Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103001483/gd1241sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103001483/gd1241Isup2.hkl |
CCDC reference: 207992
Equimolar amounts of zinc (0.123 g), CBr4 (0.626 g) and (-)sparteine (0.433 ml) were mixed in DMSO (5.376 ml). The mixture was heated at 333 K for 30 min and then filtered. The first drop of crystals was collected after 2 days (0.219 g, yield 25.3%, m.p. 566 K). These crystals exhibited a characteristic hexagonal plate habit and were identified as (I). Further crystallization produced small quantities of the orthorhombic polymorph, which can be distinguished from (I) on the basis of its quite isotropic block habit.
Data collection: XSCANS 2.21 (Siemens, 1996); cell refinement: XSCANS 2.21 (Siemens, 1996); data reduction: XSCANS 2.21 (Siemens, 1996); program(s) used to solve structure: SHELXTL-Plus (Sheldrick, 1998); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL-Plus (Sheldrick, 1998) and Mercury 1.1 (CCDC, 2002); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).
[ZnBr2(C15H26N2)] | Z = 1 |
Mr = 459.57 | F(000) = 230 |
Triclinic, P1 | Dx = 1.766 Mg m−3 |
Hall symbol: P 1 | Melting point: 566 K |
a = 7.4715 (6) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 7.7082 (7) Å | Cell parameters from 84 reflections |
c = 9.1435 (6) Å | θ = 5.0–13.0° |
α = 97.429 (6)° | µ = 6.04 mm−1 |
β = 112.808 (5)° | T = 296 K |
γ = 110.666 (6)° | Prism, colorless |
V = 432.02 (7) Å3 | 0.60 × 0.24 × 0.16 mm |
Bruker P4 diffractometer | 4244 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.048 |
Graphite monochromator | θmax = 30.0°, θmin = 2.5° |
2θ/ω scans | h = −9→10 |
Absorption correction: ψ-scan XSCANS 2.21 (Siemens, 1996) | k = −10→10 |
Tmin = 0.254, Tmax = 0.381 | l = −12→12 |
4908 measured reflections | 3 standard reflections every 97 reflections |
4908 independent reflections | intensity decay: 1% |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.040 | w = 1/[σ2(Fo2) + (0.0364P)2 + 0.6283P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.097 | (Δ/σ)max < 0.001 |
S = 1.04 | Δρmax = 0.53 e Å−3 |
4908 reflections | Δρmin = −0.77 e Å−3 |
182 parameters | Extinction correction: SHELXL97, Fc* = kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
3 restraints | Extinction coefficient: 0.0083 (17) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983); 2436 Friedel pairs |
Secondary atom site location: difference Fourier map | Absolute structure parameter: −0.016 (13) |
