Piperazinium aluminium sulfate decahydrate, (C4H12N2)0.5[Al(H2O)6](SO4)2·4H2O, exhibits a crystal structure built from isolated [Al(H2O)6]3+, SO42-, C4H12N22+ and H2O units connected by a complex hydrogen-bond network. The title compound shows strong similarities to many double aluminium sulfates, such as alums and Tutton's salts. However, since its structure is not derived directly from that of these compounds, it is assumed to be a new structure type.
Supporting information
CCDC reference: 226103
Single crystals of (I) were obtained by dissolving Al2(SO4)3.18H2O (0.75 mmol) and piperazine hexahydrate (2 mmol) in H2O (7 ml), acidified with H2SO4 (0.5 ml). The clear solution was allowed to stand for two months, until large crystals were obtained. The product was filtered off and washed with a small amount of distilled water, since the crystals appeared to be slightly soluble.
All 26 H atoms were located from difference Fourier syntheses and their positions were refined isotropically, with O—H, C—H and N—H distances restrained to 0.97 (2) Å and H—H distances restrained to 1.55 (3) Å. The atomic displacements parameters of the H atoms were fixed at 1.5Ueq of their bonded atoms.
Data collection: COLLECT (Nonius, 1998); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL DENZO (Otwinowski & Minor, 1997) and SCALEPACK; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg & Berndt, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999).
Hexaaquaaluminium hemi(piperidin-1,4-diium) bis(sulfate) tetrahydrate
top
Crystal data top
[Al(H2O)6](C4H12N2)0.5(SO4)2·4H2O | F(000) = 936 |
Mr = 443.32 | Dx = 1.725 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 11232 reflections |
a = 6.5737 (1) Å | θ = 1.0–27.5° |
b = 12.0671 (2) Å | µ = 0.45 mm−1 |
c = 21.5206 (5) Å | T = 293 K |
β = 90.0815 (7)° | Prism, colourless |
V = 1707.13 (6) Å3 | 0.52 × 0.13 × 0.08 mm |
Z = 4 | |
Data collection top
Nonius KappaCCD diffractometer | 3911 independent reflections |
Radiation source: fine-focus sealed tube | 2991 reflections with I > 2σ(I) |
Horizonally mounted graphite crystal monochromator | Rint = 0.070 |
Detector resolution: 9 pixels mm-1 | θmax = 27.5°, θmin = 1.9° |
CCD scans | h = −7→8 |
Absorption correction: analytical (de Meulenaer & Tompa, 1965) | k = −15→15 |
Tmin = 0.797, Tmax = 0.967 | l = −27→27 |
19066 measured reflections | |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.038 | Only H-atom coordinates refined |
wR(F2) = 0.105 | w = 1/[σ2(Fo2) + (0.047P)2 + 0.84P] where P = (Fo2 + 2Fc2)/3 |
S = 1.07 | (Δ/σ)max = 0.001 |
3911 reflections | Δρmax = 0.35 e Å−3 |
296 parameters | Δρmin = −0.47 e Å−3 |
39 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0181 (13) |
Crystal data top
[Al(H2O)6](C4H12N2)0.5(SO4)2·4H2O | V = 1707.13 (6) Å3 |
Mr = 443.32 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 6.5737 (1) Å | µ = 0.45 mm−1 |
