[NH₃(CH₂)₃NH₃][Ga(P₂O₇)(H₂PO₄)]: a new organic­ally templated gallium phosphate-diphosphate

Propane-1,3-di­ammonium gallium phosphate diphosphate, [NH₃(CH₂)₃NH₃][Ga(P₂O₇)(H₂PO₄)], consists of anionic chains containing GaO₆ octahedra linked by tetrahedral P₂O₇ diphosphate and PO₂(OH)₂ units charge-balanced by 1,3-di­amino­propane dications. The chains, which are held together by a network of hydrogen bonds involving both interchain and chain-di­amine interactions, are isostructural with those previously observed in [NH₃(CH₂)₂NH₃][Ga(P₂O₇)(H₂PO₄)]. Different packing arrangements are, however, adopted in the two materials.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.028
• wR factor = 0.074
• Data-to-parameter ratio = 12.8

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

Reported here is the second example of an organically templated gallophosphate in which PO₄ and P₂O₇ groups coexist as independent units. The title compound, [NH₃(CH₂)₃NH₃] [Ga(P₂O₇)(H₂PO₄)], consists of one-dimensional polymeric gallium-phosphate-diphosphate anions of formula [Ga(P₂O₇)(H₂PO₄)]_x^2- running parallel to the c axis which are charge balanced by 1,3-diaminopropane dications lying in the interchain spaces (Fig. 1). The chains are isostructural with those found in [NH₃(CH₂)₂NH₃][Ga(P₂O₇)(H₂PO₄)] (Chippindale, 2000). However, the packing of the chains and amine dications is different in the two materials; the title compound crystallizes in C2/c, whereas [NH₃(CH₂)₂NH₃][Ga(P₂O₇)(H₂PO₄)] crystallizes in Cc.

One crystallographically distinct Ga atom and two distinct P atoms are present in octahedral GaO₆ and tetrahedral-based PO₄ and P₂O₇ units with site symmetries 1, 2 and 1, respectively (Fig. 2.). The GaO₆ octahedra share all their vertices with phosphorus-based bridging units. The P1-based phosphate group bridges adjacent Ga atoms via O1. The remaining P1—O2 bonds are substantially longer, consistent with the observation in difference Fourier maps of protons associated with these atoms. This is confirmed by bond-valence calculations (Brown & Altermatt, 1985). The P2-based diphosphate group has an eclipsed conformation and bridges the Ga atoms through O3—P2—O4 linkages. The P2—O6 bond is significantly longer than the other P2—O bonds but is of comparable length to P—O bonds of P—O—P diphosphate linkages in other metal diphosphates (Chippindale, 2000; Mandel, 1975). The remaining P2—O5 bond corresponds to a P—O bond with some degree of multiple-bond character.

The structure is held together by both interchain and chain-amine hydrogen bonding. The P1—O2H groups of the P1O₂(OH)₂ units and the terminal P2—O5 groups of the diphosphate units in neighbouring chains are sufficiently close for hydrogen bonding to occur between them to generate a three-dimensional assembly. Additional hydrogen bonding occurs between the NH₃ group of the diaminocation and the framework atoms O2, O4 and O5 (Table 2).

S2. Experimental

Single crystals of [NH₃(CH₂)₃NH₃][Ga(P₂O₇)(H₂PO₄)] were prepared under solvothermal conditions. Ga₂O₃ (0.876 g) was dispersed in ethylene glycol (5.6 ml) by stirring followed by addition of 1,3-diaminopropane (1.1 ml) and a small amount of Si(OEt)₄ which acts as a mineralizer. Aqueous H₃PO₄ (3 ml, 85 wt%) was then added and the gel stirred until homogeneous, sealed in a Teflon-lined steel autoclave and heated at 433 K for 7 d. The solid product was collected by filtration, washed copiously with water and dried in air at 353 K. A clear colourless crystal was isolated from the bulk sample for analysis. Powder X-ray diffraction and CHN analysis (calculated for C₃H₁₄GaN₂O₁₁P₃: C 8.65, H 3.39, N 6.72%; experimental: C 8.61, H 3.56, N 6.76%) showed that the sample was monophasic. This was confirmed by Energy Dispersive Analytical X-rays (EDAX) performed using a Phillips CM20 Transmission Electron Microscope which showed that all crystallites contained Ga and P but no Si and had a Ga:P ratio of 0.33 (2). Thermogravimetric analysis using a Stanton Redcroft STA 1000 Thermal Analyser over the range 553–883 K at a heating rate of 10 K min^-1 under flowing N₂, showed a smooth weight loss of 18.2%, over the range 553–883 K to give a black X-ray amorphous product. Loss of 1,3-diaminopropane would correspond to a weight loss of 17.8%.