[ZnBr2(C15H26N2)] | γ = 110.666 (6)° |
Mr = 459.57 | V = 432.02 (7) Å3 |
Triclinic, P1 | Z = 1 |
a = 7.4715 (6) Å | Mo Kα radiation |
b = 7.7082 (7) Å | µ = 6.04 mm−1 |
c = 9.1435 (6) Å | T = 296 K |
α = 97.429 (6)° | 0.60 × 0.24 × 0.16 mm |
β = 112.808 (5)° |
Bruker P4 diffractometer | 4244 reflections with I > 2σ(I) |
Absorption correction: ψ-scan XSCANS 2.21 (Siemens, 1996) | Rint = 0.048 |
Tmin = 0.254, Tmax = 0.381 | 3 standard reflections every 97 reflections |
4908 measured reflections | intensity decay: 1% |
4908 independent reflections |
R[F2 > 2σ(F2)] = 0.040 | H-atom parameters constrained |
wR(F2) = 0.097 | Δρmax = 0.53 e Å−3 |
S = 1.04 | Δρmin = −0.77 e Å−3 |
4908 reflections | Absolute structure: Flack (1983); 2436 Friedel pairs |
182 parameters | Absolute structure parameter: −0.016 (13) |
3 restraints |
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. |
x | y | z | Uiso*/Ueq | ||
Zn1 | 0.64020 (6) | 0.60790 (6) | 0.13464 (5) | 0.03135 (13) | |
Br1 | 0.94293 (9) | 0.90078 (8) | 0.19208 (8) | 0.05669 (18) | |
Br2 | 0.31099 (9) | 0.57007 (9) | −0.07858 (7) | 0.05857 (18) | |
N1 | 0.7406 (6) | 0.3888 (5) | 0.1528 (5) | 0.0310 (7) | |
C2 | 0.7964 (10) | 0.3414 (8) | 0.0173 (7) | 0.0465 (12) | |
H2A | 0.8568 | 0.2488 | 0.0362 | 0.056* | |
H2B | 0.9056 | 0.4589 | 0.0204 | 0.056* | |
C3 | 0.6019 (11) | 0.2570 (9) | −0.1510 (7) | 0.0509 (13) | |
H3A | 0.6430 | 0.2234 | −0.2352 | 0.061* | |
H3B | 0.5501 | 0.3544 | −0.1742 | 0.061* | |
C4 | 0.4189 (11) | 0.0749 (9) | −0.1623 (7) | 0.0585 (16) | |
H4A | 0.2899 | 0.0351 | −0.2671 | 0.070* | |
H4B | 0.4605 | −0.0310 | −0.1595 | 0.070* | |
C5 | 0.3705 (8) | 0.1160 (7) | −0.0182 (6) | 0.0412 (11) | |
H5A | 0.2676 | −0.0045 | −0.0193 | 0.049* | |
H5B | 0.3050 | 0.2053 | −0.0322 | 0.049* | |
C6 | 0.5745 (7) | 0.2039 (6) | 0.1488 (6) | 0.0330 (9) | |
H6A | 0.6362 | 0.1103 | 0.1578 | 0.040* | |
C7 | 0.5350 (8) | 0.2371 (7) | 0.3007 (6) | 0.0350 (9) | |
H7A | 0.4297 | 0.1122 | 0.2937 | 0.042* | |
C8 | 0.9051 (7) | 0.4956 (7) | 0.4687 (6) | 0.0366 (10) | |
H8A | 1.0435 | 0.5350 | 0.5675 | 0.044* | |
N9 | 0.6050 (6) | 0.5912 (5) | 0.3492 (4) | 0.0282 (7) | |
C10 | 0.5210 (8) | 0.7348 (7) | 0.3770 (6) | 0.0387 (10) | |
H10A | 0.3732 | 0.6851 | 0.2901 | 0.046* | |
H10B | 0.6058 | 0.8552 | 0.3649 | 0.046* | |
C11 | 0.5246 (10) | 0.7812 (9) | 0.5452 (7) | 0.0511 (13) | |
H11A | 0.4759 | 0.8814 | 0.5544 | 0.061* | |
H11B | 0.4263 | 0.6655 | 0.5538 | 0.061* | |
