Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270106002575/bm1623sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270106002575/bm1623Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270106002575/bm1623IIsup3.hkl |
CCDC references: 605705; 605706
For (I), an ethanol solution (15 ml) of K[HB(Pz)_{3}] (0.100 g, 0.396 mmol) was added to an ethanol solution (15 ml) of anhydrous MgCl_{2} (0.019 g, 0.198 mmol). The resulting solution was stirred for 30 min. The solution was filtered, and the filtrate was evaporated to dryness under N_{2} atmosphere to give a white powder (0.091 g, 87% yield). Recrystallization from dry chloroform afforded colourless blocks suitable for X-ray analysis. ^{1}H NMR (CDCl_{3}, p.p.m.): δ 6.06 (t, 6H, ^{3}J = 2.0 Hz, H-4), 7.15, 7.70 (d, d, 6H each, ^{3}J = 1.8 Hz, H-3,5). Complex (II) was prepared and recrystallized as for (I), using K[HB(Pz)_{3}] (0.100 g, 0.396 mmol) and anhydrous CaCl_{2} (0.022 g, 0.198 mmol), to give a white powder (0.099 g, 92% yield). ^{1}H NMR (CDCl_{3}, p.p.m.): δ 6.15 (t, 6H, ^{3}J = 1.9 Hz, H-4), 7.51, 7.75 (d, d, 6H each, ^{3}J = 1.8 and 2.2 Hz, H-3,5).
All H atoms were refined as riding on their parent atoms, with B—H and C—H distances using in the range 0.98 Å to 0.93 Å, and with U_{iso}(H) = 1.5U_{eq}(B) for B—H and 1.2U_{eq}(C) for C—H.
For both compounds, data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: Mercury 1.4 (Bruno et al., 2002); software used to prepare material for publication: SHELXL97 and WinGX2003 (Farrugia, 1999).
[Mg(C_{9}H_{10}BN_{6})_{2}]·2CHCl_{3} | D_{x} = 1.550 Mg m^{−}^{3} |
M_{r} = 689.13 | Mo Kα radiation, λ = 0.71073 Å |
Cubic, Pa3 | Cell parameters from 600 reflections |
Hall symbol: -P 2ac 2ab 3 | θ = 20–25° |
a = 14.3475 (12) Å | µ = 0.64 mm^{−}^{1} |
V = 2953.4 (4) Å^{3} | T = 100 K |
Z = 4 | Block, colorless |
F(000) = 1400 | 0.20 × 0.12 × 0.09 mm |
Bruker SMART CCD area-detector diffractometer | 944 reflections with I > 2σ(I) |
Graphite monochromator | R_{int} = 0.055 |
ϕ and ω scans | θ_{max} = 26.0°, θ_{min} = 2.5° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −17→14 |
T_{min} = 0.883, T_{max} = 0.945 | k = −17→17 |
15868 measured reflections | l = −11→17 |
969 independent reflections |
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})] = 0.060 | Hydrogen site location: inferred from neighbouring sites |
wR(F^{2}) = 0.124 | H-atom parameters constrained |
S = 1.22 | w = 1/[σ^{2}(F_{o}^{2}) + (0.0339P)^{2} + 10.6109P] where P = (F_{o}^{2} + 2F_{c}^{2})/3 |
969 reflections | (Δ/σ)_{max} < 0.001 |
63 parameters | Δρ_{max} = 0.39 e Å^{−}^{3} |
0 restraints | Δρ_{min} = −0.36 e Å^{−}^{3} |
[Mg(C_{9}H_{10}BN_{6})_{2}]·2CHCl_{3} | Z = 4 |