S3. Refinement

The C, N and H template atoms and the framework H atoms were located in difference Fourier maps. The fractional coordinates and isotropic displacement parameters of the framework H atoms were refined. However, the template H atoms were placed geometrically during the final refinement procedure and constrained to ride on their parent atoms with U_iso(H) = 1.2U_eq(C/N).

Computing details

Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: XCAD4 (Harms, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997b); molecular graphics: ATOMS (Shape Software, 1998); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

Fig. 1. View of [NH3(CH2)3NH3][Ga(P2O7)(H2PO4)] howing the packing of the chains along the c axis and the interchain and chain–amine hydrogen bonding. Dark-green tetrahedra = PO4, mid-green tetrahedra = P2O7, pink octahedra = GaO6, blue spheres = N atoms, white spheres = C atoms and grey spheres = H atoms. Dashed red lines = interchain hydrogen bonds and dashed blue lines = chain–amine hydrogen bonds. Template H atoms have been omitted for clarity.

Fig. 2. Local coordination of atoms in [NH3(CH2)3NH3][Ga(P2O7)(H2PO4)] (50% probability displacement ellipsoids). i) -x, -y, -z, ii) -x, y, -z + 1/2, iii) x, -y, z + 1/2, iv) -x, y, -z + 1/2.

(I)

Crystal data

(C3H12N2)[Ga(P2O7)(H2PO4)]	F(000) = 840
Mr = 416.79	Dx = 2.235 Mg m^−3
Monoclinic, C2/c	Cu Kα radiation, λ = 1.54180 Å
Hall symbol: -C 2yc	Cell parameters from 23 reflections
a = 8.5390 (7) Å	θ = 10–27°
b = 15.9795 (15) Å	µ = 7.36 mm^−1
c = 9.2826 (6) Å	T = 293 K
β = 102.007 (5)°	Needle, colourless
V = 1238.89 (17) Å^3	0.3 × 0.05 × 0.03 mm
Z = 4

Data collection

Enraf-Nonius CAD-4 diffractometer	Rint = 0.036
Graphite monochromator	θmax = 74.2°, θmin = 5.5°
Serial Detector scans	h = −10→10
Absorption correction: empirical (using intensity measurements) (North et al., 1968)	k = −19→19
Tmin = 0.675, Tmax = 0.809	l = −11→0
2586 measured reflections	3 standard reflections every 60 min
1267 independent reflections	intensity decay: 2.8%
1082 reflections with I > 2σ(I)

Refinement

Refinement on F^2	1 restraint
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.028	w = 1/[σ^2(Fo^2) + (0.0406P)^2 + 1.2495P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.074	(Δ/σ)max = 0.002
S = 1.11	Δρmax = 0.76 e Å^−3
1267 reflections	Δρmin = −0.86 e Å^−3
99 parameters

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	Occ. (<1)
Ga1	0.0000	0.0000	0.0000	0.00394 (14)
P1	0.0000	0.14771 (5)	−0.2500	0.00442 (18)
P2	−0.16711 (6)	0.10312 (3)	0.22366 (6)	0.00409 (16)
O1	−0.0496 (2)	0.09882 (10)	−0.12939 (19)	0.0108 (4)
O2	0.1388 (2)	0.20867 (10)	−0.1748 (2)	0.0107 (4)
H1	0.163 (5)	0.2560 (19)	−0.231 (4)	0.057 (14)*
O3	−0.16159 (19)	0.03811 (10)	0.10564 (18)	0.0075 (3)
O4	0.17472 (19)	0.06243 (10)	0.12872 (17)	0.0078 (3)
O5	−0.2987 (2)	0.16654 (10)	0.18000 (19)	0.0116 (4)
O6	0.0000	0.15381 (13)	0.2500	0.0072 (5)
N1	0.0852 (3)	0.36775 (15)	0.0096 (2)	0.0154 (5)
H2	0.1367	0.3211	0.0438	0.019*
H3	0.1475	0.3987	−0.0352	0.019*
H4	−0.0044	0.3547	−0.0544	0.019*
C1	0.0448 (4)	0.41581 (17)	0.1339 (3)	0.0192 (6)
H5	−0.0438	0.4532	0.0959	0.023*
H6	0.1360	0.4499	0.1784	0.023*
C2	0.0000	0.3607 (2)	0.2500	0.0166 (7)
H7	−0.0896	0.3252	0.2068	0.020*	0.50
H8	0.0896	0.3252	0.2932	0.020*	0.50

