Tris(dimethyl­ammonium) hydrogen α-dodeca­molybdosilicate

The title compound, (C₂H₈N)₃[HSiMo₁₂O₄₀], has an α-Keggin heteropolyoxo anion with a central SiO₄ tetra­hedron and three dimethyl­ammonium cations. The asymmetric unit contains one Si atom and one O with site symmetry m, two Mo atoms, seven O atoms, two C atoms and one N atom with site symmetry m, and one Mo and three O atoms in general positions. These cations and anions are linked via N—H...O hydrogen bonds, forming a layer structure.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](N-C) = 0.008 Å
• R factor = 0.031
• wR factor = 0.081
• Data-to-parameter ratio = 15.2

checkCIF/PLATON results

No syntax errors found



Alert level C
RINTA01_ALERT_3_C  The value of Rint is greater than 0.10
            Rint given   0.109
PLAT020_ALERT_3_C The value of Rint is greater than 0.10 .........       0.11
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.88
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.52
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Mo3    -   O9      ..       5.04 su
PLAT430_ALERT_2_C Short Inter D...A Contact  O8     ..  O11     ..       2.85 Ang.
PLAT601_ALERT_2_C Structure Contains Solvent Accessible VOIDS of .      41.00 A   3 

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.884
            Tmax scaled      0.429 Tmin scaled      0.255
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   8 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   4 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL.

Tris(dimethylammonium) hydrogen a-dodecamolybdosilicate

Crystal data

(C2H8N)3[HSiMo12O40]	Dx = 3.316 Mg m^−3
Mr = 1957.65	Mo Kα radiation, λ = 0.71073 Å
Hexagonal, R3m	Cell parameters from 5375 reflections
Hall symbol: -R 3 2"	θ = 2.4–29.5°
a = 16.4365 (8) Å	µ = 3.85 mm^−1
c = 25.142 (2) Å	T = 293 K
V = 5882.3 (6) Å^3	Block, yellow
Z = 6	0.43 × 0.30 × 0.22 mm
F(000) = 5514

Data collection

Bruker SMART CCD area-detector diffractometer	1752 independent reflections
Radiation source: fine-focus sealed tube	1735 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.110
φ and ω scans	θmax = 28.0°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 2000)	h = −21→21
Tmin = 0.288, Tmax = 0.485	k = −16→21
13145 measured reflections	l = −33→30