C12 | 0.7514 (11) | 0.8511 (10) | 0.6861 (7) | 0.0550 (15) | |
H12A | 0.7504 | 0.8720 | 0.7926 | 0.066* | |
H12B | 0.8478 | 0.9734 | 0.6845 | 0.066* | |
C13 | 0.8302 (9) | 0.6960 (9) | 0.6631 (6) | 0.0452 (13) | |
H13A | 0.7398 | 0.5777 | 0.6743 | 0.054* | |
H13B | 0.9771 | 0.7416 | 0.7504 | 0.054* | |
C14 | 0.8245 (7) | 0.6492 (6) | 0.4918 (5) | 0.0315 (8) | |
H14A | 0.9245 | 0.7695 | 0.4878 | 0.038* | |
C15 | 0.9415 (7) | 0.4698 (7) | 0.3149 (6) | 0.0374 (10) | |
H15A | 1.0399 | 0.5955 | 0.3198 | 0.045* | |
H15B | 1.0109 | 0.3840 | 0.3192 | 0.045* | |
C16 | 0.4477 (7) | 0.3884 (6) | 0.3169 (5) | 0.0322 (9) | |
H16A | 0.3164 | 0.3525 | 0.2149 | 0.039* | |
H16B | 0.4104 | 0.3852 | 0.4074 | 0.039* | |
C17 | 0.7462 (9) | 0.2974 (7) | 0.4580 (6) | 0.0408 (10) | |
H17A | 0.8019 | 0.2021 | 0.4514 | 0.049* | |
H17B | 0.7233 | 0.3076 | 0.5555 | 0.049* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Zn1 | 0.0304 (3) | 0.0336 (3) | 0.0299 (2) | 0.0126 (2) | 0.0142 (2) | 0.0132 (2) |
Br1 | 0.0473 (3) | 0.0442 (3) | 0.0787 (4) | 0.0112 (2) | 0.0343 (3) | 0.0297 (3) |
Br2 | 0.0509 (3) | 0.0706 (4) | 0.0441 (3) | 0.0325 (3) | 0.0055 (2) | 0.0242 (3) |
N1 | 0.0305 (17) | 0.0320 (18) | 0.0334 (18) | 0.0116 (15) | 0.0196 (15) | 0.0106 (15) |
C2 | 0.057 (3) | 0.048 (3) | 0.056 (3) | 0.027 (3) | 0.043 (3) | 0.020 (2) |
C3 | 0.069 (4) | 0.051 (3) | 0.043 (3) | 0.021 (3) | 0.040 (3) | 0.014 (2) |
C4 | 0.070 (4) | 0.049 (3) | 0.042 (3) | 0.009 (3) | 0.032 (3) | 0.000 (2) |
C5 | 0.039 (2) | 0.034 (2) | 0.032 (2) | 0.0028 (19) | 0.0141 (19) | 0.0004 (18) |
C6 | 0.037 (2) | 0.028 (2) | 0.041 (2) | 0.0143 (17) | 0.0235 (19) | 0.0094 (17) |
C7 | 0.037 (2) | 0.033 (2) | 0.036 (2) | 0.0103 (18) | 0.0216 (19) | 0.0135 (18) |
C8 | 0.030 (2) | 0.045 (3) | 0.031 (2) | 0.018 (2) | 0.0086 (17) | 0.0164 (19) |
N9 | 0.0254 (16) | 0.0323 (18) | 0.0232 (15) | 0.0118 (14) | 0.0092 (13) | 0.0071 (13) |
C10 | 0.035 (2) | 0.040 (3) | 0.037 (2) | 0.018 (2) | 0.0152 (19) | 0.0048 (19) |
C11 | 0.054 (3) | 0.058 (3) | 0.044 (3) | 0.026 (3) | 0.027 (3) | 0.005 (2) |
C12 | 0.062 (4) | 0.056 (4) | 0.033 (2) | 0.021 (3) | 0.018 (2) | −0.001 (2) |
C13 | 0.040 (3) | 0.052 (3) | 0.025 (2) | 0.011 (2) | 0.0095 (19) | 0.003 (2) |
C14 | 0.0234 (18) | 0.034 (2) | 0.0262 (18) | 0.0062 (16) | 0.0075 (15) | 0.0075 (16) |
C15 | 0.027 (2) | 0.044 (3) | 0.044 (2) | 0.0180 (19) | 0.0156 (18) | 0.016 (2) |
C16 | 0.0245 (19) | 0.036 (2) | 0.030 (2) | 0.0067 (17) | 0.0148 (16) | 0.0072 (17) |