b = 12.0671 (2) Å | T = 293 K |
c = 21.5206 (5) Å | 0.52 × 0.13 × 0.08 mm |
β = 90.0815 (7)° | |
Data collection top
Nonius KappaCCD diffractometer | 3911 independent reflections |
Absorption correction: analytical (de Meulenaer & Tompa, 1965) | 2991 reflections with I > 2σ(I) |
Tmin = 0.797, Tmax = 0.967 | Rint = 0.070 |
19066 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.038 | 39 restraints |
wR(F2) = 0.105 | Only H-atom coordinates refined |
S = 1.07 | Δρmax = 0.35 e Å−3 |
3911 reflections | Δρmin = −0.47 e Å−3 |
296 parameters | |
Special details top
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Al | 0.46346 (9) | 0.06257 (5) | 0.36703 (3) | 0.01848 (17) | |
S1 | −0.04464 (7) | −0.02962 (5) | 0.19203 (3) | 0.02159 (16) | |
S2 | −0.03341 (7) | 0.19082 (5) | 0.54279 (3) | 0.02035 (16) | |
O11 | 0.1573 (2) | 0.00189 (17) | 0.21618 (8) | 0.0374 (5) | |
O12 | −0.1636 (2) | −0.08206 (15) | 0.24188 (8) | 0.0321 (4) | |
O13 | −0.1513 (3) | 0.06939 (14) | 0.16931 (8) | 0.0310 (4) | |
O14 | −0.0184 (2) | −0.10540 (14) | 0.13885 (8) | 0.0303 (4) | |
O21 | 0.0369 (2) | 0.10820 (14) | 0.58895 (8) | 0.0296 (4) | |
O22 | −0.2297 (2) | 0.15197 (15) | 0.51702 (8) | 0.0311 (4) | |
O23 | −0.0637 (3) | 0.29737 (14) | 0.57433 (8) | 0.0332 (4) | |
O24 | 0.1169 (3) | 0.20343 (15) | 0.49335 (9) | 0.0361 (4) | |
O91 | 0.6997 (2) | 0.13038 (14) | 0.39754 (8) | 0.0264 (4) | |
H11 | 0.736 (4) | 0.136 (2) | 0.4395 (8) | 0.040* | |
H12 | 0.789 (4) | 0.173 (2) | 0.3718 (11) | 0.040* | |
O92 | 0.5822 (2) | −0.07765 (14) | 0.37573 (8) | 0.0254 (4) | |
H21 | 0.538 (4) | −0.135 (2) | 0.3492 (12) | 0.038* | |
H22 | 0.713 (3) | −0.089 (2) | 0.3906 (13) | 0.038* | |
O93 | 0.3435 (2) | 0.20113 (13) | 0.35657 (8) | 0.0256 (4) | |
H31 | 0.411 (4) | 0.2691 (17) | 0.3573 (14) | 0.038* | |
H32 | 0.207 (3) | 0.210 (2) | 0.3469 (14) | 0.038* | |
O94 | 0.2249 (2) | −0.00430 (15) | 0.33620 (8) | 0.0260 (4) | |
H41 | 0.195 (4) | −0.005 (2) | 0.2947 (10) | 0.039* | |
H42 | 0.129 (4) | −0.041 (2) | 0.3617 (11) | 0.039* | |
O95 | 0.5681 (2) | 0.07082 (14) | 0.28555 (7) | 0.0260 (4) | |
H51 | 0.541 (4) | 0.1234 (19) | 0.2539 (11) | 0.039* | |
H52 | 0.664 (4) | 0.0189 (19) | 0.2694 (12) | 0.039* | |
O96 | 0.3613 (2) | 0.05051 (14) | 0.44826 (7) | 0.0236 (4) | |
H61 | 0.266 (4) | 0.1013 (18) | 0.4633 (13) | 0.035* | |
H62 | 0.329 (4) | −0.0209 (14) | 0.4600 (13) | 0.035* | |
C1 | 0.2107 (4) | −0.0345 (2) | −0.00223 (13) | 0.0346 (6) | |
H11C | 0.323 (4) | −0.073 (2) | 0.0168 (13) | 0.052* | |
H12C | 0.259 (4) | 0.008 (2) | −0.0365 (11) | 0.052* | |
N2 | 0.1358 (3) | 0.04742 (19) | 0.04449 (10) | 0.0317 (5) | |
H21N | 0.245 (4) | 0.097 (2) | 0.0569 (14) | 0.048* | |
H22N | 0.091 (4) | 0.004 (2) | 0.0806 (11) | 0.048* | |
C3 | 0.0403 (4) | −0.1119 (2) | −0.02072 (14) | 0.0342 (6) | |
