(IUCr) Crystallography Journals Online

Abstract top

The title compound, C₁₆H₂₆N₄⁴⁺·2.5ClO₄^-·1.5NO₃^-, is an organic salt in which the cation is a fully protonated tetramine. The cation lies on an inversion center and, as a consequence, both benzene rings are parallel. The central chain is found in an all-trans arrangement, a conformation different from that observed in the crystal structure of the non-protonated molecule. The charges are balanced by a mixture of nitrate and perchlorate ions. One site is occupied by an ordered perchlorate ion, while the other contains both nitrate and perchlorate ions, with occupancies of 0.75 and 0.25, respectively. In the crystal, the NH₂⁺ groups of the cation form N-HO hydrogen bonds with the anions. The NH₃⁺ groups also behave as donor groups, allowing the building of chains along [100], alternating cations and disordered anions being connected via N-HO hydrogen bonds.

Comment top

Poly(ethylene terephthalate) (PET) is a thermoplastic material, which has been increasingly used in the industry during the last decades. Its low degradability makes this material highly contaminant to the environment (Carta et al., 2003). Currently, many efforts are devoted to reduce the amount of waste PET that reaches the landfillings. Some processes are able to recycle PET into highly valued carbon materials (Parra et al., 2004), used to generate heat and electricity (Pohorely et al., 2006). An interesting approach known as 'chemical recycling' is based on the depolymerization of PET through solvolytic chain cleavage. Five processes have been probed, with different depolymerizing agents: methanolysis, glycolysis, hydrolysis, aminolysis and ammonolysis. Several reactions used catalyst, among them zinc compounds.

Our group is involved in the search for reactions relevant to the chemical degradation of PET, using acyclic polyaza zinc complexes ZnLX₂ (X = ClO₄^-, NO₃^-; L = polyaza ligand), which gave excellent results. The title salt appeared during an attempt to prepare a bimetallic catalyst. Previous works showed that complex CuL[CuCl₄] can be obtained as the product of the transmetallation of MnL(NO₃)₂ with Cu(ClO₄)₂.6H₂O in ethanol, with an excess of aqueous HCl. The same transmetallation procedure, using Zn(ClO₄)₂.6H₂O in acidic ethanol afforded pale yellow crystals as a subproduct, which were identified as the title salt by X-ray diffraction.

The salt is composed of a tetracation and a mixture of nitrate and perchlorate anions (Fig. 1). The presence of both anions in the material was confirmed by IR spectroscopy, as spectra include characteristic vibrations for these ions. The cation is fully protonated and is placed on an inversion center. As a consequence, benzene rings are parallel by symmetry. The 6-membered chain linking the benzene fragments is found in the all-trans extended conformation, contrasting with the trans-gauche-trans conformation observed in the solid-sate for the non-protonated tetramine (Rodríguez de Barbarín et al., 2007). Anions are found in two sites. One site is occupied by a non disordered perchlorate, Cl1. The other site contains a mixture of nitrate (N11) and perchlorate (Cl2), with occupancies 3/4 and 1/4, respectively (Fig. 1, inset). Because they are involved in hydrogen bonds, anions do not present orientational disorder.

NH₂⁺ and NH₃⁺ groups have different functions regarding hydrogen bonding in the crystal. NH₂⁺ donors groups are connected to anions within the asymmetric unit, forming N—H···O hydrogen bonds (Fig. 1). NH₃⁺ groups also serve as donors for N—H···O hydrogen bonds, connecting symmetry related cations via anions, to form a one-dimensional supramolecular structure where cations and anions alternate in the [100] direction (Fig. 2).

