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A new borogermanate, viz. piperazine-1,4-di­ium di­fluoro­nona­oxo­tri­germanium­di­boron, (C4H12N2)[(GeO2)3(BO1.5F)2], was solvo/hydro­thermally synthesized. The crystal structure consists of layers composed of three-membered-ring Ge3O9 subunits and nine-membered-ring channels formed by six GeO4 tetrahedra and three BO3F tetrahedral pairs. The diprotonated piperazine cations, which lie about inversion centres, are located between adjacent layers and connect the layers via hydrogen bonds.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103021747/tr1066sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270103021747/tr1066Isup2.hkl
Contains datablock I

CCDC reference: 226107

Comment top

Porous materials are widely used in industry owing to their sorption, ion-exchange and catalyst properties (Chen et al., 1989; Jansen et al., 1994), and these materials often show great structural diversity (Smith, 1988). During the past decade, the classes of porous materials, built of pure tetrahedra or mixed polyhedra, have expanded in terms of framework-forming elements (Cheetham et al., 1999)?. Recent studies have shown that germanium oxides can be crystallized by solvo/hydrothermal synthetic methods in basic solutions to form open frameworks with tetrahedral or mixed-polyhedral Ge—O coordinations, for example, in ICMM2 (Cascales et al., 1999), ASU-16 (Plevert et al., 2001), ASU-14 (Li et al., 1999) and Ge10O21(OH)·N4C6H21 (Beitone et al., 2002). Although more than 20 elements have been incorporated sucessfully into silicate frameworks, very few elements have been reported to be incorporated into germanates. One of the elements that has been incorporated is boron, although up to now only two borogermanates prepared via molecular templating methods have been reported. The first is (C2H10N2)2[(GeO2)3(BO2.5)2], a layered structure containing nine-ring channels, templated by ethylenediamine (Dadachov et al., 2000). The second is KBGe2O6, a chiral borogermanate with seven-rings channels (Lin et al., 2003). We report here another layered borogermanate containing nine- and three-membered-ring channels and templated by piperazine, viz. the title compound, (I), which is also denoted SU-13 (Stockholm University No. 13).

The asymmetric unit of (I) contains two unique Ge atoms and one unique B atom (Fig. 1). All of the Ge and B atoms are tetrahedrally coordinated, Ge by four O atoms, and B by three O atoms and one F atom (Table 1). The GeO4 and BO3F groups are vertex-connected via the O atoms, as seen in zeolites. Three GeO4 tetrahedra are connected to form a three-unit ring, a configuration that is very common in germanates. Three such rings are connected via three pairs of BO3F tetrahedra, in an alternating manner, to form a layer containing nine-unit rings composed of six GeO4 tetrahedra and three pairs of BO3F tetrahedra (Fig. 2).

The diprotonated piperazine cations are located between the adjacent layers, inside the nine-membered-ring channels (Fig. 2). The cations balance the framework charge and connect the layers, via hydrogen bonds (Table 2), into a three-dimensional structure. The Ge and B tetrahedra have average angles close to that of an ideal tetrahedron (109.5°). The Ge—O—Ge and B—O—Ge angles are all smaller than, but still close to, the T—O—T angles reported for other germanates (130°; O'Keeffe & Yaghi, 1999).

The [(GeO2)3(BO1.5F)2] layer in (I) is the same as that in (C2H10N2)2[(GeO2)3(BO2.5)2] (Dadachov et al., 2000), although the relative positions of the adjacent layers are different, as a result of the shape and size differences of the organic cations in these two compounds. The distances between the layers are also different, viz. 8.0 Å in (I) and 7.2 Å in (C2H10N2)2[(GeO2)3(BO2.5)2]. The [(GeO2)3(BO1.5F)2] layers in both borogermanates are also similar to the [(GeO2)3(GeO1.5F3)2] layer in several pure germanate compounds, for example, K4[(GeO2)3(GeO1.5F3)2] (Bu et al., 1999) and (NH4)[(GeO2)3(GeO1.5F3)2].0.67H2O (Conradsson, et al., 2000). The main structural difference between the borogermanates and the germanates is that the BO3F tetrahedral pair in [(GeO2)3(BO1.5F)2] is replaced by the GeO3F3 octahedral pair in [(GeO2)3(GeO1.5F3)2].