M_{r} = 689.13 | Mo Kα radiation |
Cubic, Pa3 | µ = 0.64 mm^{−}^{1} |
a = 14.3475 (12) Å | T = 100 K |
V = 2953.4 (4) Å^{3} | 0.20 × 0.12 × 0.09 mm |
Bruker SMART CCD area-detector diffractometer | 969 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 944 reflections with I > 2σ(I) |
T_{min} = 0.883, T_{max} = 0.945 | R_{int} = 0.055 |
15868 measured reflections |
R[F^{2} > 2σ(F^{2})] = 0.060 | 0 restraints |
wR(F^{2}) = 0.124 | H-atom parameters constrained |
S = 1.22 | w = 1/[σ^{2}(F_{o}^{2}) + (0.0339P)^{2} + 10.6109P] where P = (F_{o}^{2} + 2F_{c}^{2})/3 |
969 reflections | Δρ_{max} = 0.39 e Å^{−}^{3} |
63 parameters | Δρ_{min} = −0.36 e Å^{−}^{3} |
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles |
Refinement. Refinement of F^{2} against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F^{2}, conventional R-factors R are based on F, with F set to zero for negative F^{2}. The threshold expression of F^{2} > σ(F^{2}) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F^{2} 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 | U_{iso}*/U_{eq} | ||
Mg | 0.50000 | 0.50000 | 0.50000 | 0.0091 (3) | |
N1 | 0.49046 (18) | 0.49637 (19) | 0.34889 (19) | 0.0120 (8) | |
N2 | 0.43289 (18) | 0.43260 (18) | 0.30933 (18) | 0.0091 (7) | |
C3 | 0.4397 (2) | 0.4362 (2) | 0.2163 (2) | 0.0137 (9) | |
C4 | 0.5035 (2) | 0.5043 (3) | 0.1935 (2) | 0.0163 (10) | |
C5 | 0.5332 (2) | 0.5398 (2) | 0.2789 (2) | 0.0151 (9) | |
B1 | 0.3696 (2) | 0.3696 (2) | 0.3696 (2) | 0.0113 (7) | |
Cl1 | 0.28234 (6) | 0.22160 (6) | 0.11889 (6) | 0.0224 (3) | |
C6 | 0.1855 (3) | 0.1855 (3) | 0.1855 (3) | 0.0170 (7) | |
H1 | 0.33018 | 0.33018 | 0.33018 | 0.0135* | |
H3 | 0.40693 | 0.39921 | 0.17437 | 0.0164* | |
H4 | 0.52249 | 0.52243 | 0.13423 | 0.0195* | |
H5 | 0.57681 | 0.58726 | 0.28595 | 0.0181* | |
H6 | 0.14604 | 0.14604 | 0.14604 | 0.0204* |
U^{11} | U^{22} | U^{33} | U^{12} | U^{13} | U^{23} | |
Mg | 0.0091 (5) | 0.0091 (5) | 0.0091 (5) | −0.0005 (6) | −0.0005 (6) | −0.0005 (6) |
N1 | 0.0093 (13) | 0.0129 (13) | 0.0138 (13) | −0.0009 (10) | −0.0010 (11) | −0.0009 (11) |
N2 | 0.0099 (13) | 0.0085 (12) | 0.0090 (13) | 0.0003 (10) | −0.0018 (10) | −0.0020 (10) |
C3 | 0.0162 (16) | 0.0154 (16) | 0.0094 (15) | 0.0020 (13) | −0.0007 (13) | −0.0020 (12) |
C4 | 0.0187 (17) | 0.0183 (17) | 0.0118 (16) | −0.0010 (14) | 0.0026 (13) | 0.0031 (13) |
C5 | 0.0118 (16) | 0.0136 (16) | 0.0198 (17) | −0.0022 (13) | 0.0013 (13) | 0.0017 (13) |
B1 | 0.0113 (12) | 0.0113 (12) | 0.0113 (12) | −0.0039 (13) | −0.0039 (13) | −0.0039 (13) |
Cl1 | 0.0248 (5) | 0.0210 (5) | 0.0213 (5) | 0.0009 (3) | 0.0087 (3) | 0.0009 (3) |
