Naphthalene-1,5-diammonium bis­[trifluoridostannate(II)]

The structure of the title compound, (C₁₀H₁₂N₂)[SnF₃]₂, is made up of alternating layers of cations and anions, where the anion layers form extended polymeric sheets through a series of secondary Sn...F bonds. Strong N—H...F hydrogen bonds crosslink adjacent cation and anion layers, thereby building a three-dimensional network.

S1. Comment

Studies of organic–inorganic hybrid materials are of considerable interest (Elleuch et al., 2007). These materials enable the integration of useful organic and inorganic characteristics within a single molecular-scale composite, i.e. unique electronic and optical properties have been observed (Hill, 1998; Kagan et al., 1999). Furthermore, divalent Sn-containing halides can exhibit peculiar electrical properties, depending on the other cations present in the solid and on the electronegativity of the halogen.

In recent years, a number of hybrid compounds based on tin(IV) have been isolated and characterized (Billing et al., 2007). The structure of naphthalene-1,5-diammonium bis[trifluorostannate(II)], (I), presented here, is the first example of a salt containing tin(II) and naphthalene-1,5-diammonium. The only previously reported hybrid based on tin(II) is hydrazinium(2+) bis[trifluorostannate(II)], studied by Kaučič et al. (1988). That structure was described as being composed of monomeric [SnF₃]^- units and N₂H₆²⁺ ions, held together by hydrogen bonds. However, we have noted the presence of additional strong interionic Sn···F interactions in this structure, with Sn···F distances of 2.663 (3) and 2.752 (3) Å, which suggest that the anions actually form an extended structure through these secondary bonds.

The asymmetric unit of the title compound has two independent sites for Sn atoms and a protoned naphthalene-1,5-diammonium cation (Fig. 1). Atom Sn1 is surrounded by four F atoms, forming a distorted pseudo-trigonal–bipyramidal geometry in which one equatorial site is uncoordinated. Atoms F1 and F1ⁱ [symmetry code: (i) -x + 1, -y + 1, -z + 1] bridge asymmetrically two Sn1 atoms to produce a centrosymmetric Sn₂F₆ dimer in which the Sn1—F1ⁱ distance is significantly longer than the Sn1—F1 bond (Table 1). The Sn1—F1ⁱ distance is similar to the shortest Sn···F interaction found in hydrazinium(2+) bis[trifluorostannate(II)]. Atom Sn2 is also part of a centrosymmetric Sn₂F₆ dimer involving an even more asymmetric bridging interaction through atoms F4 and F4ⁱⁱ [symmetry code: (ii) -x + 1, -y + 1, -z]. The two dimeric entities are further connected through Sn2···F1 and Sn2···F2 interactions (Table 1), which lead to extended anionic chains involving both Sn centres with bridging F atoms. These chains run parallel to the [001] direction and atom F1 has a triply bridging function. Finally, an Sn2···F6ⁱⁱⁱ [symmetry code: (iii) x + 1, y, z] interaction cross-links the chains to give an extended polymeric sheet which lies parallel to the (010) plane (Fig. 2). As a result of the secondary interactions, atom Sn2 is surrounded by seven F atoms in a distorted pentagonal–bipyramidal geometry. The presence of the secondary Sn···F bonds results in short Sn···Sn distances (Table 1). The Sn1···Sn1ⁱ distance is similar to the Sn···Sn distance in the structure of K₃Sn₅Cl₃F₁₀ (Merazig et al., 2005), which can be described as consisting of corrugated bilayers separated by K⁺ cations and Cl^- anions.

The anion layers are interspersed with layers of cations (Fig. 3). The diammonium cation in (I) is planar, with an r.m.s. deviation of the non-H atoms of 0.03 Å, and lies parallel to the (102) plane. The cations stack in a tilted fashion along the [001] direction, which leads to an interplanar spacing of 6.337 Å. Very few studies on naphthalene-1,5-diammonium ions have been reported, these being limited to naphthalene-1,5-diammonium diiodide dihydrate (Lemmerer & Billing, 2006) and, very recently, naphthalene-1,5-diammonium dichloride (Boufas et al., 2006). In both structures, the organic moiety lies on an inversion center, while in the title compound the cation lies in a general position.