H31C | 0.081 (5) | −0.161 (2) | −0.0536 (11) | 0.051* | |
H32C | −0.007 (5) | −0.150 (2) | 0.0149 (10) | 0.051* | |
O97 | 0.4655 (3) | 0.23163 (15) | 0.20611 (8) | 0.0324 (4) | |
H71 | 0.552 (4) | 0.290 (2) | 0.2198 (13) | 0.049* | |
H72 | 0.471 (5) | 0.223 (2) | 0.1627 (8) | 0.049* | |
O98 | 0.4714 (3) | −0.03325 (16) | 0.13190 (9) | 0.0345 (4) | |
H81 | 0.378 (4) | −0.019 (3) | 0.1641 (12) | 0.052* | |
H82 | 0.589 (3) | 0.007 (2) | 0.1390 (14) | 0.052* | |
O99 | −0.0392 (2) | 0.25312 (15) | 0.33211 (9) | 0.0309 (4) | |
H91 | −0.034 (4) | 0.3237 (18) | 0.3496 (13) | 0.046* | |
H92 | −0.044 (5) | 0.264 (2) | 0.2879 (8) | 0.046* | |
O910 | 0.0302 (3) | 0.26275 (15) | 0.20148 (9) | 0.0359 (4) | |
H101 | 0.174 (3) | 0.253 (2) | 0.2008 (16) | 0.054* | |
H102 | −0.024 (4) | 0.1936 (19) | 0.1893 (16) | 0.054* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Al | 0.0163 (3) | 0.0203 (4) | 0.0189 (3) | −0.0004 (2) | 0.0001 (2) | 0.0010 (3) |
S1 | 0.0187 (3) | 0.0255 (3) | 0.0206 (3) | 0.0008 (2) | 0.0013 (2) | 0.0003 (2) |
S2 | 0.0186 (3) | 0.0213 (3) | 0.0212 (3) | 0.00004 (19) | 0.0010 (2) | 0.0000 (2) |
O11 | 0.0210 (8) | 0.0632 (13) | 0.0280 (9) | −0.0058 (8) | −0.0041 (7) | −0.0015 (9) |
O12 | 0.0297 (9) | 0.0342 (10) | 0.0324 (10) | 0.0022 (7) | 0.0091 (7) | 0.0071 (8) |
O13 | 0.0334 (9) | 0.0225 (9) | 0.0370 (10) | 0.0039 (7) | −0.0021 (7) | 0.0023 (8) |
O14 | 0.0374 (9) | 0.0284 (10) | 0.0252 (9) | 0.0073 (7) | 0.0009 (7) | −0.0042 (7) |
O21 | 0.0205 (7) | 0.0307 (9) | 0.0377 (10) | 0.0020 (6) | −0.0028 (7) | 0.0116 (8) |
O22 | 0.0275 (8) | 0.0378 (10) | 0.0279 (9) | −0.0088 (7) | −0.0086 (7) | 0.0038 (8) |
O23 | 0.0384 (9) | 0.0266 (10) | 0.0346 (10) | 0.0070 (7) | −0.0027 (8) | −0.0079 (8) |
O24 | 0.0362 (10) | 0.0341 (10) | 0.0381 (11) | −0.0010 (7) | 0.0178 (8) | 0.0034 (8) |
O91 | 0.0235 (8) | 0.0344 (10) | 0.0212 (8) | −0.0088 (7) | −0.0020 (6) | 0.0029 (7) |
O92 | 0.0221 (8) | 0.0236 (9) | 0.0305 (9) | 0.0028 (6) | −0.0036 (6) | −0.0014 (7) |
O93 | 0.0198 (8) | 0.0211 (9) | 0.0358 (10) | 0.0006 (6) | −0.0002 (7) | 0.0026 (7) |
O94 | 0.0220 (8) | 0.0336 (10) | 0.0224 (9) | −0.0072 (7) | −0.0028 (6) | 0.0016 (7) |
O95 | 0.0278 (8) | 0.0297 (9) | 0.0205 (8) | 0.0054 (7) | 0.0050 (6) | 0.0026 (7) |
O96 | 0.0261 (8) | 0.0227 (9) | 0.0221 (8) | −0.0011 (6) | 0.0041 (6) | 0.0013 (7) |
C1 | 0.0251 (12) | 0.0445 (17) | 0.0341 (15) | 0.0022 (10) | 0.0000 (10) | −0.0076 (12) |
N2 | 0.0297 (11) | 0.0381 (13) | 0.0274 (11) | −0.0059 (9) | −0.0035 (8) | −0.0004 (9) |
C3 | 0.0383 (14) | 0.0297 (14) | 0.0346 (15) | 0.0015 (11) | −0.0056 (11) | −0.0025 (12) |
O97 | 0.0405 (10) | 0.0301 (10) | 0.0265 (10) | 0.0005 (7) | 0.0007 (8) | 0.0035 (8) |
O98 | 0.0271 (9) | 0.0375 (11) | 0.0388 (11) | −0.0032 (7) | 0.0001 (7) | 0.0014 (8) |
O99 | 0.0271 (8) | 0.0297 (10) | 0.0361 (10) | −0.0004 (7) | 0.0001 (7) | 0.0042 (8) |