C6 | 0.0170 (12) | 0.0170 (12) | 0.0170 (12) | 0.0001 (14) | 0.0001 (14) | 0.0001 (14) |
Mg—N1 | 2.173 (3) | C3—H3 | 0.9300 |
N1—C5 | 1.331 (4) | C4—H4 | 0.9300 |
N1—N2 | 1.357 (4) | C5—H5 | 0.9300 |
N2—C3 | 1.339 (4) | C6—H6 | 0.9800 |
N2—B1 | 1.546 (4) | B1—H1 | 0.9800 |
C3—C4 | 1.378 (5) | Cl1—C6 | 1.764 (4) |
C4—C5 | 1.394 (4) | ||
Cl1···N2^{i} | 3.459 (3) | N2···Cl1^{x} | 3.494 (3) |
Cl1···N2^{ii} | 3.494 (3) | C3···Cl1^{x} | 3.623 (3) |
Cl1···C3^{ii} | 3.623 (3) | C3···Cl1^{ix} | 3.504 (3) |
Cl1···C3^{i} | 3.504 (3) | C3···H4^{iii} | 3.0400 |
Cl1···H5^{iii} | 3.0900 | C4···H6^{xi} | 3.0300 |
Cl1···H5^{iv} | 3.1100 | C4···H6^{xii} | 3.0300 |
N1···N1^{v} | 3.206 (4) | C4···H6^{x} | 3.0300 |
N1···N1^{vi} | 2.934 (4) | H3···H4^{iii} | 2.5200 |
N1···N2^{vi} | 3.004 (4) | H4···C3^{xiii} | 3.0400 |
N1···N1^{vii} | 2.934 (4) | H4···H3^{xiii} | 2.5200 |
N1···N2^{vii} | 3.057 (4) | H5···Cl1^{xiii} | 3.0900 |
N1···N1^{viii} | 3.206 (4) | H5···Cl1^{xiv} | 3.1100 |
N2···N1^{vii} | 3.004 (4) | H6···C4^{xv} | 3.0300 |
N2···Cl1^{ix} | 3.459 (3) | H6···C4^{ii} | 3.0300 |
N2···N1^{vi} | 3.057 (4) | H6···C4^{xvi} | 3.0300 |
N1—Mg—N1^{vi} | 84.94 (10) | N2—C3—H3 | 126.00 |
Mg—N1—N2 | 118.15 (19) | C4—C3—H3 | 126.00 |
Mg—N1—C5 | 135.4 (2) | C3—C4—H4 | 128.00 |
N2—N1—C5 | 106.3 (2) | C5—C4—H4 | 128.00 |
N1—N2—C3 | 110.3 (2) | C4—C5—H5 | 125.00 |
N1—N2—B1 | 121.2 (2) | N1—C5—H5 | 125.00 |
C3—N2—B1 | 128.5 (2) | N2—B1—N2^{vii} | 108.2 (2) |
N2—C3—C4 | 108.2 (3) | N2—B1—H1 | 111.00 |
C3—C4—C5 | 104.7 (3) | Cl1—C6—Cl1^{vi} | 110.8 (2) |
N1—C5—C4 | 110.6 (3) | Cl1—C6—H6 | 108.00 |
N1^{vi}—Mg—N1—N2 | −45.3 (2) | C5—N1—N2—B1 | −178.7 (2) |
N1^{vii}—Mg—N1—N2 | 40.1 (2) | Mg—N1—C5—C4 | 175.4 (2) |
N1^{viii}—Mg—N1—N2 | 134.7 (2) | N2—N1—C5—C4 | 0.0 (4) |
N1^{v}—Mg—N1—N2 | −139.9 (2) | N1—N2—C3—C4 | −0.1 (3) |
N1^{vi}—Mg—N1—C5 | 139.8 (3) | N1—N2—B1—N2^{vi} | 55.4 (3) |
N1^{vii}—Mg—N1—C5 | −134.9 (3) | B1—N2—C3—C4 | 178.6 (3) |
N1^{viii}—Mg—N1—C5 | −40.2 (3) | C3—N2—B1—N2^{vii} | 119.9 (3) |
N1^{v}—Mg—N1—C5 | 45.1 (3) | C3—N2—B1—N2^{vi} | −123.2 (3) |
Mg—N1—N2—C3 | −176.28 (19) | N1—N2—B1—N2^{vii} | −61.6 (3) |
Mg—N1—N2—B1 | 5.0 (3) | N2—C3—C4—C5 | 0.0 (4) |
C5—N1—N2—C3 | 0.0 (3) | C3—C4—C5—N1 | 0.0 (4) |
Symmetry codes: (i) y, −z+1/2, x−1/2; (ii) z, −x+1/2, y−1/2; (iii) −z+1/2, −x+1, y−1/2; (iv) −x+1, y−1/2, −z+1/2; (v) −y+1, −z+1, −x+1; (vi) z, x, y; (vii) y, z, x; (viii) −z+1, −x+1, −y+1; (ix) z+1/2, x, −y+1/2; (x) −y+1/2, z+1/2, x; (xi) −x+1/2, y+1/2, z; (xii) −z+1/2, x+1/2, y; (xiii) −y+1, z+1/2, −x+1/2; (xiv) −x+1, y+1/2, −z+1/2; (xv) −x+1/2, y−1/2, z; (xvi) y−1/2, z, −x+1/2. |
[Ca(C_{9}H_{10}BN_{6})_{2}]·2CHCl_{3} | D_{x} = 1.483 Mg m^{−}^{3} |
M_{r} = 704.90 | Mo Kα radiation, λ = 0.71073 Å |