Strong N—H···F hydrogen bonds cross-link adjacent cation and anion layers and thereby complete a three-dimensional network (Table 2 and Fig. 3). Atom F6 is engaged in three hydrogen bonds, while atoms F4 and F5 each accept two hydrogen bonds and atoms F2 and F3 are each involved in just one hydrogen bond, these being the strongest ones. Atom F1 does not accept any hydrogen bonds, because it is engaged in two Sn···F secondary bonds, as shown in Fig 2.

Related literature

For related literature, see: Billing et al. (2007); Boufas et al. (2006); Elleuch et al. (2007); Hill (1998); Kagan et al. (1999); Kaučič et al. (1988); Lemmerer & Billing (2006); Merazig et al. (2005).

S2. Experimental

The title compound was crystallized from a supersaturated hydrochloric acid solution (50%, 5 ml) prepared using doubly distilled water and a mixture of tin(II) fluoride (1.567 g) and 1,5-diaminonaphthalene (1.558 g). Brown thin needle-shaped single crystals of (I) were obtained at ambient temperature by slow evaporation of the solution.

S3. Refinement

The ammonium H atoms were constrained to an ideal geometry (N—H = 0.89 Å), but were allowed to rotate freely about the C—N bonds, while their isotropic displacement parameters were refined. All remaining H atoms were placed in geometrically idealized positions (C—H = 0.93 Å) and constrained to ride on their parent atoms with U_iso(H) values of 1.2U_eq(C).

Computing details

Data collection: COLLECT (Nonius, 2002); cell refinement: DIRAX (Duisenberg, 1992); data reduction: EVAL (Nonius, 2002); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: WinGX (Farrugia, 1999) and PARST (Nardelli, 1995).

Figures

	Fig. 1. The asymmetric unit of the title compound, showing the atom-labelling scheme. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level.
	Fig. 2. A packing diagram of the anionic structure, viewed down the b axis, showing how the secondary Sn···F bonds (dotted lines) form Sn2F6 dimers, chains along [001] and layers parallel to (010).
	Fig. 3. A packing diagram of the title compound, viewed down the a axis, showing the alternating layers of cations and anions and the N—H···F hydrogen bonds (dotted lines).

Naphthalene-1,5-diammonium bis[trifluoridostannate(II)]

Crystal data

(C10H12N2)[SnF3]2	F(000) = 960
Mr = 511.6	Dx = 2.493 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3109 reflections
a = 4.8983 (2) Å	θ = 5.1–27.5°
b = 22.8232 (13) Å	µ = 3.72 mm^−1
c = 12.5799 (9) Å	T = 298 K
β = 104.249 (7)°	Needle, brown
V = 1363.10 (14) Å^3	0.35 × 0.10 × 0.03 mm
Z = 4

Data collection

Nonius KappaCCD diffractometer	3109 independent reflections
Radiation source: fine-focus sealed tube	2399 reflections with I > 2σ(I)
Detector resolution: 9 pixels mm^-1	Rint = 0.063
CCD scans	θmax = 27.5°, θmin = 5.1°
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick,1996)	h = −6→4
Tmin = 0.807, Tmax = 0.929	k = −25→29
16372 measured reflections	l = −14→16