C17 | 0.049 (3) | 0.040 (2) | 0.039 (2) | 0.021 (2) | 0.021 (2) | 0.022 (2) |
Zn1—N1 | 2.077 (4) | C8—C14 | 1.532 (7) |
Zn1—N9 | 2.092 (3) | C8—C15 | 1.534 (7) |
Zn1—Br2 | 2.3590 (7) | C8—H8A | 0.9800 |
Zn1—Br1 | 2.3784 (7) | N9—C10 | 1.492 (6) |
N1—C15 | 1.488 (6) | N9—C16 | 1.492 (6) |
N1—C2 | 1.494 (6) | N9—C14 | 1.504 (5) |
N1—C6 | 1.508 (6) | C10—C11 | 1.521 (7) |
C2—C3 | 1.498 (9) | C10—H10A | 0.9700 |
C2—H2A | 0.9700 | C10—H10B | 0.9700 |
C2—H2B | 0.9700 | C11—C12 | 1.518 (9) |
C3—C4 | 1.533 (8) | C11—H11A | 0.9700 |
C3—H3A | 0.9700 | C11—H11B | 0.9700 |
C3—H3B | 0.9700 | C12—C13 | 1.532 (9) |
C4—C5 | 1.520 (7) | C12—H12A | 0.9700 |
C4—H4A | 0.9700 | C12—H12B | 0.9700 |
C4—H4B | 0.9700 | C13—C14 | 1.542 (6) |
C5—C6 | 1.521 (7) | C13—H13A | 0.9700 |
C5—H5A | 0.9700 | C13—H13B | 0.9700 |
C5—H5B | 0.9700 | C14—H14A | 0.9800 |
C6—C7 | 1.537 (6) | C15—H15A | 0.9700 |
C6—H6A | 0.9800 | C15—H15B | 0.9700 |
C7—C17 | 1.525 (7) | C16—H16A | 0.9700 |
C7—C16 | 1.541 (7) | C16—H16B | 0.9700 |
C7—H7A | 0.9800 | C17—H17A | 0.9700 |
C8—C17 | 1.531 (7) | C17—H17B | 0.9700 |
Br2···H8Ai | 2.986 | H5A···H13Biii | 2.317 |
H3A···H17Bii | 2.319 | H10B···H17Aiv | 2.390 |
N1—Zn1—N9 | 88.66 (14) | C10—N9—C16 | 111.5 (3) |
N1—Zn1—Br2 | 124.28 (11) | C10—N9—C14 | 110.6 (3) |
N9—Zn1—Br2 | 108.51 (10) | C16—N9—C14 | 112.5 (3) |
N1—Zn1—Br1 | 107.81 (10) | C10—N9—Zn1 | 105.3 (3) |
N9—Zn1—Br1 | 110.88 (10) | C16—N9—Zn1 | 108.5 (2) |
Br2—Zn1—Br1 | 113.69 (3) | C14—N9—Zn1 | 108.1 (2) |
C15—N1—C2 | 108.0 (4) | N9—C10—C11 | 115.6 (4) |
C15—N1—C6 | 110.0 (3) | N9—C10—H10A | 108.4 |
C2—N1—C6 | 108.7 (4) | C11—C10—H10A | 108.4 |
C15—N1—Zn1 | 105.6 (3) | N9—C10—H10B | 108.4 |
C2—N1—Zn1 | 111.5 (3) | C11—C10—H10B | 108.4 |
C6—N1—Zn1 | 112.9 (3) | H10A—C10—H10B | 107.5 |
N1—C2—C3 | 111.5 (5) | C12—C11—C10 | 110.5 (5) |
N1—C2—H2A | 109.3 | C12—C11—H11A | 109.5 |
C3—C2—H2A | 109.3 | C10—C11—H11A | 109.5 |
N1—C2—H2B | 109.3 | C12—C11—H11B | 109.5 |
C3—C2—H2B | 109.3 | C10—C11—H11B | 109.5 |
H2A—C2—H2B | 108.0 | H11A—C11—H11B | 108.1 |
C2—C3—C4 | 112.1 (5) | C11—C12—C13 | 108.7 (5) |
C2—C3—H3A | 109.2 | C11—C12—H12A | 110.0 |
C4—C3—H3A | 109.2 | C13—C12—H12A | 110.0 |
C2—C3—H3B | 109.2 | C11—C12—H12B | 110.0 |
C4—C3—H3B | 109.2 | C13—C12—H12B | 110.0 |
H3A—C3—H3B | 107.9 | H12A—C12—H12B | 108.3 |
C5—C4—C3 | 110.5 (4) | C12—C13—C14 | 112.2 (4) |
C5—C4—H4A | 109.6 | C12—C13—H13A | 109.2 |
C3—C4—H4A | 109.6 | C14—C13—H13A | 109.2 |
C5—C4—H4B | 109.6 | C12—C13—H13B | 109.2 |
