—H18G	0.9800
C13—C16A	1.510 (14)	C18C—H18H	0.9800
C13—C16C	1.537 (12)	C18C—H18I	0.9800
C14—C15	1.388 (4)	C19C—H19G	0.9800
C14—H14	0.9500	C19C—H19H	0.9800
C15—H15	0.9500	C19C—H19I	0.9800
N2—Cu1—N11	152.26 (9)	C13—C16A—C17A	108.5 (10)
N2—Cu1—Br20	94.09 (6)	C18A—C16A—C17A	107.3 (11)
N2—Cu1—Br21	94.96 (7)	C16A—C17A—H17A	109.5
N11—Cu1—Br20	93.97 (6)	C16A—C17A—H17B	109.5
N11—Cu1—Br21	94.75 (6)	H17A—C17A—H17B	109.5
Br20—Cu1—Br21	142.27 (2)	C16A—C17A—H17C	109.5
C6—N2—N3	105.3 (2)	H17A—C17A—H17C	109.5
C6—N2—Cu1	135.20 (19)	H17B—C17A—H17C	109.5
N3—N2—Cu1	119.44 (16)	C16A—C18A—H18A	109.5
C4—N3—N2	113.2 (2)	C16A—C18A—H18B	109.5
C4—N3—H3	123.4	H18A—C18A—H18B	109.5
N2—N3—H3	123.4	C16A—C18A—H18C	109.5
N3—C4—C5	105.2 (2)	H18A—C18A—H18C	109.5
N3—C4—C7	122.5 (2)	H18B—C18A—H18C	109.5
C5—C4—C7	132.3 (2)	C16A—C19A—H19A	109.5
C4—C5—C6	106.4 (2)	C16A—C19A—H19B	109.5
C4—C5—H5	126.8	H19A—C19A—H19B	109.5
C6—C5—H5	126.8	C16A—C19A—H19C	109.5
N2—C6—C5	110.0 (2)	H19A—C19A—H19C	109.5
N2—C6—H6	125.0	H19B—C19A—H19C	109.5
C5—C6—H6	125.0	C13—C16B—C18B	110.7 (9)
C4—C7—C8	110.6 (2)	C13—C16B—C17B	108.3 (8)
C4—C7—C10	108.8 (3)	C18B—C16B—C17B	114.5 (10)
C8—C7—C10	110.6 (3)	C13—C16B—C19B	107.9 (8)
C4—C7—C9	108.9 (3)	C18B—C16B—C19B	109.4 (9)
C8—C7—C9	108.4 (3)	C17B—C16B—C19B	105.7 (9)
C10—C7—C9	109.5 (3)	C16B—C17B—H17D	109.5
C7—C8—H8A	109.5	C16B—C17B—H17E	109.5
C7—C8—H8B	109.5	H17D—C17B—H17E	109.5
H8A—C8—H8B	109.5	C16B—C17B—H17F	109.5
C7—C8—H8C	109.5	H17D—C17B—H17F	109.5
H8A—C8—H8C	109.5	H17E—C17B—H17F	109.5
H8B—C8—H8C	109.5	C16B—C18B—H18D	109.5
C7—C9—H9A	109.5	C16B—C18B—H18E	109.5
C7—C9—H9B	109.5	H18D—C18B—H18E	109.5
H9A—C9—H9B	109.5	C16B—C18B—H18F	109.5
C7—C9—H9C	109.5	H18D—C18B—H18F	109.5
H9A—C9—H9C	109.5	H18E—C18B—H18F	109.5
H9B—C9—H9C	109.5	C16B—C19B—H19D	109.5
C7—C10—H10A	109.5	C16B—C19B—H19E	109.5
C7—C10—H10B	109.5	H19D—C19B—H19E	109.5
H10A—C10—H10B	109.5	C16B—C19B—H19F	109.5
C7—C10—H10C	109.5	H19D—C19B—H19F	109.5
H10A—C10—H10C	109.5	H19E—C19B—H19F	109.5
H10B—C10—H10C	109.5	C17C—C16C—C13	112.6 (9)
C15—N11—N12	104.7 (2)	C17C—C16C—C18C	109.0 (10)
C15—N11—Cu1	131.37 (18)	C13—C16C—C18C	108.8 (9)
N12—N11—Cu1	122.50 (16)	C17C—C16C—C19C	113.1 (10)
C13—N12—N11	112.8 (2)	C13—C16C—C19C	107.1 (8)
C13—N12—H12	123.6	C18C—C16C—C19C	105.8 (10)
N11—N12—H12	123.6	C16C—C17C—H17G	109.5
N12—C13—C14	105.9 (2)	C16C—C17C—H17H	109.5
N12—C13—C16B	123.7 (5)	H17G—C17C—H17H	109.5
C14—C13—C16B	129.9 (5)	C16C—C17C—H17I	109.5
N12—C13—C16A	124.6 (6)	H17G—C17C—H17I	109.5
C14—C13—C16A	129.5 (6)	H17H—C17C—H17I	109.5
N12—C13—C16C	119.4 (5)	C16C—C18C—H18G	109.5
C14—C13—C16C	134.7 (6)	C16C—C18C—H18H	109.5
C15—C14—C13	105.7 (2)	H18G—C18C—H18H	109.5
C15—C14—H14	127.1	C16C—C18C—H18I	109.5
C13—C14—H14	127.1	H18G—C18C—H18I	109.5
N11—C15—C14	110.9 (2)	H18H—C18C—H18I	109.5
N11—C15—H15	124.5	C16C—C19C—H19G	109.5
C14—C15—H15	124.5	C16C—C19C—H19H	109.5
C19A—C16A—C13	111.4 (11)	H19G—C19C—H19H	109.5
C19A—C16A—C18A	113.6 (12)	C16C—C19C—H19I	109.5
C13—C16A—C18A	106.3 (10)	H19G—C19C—H19I	109.5
C19A—C16A—C17A	109.4 (11)	H19H—C19C—H19I	109.5