Refinement

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)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.081	H-atom parameters constrained
S = 1.34	w = 1/[σ^2(Fo^2) + (0.014P)^2 + 41.0665P] where P = (Fo^2 + 2Fc^2)/3
1752 reflections	(Δ/σ)max = 0.001
115 parameters	Δρmax = 1.55 e Å^−3
0 restraints	Δρmin = −0.61 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Si1	0.0000	0.0000	0.23511 (8)	0.0104 (4)
Mo1	0.13563 (3)	0.067815 (16)	0.117155 (17)	0.01844 (13)
Mo2	0.21176 (2)	0.21820 (2)	0.237178 (13)	0.02002 (12)
Mo3	0.074905 (16)	0.14981 (3)	0.345728 (16)	0.01944 (13)
O1	0.0000	0.0000	0.1706 (2)	0.0132 (11)
O2	0.05390 (12)	0.1078 (2)	0.25660 (12)	0.0133 (6)
O3	0.2206 (3)	0.11032 (15)	0.07109 (14)	0.0274 (9)
O4	0.05455 (14)	0.1091 (3)	0.08785 (13)	0.0194 (7)
O5	0.18181 (19)	0.1705 (2)	0.16659 (10)	0.0207 (5)
O6	0.2337 (3)	0.11686 (13)	0.25148 (13)	0.0199 (7)
O7	0.3208 (2)	0.3106 (2)	0.22980 (10)	0.0268 (6)
O8	0.14036 (13)	0.2807 (3)	0.22515 (14)	0.0204 (7)
O9	0.19610 (18)	0.22909 (19)	0.31299 (9)	0.0209 (5)
O10	0.1056 (3)	0.05279 (13)	0.35292 (13)	0.0180 (7)
O11	0.09746 (15)	0.1949 (3)	0.40743 (14)	0.0253 (8)
C1	0.2084 (2)	0.4168 (4)	0.1248 (2)	0.0358 (14)
H1A	0.2064	0.4128	0.1629	0.054*
H1B	0.1773	0.4498	0.1129	0.054*
N2	0.16039 (18)	0.3208 (4)	0.10237 (17)	0.0291 (11)
H2A	0.1892	0.2901	0.1145	0.035*
C3	0.1584 (3)	0.3167 (5)	0.0436 (2)	0.0395 (16)
H3A	0.1261	0.2522	0.0323	0.059*
H3B	0.2215	0.3476	0.0302	0.059*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Si1	0.0105 (6)	0.0105 (6)	0.0101 (8)	0.0053 (3)	0.000	0.000
Mo1	0.0154 (2)	0.02076 (19)	0.0174 (2)	0.00771 (11)	0.00507 (15)	0.00254 (7)
Mo2	0.01244 (17)	0.01838 (18)	0.02367 (18)	0.00352 (13)	0.00257 (11)	0.00094 (11)
Mo3	0.02394 (19)	0.0202 (2)	0.01293 (19)	0.01011 (12)	−0.00233 (7)	−0.00465 (15)
O1	0.0149 (16)	0.0149 (16)	0.010 (2)	0.0074 (8)	0.000	0.000
O2	0.0137 (11)	0.0101 (14)	0.0150 (13)	0.0051 (7)	0.0000 (6)	0.0000 (12)
O3	0.022 (2)	0.0365 (18)	0.0190 (16)	0.0110 (10)	0.0074 (15)	0.0037 (7)
O4	0.0207 (13)	0.0230 (18)	0.0153 (14)	0.0115 (9)	0.0031 (7)	0.0062 (13)
O5	0.0215 (13)	0.0186 (12)	0.0188 (10)	0.0076 (11)	0.0012 (10)	−0.0008 (10)
O6	0.0182 (17)	0.0206 (13)	0.0201 (15)	0.0091 (9)	−0.0002 (13)	−0.0001 (7)
O7	0.0178 (13)	0.0219 (14)	0.0307 (13)	0.0025 (11)	0.0039 (11)	−0.0033 (11)
O8	0.0223 (14)	0.0131 (16)	0.0227 (16)	0.0066 (8)	0.0000 (7)	0.0000 (13)
O9	0.0170 (12)	0.0220 (13)	0.0170 (10)	0.0046 (11)	−0.0018 (9)	−0.0019 (10)
O10	0.0180 (17)	0.0173 (12)	0.0190 (15)	0.0090 (8)	−0.0024 (13)	−0.0012 (7)
O11	0.0321 (16)	0.024 (2)	0.0171 (15)	0.0121 (10)	−0.0039 (7)	−0.0078 (14)
C1	0.046 (3)	0.022 (3)	0.032 (3)	0.0108 (14)	0.0012 (12)	0.002 (2)
N2	0.035 (2)	0.024 (2)	0.024 (2)	0.0122 (12)	0.0046 (9)	0.0092 (19)
C3	0.054 (3)	0.032 (3)	0.026 (3)	0.0161 (17)	0.0012 (12)	0.002 (2)

Geometric parameters (Å, º)