N,N'-Bis(2-ammoniobenzyl)ethane-1,2-diammonium–nitrate– perchlorate (1/1.5/2.5) top

Crystal data top

C₁₆H₂₆N₄⁴⁺·2.5ClO₄⁻·1.5NO₃⁻	F(000) = 638
M_r = 616.05	D_x = 1.697 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 73 reflections
a = 8.427 (3) Å	θ = 5.0–12.4°
b = 12.637 (3) Å	µ = 0.41 mm⁻¹
c = 11.834 (3) Å	T = 298 K
β = 106.97 (2)°	Irregular, pale yellow
V = 1205.4 (6) Å³	0.6 × 0.4 × 0.4 mm
Z = 2

Data collection top

Siemens P4 diffractometer	R_int = 0.057
Radiation source: fine-focus sealed tube	θ_max = 25.1°, θ_min = 2.4°
graphite	h = −10→10
ω scans	k = −15→15
6392 measured reflections	l = −14→14
2125 independent reflections	3 standard reflections every 97 reflections
1757 reflections with I > 2σ(I)	intensity decay: <1%

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.119	H-atom parameters constrained
S = 1.14	w = 1/[σ²(F_o²) + (0.0221P)² + 1.6735P] where P = (F_o² + 2F_c²)/3
2125 reflections	(Δ/σ)_max < 0.001
218 parameters	Δρ_max = 0.25 e Å⁻³
8 restraints	Δρ_min = −0.27 e Å⁻³
0 constraints

Crystal data top

C₁₆H₂₆N₄⁴⁺·2.5ClO₄⁻·1.5NO₃⁻	V = 1205.4 (6) Å³
M_r = 616.05	Z = 2
Monoclinic, P2₁/n	Mo Kα radiation
a = 8.427 (3) Å	µ = 0.41 mm⁻¹
b = 12.637 (3) Å	T = 298 K
c = 11.834 (3) Å	0.6 × 0.4 × 0.4 mm
β = 106.97 (2)°

Data collection top

Siemens P4 diffractometer	R_int = 0.057
6392 measured reflections	θ_max = 25.1°
2125 independent reflections	3 standard reflections every 97 reflections
1757 reflections with I > 2σ(I)	intensity decay: <1%

Refinement top

R[F² > 2σ(F²)] = 0.050	H-atom parameters constrained
wR(F²) = 0.119	Δρ_max = 0.25 e Å⁻³
S = 1.14	Δρ_min = −0.27 e Å⁻³
2125 reflections	Absolute structure: ?
218 parameters	Flack parameter: ?
8 restraints	Rogers parameter: ?

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
N1	−0.1084 (4)	0.6532 (2)	0.2742 (2)	0.0430 (7)
H1A	−0.2090	0.6242	0.2538	0.065*
H1B	−0.1163	0.7215	0.2897	0.065*
H1C	−0.0445	0.6208	0.3381	0.065*
C2	−0.0347 (4)	0.6416 (2)	0.1763 (3)	0.0326 (7)
C3	−0.1440 (4)	0.6359 (2)	0.0652 (3)	0.0399 (8)
H3A	−0.2578	0.6371	0.0546	0.048*
C4	−0.0826 (5)	0.6283 (2)	−0.0310 (3)	0.0434 (8)
H4A	−0.1553	0.6235	−0.1070	0.052*
C5	0.0852 (5)	0.6280 (3)	−0.0143 (3)	0.0430 (8)
H5A	0.1263	0.6245	−0.0791	0.052*
C6	0.1929 (4)	0.6327 (2)	0.0979 (3)	0.0394 (8)
H6A	0.3066	0.6313	0.1082	0.047*
C7	0.1348 (4)	0.6396 (2)	0.1969 (3)	0.0311 (7)
C8	0.2604 (4)	0.6487 (2)	0.3159 (3)	0.0371 (7)
H8A	0.2095	0.6834	0.3696	0.044*
H8B	0.3513	0.6928	0.3091	0.044*
N9	0.3283 (3)	0.5437 (2)	0.3671 (2)	0.0350 (6)
H9A	0.2457	0.5053	0.3806	0.042*
H9B	0.3660	0.5085	0.3140	0.042*
C10	0.4644 (4)	0.5534 (3)	0.4787 (3)	0.0380 (8)
H10A	0.4225	0.5862	0.5384	0.046*
H10B	0.5509	0.5985	0.4662	0.046*
Cl1	−0.00237 (10)	0.35712 (6)	0.40133 (7)	0.0396 (2)
O1	−0.1221 (4)	0.3829 (3)	0.4604 (3)	0.0752 (9)
O2	0.0116 (4)	0.4419 (2)	0.3253 (2)	0.0643 (8)
O3	0.1540 (4)	0.3438 (2)	0.4887 (2)	0.0648 (8)
O4	−0.0495 (4)	0.2635 (2)	0.3332 (3)	0.0647 (8)
Cl2	0.5512 (9)	0.4371 (6)	0.1804 (8)	0.0358 (15)	0.25
O5	0.587 (4)	0.5336 (15)	0.244 (2)	0.039 (7)	0.25
O6	0.5011 (19)	0.4701 (12)	0.0603 (8)	0.083 (4)	0.25
O7	0.415 (4)	0.394 (4)	0.211 (4)	0.083 (14)	0.25
O8	0.675 (2)	0.3628 (14)	0.186 (2)	0.052 (5)	0.25
N11	0.5525 (14)	0.4327 (9)	0.2076 (9)	0.068 (4)	0.75
O12	0.5925 (19)	0.5250 (7)	0.2380 (11)	0.071 (4)	0.75
O13	0.4469 (14)	0.3860 (9)	0.2416 (13)	0.056 (2)	0.75
O14	0.6277 (12)	0.3811 (8)	0.1526 (9)	0.099 (3)	0.75

