Layered zincoarsenate templated by N,N,N',N'-tetra­methyl­ethyl­ene-di­amine mol­ecules

The title compound, N,N,N',N'-tetra­methyl­ethyl­enedi­ammon­ium di­aqua­(arsenate)­(hydrogen arsenate)­dizinc(II), (C₆H₁₈N₂)_0.5[Zn₂(AsO₄)(HAsO₄)(H₂O)₂], is a new zincoarsenate obtained by hydro­thermal synthesis. The structure consists of infinite two-dimensional anionic layers alternating with planes containing centrosymmetric organic diprotonated template N,N,N',N'-tetra­methyl­ethyl­enedi­ammonium cations, [H₃N­C₆H₁₂NH₃]²⁺. The latter are interconnected to the framework through hydrogen bonds.

S1. Comment

Microporous compounds with an anionic framework are of particular interest because of their catalytic properties (Thomas, 1988) and their use as molecular sieves. During the last decade, many aluminophosphates (Chippindale et al., 1992; Yao et al., 1999), gallophosphates (Jones et al., 1991; Chippindale et al., 1998) and zincophosphates (Harrison et al., 1992; Chavez et al., 1999) with open frameworks have been synthesized hydrothermally. Replacement of phosphate by arsenate in the framework leads to a variety of phases (Bu et al., 1998; Harrison et al., 1999), some of which are analogous to zincophosphates (Harrison et al., 1999). In our search for novel framework structures containing zinc in combination with P or As atoms, we have discovered two new zincophosphate materials, namely Zn₂(HPO₄)₂Cl₂·2NC₆H₁₄ (Trojette et al., 1998) and [H₂N₂C₆H₁₆]_0.5[Zn₂(PO₄)(HPO₄)(H₂O)]·H₂O (Hajem et al., 1999). As part of these studies, we have examined the structure of [H₂N₂C₆H₁₆]_0.5[Zn₂(AsO₄)(HAsO₄)(H₂O)₂], (I) and report here its synthesis and structural characterization.

The title compound contains a layered structure (Fig. 1) consisting of organic sheets corresponding to N,N,N',N'-tetramethylethylenediamine (TMEDA) molecules and inorganic layers alternating along [010].

In the framework structure, the Zn atoms exhibit two types of coordination. The polyhedron around Zn1 is a distorted trigonal bipyramid formed by four O atoms and one terminal water molecule (OW2). The Zn2 atom is surrounded by five O atoms and one terminal water molecule (OW1) resulting in an octahedral coordination. The two As atoms are tetrahedrally coordinated by O atoms. The As1 atom has two As—O bonds bridging to Zn atoms. The remaining As—O bonds consist of an As1—O4H group and an As1═O1 double bond. For the As2 atom, three of the coordinating O atoms are bonded to Zn atoms, while the fourth O atom is terminal (As2═O5).

The two-dimensional framework can be considered as a parallel arrangement (along the [101] direction) of chains built up from ZnO₆ and ZnO₅ polyhedra interconnected by AsO₄ tetrahedra (Fig. 2). Each chain makes –Zn1–Zn1–Zn2–Zn2– linkages (oxygen designation omitted) and every zinc polyhedron shares two edges with its nearest neighbor zinc polyhedron through four trigonally coordinated O atoms. These O atoms have a trigonal coordination because they contain not only Zn—O—Zn linkages, but also Zn—O—As linkages.

The TMEDA molecules are inserted between the inorganic layers and give rise to hydrogen bonds between H atoms of the protonated amine and O atoms of the framework (N—HN···O8; Fig. 1). Finally, the terminal –OH and OH₂ groups participate in in-sheet hydrogen bonds, i.e. O4—HO4···O8, OW1—H1W1···O1, OW1—H2W1···O5, OW2—H1W2···O5 and OW2—H2W2···O1.

S2. Experimental

The title compound was synthesized hydrothermally from a 1:2:2:3:100 mixture of ZnO (0.12 g), HCl (38%, 0.29 g), H₃AsO₄ (80%, 0.51 g), C₆H₁₆N₂ (0.50 g) and H₂O (2.58 g). A thick gel formed which was then heated at 373 K for 7 d. The crystalline obtained product was filtered, washed with distilled water and dried in air at room temperature.

S3. Refinement

H atoms other than those of the aqua ligands or NH groups were treated as riding with O—H = 0.82 and C—H = 0.96–0.97 Å. The H atoms of NH groups were refined freely and aqua H atoms were refined with DFIX constraints and O—H = 0.90 Å.

Computing details

Data collection: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); cell refinement: CAD-4 EXPRESS; data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. View of the structure of (I) down the a axis showing the location of the TMEDA molecules.
	Fig. 2. A polyhedral representation of the anion sheet viewed down the b direction.