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)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.070	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0297P)^2 + 0.1446P] where P = (Fo^2 + 2Fc^2)/3
3109 reflections	(Δ/σ)max < 0.001
189 parameters	Δρmax = 0.55 e Å^−3
0 restraints	Δρmin = −1.15 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Sn1	0.22678 (6)	0.449054 (15)	0.40894 (3)	0.03111 (11)
F1	0.5056 (6)	0.51279 (12)	0.3925 (2)	0.0473 (7)
F2	0.2569 (5)	0.42246 (13)	0.2553 (2)	0.0426 (7)
F3	0.5322 (6)	0.38841 (13)	0.4644 (2)	0.0518 (8)
Sn2	0.60130 (5)	0.522339 (13)	0.18029 (2)	0.02407 (10)
F4	0.5563 (5)	0.56460 (12)	0.02676 (19)	0.0329 (6)
F5	0.7060 (5)	0.60489 (11)	0.2488 (2)	0.0345 (6)
F6	0.1958 (5)	0.54892 (12)	0.1594 (2)	0.0396 (7)
N1	0.9988 (7)	0.10273 (15)	0.5513 (3)	0.0248 (8)
H1A	1.0645	0.0919	0.6208	0.057 (17)*
H1B	1.1073	0.0878	0.5108	0.031 (12)*
H1C	0.8234	0.0896	0.5267	0.056 (16)*
N2	0.7492 (7)	0.35793 (16)	0.6697 (3)	0.0274 (8)
H2A	0.9242	0.3709	0.696	0.058 (17)*
H2B	0.6377	0.3727	0.7092	0.055 (16)*
H2C	0.6875	0.3691	0.6001	0.055 (16)*
C1	0.8799 (7)	0.26108 (18)	0.6074 (3)	0.0198 (9)
C2	0.7460 (7)	0.29347 (18)	0.6760 (3)	0.0209 (9)
C3	0.6129 (8)	0.2677 (2)	0.7465 (3)	0.0270 (10)
H3	0.5288	0.2904	0.791	0.032*
C4	0.6042 (8)	0.2063 (2)	0.7510 (3)	0.0290 (10)
H4	0.5129	0.1883	0.799	0.035*
C5	0.7270 (8)	0.1723 (2)	0.6864 (3)	0.0262 (10)
H5	0.7187	0.1317	0.6905	0.031*
C6	0.8671 (7)	0.19910 (18)	0.6132 (3)	0.0197 (8)
C7	1.0004 (7)	0.16643 (18)	0.5439 (3)	0.0212 (9)
C8	1.1365 (8)	0.1929 (2)	0.4747 (3)	0.0283 (10)
H8	1.2223	0.1703	0.4305	0.034*
C9	1.1467 (8)	0.2543 (2)	0.4702 (3)	0.0284 (10)
H9	1.2397	0.2723	0.4227	0.034*
C10	1.0228 (8)	0.2877 (2)	0.5341 (3)	0.0271 (10)
H10	1.0311	0.3284	0.53	0.033*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sn1	0.02968 (17)	0.0347 (2)	0.02938 (18)	0.00170 (13)	0.00803 (13)	−0.00094 (14)
F1	0.0667 (18)	0.0356 (18)	0.0384 (16)	−0.0138 (14)	0.0108 (14)	−0.0005 (14)
F2	0.0550 (16)	0.0445 (19)	0.0248 (14)	−0.0014 (13)	0.0032 (12)	−0.0078 (13)
F3	0.075 (2)	0.0412 (19)	0.0329 (15)	0.0242 (15)	0.0011 (14)	0.0038 (14)
Sn2	0.02485 (15)	0.02108 (18)	0.02580 (17)	0.00219 (12)	0.00533 (12)	0.00108 (13)
F4	0.0301 (12)	0.0412 (17)	0.0283 (13)	−0.0047 (10)	0.0088 (10)	0.0094 (12)
F5	0.0326 (13)	0.0283 (16)	0.0443 (15)	−0.0019 (10)	0.0125 (11)	−0.0097 (12)
F6	0.0249 (12)	0.0556 (19)	0.0406 (15)	0.0068 (11)	0.0123 (11)	0.0142 (14)
N1	0.0281 (18)	0.025 (2)	0.0209 (19)	0.0025 (15)	0.0049 (15)	−0.0016 (16)
N2	0.0277 (18)	0.030 (2)	0.024 (2)	0.0033 (15)	0.0069 (15)	−0.0051 (17)
C1	0.0133 (17)	0.025 (2)	0.020 (2)	0.0014 (16)	0.0020 (15)	0.0002 (18)
C2	0.0200 (18)	0.019 (2)	0.023 (2)	0.0034 (15)	0.0021 (16)	0.0005 (18)
C3	0.029 (2)	0.035 (3)	0.021 (2)	0.0025 (18)	0.0127 (17)	−0.0047 (19)
C4	0.027 (2)	0.036 (3)	0.028 (2)	−0.0018 (18)	0.0152 (18)	0.007 (2)
C5	0.0213 (19)	0.030 (3)	0.027 (2)	−0.0012 (17)	0.0059 (17)	0.000 (2)
C6	0.0157 (17)	0.023 (2)	0.020 (2)	0.0002 (15)	0.0049 (15)	−0.0024 (18)
C7	0.0187 (18)	0.025 (2)	0.0173 (19)	0.0005 (16)	0.0000 (15)	−0.0007 (18)
C8	0.025 (2)	0.039 (3)	0.023 (2)	0.0069 (18)	0.0092 (17)	−0.003 (2)
C9	0.031 (2)	0.030 (3)	0.028 (2)	−0.0004 (19)	0.0156 (18)	0.009 (2)
C10	0.028 (2)	0.024 (3)	0.032 (2)	−0.0032 (18)	0.0121 (18)	0.004 (2)