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0417 (16)	0.0511 (17)	0.0434 (15)	0.0065 (14)	0.0236 (13)	0.0043 (13)
C2	0.0406 (18)	0.0254 (14)	0.0364 (16)	0.0035 (13)	0.0186 (14)	0.0037 (13)
C3	0.0373 (18)	0.0331 (16)	0.0472 (19)	0.0030 (14)	0.0089 (15)	0.0045 (15)
C4	0.062 (2)	0.0306 (16)	0.0344 (17)	0.0060 (16)	0.0086 (16)	0.0029 (14)
C5	0.065 (3)	0.0361 (18)	0.0336 (17)	0.0020 (17)	0.0231 (17)	0.0038 (14)
C6	0.0451 (19)	0.0333 (16)	0.0475 (18)	−0.0014 (15)	0.0255 (16)	0.0056 (15)
C7	0.0393 (18)	0.0221 (14)	0.0347 (15)	−0.0016 (13)	0.0153 (13)	0.0033 (12)
C8	0.0392 (18)	0.0305 (16)	0.0421 (17)	−0.0037 (14)	0.0128 (15)	−0.0009 (14)
N9	0.0333 (15)	0.0368 (14)	0.0337 (13)	−0.0012 (11)	0.0081 (12)	−0.0022 (11)
C10	0.0333 (18)	0.0418 (18)	0.0355 (17)	−0.0007 (14)	0.0047 (14)	−0.0050 (14)
Cl1	0.0461 (5)	0.0334 (4)	0.0467 (5)	−0.0010 (4)	0.0250 (4)	0.0020 (3)
O1	0.069 (2)	0.088 (2)	0.089 (2)	0.0045 (17)	0.0545 (18)	−0.0055 (18)
O2	0.084 (2)	0.0519 (16)	0.0603 (16)	−0.0161 (15)	0.0263 (15)	0.0158 (13)
O3	0.0577 (18)	0.0691 (18)	0.0606 (16)	0.0068 (15)	0.0065 (14)	−0.0013 (14)
O4	0.0669 (19)	0.0407 (14)	0.086 (2)	−0.0074 (13)	0.0213 (16)	−0.0149 (14)
Cl2	0.028 (3)	0.033 (3)	0.051 (3)	−0.006 (2)	0.018 (2)	−0.007 (2)
O5	0.039 (13)	0.049 (16)	0.039 (9)	0.007 (10)	0.026 (9)	0.002 (9)
O6	0.105 (11)	0.110 (10)	0.037 (6)	−0.004 (9)	0.027 (7)	0.017 (7)
O7	0.059 (14)	0.12 (2)	0.08 (3)	−0.036 (15)	0.030 (17)	−0.020 (16)
O8	0.029 (7)	0.032 (6)	0.094 (12)	0.010 (6)	0.019 (7)	−0.005 (7)
N11	0.070 (6)	0.079 (7)	0.060 (6)	0.024 (5)	0.026 (4)	−0.002 (4)
O12	0.082 (8)	0.029 (4)	0.118 (7)	−0.005 (4)	0.055 (6)	−0.006 (4)
O13	0.060 (5)	0.052 (3)	0.062 (6)	−0.016 (3)	0.028 (5)	−0.003 (3)
O14	0.104 (7)	0.097 (5)	0.122 (8)	0.031 (4)	0.075 (6)	−0.015 (5)