N,N,N',N'-tetramethylethylenediammonium (arsenate)diaqua(hydrogen arsenate)dizinc(II)

Crystal data

(C6H18N2)0.5[Zn2(AsO4)(HAsO4)(H2O)2]	Z = 2
Mr = 504.73	F(000) = 490
Triclinic, P1	Dx = 2.922 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71069 Å
a = 8.087 (1) Å	Cell parameters from 25 reflections
b = 11.354 (2) Å	θ = 11.2–13.9°
c = 6.622 (2) Å	µ = 9.95 mm^−1
α = 101.15 (2)°	T = 293 K
β = 96.64 (2)°	Plate, colourless
γ = 102.79 (1)°	0.45 × 0.25 × 0.14 mm
V = 573.7 (2) Å^3

Data collection

Enraf-Nonius CAD-4 diffractometer	2284 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.020
Graphite monochromator	θmax = 27.0°, θmin = 2.6°
ω/2θ scans	h = −10→10
Absorption correction: ψ scan (North et al., 1968)	k = −14→0
Tmin = 0.063, Tmax = 0.248	l = −8→8
2630 measured reflections	2 standard reflections every 120 min
2499 independent reflections	intensity decay: 0.7%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.027	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.077	Calculated w = 1/[σ^2(Fo^2) + (0.0505P)^2 + 0.775P] where P = (Fo^2 + 2Fc^2)/3
S = 1.12	(Δ/σ)max < 0.001
2499 reflections	Δρmax = 1.45 e Å^−3
196 parameters	Δρmin = −0.79 e Å^−3
5 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0095 (10)

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
As1	0.45470 (4)	0.15530 (3)	0.18012 (5)	0.0092 (1)
As2	−0.13060 (4)	0.12917 (3)	−0.31863 (5)	0.0080 (1)
Zn1	0.11517 (5)	−0.04617 (4)	−0.15912 (6)	0.0119 (1)
Zn2	0.43666 (5)	0.08903 (4)	−0.33855 (6)	0.0107 (1)
O1	0.3695 (3)	0.2702 (2)	0.2734 (4)	0.0184 (5)
O2	0.4659 (3)	0.0665 (2)	0.3523 (3)	0.0125 (5)
O3	0.3543 (3)	0.0721 (2)	−0.0584 (4)	0.0137 (5)
O4	0.6634 (3)	0.2186 (3)	0.1535 (4)	0.0240 (6)
HO4	0.6724	0.2048	0.0296	0.05 (2)*
O5	0.0273 (3)	0.2501 (2)	−0.3265 (4)	0.0157 (5)
O6	−0.1891 (3)	0.0324 (2)	−0.5578 (3)	0.0113 (5)
O7	−0.0696 (3)	0.0499 (2)	−0.1435 (4)	0.0138 (5)
O8	−0.2938 (3)	0.1892 (2)	−0.2375 (4)	0.0122 (5)
OW1	0.3595 (3)	0.2523 (2)	−0.3272 (4)	0.0165 (5)
OW2	−0.0281 (3)	−0.2236 (2)	−0.2659 (4)	0.0170 (5)
N	0.2025 (4)	0.5578 (3)	0.2035 (5)	0.0192 (6)
C1	0.2376 (6)	0.5494 (4)	0.4263 (6)	0.0294 (9)
H1C1	0.1718	0.5953	0.5071	0.05 (2)*
H2C1	0.3578	0.5834	0.4800	0.07 (2)*
H3C1	0.2057	0.4641	0.4349	0.03 (1)*
C2	0.3305 (5)	0.5121 (4)	0.0834 (7)	0.0273 (9)
H1C2	0.3127	0.5257	−0.0553	0.03 (1)*
H2C2	0.3160	0.4251	0.0764	0.05 (2)*
H3C2	0.4447	0.5563	0.1520	0.04 (1)*
C3	0.0206 (5)	0.4912 (4)	0.1097 (6)	0.0196 (7)
H1C3	−0.0567	0.5228	0.1951	0.02 (1)*
H2C3	0.0035	0.4035	0.1065	0.01 (1)*
HN	0.218 (6)	0.639 (1)	0.203 (7)	0.02 (1)*
H1W1	0.361 (6)	0.265 (5)	−0.457 (3)	0.03 (1)*
H2W1	0.255 (4)	0.247 (7)	−0.291 (12)	0.09 (3)*
H1W2	−0.031 (7)	−0.242 (5)	−0.405 (2)	0.03 (1)*
H2W2	−0.139 (3)	−0.238 (6)	−0.250 (10)	0.06 (2)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
As1	0.0090 (2)	0.0121 (2)	0.0062 (2)	0.0021 (1)	0.0003 (1)	0.0026 (1)
As2	0.0074 (2)	0.0109 (2)	0.0059 (2)	0.0034 (1)	0.0005 (1)	0.0017 (1)
Zn1	0.0106 (2)	0.0157 (2)	0.0088 (2)	0.0020 (1)	0.0013 (1)	0.0027 (1)
Zn2	0.0112 (2)	0.0137 (2)	0.0078 (2)	0.0045 (1)	0.0017 (1)	0.0025 (1)
O1	0.023 (1)	0.016 (1)	0.018 (1)	0.009 (1)	0.003 (1)	0.003 (1)
O2	0.016 (1)	0.017 (1)	0.008 (1)	0.008 (1)	0.003 (1)	0.005 (1)
O3	0.011 (1)	0.020 (1)	0.007 (1)	0.001 (1)	0.000 (1)	0.002 (1)
O4	0.013 (1)	0.039 (2)	0.012 (1)	−0.008 (1)	0.001 (1)	0.005 (1)
O5	0.011 (1)	0.015 (1)	0.018 (1)	0.000 (1)	0.003 (1)	0.002 (1)
O6	0.010 (1)	0.015 (1)	0.007 (1)	0.002 (1)	0.000 (1)	0.000 (1)
O7	0.014 (1)	0.024 (1)	0.009 (1)	0.009 (1)	0.003 (1)	0.008 (1)
O8	0.010 (1)	0.014 (1)	0.014 (1)	0.004 (1)	0.004 (1)	0.003 (1)
OW1	0.015 (1)	0.019 (1)	0.016 (1)	0.006 (1)	0.002 (1)	0.004 (1)
OW2	0.017 (1)	0.019 (1)	0.016 (1)	0.004 (1)	0.004 (1)	0.005 (1)
N	0.021 (2)	0.012 (1)	0.023 (2)	0.003 (1)	0.000 (1)	0.003 (1)
C1	0.030 (2)	0.028 (2)	0.023 (2)	0.000 (2)	−0.005 (2)	0.003 (2)
C2	0.021 (2)	0.025 (2)	0.033 (2)	0.007 (2)	0.001 (2)	−0.001 (2)
C3	0.019 (2)	0.017 (2)	0.021 (2)	0.003 (1)	0.000 (1)	0.004 (1)