Geometric parameters (Å, º)

Sn1—F1	2.040 (3)	N2—H2B	0.89
Sn1—F1^i	2.665 (3)	N2—H2C	0.89
Sn1—F2	2.065 (2)	C1—C2	1.414 (5)
Sn1—F3	2.031 (3)	C1—C6	1.419 (6)
Sn2—F1	2.830 (3)	C1—C10	1.425 (5)
Sn2—F2	3.117 (3)	C2—C3	1.357 (6)
Sn2—F4	2.121 (2)	C3—C4	1.406 (6)
Sn2—F4^ii	3.214 (3)	C3—H3	0.93
Sn2—F5	2.083 (2)	C4—C5	1.365 (6)
Sn2—F6	2.031 (2)	C4—H4	0.93
Sn2—F6^iii	3.049 (2)	C5—C6	1.415 (5)
Sn1—Sn1^i	3.8473 (7)	C5—H5	0.93
Sn1—Sn2	4.1272 (5)	C6—C7	1.423 (5)
Sn2—Sn2^ii	4.5149 (5)	C7—C8	1.361 (6)
N1—C7	1.457 (5)	C8—C9	1.406 (6)
N1—H1A	0.89	C8—H8	0.93
N1—H1B	0.89	C9—C10	1.355 (6)
N1—H1C	0.89	C9—H9	0.93
N2—C2	1.473 (5)	C10—H10	0.93
N2—H2A	0.89
F1—Sn1—F3	93.77 (13)	H2A—N2—H2B	109.5
F1—Sn1—F2	84.88 (11)	C2—N2—H2C	109.5
F2—Sn1—F3	84.54 (11)	H2A—N2—H2C	109.5
F1—Sn1—F1^i	71.04 (11)	H2B—N2—H2C	109.5
F2—Sn1—F1^i	147.26 (10)	C2—C1—C6	117.2 (3)
F3—Sn1—F1^i	75.53 (10)	C2—C1—C10	123.2 (4)
Sn1—F1—Sn1^i	108.97 (10)	C6—C1—C10	119.6 (4)
Sn1—F1—Sn2	114.90 (11)	C3—C2—C1	122.8 (4)
Sn1—F2—Sn2	103.72 (10)	C3—C2—N2	118.7 (4)
F6—Sn2—F5	85.22 (10)	C1—C2—N2	118.5 (3)
F6—Sn2—F4	82.37 (9)	C2—C3—C4	118.9 (4)
F5—Sn2—F4	85.73 (10)	C2—C3—H3	120.6
F6—Sn2—F1	76.19 (9)	C4—C3—H3	120.6
F5—Sn2—F1	76.13 (9)	C5—C4—C3	121.3 (4)
F4—Sn2—F1	152.83 (9)	C5—C4—H4	119.3
F6—Sn2—F2	70.89 (9)	C3—C4—H4	119.3
F5—Sn2—F2	129.23 (8)	C4—C5—C6	119.9 (4)
F4—Sn2—F2	131.72 (8)	C4—C5—H5	120.1
F1—Sn2—F2	55.28 (7)	C6—C5—H5	120.1
F6—Sn2—F4^ii	92.72 (9)	C5—C6—C1	119.9 (3)
F5—Sn2—F4^ii	151.59 (8)	C5—C6—C7	122.8 (4)