C3—C4—H4B | 109.6 | C14—C13—H13B | 109.2 |
H4A—C4—H4B | 108.1 | H13A—C13—H13B | 107.9 |
C4—C5—C6 | 111.5 (5) | N9—C14—C8 | 110.7 (3) |
C4—C5—H5A | 109.3 | N9—C14—C13 | 112.5 (4) |
C6—C5—H5A | 109.3 | C8—C14—C13 | 112.5 (4) |
C4—C5—H5B | 109.3 | N9—C14—H14A | 106.9 |
C6—C5—H5B | 109.3 | C8—C14—H14A | 106.9 |
H5A—C5—H5B | 108.0 | C13—C14—H14A | 106.9 |
N1—C6—C5 | 110.7 (4) | N1—C15—C8 | 114.4 (4) |
N1—C6—C7 | 111.1 (3) | N1—C15—H15A | 108.7 |
C5—C6—C7 | 114.2 (4) | C8—C15—H15A | 108.7 |
N1—C6—H6A | 106.8 | N1—C15—H15B | 108.7 |
C5—C6—H6A | 106.8 | C8—C15—H15B | 108.7 |
C7—C6—H6A | 106.8 | H15A—C15—H15B | 107.6 |
C17—C7—C6 | 108.4 (4) | N9—C16—C7 | 113.3 (3) |
C17—C7—C16 | 109.1 (4) | N9—C16—H16A | 108.9 |
C6—C7—C16 | 115.8 (4) | C7—C16—H16A | 108.9 |
C17—C7—H7A | 107.7 | N9—C16—H16B | 108.9 |
C6—C7—H7A | 107.7 | C7—C16—H16B | 108.9 |
C16—C7—H7A | 107.7 | H16A—C16—H16B | 107.7 |
C17—C8—C14 | 110.3 (4) | C7—C17—C8 | 106.6 (4) |
C17—C8—C15 | 108.3 (4) | C7—C17—H17A | 110.4 |
C14—C8—C15 | 114.7 (4) | C8—C17—H17A | 110.4 |
C17—C8—H8A | 107.8 | C7—C17—H17B | 110.4 |
C14—C8—H8A | 107.8 | C8—C17—H17B | 110.4 |
C15—C8—H8A | 107.8 | H17A—C17—H17B | 108.6 |
N9—Zn1—N1—C15 | −61.8 (3) | Br2—Zn1—N9—C14 | −170.5 (2) |
Br2—Zn1—N1—C15 | −173.4 (2) | Br1—Zn1—N9—C14 | −44.9 (3) |
Br1—Zn1—N1—C15 | 49.7 (3) | C16—N9—C10—C11 | 74.6 (5) |
N9—Zn1—N1—C2 | −178.8 (3) | C14—N9—C10—C11 | −51.5 (5) |
Br2—Zn1—N1—C2 | 69.6 (4) | Zn1—N9—C10—C11 | −168.0 (4) |
Br1—Zn1—N1—C2 | −67.3 (3) | N9—C10—C11—C12 | 55.6 (7) |
N9—Zn1—N1—C6 | 58.4 (3) | C10—C11—C12—C13 | −55.8 (7) |
Br2—Zn1—N1—C6 | −53.2 (3) | C11—C12—C13—C14 | 56.8 (6) |
Br1—Zn1—N1—C6 | 170.0 (2) | C10—N9—C14—C8 | 176.6 (4) |
C15—N1—C2—C3 | 179.5 (4) | C16—N9—C14—C8 | 51.1 (4) |
C6—N1—C2—C3 | 60.2 (6) | Zn1—N9—C14—C8 | −68.7 (4) |
Zn1—N1—C2—C3 | −64.9 (5) | C10—N9—C14—C13 | 49.7 (5) |
N1—C2—C3—C4 | −56.7 (7) | C16—N9—C14—C13 | −75.7 (5) |
C2—C3—C4—C5 | 51.6 (7) | Zn1—N9—C14—C13 | 164.5 (3) |
C3—C4—C5—C6 | −51.9 (7) | C17—C8—C14—N9 | −58.9 (5) |
C15—N1—C6—C5 | −178.4 (4) | C15—C8—C14—N9 | 63.6 (5) |
C2—N1—C6—C5 | −60.3 (5) | C17—C8—C14—C13 | 67.9 (5) |
Zn1—N1—C6—C5 | 64.0 (4) | C15—C8—C14—C13 | −169.6 (4) |
C15—N1—C6—C7 | 53.7 (5) | C12—C13—C14—N9 | −54.7 (5) |
C2—N1—C6—C7 | 171.7 (4) | C12—C13—C14—C8 | 179.5 (4) |
Zn1—N1—C6—C7 | −64.0 (4) | C2—N1—C15—C8 | −170.7 (4) |
C4—C5—C6—N1 | 57.4 (5) | C6—N1—C15—C8 | −52.2 (5) |
C4—C5—C6—C7 | −176.3 (4) | Zn1—N1—C15—C8 | 69.9 (4) |
N1—C6—C7—C17 | −62.0 (5) | C17—C8—C15—N1 | 57.3 (5) |