Geometric parameters (Å, º)

As1—O1	1.656 (2)	O4—HO4	0.8200
As1—O2	1.669 (2)	O6—Zn1^i	2.056 (2)
As1—O3	1.683 (2)	O6—Zn2^i	2.116 (2)
As1—O4	1.725 (2)	O7—Zn1^ii	2.086 (2)
As2—O5	1.669 (2)	O8—Zn2^viii	2.182 (2)
As2—O6	1.692 (2)	OW1—H1W1	0.896 (10)
As2—O7	1.693 (2)	OW1—H2W1	0.898 (10)
As2—O8	1.707 (2)	OW2—H1W2	0.900 (10)
Zn1—OW2	2.032 (3)	OW2—H2W2	0.900 (10)
Zn1—O7	2.036 (2)	N—C1	1.495 (5)
Zn1—O3	2.048 (2)	N—C3	1.496 (5)
Zn1—O6^i	2.056 (2)	N—C2	1.497 (5)
Zn1—O7^ii	2.086 (2)	N—HN	0.901 (10)
Zn1—Zn1^ii	3.1508 (10)	C1—H1C1	0.9600
Zn2—O2^iii	2.061 (2)	C1—H2C1	0.9600
Zn2—O3	2.071 (2)	C1—H3C1	0.9600
Zn2—OW1	2.074 (3)	C2—H1C2	0.9600
Zn2—O2^iv	2.078 (2)	C2—H2C2	0.9600
Zn2—O6^i	2.116 (2)	C2—H3C2	0.9600
Zn2—O8^v	2.182 (2)	C3—C3^ix	1.514 (7)
Zn2—Zn2^vi	3.0757 (10)	C3—H1C3	0.9700
O2—Zn2^vii	2.061 (2)	C3—H2C3	0.9700
O2—Zn2^iv	2.078 (2)
O1—As1—O2	109.78 (12)	O6^i—Zn2—Zn2^vi	86.76 (7)
O1—As1—O3	113.58 (12)	O8^v—Zn2—Zn2^vi	86.47 (7)
O2—As1—O3	112.19 (12)	As1—O2—Zn2^vii	133.09 (14)
O1—As1—O4	108.11 (14)	As1—O2—Zn2^iv	129.96 (13)
O2—As1—O4	106.62 (13)	Zn2^vii—O2—Zn2^iv	95.98 (10)
O3—As1—O4	106.18 (12)	As1—O3—Zn1	131.82 (13)
O5—As2—O6	109.33 (12)	As1—O3—Zn2	126.01 (13)
O5—As2—O7	111.73 (12)	Zn1—O3—Zn2	101.54 (10)
O6—As2—O7	108.98 (12)	As1—O4—HO4	109.5
O5—As2—O8	106.16 (12)	As2—O6—Zn1^i	132.13 (13)
O6—As2—O8	112.70 (11)	As2—O6—Zn2^i	122.90 (12)
O7—As2—O8	107.97 (11)	Zn1^i—O6—Zn2^i	99.79 (10)
OW2—Zn1—O7	101.80 (10)	As2—O7—Zn1	126.44 (13)
OW2—Zn1—O3	147.79 (10)	As2—O7—Zn1^ii	132.93 (14)
O7—Zn1—O3	110.39 (10)	Zn1—O7—Zn1^ii	99.70 (10)
OW2—Zn1—O6^i	93.94 (10)	As2—O8—Zn2^viii	122.08 (13)
O7—Zn1—O6^i	103.08 (9)	Zn2—OW1—H1W1	104 (3)
O3—Zn1—O6^i	80.28 (9)	Zn2—OW1—H2W1	112 (5)
OW2—Zn1—O7^ii	90.88 (10)	H1W1—OW1—H2W1	112 (6)
O7—Zn1—O7^ii	80.30 (10)	Zn1—OW2—H1W2	107 (3)
