New organically templated vanadium tellurites: (H₂pn)[V₂TeO₈] (pn is propane-1,3-diamine)

The title compound, poly[propane-1,3-diaminium hexa-μ-oxido-dioxidotellurium(IV)divanadium(V)], (C₃H₁₂N₂)[V₂O₈Te] or (H₂pn)[V₂TeO₈] (pn is propane-1,3-diamine), contains a two-dimensional anionic layer and the diprotonated pn cation for charge compensation. The anionic layer consists of pyrovanadates and [TeO₃] pyramids, which are linked alternately through corner-sharing to form a one-dimensional chain. These one-dimensional chains are crosslinked through two weak Te—O bonds, constructing an anionic layer. Hydrogen bonds are observed involving the diprotonated pn cation and the O atoms of the anionic framework.

S1. Comment

A large variety of inorganic open framework compounds have been reported during the past decade, most of which are metal silicates, phosphates and carboxylates (Cheetham et al., 1999; Yu & Xu, 2006; Natarajan & Mandal, 2008). Recently, studies of such materials have been extended to include using oxotellurites as anionic units. The stereochemically active lone pair electrons of Te^IV can act as a structure-directing agent, exerting a significant influence on the Te coordination geometries, as well as on the structures of the compounds formed with other metals, and subsequently on their physical properties (Rao et al., 2006; Kim et al., 2007; Mao et al., 2008). It is noteworthy that vanadium can also adopt various coordination behaviors (Chiang & Chuang, 2005). The variety in the coordination chemistry of tellurium(IV) and vanadium suggests that a great deal of flexibility is possible in any framework architecture formed by them and indicates the potential for a variety of open framework topologies.

Most inorganic open framework materials are prepared under mild conditions in the presence of organic amines as structure-directing agents. The protonated organic amines usually occupy the structural voids and contribute to the stability of the framework through hydrogen bonding. This has promoted the formation of various interesting three-dimensional open-framework, two-dimensional layer and one-dimensional chain structures (Cheetham et al., 1999; Yu & Xu, 2006; Natarajan & Mandal, 2008). So far, four organically templated vanadium tellurites, including one three-dimensional, [H₂en]₂[V₂Te₆O₁₈], and three two-dimensional, [H₂en][(VO₂)(TeO₃)]₂.H₂O, [H₂pip][(VO₂)(TeO₃)]₂ and [H₂en][VTeO₅] (en is ethylenediamine and pip is piperazine), have been reported (Feng & Mao, 2005; Gao et al., 2005; Jung et al., 2006). In our previous work, we have obtained several vanadium selenites and molybdenum tellurites (Lian et al., 2004; Hou et al., 2005, 2006). For the present work, we used propane-1,3-diamine (pn) as a structure-directing agent, and prepared a new organically templated vanadium tellurite, [H₂pn][V₂TeO₈], (I), which contains a layered inorganic skeleton.

The asymmetric unit of (I) contains two crystallographically unique V atoms, one Te and eight O atoms, and one doubly protonated pn cation (Fig. 1). All atoms reside on general positions. Atoms V1 and V2 both have a slightly distorted tetrahedral environment (Table 1) with V—O bond lengths of 1.602 (2)–1.8085 (18) Å and O—V—O bond angles in the range 107.03 (11)–113.49 (10)°. The V1- and V2-centered tetrahedra are joined to form a pyrovanadate unit by sharing a vertex at atom O6. Atom Te1 has a pyramidal coordination geometry with one terminal atom, O1, and two bridging atoms (O2 and O3). The lone pair of electrons occupies an apical position. The Te—O_terminal bond, Te1—O1, is shorter than the Te—O_bridging bonds, Te1—O2 and Te1—O3 (Table 1). Bond valence sum calculations give values of 4.10 for Te1, and 5.10 and 5.12 for V1 and V2, respectively (Brown & Shannon, 1973), consistent with the oxidation states of +4 for Te and +5 for V.

The pyrovanadate unit and [TeO₃] pyramid are bridged by atoms O2 and O3 into an alternating sequence, forming a [V₂TeO₈]_n^2n- chain along the [101] direction. As shown in Fig. 2, the [V₂TeO₈]_n^2n- chains are further situated abreast on the (202) plane, and each chain connects with two adjacent chains through two weak Te—O bonds, namely Te1 — O5B [2.421 (2) Å] and Te1—O8C [2.646 (2) Å; symmetry codes are given in the Fig. 1 caption], forming a two-dimensional [V₂TeO₈]_n^2n- anionic inorganic skeleton. The importance of weak Te—O bonds had also been observed in another two-dimensional vanadium tellurite, [H₂en][VTeO₅]₂ (Jung et al., 2006), which has a one-dimensional anionic chain similar to that of NaVTeO₅ (Darriet et al., 1972), if one disregards the weak Te—O bonds [2.466 (3) Å].