Experimental top

The title compound (I), was synthesized via a solvo/hydrothermal route using a mixture of pyridine and water. In a typical synthesis, GeO2 (0.25 g), H3BO3 (0.75 g) and piperazine (2.4 g) were dissolved in a mixed solution of pyridine (7.7 ml) and H2 (O1.7 ml). HF (0.17 ml, 40 wt%) was added, and the mixture was stirred continuously for 3 h. The final solution had a molar ratio of GeO2: 40pyridine: 38H2O: 5H3BO3: 12piperazine: 2HF and a pH higher than 13. The solution was sealed in a Teflon-lined autoclave, heated and kept at 438 K for 3 d. The autoclave was left to cool to room temperature. The products were filtered, washed with distilled water and dried at room temperature. Two distinct kinds of large colourless crystals were obtained, viz. (I) and ASU-14 (Li et al., 1999). All reagents (Aldrich) were of analytical grades and were not further purified before use.

Refinement top

All H-atoms were positioned geometrically and allowed to ride on their parent atoms (C—H=0.97 Å and N—H=0.90 Å).

Computing details top

Data collection: EXPOSURE (Stoe & Cie, 1997); cell refinement: CELL (Stoe & Cie, 1997); data reduction: INTEGRATE (Stoe & Cie, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2000); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. A view of (I), showing the atomic labelling scheme and displacement ellipsoids at the 50% probability level. [Symmetry codes: (i) 1 − x, y, 1/2 − z; (ii) 1/2 + x, y − 1/2, 1/2 − z; (iii) −x, −y, 1 − z; (iv) 1/2 − x, y − 1/2, z.]
[Figure 2] Fig. 2. The structure of (I), viewed along the c axis. GeO4 tetrahedra are shown in light gray and BO3F tetrahedra in dark gray. The diprotonated piperazine cations sit inside the nen-membered-ring channels.
(I) top
Crystal data top
B2F2Ge3O9·C4H12N2F(000) = 984
Mr = 509.54Dx = 2.574 Mg m3
Orthorhombic, PbcnMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2abCell parameters from 5000 reflections
a = 6.9776 (14) Åθ = 3.4–25.9°
b = 11.779 (2) ŵ = 6.89 mm1
c = 15.997 (3) ÅT = 293 K
V = 1314.8 (4) Å3Plate, colourless
Z = 40.15 × 0.10 × 0.08 mm
Data collection top
Stoe IPDS
diffractometer
1278 independent reflections
Radiation source: fine-focus sealed tube1092 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.034
Detector resolution: 6.0 pixels mm-1θmax = 25.9°, θmin = 3.4°
ϕ–oscill., ϕ–incr.=1.4°; 129 exposure scansh = 88
Absorption correction: numerical
(X-RED; Stoe & Cie, 1997)
k = 1414
Tmin = 0.444, Tmax = 0.558l = 1919
8492 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.019Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.046H-atom parameters constrained
S = 1.00 w = 1/[σ2(Fo2) + (0.0299P)2]
where P = (Fo2 + 2Fc2)/3
1278 reflections(Δ/σ)max = 0.010
101 parametersΔρmax = 0.36 e Å3
0 restraintsΔρmin = 0.40 e Å3
Crystal data top
B2F2Ge3O9·C4H12N2V = 1314.8 (4) Å3
Mr = 509.54Z = 4
Orthorhombic, PbcnMo Kα radiation
a = 6.9776 (14) ŵ = 6.89 mm1
b = 11.779 (2) ÅT = 293 K
c = 15.997 (3) Å0.15 × 0.10 × 0.08 mm
Data collection top
Stoe IPDS
diffractometer
1278 independent reflections
Absorption correction: numerical
(X-RED; Stoe & Cie, 1997)
1092 reflections with I > 2σ(I)
Tmin = 0.444, Tmax = 0.558Rint = 0.034
8492 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0190 restraints
wR(F2) = 0.046H-atom parameters constrained
S = 1.00Δρmax = 0.36 e Å3
1278 reflectionsΔρmin = 0.40 e Å3
101 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
xyzUiso*/Ueq