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3···Br20	0.88	2.69	3.200 (2)	118
N12—H12···Br20	0.88	2.64	3.194 (2)	122

(II) trans-dibromotetrakis(5-tert-butylpyrazole-N²)copper(II)

Crystal data

[CuBr2(C7H12N2)4]	F(000) = 1484
Mr = 720.10	Dx = 1.359 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 19.5985 (3) Å	Cell parameters from 29739 reflections
b = 11.9918 (2) Å	θ = 3.7–27.5°
c = 15.9131 (2) Å	µ = 2.92 mm^−1
β = 109.8260 (6)°	T = 150 K
V = 3518.24 (9) Å^3	Rectangular prism, deep blue
Z = 4	0.49 × 0.34 × 0.17 mm

Data collection

Nonius KappaCCD diffractometer	4019 independent reflections
Radiation source: fine-focus sealed tube	3655 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.077
Detector resolution: 9.091 pixels mm^-1	θmax = 27.5°, θmin = 3.7°
area–detector scans	h = −25→25
Absorption correction: multi-scan (SORTAV; Blessing, 1995)	k = −15→15
Tmin = 0.329, Tmax = 0.637	l = −20→20
29739 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: see text
R[F^2 > 2σ(F^2)] = 0.026	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.070	w = 1/[σ^2(Fo^2) + (0.0327P)^2 + 2.2831P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.001
4019 reflections	Δρmax = 0.26 e Å^−3
187 parameters	Δρmin = −0.44 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0027 (2)

Special details

Experimental. Detector set at 30 mm from sample with different 2theta offsets 1 degree phi exposures for chi=0 degree settings 1 degree omega exposures for chi=90 degree settings

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. For both compounds, structure solution was achieved by direct methods using SHELXS97 (Sheldrick, 1990), while least squares refinement used SHELXL97 (Sheldrick, 1997).

No disorder was detected during refinement. All C-bound H atoms were placed in calculated positions and refined using a riding model, at fixed C—H distances of 0.95 Å for the sp² C—H bonds and 0.98 Å for the methyl C—H bonds. All N-bound H atoms were located in the difference map and allowed to refine freely. All non-H atoms were refined anisotropically, and no restraints were applied.