O910 | 0.0347 (9) | 0.0249 (10) | 0.0481 (12) | −0.0004 (7) | −0.0026 (8) | 0.0027 (9) |
Geometric parameters (Å, º) top
Al—O93 | 1.8620 (17) | O95—H51 | 0.948 (17) |
Al—O92 | 1.8726 (17) | O95—H52 | 0.956 (17) |
Al—O91 | 1.8733 (16) | O96—H61 | 0.935 (16) |
Al—O96 | 1.8792 (17) | O96—H62 | 0.924 (16) |
Al—O94 | 1.8835 (16) | C1—N2 | 1.494 (3) |
Al—O95 | 1.8872 (17) | C1—C3 | 1.512 (4) |
S1—O13 | 1.4689 (17) | C1—H11C | 0.964 (17) |
S1—O12 | 1.4715 (17) | C1—H12C | 0.955 (17) |
S1—O11 | 1.4745 (16) | N2—C3i | 1.485 (3) |
S1—O14 | 1.4753 (17) | N2—H21N | 0.974 (17) |
S2—O24 | 1.4611 (17) | N2—H22N | 0.982 (17) |
S2—O23 | 1.4677 (18) | C3—N2i | 1.485 (3) |
S2—O22 | 1.4797 (16) | C3—H31C | 0.959 (17) |
S2—O21 | 1.4809 (17) | C3—H32C | 0.946 (17) |
O91—H11 | 0.935 (17) | O97—H71 | 0.946 (17) |
O91—H12 | 0.958 (16) | O97—H72 | 0.941 (17) |
O92—H21 | 0.940 (17) | O98—H81 | 0.944 (17) |
O92—H22 | 0.927 (16) | O98—H82 | 0.929 (17) |
O93—H31 | 0.933 (16) | O99—H91 | 0.931 (17) |
O93—H32 | 0.93 (2) | O99—H92 | 0.961 (17) |
O94—H41 | 0.91 (2) | O910—H101 | 0.950 (17) |
O94—H42 | 0.945 (17) | O910—H102 | 0.945 (17) |
| | | |
O93—Al—O92 | 178.70 (9) | Al—O93—H32 | 122.4 (16) |
O93—Al—O91 | 90.05 (8) | H31—O93—H32 | 112 (2) |
O92—Al—O91 | 90.83 (8) | Al—O94—H41 | 121.5 (17) |
O93—Al—O96 | 91.73 (8) | Al—O94—H42 | 123.5 (17) |
O92—Al—O96 | 89.22 (8) | H41—O94—H42 | 115 (2) |
O91—Al—O96 | 90.29 (7) | Al—O95—H51 | 129.5 (16) |
O93—Al—O94 | 89.42 (8) | Al—O95—H52 | 123.0 (16) |
O92—Al—O94 | 89.70 (8) | H51—O95—H52 | 108 (2) |
O91—Al—O94 | 179.47 (9) | Al—O96—H61 | 120.8 (17) |
O96—Al—O94 | 89.77 (7) | Al—O96—H62 | 114.3 (17) |
O93—Al—O95 | 89.73 (8) | H61—O96—H62 | 111 (2) |
O92—Al—O95 | 89.32 (8) | N2—C1—C3 | 109.9 (2) |
O91—Al—O95 | 89.97 (8) | N2—C1—H11C | 107 (2) |
O96—Al—O95 | 178.52 (8) | C3—C1—H11C | 112.3 (19) |
O94—Al—O95 | 89.99 (8) | N2—C1—H12C | 106 (2) |
O13—S1—O12 | 109.78 (10) | C3—C1—H12C | 112.1 (19) |
O13—S1—O11 | 109.68 (11) | H11C—C1—H12C | 110 (2) |
O12—S1—O11 | 109.45 (11) | C3i—N2—C1 | 111.9 (2) |
O13—S1—O14 | 107.60 (10) | C3i—N2—H21N | 110.3 (18) |
O12—S1—O14 | 111.22 (11) | C1—N2—H21N | 110.3 (18) |
O11—S1—O14 | 109.09 (10) | C3i—N2—H22N | 108.4 (18) |
O24—S2—O23 | 109.76 (11) | C1—N2—H22N | 106.4 (19) |
O24—S2—O22 | 110.51 (11) | H21N—N2—H22N | 109 (2) |
O23—S2—O22 | 109.39 (10) | N2i—C3—C1 | 110.1 (2) |
O24—S2—O21 | 110.36 (10) | N2i—C3—H31C | 106.4 (19) |
O23—S2—O21 | 108.79 (11) | C1—C3—H31C | 111.6 (19) |
O22—S2—O21 | 108.01 (10) | N2i—C3—H32C | 106.2 (19) |
Al—O91—H11 | 125.3 (16) | C1—C3—H32C | 109.2 (19) |
Al—O91—H12 | 122.7 (16) | H31C—C3—H32C | 113 (2) |
H11—O91—H12 | 111 (2) | H71—O97—H72 | 112 (2) |
Al—O92—H21 | 118.3 (17) | H81—O98—H82 | 109 (2) |
Al—O92—H22 | 123.4 (17) | H91—O99—H92 | 106 (2) |
H21—O92—H22 | 113 (2) | H101—O910—H102 | 105 (2) |
Al—O93—H31 | 125.9 (16) | | |