C5—C6—C7—C17 | 172.0 (4) | C14—C8—C15—N1 | −66.3 (5) |
N1—C6—C7—C16 | 61.0 (5) | C10—N9—C16—C7 | −175.6 (4) |
C5—C6—C7—C16 | −65.0 (5) | C14—N9—C16—C7 | −50.7 (5) |
N1—Zn1—N9—C10 | −178.1 (3) | Zn1—N9—C16—C7 | 68.9 (4) |
Br2—Zn1—N9—C10 | −52.2 (3) | C17—C7—C16—N9 | 56.4 (5) |
Br1—Zn1—N9—C10 | 73.3 (3) | C6—C7—C16—N9 | −66.2 (5) |
N1—Zn1—N9—C16 | −58.6 (3) | C6—C7—C17—C8 | 65.4 (5) |
Br2—Zn1—N9—C16 | 67.3 (3) | C16—C7—C17—C8 | −61.6 (5) |
Br1—Zn1—N9—C16 | −167.2 (2) | C14—C8—C17—C7 | 64.2 (5) |
N1—Zn1—N9—C14 | 63.6 (3) | C15—C8—C17—C7 | −62.0 (5) |
Symmetry codes: (i) x−1, y, z−1; (ii) x, y, z−1; (iii) x−1, y−1, z−1; (iv) x, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | [ZnBr2(C15H26N2)] |
Mr | 459.57 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 296 |
a, b, c (Å) | 7.4715 (6), 7.7082 (7), 9.1435 (6) |
α, β, γ (°) | 97.429 (6), 112.808 (5), 110.666 (6) |
V (Å3) | 432.02 (7) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 6.04 |
Crystal size (mm) | 0.60 × 0.24 × 0.16 |
Data collection | |
Diffractometer | Bruker P4 diffractometer |
Absorption correction | ψ-scan XSCANS 2.21 (Siemens, 1996) |
Tmin, Tmax | 0.254, 0.381 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4908, 4908, 4244 |
Rint | 0.048 |
(sin θ/λ)max (Å−1) | 0.703 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.040, 0.097, 1.04 |
No. of reflections | 4908 |
No. of parameters | 182 |
No. of restraints | 3 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.53, −0.77 |
Absolute structure | Flack (1983); 2436 Friedel pairs |
Absolute structure parameter | −0.016 (13) |
Computer programs: XSCANS 2.21 (Siemens, 1996), SHELXL97 (Sheldrick, 1997), SHELXTL-Plus (Sheldrick, 1998) and Mercury 1.1 (CCDC, 2002).
Br2···H8Ai | 2.986 | H5A···H13Biii | 2.317 |
H3A···H17Bii | 2.319 | H10B···H17Aiv | 2.390 |
Symmetry codes: (i) x−1, y, z−1; (ii) x, y, z−1; (iii) x−1, y−1, z−1; (iv) x, y+1, z. |
The correlation between the tetrahedral coordination of the CuII ion in type 1 blue copper proteins and some unique spectroscopic features reported for these proteins is a well established fact (Krishnan, 1978; Colman et al., 1978; Solomon et al., 1992; Holland & Tolman, 2000). Well studied examples are the intense absorption observed in electronic spectra near 600 nm (ε ≈ 5000 M−1 cm−1) and the small Cu hyperfine splitting observed in EPR spectra (A// < 70 × 10−4 cm−1), which is reduced to less than half the value observed in common CuII coordination complexes.