O3—Zn1—O7^ii	93.23 (10)	Zn1—OW2—H2W2	116 (4)
O6^i—Zn1—O7^ii	173.39 (9)	H1W2—OW2—H2W2	105 (5)
OW2—Zn1—Zn1^ii	98.18 (7)	C1—N—C3	110.1 (3)
O7—Zn1—Zn1^ii	40.73 (6)	C1—N—C2	110.8 (3)
O3—Zn1—Zn1^ii	105.22 (7)	C3—N—C2	112.9 (3)
O6^i—Zn1—Zn1^ii	143.50 (7)	C1—N—HN	107 (3)
O7^ii—Zn1—Zn1^ii	39.57 (7)	C3—N—HN	109 (3)
O2^iii—Zn2—O3	165.18 (10)	C2—N—HN	107 (3)
O2^iii—Zn2—OW1	94.28 (10)	N—C1—H1C1	109.5
O3—Zn2—OW1	91.03 (10)	N—C1—H2C1	109.5
O2^iii—Zn2—O2^iv	84.02 (10)	H1C1—C1—H2C1	109.5
O3—Zn2—O2^iv	91.70 (9)	N—C1—H3C1	109.5
OW1—Zn2—O2^iv	175.24 (10)	H1C1—C1—H3C1	109.5
O2^iii—Zn2—O6^i	87.27 (9)	H2C1—C1—H3C1	109.5
O3—Zn2—O6^i	78.38 (9)	N—C2—H1C2	109.5
OW1—Zn2—O6^i	96.46 (10)	N—C2—H2C2	109.5
O2^iv—Zn2—O6^i	87.91 (10)	H1C2—C2—H2C2	109.5
O2^iii—Zn2—O8^v	91.28 (9)	N—C2—H3C2	109.5
O3—Zn2—O8^v	102.36 (9)	H1C2—C2—H3C2	109.5
OW1—Zn2—O8^v	92.10 (9)	H2C2—C2—H3C2	109.5
O2^iv—Zn2—O8^v	83.50 (9)	N—C3—C3^ix	110.4 (4)
O6^i—Zn2—O8^v	171.40 (9)	N—C3—H1C3	109.6
O2^iii—Zn2—Zn2^vi	42.22 (7)	C3^ix—C3—H1C3	109.6
O3—Zn2—Zn2^vi	131.90 (7)	N—C3—H2C3	109.6
OW1—Zn2—Zn2^vi	136.34 (7)	C3^ix—C3—H2C3	109.6
O2^iv—Zn2—Zn2^vi	41.80 (6)	H1C3—C3—H2C3	108.1

Symmetry codes: (i) −x, −y, −z−1; (ii) −x, −y, −z; (iii) x, y, z−1; (iv) −x+1, −y, −z; (v) x+1, y, z; (vi) −x+1, −y, −z−1; (vii) x, y, z+1; (viii) x−1, y, z; (ix) −x, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N—HN···O8^ix	0.90 (1)	1.87 (1)	2.760 (4)	168 (4)
O4—HO4···O8^v	0.82	1.80	2.619 (4)	174
OW1—H1W1···O1^iii	0.90 (1)	1.81 (1)	2.700 (4)	173 (5)
OW1—H2W1···O5	0.90 (1)	1.84 (3)	2.682 (3)	156 (7)
OW2—H1W2···O5^i	0.90 (1)	1.77 (1)	2.659 (4)	170 (5)
OW2—H2W2···O1^ii	0.90 (1)	1.80 (2)	2.686 (4)	169 (6)

Symmetry codes: (i) −x, −y, −z−1; (ii) −x, −y, −z; (iii) x, y, z−1; (v) x+1, y, z; (ix) −x, −y+1, −z.