Symmetry code: (i) −x, −y, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O91—H11···O22ii | 0.94 (2) | 1.70 (2) | 2.625 (2) | 172 (3) |
O91—H12···O99ii | 0.96 (2) | 1.72 (2) | 2.670 (2) | 174 (3) |
O92—H21···O910iii | 0.94 (2) | 1.71 (2) | 2.648 (3) | 177 (3) |
O92—H22···O21iv | 0.93 (2) | 1.72 (2) | 2.642 (2) | 175 (3) |
O93—H31···O14v | 0.93 (2) | 1.67 (2) | 2.604 (2) | 176 (3) |
O93—H32···O99 | 0.93 (2) | 1.73 (2) | 2.645 (2) | 169 (2) |
O94—H41···O11 | 0.91 (2) | 1.71 (2) | 2.621 (2) | 175 (3) |
O94—H42···O21vi | 0.95 (2) | 1.73 (2) | 2.671 (2) | 177 (3) |
O95—H51···O97 | 0.95 (2) | 1.74 (2) | 2.672 (2) | 170 (3) |
O95—H52···O12ii | 0.96 (2) | 1.77 (2) | 2.720 (2) | 177 (3) |
O96—H61···O24 | 0.94 (2) | 1.70 (2) | 2.633 (2) | 173 (3) |
O96—H62···O22vi | 0.92 (2) | 1.78 (2) | 2.698 (2) | 172 (2) |
O97—H71···O12v | 0.95 (2) | 1.90 (2) | 2.828 (3) | 165 (3) |
O97—H72···O23vii | 0.94 (2) | 1.93 (2) | 2.864 (3) | 171 (3) |
O98—H81···O11 | 0.94 (2) | 1.85 (2) | 2.783 (2) | 169 (3) |
O98—H82···O13ii | 0.93 (2) | 1.97 (2) | 2.886 (2) | 167 (3) |
O99—H91···O98v | 0.93 (2) | 1.82 (2) | 2.728 (3) | 165 (3) |
O99—H92···O910 | 0.96 (2) | 1.92 (2) | 2.851 (3) | 161 (3) |
O910—H101···O97 | 0.95 (2) | 1.94 (2) | 2.887 (3) | 176 (3) |
O910—H102···O13 | 0.95 (2) | 1.77 (2) | 2.710 (3) | 174 (3) |
N2—H21N···O23vii | 0.97 (2) | 1.83 (2) | 2.796 (3) | 173 (3) |
N2—H22N···O14 | 0.98 (2) | 1.96 (2) | 2.925 (3) | 167 (3) |
Symmetry codes: (ii) x+1, y, z; (iii) −x+1/2, y−1/2, −z+1/2; (iv) −x+1, −y, −z+1; (v) −x+1/2, y+1/2, −z+1/2; (vi) −x, −y, −z+1; (vii) x+1/2, −y+1/2, z−1/2. |
Experimental details
Crystal data |
Chemical formula | [Al(H2O)6](C4H12N2)0.5(SO4)2·4H2O |
Mr | 443.32 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 6.5737 (1), 12.0671 (2), 21.5206 (5) |
β (°) | 90.0815 (7) |
V (Å3) | 1707.13 (6) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.45 |
Crystal size (mm) | 0.52 × 0.13 × 0.08 |
|
Data collection |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | Analytical (de Meulenaer & Tompa, 1965) |
Tmin, Tmax | 0.797, 0.967 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 19066, 3911, 2991 |
Rint | 0.070 |
(sin θ/λ)max (Å−1) | 0.650 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.038, 0.105, 1.07 |
No. of reflections | 3911 |
No. of parameters | 296 |
No. of restraints | 39 |
H-atom treatment | Only H-atom coordinates refined |
Δρmax, Δρmin (e Å−3) | 0.35, −0.47 |
Selected bond lengths (Å) topAl—O93 | 1.8620 (17) | S2—O23 | 1.4677 (18) |
Al—O92 | 1.8726 (17) | S2—O22 | 1.4797 (16) |
Al—O91 | 1.8733 (16) | S2—O21 | 1.4809 (17) |
Al—O96 | 1.8792 (17) | C1—N2 | 1.494 (3) |
Al—O94 | 1.8835 (16) | C1—C3 | 1.512 (4) |
Al—O95 | 1.8872 (17) | C1—H11C | 0.964 (17) |
S1—O13 | 1.4689 (17) | C1—H12C | 0.955 (17) |
S1—O12 | 1.4715 (17) | N2—C3i | 1.485 (3) |