Cubic, Pa3 | Cell parameters from 600 reflections |
Hall symbol: -P 2ac 2ab 3 | θ = 20–25° |
a = 14.6697 (9) Å | µ = 0.74 mm^{−}^{1} |
V = 3156.9 (3) Å^{3} | T = 100 K |
Z = 4 | Block, colorless |
F(000) = 1432 | 0.3 × 0.2 × 0.2 mm |
Bruker SMART CCD area-detector diffractometer | 1272 reflections with I > 2σ(I) |
Graphite monochromator | R_{int} = 0.033 |
ϕ and ω scans | θ_{max} = 28.3°, θ_{min} = 2.4° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −18→18 |
T_{min} = 0.808, T_{max} = 0.866 | k = −18→12 |
17681 measured reflections | l = −19→18 |
1293 independent reflections |
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})] = 0.051 | Hydrogen site location: inferred from neighbouring sites |
wR(F^{2}) = 0.109 | H-atom parameters constrained |
S = 1.31 | w = 1/[σ^{2}(F_{o}^{2}) + (0.0316P)^{2} + 4.1829P] where P = (F_{o}^{2} + 2F_{c}^{2})/3 |
1293 reflections | (Δ/σ)_{max} < 0.001 |
63 parameters | Δρ_{max} = 0.44 e Å^{−}^{3} |
0 restraints | Δρ_{min} = −0.40 e Å^{−}^{3} |
[Ca(C_{9}H_{10}BN_{6})_{2}]·2CHCl_{3} | Z = 4 |
M_{r} = 704.90 | Mo Kα radiation |
Cubic, Pa3 | µ = 0.74 mm^{−}^{1} |
a = 14.6697 (9) Å | T = 100 K |
V = 3156.9 (3) Å^{3} | 0.3 × 0.2 × 0.2 mm |
Bruker SMART CCD area-detector diffractometer | 1293 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1272 reflections with I > 2σ(I) |
T_{min} = 0.808, T_{max} = 0.866 | R_{int} = 0.033 |
17681 measured reflections |
R[F^{2} > 2σ(F^{2})] = 0.051 | 0 restraints |
wR(F^{2}) = 0.109 | H-atom parameters constrained |
S = 1.31 | Δρ_{max} = 0.44 e Å^{−}^{3} |
1293 reflections | Δρ_{min} = −0.40 e Å^{−}^{3} |
63 parameters |
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles |
Refinement. Refinement of F^{2} against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F^{2}, conventional R-factors R are based on F, with F set to zero for negative F^{2}. The threshold expression of F^{2} > σ(F^{2}) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F^{2} 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 | U_{iso}*/U_{eq} | ||
Ca | 0.50000 | 0.50000 | 0.50000 | 0.0141 (1) | |
N1 | 0.48740 (12) | 0.48337 (13) | 0.33608 (12) | 0.0192 (5) | |
N2 | 0.42579 (11) | 0.42280 (11) | 0.30197 (11) | 0.0148 (5) | |
C3 | 0.42747 (16) | 0.42495 (15) | 0.21011 (14) | 0.0207 (6) | |
C4 | 0.49139 (16) | 0.48835 (16) | 0.18296 (15) | 0.0245 (7) | |
C5 | 0.52681 (15) | 0.52263 (16) | 0.26431 (15) | 0.0225 (6) | |
B1 | 0.36350 (15) | 0.36350 (15) | 0.36350 (15) | 0.0146 (4) | |
Cl1 | 0.28142 (5) | 0.21172 (5) | 0.12085 (5) | 0.0376 (2) | |
C6 | 0.18308 (16) | 0.18308 (16) | 0.18308 (16) | 0.0237 (5) | |
H1 | 0.32493 | 0.32493 | 0.32493 | 0.0175* | |