Ge10.22110 (4)0.29873 (2)0.234953 (16)0.00981 (9)
Ge20.50000.02738 (3)0.25000.00902 (10)
B10.4634 (4)0.2154 (2)0.36068 (17)0.0120 (6)
F10.4338 (3)0.21278 (15)0.44838 (9)0.0255 (4)
O10.3539 (3)0.31078 (15)0.32642 (11)0.0149 (4)
O20.3879 (3)0.10669 (15)0.32676 (11)0.0147 (4)
O30.6688 (3)0.22610 (16)0.34489 (11)0.0168 (4)
O40.1721 (3)0.43889 (15)0.20393 (11)0.0156 (4)
O50.00000.2311 (2)0.25000.0176 (6)
N10.1437 (3)0.0016 (2)0.43606 (14)0.0182 (5)
H1A0.23910.03280.40790.080*
H1B0.12840.07150.41450.080*
C10.1979 (4)0.0113 (3)0.52590 (18)0.0262 (7)
H2A0.22670.06340.54810.080*
H2B0.31190.05780.53120.080*
C20.0358 (4)0.0640 (3)0.42471 (17)0.0234 (6)
H3A0.06950.06560.36590.080*
H3B0.01620.14150.44310.080*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ge10.00628 (15)0.00709 (14)0.01606 (14)0.00107 (10)0.00041 (9)0.00130 (9)
Ge20.00828 (19)0.00549 (19)0.01328 (17)0.0000.00214 (13)0.000
B10.0109 (16)0.0098 (13)0.0153 (13)0.0005 (11)0.0028 (10)0.0001 (10)
F10.0292 (9)0.0303 (9)0.0170 (8)0.0010 (8)0.0044 (7)0.0001 (7)
O10.0140 (10)0.0104 (9)0.0203 (9)0.0040 (8)0.0036 (7)0.0040 (7)
O20.0147 (11)0.0082 (9)0.0212 (9)0.0022 (8)0.0076 (7)0.0029 (7)
O30.0090 (10)0.0195 (11)0.0220 (10)0.0010 (8)0.0002 (7)0.0086 (7)
O40.0176 (10)0.0095 (9)0.0197 (10)0.0026 (8)0.0052 (7)0.0030 (7)
O50.0089 (13)0.0097 (13)0.0342 (15)0.0000.0024 (10)0.000
N10.0193 (13)0.0188 (11)0.0166 (11)0.0062 (11)0.0065 (9)0.0032 (9)
C10.0183 (15)0.0378 (19)0.0225 (14)0.0004 (14)0.0032 (11)0.0086 (13)
C20.0207 (17)0.0291 (16)0.0205 (13)0.0014 (13)0.0006 (11)0.0104 (11)
Geometric parameters (Å, º) top
Ge1—O11.7376 (18)C1—C2iii1.513 (4)
Ge1—O3i1.7186 (18)N1—C11.490 (4)
Ge1—O41.7575 (18)N1—C21.482 (4)
Ge1—O51.7529 (12)N1—H1A0.9000
Ge2—O21.7299 (17)N1—H1B0.9000
Ge2—O4ii1.7524 (18)C1—H2A0.9700
B1—F11.419 (3)C1—H2B0.9700
B1—O11.465 (3)C2—H3A0.9700
B1—O21.488 (3)C2—H3B0.9700
B1—O31.460 (3)
O3i—Ge1—O1115.35 (9)Ge1—O5—Ge1v125.94 (15)
O3i—Ge1—O5105.63 (8)Ge2vi—O4—Ge1124.98 (10)
O1—Ge1—O5113.00 (7)C2—N1—C1111.9 (2)
O3i—Ge1—O4110.16 (9)C2—N1—H1A109.2
O1—Ge1—O4105.36 (9)C1—N1—H1A109.2
O5—Ge1—O4107.12 (10)C2—N1—H1B109.2
O2—Ge2—O2i114.63 (12)C1—N1—H1B109.2
O2—Ge2—O4iv108.06 (9)H1A—N1—H1B107.9
O2i—Ge2—O4iv109.42 (9)N1—C1—C2iii110.2 (2)
O2—Ge2—O4ii109.42 (9)N1—C1—H2A109.6
O2i—Ge2—O4ii108.06 (9)C2iii—C1—H2A109.6
O4iv—Ge2—O4ii107.01 (12)N1—C1—H2B109.6
F1—B1—O3108.4 (2)C2iii—C1—H2B109.6
F1—B1—O1108.1 (2)H2A—C1—H2B108.1
O3—B1—O1112.4 (2)N1—C2—C1iii110.8 (2)
F1—B1—O2106.9 (2)N1—C2—H3A109.5
O3—B1—O2111.0 (2)C1iii—C2—H3A109.5
O1—B1—O2109.8 (2)N1—C2—H3B109.5
B1—O1—Ge1122.06 (16)C1iii—C2—H3B109.5
B1—O2—Ge2124.31 (16)H3A—C2—H3B108.1
B1—O3—Ge1i127.59 (16)
F1—B1—O1—Ge1136.91 (18)F1—B1—O3—Ge1i145.36 (17)
O3—B1—O1—Ge1103.4 (2)O1—B1—O3—Ge1i25.9 (3)
O2—B1—O1—Ge120.7 (3)O2—B1—O3—Ge1i97.6 (2)
O3i—Ge1—O1—B142.6 (2)O3i—Ge1—O4—Ge2vi158.85 (12)
O5—Ge1—O1—B179.1 (2)O1—Ge1—O4—Ge2vi76.13 (14)
O4—Ge1—O1—B1164.28 (18)O5—Ge1—O4—Ge2vi44.44 (14)
F1—B1—O2—Ge2138.57 (18)O3i—Ge1—O5—Ge1v136.30 (7)
O3—B1—O2—Ge220.5 (3)O1—Ge1—O5—Ge1v96.72 (7)
O1—B1—O2—Ge2104.4 (2)O4—Ge1—O5—Ge1v18.87 (6)
O2i—Ge2—O2—B136.80 (17)C2—N1—C1—C2iii56.3 (4)
O4iv—Ge2—O2—B1159.08 (19)C1—N1—C2—C1iii56.6 (4)
O4ii—Ge2—O2—B184.7 (2)
Symmetry codes: (i) x+1, y, z+1/2; (ii) x+1/2, y1/2, z+1/2; (iii) x, y, z+1; (iv) x+1/2, y1/2, z; (v) x, y, z+1/2; (vi) x1/2, y+1/2, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O20.901.882.754 (3)164.6
N1—H1B···O1iv0.901.982.822 (3)155.0
Symmetry code: (iv) x+1/2, y1/2, z.