The interlayer space is occupied by H₂pn cations. In order to balance the negative charge of the anionic framework, the two terminal amine groups of the propane-1,3-diamine molecules are protonated. Both of the protonated NH₃ groups act as hydrogen-bond donors to form six hydrogen bonds in which five O atoms of the anionic layers act as acceptors (Table 2). The two shortest hydrogen bonds, with short O···N contact distances of 2.717 (3) and 2.789 (3) Å, and nearly linear N—H···O angles, involve the terminal atom O1 of the [TeO₃] pyramid. These moderately strong hydrogen bonds may play a key role in the formation of the uncommon Te-centered polyhedron in the solid state, and they undoubtedly enhance the stability of the layered architecture.

This study shows that weak Te—O bonds as well as hydrogen bonds have an important effect on the formation of the structure of the final product.

Related literature

For related literature, see: Brown & Shannon (1973); Cheetham et al. (1999); Chiang & Chuang (2005); Darriet et al. (1972); Feng & Mao (2005); Gao et al. (2005); Hou et al. (2005, 2006); Jung et al. (2006); Kim et al. (2007); Lian et al. (2004); Mao et al. (2008); Natarajan & Mandal (2008); Rao et al. (2006); Yu & Xu (2006).

S2. Experimental

The reactants NaVO₃.2H₂O (0.314 g, 2 mmol), Na₂TeO₃ (0.442 g, 2 mmol) and propane-1,3-diamine (0.17 ml, 2 mmol) were added to 7 ml of water. The mixture, a gel, was placed in a 25 ml Teflon-lined stainless steel vessel and heated at 363 K for 60 h. After slow cooling to room temperature, pale-brown block crystals of the title compound suitable for X-ray analysis were isolated from the solution by filtration.

S3. Refinement

Carbon-bound H atoms were positioned geometrically and were included in the refinement in the riding-model approximation [U_iso(H) = 1.2U_eq(C) and C—H = 0.97 Å]. H atoms bonded to N atoms were positioned geometrically and were included in the refinement as part of a rigid rotating group [U_iso(H) = 1.5U_eq(N) and N—H = 0.89 Å].

Computing details

Data collection: CrystalClear (Rigaku, 2002); cell refinement: CrystalClear (Rigaku, 2002); data reduction: CrystalClear (Rigaku, 2002); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. Asymmetric unit and some symmetry-related atoms of 1, showing 30% probability displacement. The weak Te—O bonds are drawn in dashed lines. [symmetry code: (a) 1/2 + x, 1/2 - y, 1/2 + z; (b) 1.5 - x, 1/2 + y, 1/2 - z; (c) 2 - x, 1 - y, 1 - z.]
	Fig. 2. Packing diagram of 1, the hydrogen-bond interactions are drawn in cyan and weak Te—O bonds are drawn as dashed lines.

poly[propane-1,3-diaminium hexa-µ-oxido-dioxidotellurium(IV)divanadium(V)]

Crystal data

(C3H12N2)[V2O8Te]	F(000) = 824
Mr = 433.63	Dx = 2.605 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 25 reflections
a = 8.6312 (17) Å	θ = 12–18°
b = 8.4130 (17) Å	µ = 4.31 mm^−1
c = 15.301 (3) Å	T = 293 K
β = 95.71 (3)°	Block, pale brown
V = 1105.5 (4) Å^3	0.12 × 0.10 × 0.06 mm
Z = 4

Data collection

Rigaku Mercury CCD area-detector diffractometer	2534 independent reflections
Radiation source: fine-focus sealed tube	2292 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.048
ω scans	θmax = 27.5°, θmin = 2.6°
Absorption correction: multi-scan (RAPID-AUTO; Rigaku, 1998)	h = 0→11
Tmin = 0.626, Tmax = 0.782	k = 0→10
10515 measured reflections	l = −19→19