H3 | 0.39159 | 0.38966 | 0.17156 | 0.0248* | |
H4 | 0.50730 | 0.50458 | 0.12378 | 0.0294* | |
H5 | 0.57195 | 0.56700 | 0.26794 | 0.0270* | |
H6 | 0.14451 | 0.14451 | 0.14451 | 0.0284* |
U^{11} | U^{22} | U^{33} | U^{12} | U^{13} | U^{23} | |
Ca | 0.0141 (2) | 0.0141 (2) | 0.0141 (2) | −0.0023 (2) | −0.0023 (2) | −0.0023 (2) |
N1 | 0.0184 (9) | 0.0214 (9) | 0.0177 (9) | −0.0059 (7) | −0.0014 (7) | 0.0005 (7) |
N2 | 0.0151 (8) | 0.0167 (8) | 0.0125 (8) | −0.0001 (6) | −0.0001 (6) | −0.0002 (6) |
C3 | 0.0241 (11) | 0.0239 (10) | 0.0141 (9) | −0.0014 (9) | −0.0011 (8) | −0.0022 (8) |
C4 | 0.0287 (12) | 0.0282 (12) | 0.0167 (10) | −0.0036 (9) | 0.0038 (9) | 0.0027 (9) |
C5 | 0.0215 (10) | 0.0255 (11) | 0.0205 (10) | −0.0057 (9) | 0.0022 (8) | 0.0030 (8) |
B1 | 0.0146 (7) | 0.0146 (7) | 0.0146 (7) | −0.0013 (8) | −0.0013 (8) | −0.0013 (8) |
Cl1 | 0.0416 (4) | 0.0370 (4) | 0.0341 (3) | −0.0098 (3) | 0.0157 (3) | −0.0097 (3) |
C6 | 0.0237 (8) | 0.0237 (8) | 0.0237 (8) | −0.0017 (9) | −0.0017 (9) | −0.0017 (9) |
Ca—N1 | 2.4241 (18) | C3—H3 | 0.9300 |
N1—C5 | 1.332 (3) | C4—H4 | 0.9300 |
N1—N2 | 1.363 (2) | C5—H5 | 0.9300 |
N2—C3 | 1.348 (3) | C6—H6 | 0.9800 |
N2—B1 | 1.551 (3) | B1—H1 | 0.9800 |
C3—C4 | 1.380 (3) | Cl1—C6 | 1.758 (2) |
C4—C5 | 1.395 (3) | ||
N1···N1^{i} | 3.098 (3) | C4···H6^{v} | 3.0900 |
N1···N2^{i} | 3.120 (2) | C4···H4^{vi} | 3.0600 |
N1···N1^{ii} | 3.098 (3) | H4···C4^{vii} | 3.0600 |
N1···N2^{ii} | 3.116 (2) | H4···H4^{vii} | 2.5400 |
N2···N1^{i} | 3.116 (2) | H4···H4^{vi} | 2.5400 |
N2···N1^{ii} | 3.120 (2) | H6···C4^{viii} | 3.0900 |
C4···H6^{iii} | 3.0900 | H6···C4^{ix} | 3.0900 |
C4···H6^{iv} | 3.0900 | H6···C4^{x} | 3.0900 |
N1—Ca—N1^{i} | 79.45 (6) | N2—C3—H3 | 126.00 |
Ca—N1—N2 | 118.72 (12) | C4—C3—H3 | 126.00 |
Ca—N1—C5 | 135.03 (15) | C3—C4—H4 | 128.00 |
N2—N1—C5 | 106.23 (17) | C5—C4—H4 | 128.00 |
N1—N2—C3 | 109.86 (17) | C4—C5—H5 | 124.00 |
N1—N2—B1 | 122.87 (16) | N1—C5—H5 | 124.00 |
C3—N2—B1 | 127.26 (17) | N2—B1—N2^{ii} | 109.80 (16) |
N2—C3—C4 | 108.47 (19) | N2—B1—H1 | 109.00 |
C3—C4—C5 | 104.43 (19) | Cl1—C6—Cl1^{i} | 110.74 (13) |
N1—C5—C4 | 111.0 (2) | Cl1—C6—H6 | 108.00 |
N1^{i}—Ca—N1—N2 | −40.39 (14) | C5—N1—N2—B1 | −178.87 (18) |
N1^{ii}—Ca—N1—N2 | 40.70 (14) | Ca—N1—C5—C4 | −178.12 (16) |
N1^{xi}—Ca—N1—N2 | 139.61 (14) | N2—N1—C5—C4 | 0.1 (2) |
N1^{xii}—Ca—N1—N2 | −139.30 (14) | N1—N2—C3—C4 | −0.1 (2) |
N1^{i}—Ca—N1—C5 | 137.7 (2) | N1—N2—B1—N2^{i} | 60.6 (2) |
N1^{ii}—Ca—N1—C5 | −141.3 (2) | B1—N2—C3—C4 | 178.71 (19) |
N1^{xi}—Ca—N1—C5 | −42.4 (2) | C3—N2—B1—N2^{ii} | 121.1 (2) |
N1^{xii}—Ca—N1—C5 | 38.8 (2) | C3—N2—B1—N2^{i} | −118.1 (2) |
Ca—N1—N2—C3 | 178.57 (14) | N1—N2—B1—N2^{ii} | −60.2 (2) |