Experimental details

Crystal data
Chemical formulaB2F2Ge3O9·C4H12N2
Mr509.54
Crystal system, space groupOrthorhombic, Pbcn
Temperature (K)293
a, b, c (Å)6.9776 (14), 11.779 (2), 15.997 (3)
V3)1314.8 (4)
Z4
Radiation typeMo Kα
µ (mm1)6.89
Crystal size (mm)0.15 × 0.10 × 0.08
Data collection
DiffractometerStoe IPDS
diffractometer
Absorption correctionNumerical
(X-RED; Stoe & Cie, 1997)
Tmin, Tmax0.444, 0.558
No. of measured, independent and
observed [I > 2σ(I)] reflections
8492, 1278, 1092
Rint0.034
(sin θ/λ)max1)0.615
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.019, 0.046, 1.00
No. of reflections1278
No. of parameters101
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.36, 0.40

Computer programs: EXPOSURE (Stoe & Cie, 1997), CELL (Stoe & Cie, 1997), INTEGRATE (Stoe & Cie, 1997), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg, 2000), SHELXL97.

Selected geometric parameters (Å, º) top
Ge1—O11.7376 (18)B1—O11.465 (3)
Ge1—O3i1.7186 (18)B1—O21.488 (3)
Ge1—O41.7575 (18)B1—O31.460 (3)
Ge1—O51.7529 (12)C1—C2iii1.513 (4)
Ge2—O21.7299 (17)N1—C11.490 (4)
Ge2—O4ii1.7524 (18)N1—C21.482 (4)
B1—F11.419 (3)
B1—O1—Ge1122.06 (16)Ge1—O5—Ge1iv125.94 (15)
B1—O2—Ge2124.31 (16)Ge2v—O4—Ge1124.98 (10)
B1—O3—Ge1i127.59 (16)
Symmetry codes: (i) x+1, y, z+1/2; (ii) x+1/2, y1/2, z+1/2; (iii) x, y, z+1; (iv) x, y, z+1/2; (v) x1/2, y+1/2, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O20.901.882.754 (3)164.6
N1—H1B···O1vi0.901.982.822 (3)155.0
Symmetry code: (vi) x+1/2, y1/2, z.
 

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