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)] = 0.021	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.052	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.026P)^2 + 0.261P] where P = (Fo^2 + 2Fc^2)/3
2534 reflections	(Δ/σ)max = 0.001
145 parameters	Δρmax = 0.70 e Å^−3
0 restraints	Δρmin = −1.86 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
Te1	0.863963 (16)	0.450375 (18)	0.220130 (9)	0.01436 (6)
V1	0.84702 (5)	0.26099 (5)	0.41423 (3)	0.01581 (9)
V2	1.03793 (5)	0.21466 (5)	0.61751 (2)	0.01558 (9)
O1	1.0455 (2)	0.4173 (2)	0.17084 (12)	0.0206 (4)
O2	0.7449 (2)	0.2921 (2)	0.15070 (11)	0.0218 (4)
O5	0.7118 (2)	0.1141 (2)	0.40709 (12)	0.0268 (4)
O7	0.9590 (3)	0.0544 (2)	0.65393 (14)	0.0310 (5)
O8	0.9657 (2)	0.3679 (2)	0.66646 (13)	0.0289 (4)
O6	1.0005 (2)	0.2198 (2)	0.49999 (12)	0.0261 (4)
O4	0.7593 (2)	0.4220 (3)	0.43582 (14)	0.0334 (5)
O3	0.9174 (2)	0.2837 (2)	0.30886 (11)	0.0207 (4)
C1	0.3979 (3)	0.5139 (3)	0.37754 (17)	0.0227 (5)
H1A	0.3596	0.5629	0.4286	0.027*
H1B	0.5108	0.5132	0.3862	0.027*
C2	0.3382 (3)	0.3441 (3)	0.36847 (16)	0.0221 (5)
H2A	0.2267	0.3447	0.3521	0.027*
H2B	0.3877	0.2900	0.3227	0.027*
C3	0.3738 (3)	0.2570 (3)	0.45486 (16)	0.0210 (5)
H3A	0.4855	0.2542	0.4704	0.025*
H3B	0.3267	0.3129	0.5009	0.025*
N1	0.3457 (2)	0.6083 (3)	0.29779 (14)	0.0215 (4)
H1C	0.3818	0.7072	0.3043	0.032*
H1E	0.2421	0.6102	0.2903	0.032*
H1D	0.3820	0.5641	0.2511	0.032*
N2	0.3120 (2)	0.0919 (3)	0.44732 (14)	0.0216 (5)
H2C	0.3336	0.0417	0.4983	0.032*
H2D	0.3562	0.0405	0.4054	0.032*
H2E	0.2094	0.0948	0.4338	0.032*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Te1	0.01318 (10)	0.01649 (9)	0.01367 (9)	0.00006 (5)	0.00266 (6)	−0.00034 (5)
V1	0.0151 (2)	0.0193 (2)	0.01296 (19)	−0.00030 (16)	0.00081 (15)	0.00226 (16)
V2	0.01425 (19)	0.0197 (2)	0.01257 (19)	0.00033 (16)	0.00034 (14)	−0.00054 (17)
O1	0.0166 (8)	0.0220 (8)	0.0247 (9)	0.0022 (7)	0.0092 (7)	0.0042 (8)
O2	0.0188 (9)	0.0224 (9)	0.0232 (9)	−0.0022 (7)	−0.0027 (7)	−0.0035 (8)
O5	0.0249 (10)	0.0311 (10)	0.0249 (9)	−0.0078 (9)	0.0045 (7)	0.0033 (9)
O7	0.0329 (11)	0.0325 (12)	0.0281 (11)	−0.0087 (9)	0.0049 (8)	0.0054 (9)
O8	0.0214 (9)	0.0332 (11)	0.0322 (10)	0.0049 (9)	0.0029 (7)	−0.0082 (9)
O6	0.0243 (9)	0.0355 (10)	0.0176 (8)	0.0017 (9)	−0.0021 (7)	0.0027 (9)
O4	0.0327 (12)	0.0310 (11)	0.0373 (12)	0.0082 (9)	0.0078 (9)	−0.0032 (10)
O3	0.0241 (9)	0.0232 (9)	0.0152 (8)	0.0019 (8)	0.0035 (7)	0.0037 (7)
C1	0.0237 (13)	0.0211 (12)	0.0230 (13)	−0.0040 (11)	0.0005 (10)	−0.0022 (11)
C2	0.0259 (13)	0.0192 (12)	0.0209 (12)	−0.0028 (11)	0.0001 (10)	−0.0007 (11)
C3	0.0233 (13)	0.0197 (12)	0.0201 (12)	−0.0002 (10)	0.0027 (10)	−0.0012 (10)
N1	0.0207 (10)	0.0200 (11)	0.0246 (11)	0.0006 (9)	0.0061 (8)	0.0032 (9)
N2	0.0257 (12)	0.0204 (11)	0.0195 (10)	0.0009 (10)	0.0063 (8)	0.0013 (9)

Geometric parameters (Å, º)