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

	x	y	z	Uiso*/Ueq
Cu1	0.2500	0.2500	0.0000	0.03027 (10)
N2	0.35090 (8)	0.31214 (12)	0.05144 (9)	0.0314 (3)
N3	0.41078 (8)	0.24737 (13)	0.06997 (10)	0.0303 (3)
H3	0.4028 (11)	0.1775 (18)	0.0576 (13)	0.031 (5)*
C4	0.47233 (9)	0.30750 (15)	0.09398 (12)	0.0331 (4)
C5	0.45117 (11)	0.41710 (17)	0.09161 (17)	0.0488 (5)
H5	0.4812	0.4794	0.1052	0.059*
C6	0.37558 (11)	0.41606 (17)	0.06466 (15)	0.0457 (5)
H6	0.3466	0.4793	0.0570	0.055*
C7	0.54601 (10)	0.25549 (16)	0.11226 (13)	0.0381 (4)
C8	0.56461 (15)	0.2589 (3)	0.02676 (18)	0.0686 (8)
H8A	0.6115	0.2261	0.0376	0.082*
H8B	0.5652	0.3349	0.0081	0.082*
H8C	0.5289	0.2178	−0.0192	0.082*
C9	0.60229 (13)	0.3221 (2)	0.18558 (18)	0.0640 (7)
H9A	0.6493	0.2893	0.1976	0.077*
H9B	0.5898	0.3210	0.2389	0.077*
H9C	0.6030	0.3978	0.1662	0.077*
C10	0.54679 (14)	0.1342 (2)	0.1417 (2)	0.0708 (8)
H10A	0.5943	0.1034	0.1531	0.085*
H10B	0.5120	0.0922	0.0953	0.085*
H10C	0.5346	0.1308	0.1952	0.085*
N11	0.24815 (8)	0.20208 (12)	0.11981 (9)	0.0303 (3)
N12	0.20697 (8)	0.25908 (12)	0.15857 (10)	0.0284 (3)
H12	0.1929 (11)	0.3200 (18)	0.1395 (13)	0.031 (5)*
C13	0.19824 (9)	0.20293 (14)	0.22722 (10)	0.0282 (3)
C14	0.23621 (11)	0.10438 (16)	0.23377 (12)	0.0370 (4)
H14	0.2411	0.0475	0.2751	0.044*
C15	0.26576 (10)	0.10787 (16)	0.16548 (12)	0.0363 (4)
H15	0.2940	0.0517	0.1536	0.044*
C16	0.15555 (10)	0.24795 (15)	0.28280 (12)	0.0346 (4)
C17	0.11354 (12)	0.35283 (18)	0.24082 (14)	0.0451 (5)
H17A	0.0869	0.3796	0.2774	0.054*
H17B	0.0804	0.3356	0.1823	0.054*
H17C	0.1469	0.4093	0.2364	0.054*
C18	0.10189 (17)	0.1578 (2)	0.2878 (2)	0.0751 (9)
H18A	0.0738	0.1845	0.3227	0.090*
H18B	0.1280	0.0921	0.3151	0.090*
H18C	0.0701	0.1402	0.2286	0.090*