Ca—N1—N2—B1 | −0.3 (2) | N2—C3—C4—C5 | 0.2 (3) |
C5—N1—N2—C3 | 0.0 (2) | C3—C4—C5—N1 | −0.2 (3) |
Symmetry codes: (i) z, x, y; (ii) y, z, x; (iii) −x+1/2, y+1/2, z; (iv) −z+1/2, x+1/2, y; (v) −y+1/2, z+1/2, x; (vi) y, −z+1/2, x−1/2; (vii) z+1/2, x, −y+1/2; (viii) −x+1/2, y−1/2, z; (ix) z, −x+1/2, y−1/2; (x) y−1/2, z, −x+1/2; (xi) −z+1, −x+1, −y+1; (xii) −y+1, −z+1, −x+1. |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | [Mg(C_{9}H_{10}BN_{6})_{2}]·2CHCl_{3} | [Ca(C_{9}H_{10}BN_{6})_{2}]·2CHCl_{3} |
M_{r} | 689.13 | 704.90 |
Crystal system, space group | Cubic, Pa3 | Cubic, Pa3 |
Temperature (K) | 100 | 100 |
a (Å) | 14.3475 (12) | 14.6697 (9) |
V (Å^{3}) | 2953.4 (4) | 3156.9 (3) |
Z | 4 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm^{−}^{1}) | 0.64 | 0.74 |
Crystal size (mm) | 0.20 × 0.12 × 0.09 | 0.3 × 0.2 × 0.2 |
Data collection | ||
Diffractometer | Bruker SMART CCD area-detector diffractometer | Bruker SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) | Multi-scan (SADABS; Sheldrick, 1996) |
T_{min}, T_{max} | 0.883, 0.945 | 0.808, 0.866 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 15868, 969, 944 | 17681, 1293, 1272 |
R_{int} | 0.055 | 0.033 |
(sin θ/λ)_{max} (Å^{−}^{1}) | 0.617 | 0.666 |
Refinement | ||
R[F^{2} > 2σ(F^{2})], wR(F^{2}), S | 0.060, 0.124, 1.22 | 0.051, 0.109, 1.31 |
No. of reflections | 969 | 1293 |
No. of parameters | 63 | 63 |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained |
w = 1/[σ^{2}(F_{o}^{2}) + (0.0339P)^{2} + 10.6109P] where P = (F_{o}^{2} + 2F_{c}^{2})/3 | w = 1/[σ^{2}(F_{o}^{2}) + (0.0316P)^{2} + 4.1829P] where P = (F_{o}^{2} + 2F_{c}^{2})/3 | |
Δρ_{max}, Δρ_{min} (e Å^{−}^{3}) | 0.39, −0.36 | 0.44, −0.40 |
Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), Mercury 1.4 (Bruno et al., 2002), SHELXL97 and WinGX2003 (Farrugia, 1999).
Mg—N1 | 2.173 (3) | ||
N1—Mg—N1^{i} | 84.94 (10) | Mg—N1—C5 | 135.4 (2) |
Mg—N1—N2 | 118.15 (19) |
Symmetry code: (i) z, x, y. |
Ca—N1 | 2.4241 (18) | ||
N1—Ca—N1^{i} | 79.45 (6) | Ca—N1—C5 | 135.03 (15) |
Ca—N1—N2 | 118.72 (12) |
Symmetry code: (i) z, x, y. |
The coordination chemistry of the tris(pyrazolyl)borate ligand (Tp) has been extensively studied since its introduction in 1966 (Trofimenko, 1966). Tp forms a great variety of complexes with most metals and metalloids in a tridentate fashion. Trofimenko (1999) has termed this ligand and its derivatives `scorpionates', since the two equatorial pyrazole (Pz) rings look like the claws and the pseudoaxial pyrazole ring looks like the stinger of a scorpion. In this paper, we report the structures of the Mg^{2+}, (I), and Ca^{2+}, (II), bis[hydrotris(pyrazolyl)borate] chloroform disolvates.