Si1—O1	1.622 (5)	Mo2—O9	1.943 (2)
Si1—O2	1.627 (3)	Mo2—O2	2.357 (2)
Si1—O2^i	1.627 (3)	Mo3—O11	1.679 (3)
Si1—O2^ii	1.627 (3)	Mo3—O10	1.906 (4)
Mo1—O3	1.675 (4)	Mo3—O9	1.936 (3)
Mo1—O4^ii	1.9193 (17)	Mo3—O2	2.319 (3)
Mo1—O4	1.9193 (17)	C1—N2	1.478 (8)
Mo1—O5	1.921 (3)	C1—H1A	0.9604
Mo1—O5^iii	1.921 (3)	C1—H1B	0.9599
Mo1—O1	2.352 (3)	N2—C3	1.478 (7)
Mo2—O7	1.682 (3)	N2—H2A	0.9000
Mo2—O5	1.903 (3)	C3—H3A	0.9614
Mo2—O6	1.907 (4)	C3—H3B	0.9600
Mo2—O8	1.931 (4)
O1—Si1—O2	109.40 (13)	O10—Mo3—O9	89.42 (14)
O2—Si1—O2^i	109.55 (13)	O11—Mo3—O9^iv	99.79 (13)
O3—Mo1—O4	99.73 (13)	O9—Mo3—O9^iv	87.64 (17)
O4^ii—Mo1—O4	89.0 (2)	O11—Mo3—O2	172.46 (17)
O3—Mo1—O5	101.55 (13)	O10^i—Mo3—O2	84.54 (12)
O4^ii—Mo1—O5	158.69 (12)	O10—Mo3—O2	84.54 (12)
O4—Mo1—O5	88.67 (14)	O9—Mo3—O2	74.90 (9)
O5—Mo1—O5^iii	85.88 (17)	Si1—O1—Mo1	124.83 (10)
O3—Mo1—O1	171.09 (18)	Mo1^ii—O1—Mo1	90.61 (15)
O4—Mo1—O1	74.08 (11)	Si1—O1—Mo1^i	124.83 (10)
O5—Mo1—O1	84.91 (11)	Mo1—O1—Mo1^i	90.61 (15)
O7—Mo2—O5	102.03 (12)	Si1—O2—Mo3	124.34 (18)
O7—Mo2—O6	103.18 (15)	Si1—O2—Mo2	124.06 (10)
O5—Mo2—O6	86.50 (13)	Mo3—O2—Mo2	91.62 (10)
O7—Mo2—O8	99.12 (14)	Mo2—O2—Mo2^iv	91.43 (12)
O5—Mo2—O8	88.41 (13)	Mo1^i—O4—Mo1	121.18 (18)
O6—Mo2—O8	157.69 (15)	Mo2—O5—Mo1	150.79 (16)
O7—Mo2—O9	98.94 (12)	Mo2^iii—O6—Mo2	151.1 (2)
O5—Mo2—O9	159.02 (11)	Mo2^iv—O8—Mo2	121.76 (19)
O6—Mo2—O9	89.27 (13)	Mo3—O9—Mo2	119.61 (13)
O8—Mo2—O9	87.76 (14)	Mo3^ii—O10—Mo3	151.3 (2)
O7—Mo2—O2	169.56 (12)	N2—C1—H1A	109.0
O5—Mo2—O2	85.27 (11)	N2—C1—H1B	109.5
O6—Mo2—O2	84.53 (13)	H1A—C1—H1B	109.9
O8—Mo2—O2	73.40 (11)	C3—N2—C1	114.7 (5)
O9—Mo2—O2	73.87 (11)	C3—N2—H2A	108.6
O11—Mo3—O10	100.92 (14)	C1—N2—H2A	108.6
O10^i—Mo3—O10	86.1 (2)	N2—C3—H3A	109.4
O11—Mo3—O9	99.79 (13)	N2—C3—H3B	109.5
O10^i—Mo3—O9	159.29 (13)	H3A—C3—H3B	109.4

Symmetry codes: (i) −y, x−y, z; (ii) −x+y, −x, z; (iii) x, x−y, z; (iv) −x+y, y, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···O5	0.90	2.31	3.115 (5)	148
N2—H2A···O7^v	0.90	2.37	3.030 (3)	131

Symmetry code: (v) −x+2/3, −x+y+1/3, −z+1/3.