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ga1	0.0049 (2)	0.0041 (2)	0.0037 (2)	−0.00099 (13)	0.00279 (15)	−0.00090 (14)
P1	0.0062 (4)	0.0026 (3)	0.0046 (4)	0.000	0.0015 (3)	0.000
P2	0.0043 (3)	0.0040 (3)	0.0043 (3)	0.00169 (19)	0.0015 (2)	0.0002 (2)
O1	0.0160 (9)	0.0075 (8)	0.0108 (8)	0.0004 (6)	0.0070 (7)	0.0043 (7)
O2	0.0107 (8)	0.0076 (8)	0.0126 (8)	−0.0044 (6)	−0.0003 (7)	−0.0004 (7)
O3	0.0081 (8)	0.0074 (8)	0.0083 (8)	−0.0019 (6)	0.0048 (6)	−0.0032 (6)
O4	0.0079 (8)	0.0109 (8)	0.0057 (8)	−0.0032 (6)	0.0037 (6)	−0.0032 (7)
O5	0.0101 (8)	0.0098 (8)	0.0133 (9)	0.0074 (6)	−0.0009 (7)	−0.0007 (7)
O6	0.0071 (11)	0.0022 (10)	0.0120 (12)	0.000	0.0015 (9)	0.000
N1	0.0122 (10)	0.0241 (11)	0.0109 (11)	0.0013 (9)	0.0048 (9)	0.0028 (9)
C1	0.0274 (14)	0.0155 (12)	0.0175 (14)	−0.0050 (10)	0.0109 (12)	−0.0018 (11)
C2	0.0238 (19)	0.0135 (16)	0.0164 (18)	0.000	0.0130 (16)	0.000

Geometric parameters (Å, º)

Ga1—O3^i	1.949 (2)	O4—P2^iii	1.530 (2)
Ga1—O3	1.949 (2)	O6—P2^iii	1.615 (1)
Ga1—O1^i	1.976 (2)	O2—H1	0.97 (2)
Ga1—O1	1.976 (2)	N1—C1	1.485 (3)
Ga1—O4	1.977 (2)	N1—H2	0.890
Ga1—O4^i	1.977 (2)	N1—H3	0.890
P1—O1^ii	1.497 (2)	N1—H4	0.890
P1—O1	1.497 (2)	C1—C2	1.502 (3)
P1—O2	1.580 (2)	C1—H5	0.970
P1—O2^ii	1.580 (2)	C1—H6	0.970
P2—O5	1.505 (2)	C2—C1^iii	1.502 (3)
P2—O3	1.518 (2)	C2—H7	0.970
P2—O4^iii	1.530 (2)	C2—H8	0.970
P2—O6	1.615 (1)
O1^i—Ga1—O1	180	O3—P2—O6	107.07 (8)
O3^i—Ga1—O3	180	O4^iii—P2—O6	106.16 (7)
O4—Ga1—O4^i	180	P1—O1—Ga1	144.43 (11)
O3^i—Ga1—O1^i	88.36 (7)	P1—O2—H1	118 (3)
O3—Ga1—O1^i	91.64 (7)	P2—O3—Ga1	135.12 (10)
O3^i—Ga1—O1	91.64 (7)	P2^iii—O4—Ga1	126.05 (10)
O3—Ga1—O1	88.36 (7)	P2—O6—P2^iii	119.78 (14)
O3^i—Ga1—O4	86.42 (7)	C1—N1—H2	109.5
O3—Ga1—O4	93.58 (7)	C1—N1—H3	109.5
O1^i—Ga1—O4	89.79 (7)	H2—N1—H3	109.5
O1—Ga1—O4	90.21 (7)	C1—N1—H4	109.5
O3^i—Ga1—O4^i	93.58 (7)	H2—N1—H4	109.5
O3—Ga1—O4^i	86.42 (7)	H3—N1—H4	109.5
O1^i—Ga1—O4^i	90.21 (7)	N1—C1—C2	112.9 (2)
O1—Ga1—O4^i	89.79 (7)	N1—C1—H5	109.0
O1^ii—P1—O1	117.08 (14)	C2—C1—H5	109.0
O1^ii—P1—O2	110.44 (9)	N1—C1—H6	109.0
O1—P1—O2	107.11 (9)	C2—C1—H6	109.0
O1^ii—P1—O2^ii	107.11 (9)	H5—C1—H6	107.8
O1—P1—O2^ii	110.44 (9)	C1^iii—C2—C1	108.2 (3)
O2—P1—O2^ii	103.88 (13)	C1^iii—C2—H7	110.1
O5—P2—O3	113.59 (10)	C1—C2—H7	110.1
O5—P2—O4^iii	111.03 (10)	C1^iii—C2—H8	110.1
O3—P2—O4^iii	111.65 (9)	C1—C2—H8	110.1
O5—P2—O6	106.84 (10)	H7—C2—H8	108.4

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H1···O5^iv	0.97 (2)	1.56 (2)	2.526 (2)	179 (4)
N1—H2···O2^v	0.89	2.10	2.810 (3)	136
N1—H3···O4^v	0.89	2.00	2.862 (3)	163
N1—H4···O5^vi	0.89	1.87	2.755 (3)	175

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