S1—O11 | 1.4745 (16) | C3—H31C | 0.959 (17) |
S1—O14 | 1.4753 (17) | C3—H32C | 0.946 (17) |
S2—O24 | 1.4611 (17) | | |
Symmetry code: (i) −x, −y, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O91—H11···O22ii | 0.935 (17) | 1.696 (17) | 2.625 (2) | 172 (3) |
O91—H12···O99ii | 0.958 (16) | 1.715 (17) | 2.670 (2) | 174 (3) |
O92—H21···O910iii | 0.940 (17) | 1.709 (17) | 2.648 (3) | 177 (3) |
O92—H22···O21iv | 0.927 (16) | 1.717 (17) | 2.642 (2) | 175 (3) |
O93—H31···O14v | 0.933 (16) | 1.673 (17) | 2.604 (2) | 176 (3) |
O93—H32···O99 | 0.93 (2) | 1.73 (2) | 2.645 (2) | 169 (2) |
O94—H41···O11 | 0.91 (2) | 1.71 (2) | 2.621 (2) | 175 (3) |
O94—H42···O21vi | 0.945 (17) | 1.727 (17) | 2.671 (2) | 177 (3) |
O95—H51···O97 | 0.948 (17) | 1.735 (17) | 2.672 (2) | 170 (3) |
O95—H52···O12ii | 0.956 (17) | 1.765 (17) | 2.720 (2) | 177 (3) |
O96—H61···O24 | 0.935 (16) | 1.702 (17) | 2.633 (2) | 173 (3) |
O96—H62···O22vi | 0.924 (16) | 1.780 (17) | 2.698 (2) | 172 (2) |
O97—H71···O12v | 0.946 (17) | 1.902 (18) | 2.828 (3) | 165 (3) |
O97—H72···O23vii | 0.941 (17) | 1.930 (18) | 2.864 (3) | 171 (3) |
O98—H81···O11 | 0.944 (17) | 1.851 (17) | 2.783 (2) | 169 (3) |
O98—H82···O13ii | 0.929 (17) | 1.972 (19) | 2.886 (2) | 167 (3) |
O99—H91···O98v | 0.931 (17) | 1.819 (19) | 2.728 (3) | 165 (3) |
O99—H92···O910 | 0.961 (17) | 1.923 (19) | 2.851 (3) | 161 (3) |
O910—H101···O97 | 0.950 (17) | 1.939 (18) | 2.887 (3) | 176 (3) |
O910—H102···O13 | 0.945 (17) | 1.769 (18) | 2.710 (3) | 174 (3) |
N2—H21N···O23vii | 0.974 (17) | 1.827 (17) | 2.796 (3) | 173 (3) |
N2—H22N···O14 | 0.982 (17) | 1.960 (17) | 2.925 (3) | 167 (3) |
Symmetry codes: (ii) x+1, y, z; (iii) −x+1/2, y−1/2, −z+1/2; (iv) −x+1, −y, −z+1; (v) −x+1/2, y+1/2, −z+1/2; (vi) −x, −y, −z+1; (vii) x+1/2, −y+1/2, z−1/2. |
Studies in sulfate-based chemistry have recently experienced a resurgence in interest, with the use of the SO42− anion as a tetrahedral building block and amines as templates (Choudhury et al., 2001; Norquist et al., 2003). The new amine lanthanum sulfates obtained recently (Bataille & Louër, 2002; Xing et al., 2003) also offer a promising route to open structures. In a similar manner, by using trivalent aluminium, it would be expected that materials with open frameworks constructed only from tetrahedral building units can be prepared. Instead, the crystal structure of the new aluminium piperazinium sulfate decahydrate obtained here, viz. (C4H12N2)0.5Al(H2O)6(SO4)2·4H2O, (I), consists of isolated entities linked through a complex hydrogen-bond network. The present work also deals with the similarities of the crystal structure of (I) to those of other double aluminium sulfates, such as Tutton's salts and alums, although structural features are different.