C19	0.20784 (15)	0.2747 (2)	0.37618 (14)	0.0625 (7)
H19A	0.1812	0.3036	0.4120	0.075*
H19B	0.2424	0.3293	0.3721	0.075*
H19C	0.2329	0.2080	0.4032	0.075*
Br20	0.181354 (10)	0.468494 (13)	0.023977 (11)	0.03249 (8)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.02651 (16)	0.04470 (19)	0.02063 (15)	−0.00107 (12)	0.00933 (11)	0.00212 (11)
N2	0.0284 (7)	0.0351 (7)	0.0308 (7)	0.0029 (6)	0.0102 (6)	−0.0009 (6)
N3	0.0290 (7)	0.0309 (8)	0.0314 (7)	0.0022 (6)	0.0108 (6)	0.0003 (6)
C4	0.0300 (8)	0.0380 (9)	0.0322 (8)	0.0014 (7)	0.0115 (7)	−0.0002 (7)
C5	0.0348 (10)	0.0371 (10)	0.0706 (14)	−0.0033 (8)	0.0131 (9)	−0.0069 (10)
C6	0.0356 (10)	0.0357 (10)	0.0624 (13)	0.0052 (8)	0.0122 (9)	−0.0059 (9)
C7	0.0307 (9)	0.0458 (10)	0.0393 (10)	0.0065 (8)	0.0136 (8)	0.0020 (8)
C8	0.0549 (15)	0.108 (2)	0.0508 (14)	0.0288 (15)	0.0284 (11)	0.0071 (14)
C9	0.0361 (11)	0.0804 (17)	0.0656 (15)	0.0069 (11)	0.0042 (10)	−0.0158 (13)
C10	0.0458 (13)	0.0585 (14)	0.111 (2)	0.0187 (11)	0.0306 (14)	0.0262 (15)
N11	0.0327 (7)	0.0366 (7)	0.0237 (6)	0.0043 (6)	0.0125 (6)	0.0010 (6)
N12	0.0338 (8)	0.0285 (7)	0.0265 (7)	0.0039 (6)	0.0148 (6)	0.0029 (6)
C13	0.0307 (8)	0.0318 (8)	0.0231 (7)	−0.0028 (6)	0.0102 (6)	0.0002 (6)
C14	0.0502 (11)	0.0332 (9)	0.0317 (9)	0.0072 (8)	0.0191 (8)	0.0077 (7)
C15	0.0454 (10)	0.0367 (9)	0.0299 (8)	0.0127 (8)	0.0166 (7)	0.0041 (7)
C16	0.0393 (10)	0.0388 (9)	0.0319 (9)	0.0029 (7)	0.0201 (8)	0.0026 (7)
C17	0.0479 (11)	0.0497 (11)	0.0441 (11)	0.0141 (9)	0.0237 (9)	0.0035 (9)
C18	0.092 (2)	0.0581 (14)	0.111 (2)	−0.0127 (14)	0.082 (2)	−0.0027 (15)
C19	0.0680 (16)	0.0860 (17)	0.0318 (10)	0.0301 (13)	0.0146 (10)	−0.0101 (11)
Br20	0.04245 (13)	0.02641 (11)	0.03100 (11)	0.00415 (6)	0.01558 (8)	0.00061 (6)