Geometric parameters (Å, °) top

N1—C2	1.473 (4)	N9—C10	1.480 (4)
N1—H1A	0.8900	N9—H9A	0.9000
N1—H1B	0.8900	N9—H9B	0.9000
N1—H1C	0.8900	C10—C10ⁱ	1.503 (6)
C2—C3	1.369 (4)	C10—H10A	0.9700
C2—C7	1.378 (4)	C10—H10B	0.9700
C3—C4	1.385 (5)	Cl1—O4	1.421 (3)
C3—H3A	0.9300	Cl1—O1	1.423 (3)
C4—C5	1.369 (5)	Cl1—O2	1.426 (3)
C4—H4A	0.9300	Cl1—O3	1.428 (3)
C5—C6	1.374 (5)	Cl2—O8	1.389 (9)
C5—H5A	0.9300	Cl2—O7	1.409 (10)
C6—C7	1.398 (4)	Cl2—O5	1.417 (10)
C6—H6A	0.9300	Cl2—O6	1.422 (9)
C7—C8	1.498 (4)	N11—O14	1.222 (8)
C8—N9	1.501 (4)	N11—O13	1.229 (8)
C8—H8A	0.9700	N11—O12	1.238 (8)
C8—H8B	0.9700

C2—N1—H1A	109.5	H8A—C8—H8B	107.8
C2—N1—H1B	109.5	C10—N9—C8	113.1 (2)
H1A—N1—H1B	109.5	C10—N9—H9A	109.0
C2—N1—H1C	109.5	C8—N9—H9A	109.0
H1A—N1—H1C	109.5	C10—N9—H9B	109.0
H1B—N1—H1C	109.5	C8—N9—H9B	109.0
C3—C2—C7	122.8 (3)	H9A—N9—H9B	107.8
C3—C2—N1	116.1 (3)	N9—C10—C10ⁱ	110.7 (3)
C7—C2—N1	121.0 (3)	N9—C10—H10A	109.5
C2—C3—C4	119.0 (3)	C10ⁱ—C10—H10A	109.5
C2—C3—H3A	120.5	N9—C10—H10B	109.5
C4—C3—H3A	120.5	C10ⁱ—C10—H10B	109.5
C5—C4—C3	120.0 (3)	H10A—C10—H10B	108.1
C5—C4—H4A	120.0	O4—Cl1—O1	110.36 (19)
C3—C4—H4A	120.0	O4—Cl1—O2	109.21 (17)
C4—C5—C6	120.2 (3)	O1—Cl1—O2	109.82 (19)
C4—C5—H5A	119.9	O4—Cl1—O3	111.00 (17)
C6—C5—H5A	119.9	O1—Cl1—O3	107.96 (19)
C5—C6—C7	121.2 (3)	O2—Cl1—O3	108.46 (19)
C5—C6—H6A	119.4	O8—Cl2—O7	112 (2)
C7—C6—H6A	119.4	O8—Cl2—O5	121.0 (17)
C2—C7—C6	116.8 (3)	O7—Cl2—O5	105 (3)
C2—C7—C8	125.2 (3)	O8—Cl2—O6	104.3 (13)
C6—C7—C8	117.9 (3)	O7—Cl2—O6	110 (2)
C7—C8—N9	113.2 (2)	O5—Cl2—O6	103.4 (13)
C7—C8—H8A	108.9	O14—N11—O13	117.1 (12)
N9—C8—H8A	108.9	O14—N11—O12	121.2 (12)
C7—C8—H8B	108.9	O13—N11—O12	121.3 (12)
N9—C8—H8B	108.9