Alums [general formula AIMIII(SO4)2.12H2O] and Tutton's salts [general formula AI2MII(SO4)2·6H2O] are two large families of double salts that include the sulfate anion. The chemical formula of (I) can be written as [(C4H12N2)0.5]Al(SO4)2.10H2O. Compound (I) is related to the alum family, except that A is a divalent cation with halved stoichiometry and the compound is decahydrated. Nevertheless, the space-group symmetry of (I) (P21/n) is comparable to that of dimethylammonium aluminium sulfate hexahydrate (P21/n; Galesic & Jordanovska, 1992) and Tutton's salts (P21/a; see e.g. Maslen et al., 1988), while alums crystallize with a cubic symmetry. The structure of (I) (Figs. 1 and 2) consists of Al3+ ions octahedrally coordinated by six water molecules, sulfate tetrahedra, piperazinium cations and non-bonded water molecules, linked by hydrogen bonds only. This feature has already been observed in, for example, piperazinium sulfate monohydrate (Jayaraman et al., 2002). Contrarily to other double aluminium sulfates, for which the metal atom is located at the origin of the cell, the Al atom in the crystal structure of (I) lies on a general position. Selected bond lengths are given in Table 1. The Al—OW bond lengths range from 1.862 (2) to 1.887 (2) Å [mean 1.876 (2) Å], in agreement with the value (1.876 Å) calculated from the bond-valence program VALENCE (Brown, 1996) for a sixfold oxygen-coordinated Al atom. The S—O distances fall into the range 1.461 (2)–1.481 (2) Å [mean 1.473 (2) Å], which is comparable to the value (1.474 Å) calculated from the bond-valence method. This bond length fits well with that observed in many Tutton's salts, while it is generally slightly smaller in alums (Petrusevski, 1994). No disorder of the amine group is observed, and the centre of the piperazinium group corresponds to the inversion centre of the unit cell. In the dimethylammonium salt (Galesic & Jordanovska, 1992), the amine group is disordered around the inversion centre, and in α alums, the monovalent AI cations are disordered around the special position 4 b of space group Pa3 (Larson & Cromer, 1967), while in Tutton's salts, the AI cations lie in general positions (Maslen et al., 1988). The presence of a diprotonated amine group and ten water molecules leads to a complex hydrogen bond network, involving 22 H atoms (Table 2).
With respect to the arguments given above, it is clear that the crystal structure of (I) has some similarities with the other double aluminium sulfate salts. Nevertheless, these similarities are not sufficent to allow us to consider (I) as belonging to the known families of double salts, such as alums and Tutton's salts. For this reason, it is likely that (I) is the first member of a new family of double aluminium sulfates. It is therefore of interest to investigate further new aluminium sulfates prepared in the presence of diprotonated amines, in order to establish whether similarities exist with (I).