The molecular structures of (I) and (II) are shown in Figs. 1(a) and 2(a), and selected bond lengths and angles are listed in Tables 1 and 2, respectively. In each complex the metal occupies a site of 3 symmetry and both Tp ligands are symmetrically tridentate; the geometry about the metal is trigonally distorted octahedral, with M—N bond lengths of 2.173 (3) Å in (I) and 2.4241 (18) Å in (II). The corresponding intraligand N—M—N bond angles are 84.94 (10) and 79.45 (6)°. The N···N distances, which correlate with the bite angles of the ligand, are 2.934 (2) and 3.098 (2) Å, respectively, and are governed by the relative ionic radii of the Mg^{2+} (0.65 Å) and Ca^{2+} (0.99 Å) ions (Huheey et al., 1993).
The coordination geometry in (I) and (II) is very similar to that seen in the corresponding unsolvated [HB(Pz)_{3}]_{2}Mg and [HB(Pz)_{3}]_{2}Ca complexes (Sohrin et al., 1994). The former crystallizes in the triclinic space group P1, with two crystallographically independent molecules lying across different inversion centres, whereas the latter crystallizes in the monoclinic space group C2/c, with two crystallographically independent molecules on twofold rotation axes. In contrast, the chloroform solvates (I) and (II) exhibit high symmetry and crystallize in the cubic space group Pa3, with the metals on sites of 3 symmetry and the chloroform molecules on threefold rotation axes. The influence of CHCl_{3} on the regulation of crystal structure has been documented by comparing the structures of the chloroform solvate (monoclinic, space group P2_{1}/c; Nielson et al., 2003) and the toluene solvate (triclinic, space group P1; Davidson et al., 2003) of the zwitterion bis[tris(3,5-dimethyl-2-oxidobenzyl-κO)ammonium]zirconium(IV), and those of trans-bis(2,2-diphenylethylamine-κN)bis(5,5-diphenylhydantoinato-κN^{3})copper(II) and its chloroform solvate (triclinic, space group P1, and orthorhombic, space group Pbca, respectively; Akitsu & Binaga, 2005). In both cases, chloroform influences crystallization to give structures that are more symmetric than those observed for unsolvated complexes or those solvated by other solvents.
##AUTHOR: The following has been re-written so please check carefully: Chloroform molecules play an important role in the development of the supramolecular architecture of (I) and (II), its inclusion is governed by electrophile–nuclephile C—Cl···π interactions (Csöregh et al., 1996) to form a three-dimensional network. Each Cl atom of the chloroform solvent interacts with two pyrazole rings in the same neighbouring molecule. In (I) (Fig. 3), the relevant parameters are C6—Cl1···Pz^{vi} = 3.5018 (16) Å, C6—Cl1···Pz^{vi} = 91.14 (14)°, C6—Cl1···Pz^{vii} = 3.4906 (16) Å, C6—Cl1···Pz^{vii} = 165.05 (15)°, Cl···Pz···Cl = 158.4 (2)° and Pz···Cl···Pz = 75.7 (2)° [Pz is the centroid of the pyrazole ring; symmetry codes: (vi) z, −x + 1/2, y − 1/2; (vii) y, −z + 1/2, x − 1/2.] The corresponding values for (II) are 3.5148 (12) Å, 94.06 (8)°, 3.5443 (12) Å, 170.79 (9)°, 163.0 (2)° and 76.8 (2)°. Each chloroform molecule is therefore linked to three molecules of the metal complex, generating the three-dimensional network structure.
Interaction lengths and angles are in the mean range for this electrophile–nucleophile π···X···π motif (Csöregh et al., 1996), as well as for C—Cl···π database studies carried out on organic crystal structures (Prasanna & Row, 2000) and in proteins (Saraogi et al., 2003). The experimental data typical of Cl···π-facial interactions (Galan-Mascaros et al., 1996), which have been found in both chloride (Demeshko et al., 2004) and C—Cl (Aravindan et al., 2003) interactions with π-deficient heterocycles.
In summary, chloroform inclusion in Mg[(HB(Pz)_{3})_{2}] and Ca[(HB(Pz)_{3})_{2}] complexes not only leads to highly symmetric structures, in contrast to the unsolvated complexes, but also plays an important role in stabilizing the supramolecular architecture through Pz···Cl···Pz interactions.