C7—C2—C3—C4	−0.3 (5)	C5—C6—C7—C2	−0.1 (4)
N1—C2—C3—C4	178.0 (3)	C5—C6—C7—C8	−177.7 (3)
C2—C3—C4—C5	−0.8 (5)	C2—C7—C8—N9	98.7 (3)
C3—C4—C5—C6	1.5 (5)	C6—C7—C8—N9	−83.9 (3)
C4—C5—C6—C7	−1.0 (5)	C7—C8—N9—C10	174.1 (3)
C3—C2—C7—C6	0.7 (4)	C8—N9—C10—C10ⁱ	−175.9 (3)
N1—C2—C7—C6	−177.5 (3)	O8—Cl2—O6—O6ⁱⁱ	−79 (5)
C3—C2—C7—C8	178.2 (3)	O7—Cl2—O6—O6ⁱⁱ	160 (6)
N1—C2—C7—C8	−0.1 (4)	O5—Cl2—O6—O6ⁱⁱ	48 (6)

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

Hydrogen-bond geometry (Å, °) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1C···O2	0.89	2.32	2.856 (4)	118
N1—H1B···O13ⁱⁱⁱ	0.89	2.61	3.270 (13)	132
N9—H9B···O5	0.90	2.27	2.96 (3)	133
N9—H9B···O12	0.90	2.35	3.055 (15)	136
N9—H9A···O2	0.90	2.05	2.872 (4)	151
N9—H9A···O3	0.90	2.64	3.441 (4)	149
N9—H9B···O7	0.90	2.02	2.89 (5)	163
N9—H9B···O13	0.90	1.98	2.836 (13)	157
N1—H1A···O5^iv	0.89	2.04	2.91 (3)	165
N1—H1A···O12^iv	0.89	2.05	2.920 (13)	164
N1—H1B···O8ⁱⁱⁱ	0.89	1.90	2.78 (2)	170
N1—H1B···O14ⁱⁱⁱ	0.89	2.14	3.026 (11)	174
N1—H1C···O1^v	0.89	2.39	3.207 (4)	153

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

Table 1
Hydrogen-bond geometry (Å, °) top

D—H···A	D—H	H···A	D···A	D—H···A
N9—H9A···O2	0.90	2.05	2.872 (4)	151
N9—H9B···O7	0.90	2.02	2.89 (5)	163
N9—H9B···O13	0.90	1.98	2.836 (13)	157
N1—H1A···O5ⁱ	0.89	2.04	2.91 (3)	165
N1—H1A···O12ⁱ	0.89	2.05	2.920 (13)	164
N1—H1B···O8ⁱⁱ	0.89	1.90	2.78 (2)	170
N1—H1B···O14ⁱⁱ	0.89	2.14	3.026 (11)	174
N1—H1C···O1ⁱⁱⁱ	0.89	2.39	3.207 (4)	153

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

supplementary materials

N,N'-Bis(2-ammoniobenzyl)ethane-1,2-diammonium-nitrate-perchlorate (1/1.5/2.5)

L. A. Garza Rodríguez, S. Bernès, B. Nájera Martínez, P. Elizondo Martínez and N. Pérez Rodríguez

	Fig. 1. The structure of the title compound, with displacement ellipsoids at the 30% probability level. Dashed lines represent hydrogen bonds in the asymmetric unit. The inset shows the anionic site with two disordered anions: nitrate N11 (occupancy = 3/4) and perchlorate Cl2 (occupancy = 1/4).
	Fig. 2. A part of the crystal structure of the title compound, with hydrogen bonds represented with dashed lines. Green anions are perchlorate and blue anions are nitrate. For the sake of clarity, some perchlorate ions have been omitted (hanging contacts). The crystal is viewed almost along [010].