Geometric parameters (Å, º)

Cu1—N2	2.0094 (14)	N11—C15	1.324 (2)
Cu1—N11	2.0032 (14)	N11—N12	1.355 (2)
Cu1—Br20	3.0280 (2)	N12—C13	1.343 (2)
N2—C6	1.328 (3)	N12—H12	0.80 (2)
N2—N3	1.354 (2)	C13—C14	1.382 (3)
N3—C4	1.345 (2)	C13—C16	1.509 (2)
N3—H3	0.86 (2)	C14—C15	1.395 (3)
C4—C5	1.375 (3)	C14—H14	0.9300
C4—C7	1.508 (2)	C15—H15	0.9300
C5—C6	1.396 (3)	C16—C19	1.526 (3)
C5—H5	0.9300	C16—C17	1.527 (3)
C6—H6	0.9300	C16—C18	1.528 (3)
C7—C8	1.524 (3)	C17—H17A	0.9600
C7—C10	1.526 (3)	C17—H17B	0.9600
C7—C9	1.531 (3)	C17—H17C	0.9600
C8—H8A	0.9600	C18—H18A	0.9600
C8—H8B	0.9600	C18—H18B	0.9600
C8—H8C	0.9600	C18—H18C	0.9600
C9—H9A	0.9600	C19—H19A	0.9600
C9—H9B	0.9600	C19—H19B	0.9600
C9—H9C	0.9600	C19—H19C	0.9600
C10—H10A	0.9600	Br20—H3^i	2.45 (2)
C10—H10B	0.9600	Br20—H12	2.51 (2)
C10—H10C	0.9600
N2—Cu1—N11	92.96 (6)	C7—C10—H10C	109.5
N2—Cu1—Br20	92.62 (4)	H10A—C10—H10C	109.5
N11—Cu1—Br20	88.63 (4)	H10B—C10—H10C	109.5
N2—Cu1—N11^i	87.04 (6)	C15—N11—N12	105.36 (14)
N11^i—Cu1—Br20	91.37 (4)	C15—N11—Cu1	132.97 (12)
N2^i—Cu1—Br20	87.38 (4)	N12—N11—Cu1	119.62 (11)
N2^i—Cu1—N2	180	C13—N12—N11	112.17 (14)
N11^i—Cu1—N11	180	C13—N12—H12	129.9 (15)
Br20^i—Cu1—Br20	180	N11—N12—H12	117.9 (15)
C6—N2—N3	105.17 (14)	N12—C13—C14	106.03 (15)
C6—N2—Cu1	131.92 (13)	N12—C13—C16	123.14 (15)
N3—N2—Cu1	122.46 (11)	C14—C13—C16	130.82 (16)
C4—N3—N2	112.47 (15)	C13—C14—C15	105.72 (15)
C4—N3—H3	131.5 (13)	C13—C14—H14	127.1
N2—N3—H3	115.5 (13)	C15—C14—H14	127.1
N3—C4—C5	105.76 (16)	N11—C15—C14	110.70 (16)
N3—C4—C7	122.76 (16)	N11—C15—H15	124.6
C5—C4—C7	131.36 (18)	C14—C15—H15	124.6
C4—C5—C6	106.18 (18)	C13—C16—C19	108.86 (16)
C4—C5—H5	126.9	C13—C16—C17	111.23 (15)
C6—C5—H5	126.9	C19—C16—C17	109.71 (17)
N2—C6—C5	110.42 (17)	C13—C16—C18	107.78 (16)
N2—C6—H6	124.8	C19—C16—C18	110.2 (2)
C5—C6—H6	124.8	C17—C16—C18	109.06 (19)
C4—C7—C8	108.67 (16)	C16—C17—H17A	109.5
C4—C7—C10	111.25 (17)	C16—C17—H17B	109.5
C8—C7—C10	108.6 (2)	H17A—C17—H17B	109.5
C4—C7—C9	109.05 (17)	C16—C17—H17C	109.5
C8—C7—C9	109.7 (2)	H17A—C17—H17C	109.5
C10—C7—C9	109.5 (2)	H17B—C17—H17C	109.5
C7—C8—H8A	109.5	C16—C18—H18A	109.5
C7—C8—H8B	109.5	C16—C18—H18B	109.5
H8A—C8—H8B	109.5	H18A—C18—H18B	109.5
C7—C8—H8C	109.5	C16—C18—H18C	109.5
H8A—C8—H8C	109.5	H18A—C18—H18C	109.5
H8B—C8—H8C	109.5	H18B—C18—H18C	109.5
C7—C9—H9A	109.5	C16—C19—H19A	109.5
C7—C9—H9B	109.5	C16—C19—H19B	109.5
H9A—C9—H9B	109.5	H19A—C19—H19B	109.5
C7—C9—H9C	109.5	C16—C19—H19C	109.5
H9A—C9—H9C	109.5	H19A—C19—H19C	109.5
H9B—C9—H9C	109.5	H19B—C19—H19C	109.5
C7—C10—H10A	109.5	H3^i—Br20—H12	76.1 (6)
C7—C10—H10B	109.5	H3^i—Br20—Cu1	64.1 (5)
H10A—C10—H10B	109.5	H12—Br20—Cu1	63.0 (5)

Symmetry code: (i) −x+1/2, −y+1/2, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3···Br20^i	0.86 (2)	2.45 (2)	3.2195 (15)	148 (2)
N12—H12···Br20	0.80 (2)	2.51 (2)	3.2275 (15)	149 (2)

Symmetry code: (i) −x+1/2, −y+1/2, −z.