In this context, numerous CuII complexes containing sparteine as a ligand have been synthesized, with the hope of accurately modeling spectroscopic and structural features of the catalytic center of these proteins (Boschmann et al., 1974; Choi et al., 1975; Kim et al., 2001). For the X-ray-characterized complexes, the expected distorted tetrahedral geometry has been observed in most cases, although the spectroscopic characteristics of these complexes did not always fit correctly with those of the proteins (Childers et al., 1975; Lopez et al., 1998; Choi et al., 1995; Lee et al., 2000).
During the course of our work dealing with this class of compounds, we prepared by direct synthesis a series of complexes with the general formula M(SP)X2 where SP is the naturally occurring (-)-sparteine ligand, X = Cl or Br, and M = CuII or ZnII. The CuII complexes are intended to be used for modeling the active site of type 1 blue copper proteins (structurally and spectroscopically), while the ZnII complexes are used as diluting agents for measuring the hyperfine, and eventually the super-hyperfine, coupling by electron paramagnetic resonance (EPR) on powdered samples. To validate the EPR, isostructurality between Cu and Zn complexes has first to be established by X-ray diffraction. In the case of X = Br, both metals yielded two isomorphous polymorphic crystalline phases, one in space group P1 and one in P212121, when a direct synthesis was used, i.e. using metallic copper or zinc as a starting material (see experimental section). The Zn complex here described, (I), corresponds to the triclinic polymorph of Zn(SP)Br2. The orthorhombic phase, which is synthesized using zinc(II) bromide as a starting material, was reported very recently by Lee et al. (2002).
The molecular structure of (I) is, within the experimental s.u. values, identical (Fig. 1) to that of the reported orthorhombic phase: the r.m.s. deviation between the two structures is 0.0362 Å (excluding H atoms). The largest observed deviation for the fit, 0.082 Å, arises from the Br atoms.
In contrast, the symmetry change induces dramatic differences for the packing structures. The orthorhombic phase is stabilized through two intermolecular contacts involving both the Br atoms and the methylene or methine H atoms belonging to the SP ligands of symmetry-related molecules: Zn—Br1···H15Bi [contact = 2.910 Å, angle = 156.0°; (i) 1/2 − x, 1 − y, −1/2 + z] and Zn—Br2···H7ii (contact = 2.933 Å, angle = 160.0°; (ii) 1/2 − x, −y, −1/2 + z). The Br···H separations are then 0.14 and 0.12 Å shorter than the van der Waals distance. This arrangement generates layers of connected molecules, with the layers normal to the a axis of the orthorhombic cell (Fig. 2).
In the case of (I), the only operators available for connecting molecules are axis translations. A single short Br···H contact is observed (Table 1), which corresponds to a relatively weak interaction, with a difference from the van der Waals distance of 0.06 Å; the resulting network of interconnected molecules is one dimensional (Fig. 3). In spite of these weak contacts, the packing index (Spek, 2003) is lowered from 0.683 for the orthorhombic phase to 0.681 for (I). This more efficient packing for (I) is confirmed by the analysis of the intermolecular H···H contacts. The shortest contact observed for the orthorhombic phase is H3A···H11Bi = 2.403 Å [(i) 1 + x, y, z], i.e. a separation equal to the van der Waals distance. However, for (I), the shortest H···H separation is 2.317 Å (Table 1), which corresponds to an actual H···H contact (Fig. 3).
Finally, the metal–metal separations are significantly affected by the symmetry. The observed distances are Zn···Zni = 6.534 Å [(i) 1/2 + x, 1/2 − y, −z] in the orthorhombic case versus Zn···Znii = 7.4715 (6) Å [(ii) 1 + x, y, z] for (I). This difference of ca 1 Å is unimportant for the ZnII-based compounds but essential for the corresponding CuII-based compounds that are intended for modeling. Considering that the metal centers should be magnetically isolated in the native proteins, the triclinic phase seems to be a more suitable magnetic model than the orthorhombic one.