F4—Sn2—F4^ii	65.94 (10)	C1—C6—C7	117.3 (3)
F1—Sn2—F4^ii	130.88 (7)	C8—C7—C6	122.1 (4)
F2—Sn2—F4^ii	75.77 (6)	C8—C7—N1	119.6 (4)
Sn2—F4—Sn2^ii	114.06 (10)	C6—C7—N1	118.3 (3)
Sn2—F6—Sn2^iv	148.64 (12)	C7—C8—C9	119.7 (4)
C7—N1—H1A	109.5	C7—C8—H8	120.1
C7—N1—H1B	109.5	C9—C8—H8	120.1
H1A—N1—H1B	109.5	C10—C9—C8	120.8 (4)
C7—N1—H1C	109.5	C10—C9—H9	119.6
H1A—N1—H1C	109.5	C8—C9—H9	119.6
H1B—N1—H1C	109.5	C9—C10—C1	120.5 (4)
C2—N2—H2A	109.5	C9—C10—H10	119.8
C2—N2—H2B	109.5	C1—C10—H10	119.8
C3—C2—C1—C10	−179.3 (4)	C1—C2—C3—C4	−0.8 (6)
C5—C6—C7—C8	−179.4 (4)	C2—C3—C4—C5	0.2 (6)
C6—C1—C2—C3	1.0 (5)	C3—C4—C5—C6	0.1 (6)
C6—C1—C2—N2	−178.4 (3)	C4—C5—C6—C1	0.1 (5)
C2—C1—C10—C9	−179.9 (4)	C4—C5—C6—C7	179.8 (4)
C10—C1—C2—N2	1.3 (5)	C1—C6—C7—N1	177.8 (3)
C2—C1—C6—C5	−0.7 (5)	C1—C6—C7—C8	0.3 (5)
C2—C1—C6—C7	179.7 (3)	C5—C6—C7—N1	−1.8 (5)
C10—C1—C6—C5	179.6 (3)	N1—C7—C8—C9	−177.8 (3)
C10—C1—C6—C7	−0.1 (5)	C6—C7—C8—C9	−0.3 (6)
C6—C1—C10—C9	−0.1 (6)	C7—C8—C9—C10	0.1 (6)
N2—C2—C3—C4	178.6 (3)	C8—C9—C10—C1	0.1 (6)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···F2^v	0.89	1.75	2.630 (4)	168
N1—H1B···F4^vi	0.89	1.90	2.744 (4)	158
N1—H1B···F6^vii	0.89	2.45	2.863 (4)	109
N1—H1C···F4^vii	0.89	1.90	2.792 (4)	178
N1—H1C···F6^vii	0.89	2.50	2.863 (4)	105
N2—H2A···F5^viii	0.89	1.86	2.747 (4)	178
N2—H2B···F5^i	0.89	1.95	2.805 (4)	160
N2—H2B···F6^i	0.89	2.44	2.988 (4)	121
N2—H2C···F3	0.89	1.75	2.633 (4)	174

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