Te1—O1	1.8263 (17)	C1—C2	1.520 (4)
Te1—O2	1.9343 (18)	C1—H1A	0.9700
Te1—O3	1.9742 (18)	C1—H1B	0.9700
Te1—O5^i	2.421 (2)	C2—C3	1.516 (3)
Te1—O8^ii	2.646 (2)	C2—H2A	0.9700
V1—O4	1.602 (2)	C2—H2B	0.9700
V1—O5	1.6957 (19)	C3—N2	1.488 (3)
V1—O3	1.7888 (17)	C3—H3A	0.9700
V1—O6	1.8031 (19)	C3—H3B	0.9700
V2—O7	1.6339 (19)	N1—H1C	0.8900
V2—O8	1.645 (2)	N1—H1E	0.8900
V2—O6	1.7954 (19)	N1—H1D	0.8900
V2—O2^iii	1.8085 (18)	N2—H2C	0.8900
O2—V2^iv	1.8085 (18)	N2—H2D	0.8900
O5—Te1^v	2.421 (2)	N2—H2E	0.8900
C1—N1	1.488 (3)
O1—Te1—O2	95.69 (8)	C2—C1—H1A	109.5
O1—Te1—O3	91.40 (8)	N1—C1—H1B	109.5
O2—Te1—O3	87.92 (8)	C2—C1—H1B	109.5
O1—Te1—O5^i	85.91 (7)	H1A—C1—H1B	108.1
O2—Te1—O5^i	82.19 (7)	C3—C2—C1	109.7 (2)
O3—Te1—O5^i	169.43 (7)	C3—C2—H2A	109.7
O1—Te1—O8^ii	85.15 (7)	C1—C2—H2A	109.7
O2—Te1—O8^ii	171.16 (7)	C3—C2—H2B	109.7
O3—Te1—O8^ii	83.26 (7)	C1—C2—H2B	109.7
O5^i—Te1—O8^ii	106.65 (7)	H2A—C2—H2B	108.2
O4—V1—O5	107.03 (11)	N2—C3—C2	110.1 (2)
O4—V1—O3	107.78 (10)	N2—C3—H3A	109.6
O5—V1—O3	108.26 (9)	C2—C3—H3A	109.6
O4—V1—O6	109.90 (11)	N2—C3—H3B	109.6
O5—V1—O6	110.98 (9)	C2—C3—H3B	109.6
O3—V1—O6	112.68 (9)	H3A—C3—H3B	108.2
O7—V2—O8	107.58 (10)	C1—N1—H1C	109.5
O7—V2—O6	108.78 (10)	C1—N1—H1E	109.5
O8—V2—O6	113.49 (10)	H1C—N1—H1E	109.5
O7—V2—O2^iii	108.19 (10)	C1—N1—H1D	109.5
O8—V2—O2^iii	107.76 (9)	H1C—N1—H1D	109.5
O6—V2—O2^iii	110.87 (9)	H1E—N1—H1D	109.5
V2^iv—O2—Te1	129.18 (10)	C3—N2—H2C	109.5
V1—O5—Te1^v	126.54 (9)	C3—N2—H2D	109.5
V2—O6—V1	141.21 (12)	H2C—N2—H2D	109.5
V1—O3—Te1	128.22 (10)	C3—N2—H2E	109.5
N1—C1—C2	110.8 (2)	H2C—N2—H2E	109.5
N1—C1—H1A	109.5	H2D—N2—H2E	109.5

Symmetry codes: (i) −x+3/2, y+1/2, −z+1/2; (ii) −x+2, −y+1, −z+1; (iii) x+1/2, −y+1/2, z+1/2; (iv) x−1/2, −y+1/2, z−1/2; (v) −x+3/2, y−1/2, −z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1C···O1^i	0.89	1.90	2.789 (3)	175
N1—H1E···O8^vi	0.89	1.98	2.803 (3)	153
N1—H1D···O7^iv	0.89	1.96	2.846 (3)	174
N2—H2C···O5^vii	0.89	2.02	2.846 (3)	154
N2—H2E···O7^vii	0.89	2.26	2.944 (3)	134
N2—H2D···O1^v	0.89	1.83	2.717 (3)	173
N2—H2E···O6^viii	0.89	2.40	3.077 (3)	133

Symmetry codes: (i) −x+3/2, y+1/2, −z+1/2; (iv) x−1/2, −y+1/2, z−1/2; (v) −x+3/2, y−1/2, −z+1/2; (vi) −x+1, −y+1, −z+1; (vii) −x+1, −y, −z+1; (viii) x−1, y, z.