Di-μ-chlorido-bis­[chlorido(1,4,6-trimethyl-6-nitro-1,4-diazepine)copper(II)]

Bortoluzzi, A.J.; Neves, A.; Peralta, R.A.; Camargo, T.P.; Weiss, V.C.

doi:10.1107/S1600536808043390

metal-organic compounds

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ISSN: 2056-9890

Volume 65| Part 2| February 2009| Pages m144-m145

doi:10.1107/S1600536808043390

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Di-μ-chlorido-bis[chlorido(1,4,6-trimethyl-6-nitro-1,4-diazepine)copper(II)]

Adailton J. Bortoluzzi,^a ^* Ademir Neves,^a Rosely A. Peralta,^a Tiago P. Camargo ^a and Vitor C. Weiss ^a

^aDepto. de Química–UFSC, 88040-900 Florianópolis, SC, Brazil
^*Correspondence e-mail: adajb@qmc.ufsc.br

(Received 3 December 2008; accepted 19 December 2008; online 8 January 2009)

The title neutral copper complex, [Cu₂Cl₄(C₈H₁₇N₃O₂)₂], shows a binuclear center with a Cu—(μ-Cl)₂—Cu core, in which each copper ion is coordinated by the N,N,O donor atoms of the tridentate ligand 1,4,6-trimethyl-6-nitro-1,4-diazepine (meaaz-NO₂) and three chloride exogenous ligands. Each metal ion is facially coordinated by meaaz-NO₂ through N,N,O donor atoms, whereas two bridging and one terminal chloride ions occupy the other face of the highly Jahn–Teller-distorted octahedron. Two N atoms from tertiary amine groups of the meaaz-NO₂ ligand and two exogenous Cl atoms with short Cu—N and Cu—Cl distances define the equatorial plane. The coordination around each Cu^II ion is completed by another Cl atom and an O atom from the NO₂ group, in the axial positions. The binuclear complex exhibits a centrosymmetric structure with point symmetry $[\overline{1}]$ .

Related literature

For related literature, see: Belousoff et al. (2006 ); Deal & Burstyn (1996 ); Fry et al. (2005 ); Hegg & Burstyn (1998 ); Peralta et al. (2005 ); Rodriguez, et al. (1999 ); Romba et al. (2006 ). For the synthesis of the meaaz-NO₂ ligand see Ge et al. (2006 ). For related structures, see: Astner et al. (2008 ); Schwindinger et al. (1980 ); Steed et al. (2007 ).

Experimental

Crystal data

[Cu₂Cl₄(C₈H₁₇N₃O₂)₂]
M_r = 643.37
Monoclinic, P 2₁ /n
a = 10.5478 (2) Å
b = 10.9251 (2) Å
c = 11.4430 (2) Å
β = 102.297 (1)°
V = 1288.39 (4) Å³
Z = 2
Mo Kα radiation
μ = 2.10 mm⁻¹
T = 296 (2) K
0.31 × 0.14 × 0.09 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2006 ) T_min = 0.562, T_max = 0.833
25284 measured reflections
2528 independent reflections
2080 reflections with I > 2σ(I)
R_int = 0.036

Refinement

R[F² > 2σ(F²)] = 0.030
wR(F²) = 0.083
S = 1.07
2528 reflections
148 parameters
H-atom parameters constrained
Δρ_max = 0.76 e Å⁻³
Δρ_min = −0.37 e Å⁻³

Data collection: APEX2, BIS and COSMO (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2003 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808043390/pk2138sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808043390/pk2138Isup2.hkl

checkCIF report

Comment top

Tridentate ligands that are able to force facial geometry, such as 1,4,7-tacn (1,4,7-triazacyclononane), daza (1,4-diazepan-6-amine) (Romba, et al., 2006), tach (cis,cis-1,3,5-triaminocyclohexane) (Hegg & Burstyn, 1998), play an important role in the stabilization of a great number of structural motifs in coordination compounds and in biological systems (Peralta et al., 2005). Copper complexes with this kind of ligand have been reported over the past few years with a view to the study of the hydrolysis of phosphate esters, proteins and DNA (Deal & Burstyn, 1996; Fry et al., 2005). Indeed such copper(II) complexes exhibit high catalytic reactivity in the hydrolysis of DNA model diesters as bis(4-nitrophenyl)phosphate with rate constants of ≈ 10 ^-4 s^-1 (Belousoff et al., 2006). In this context we report herein the synthesis and X-ray analysis of a new dinuclear copper complex with the tridentate ligand meaaz-NO₂.

This neutral copper complex exhibits a centrosymmetric structure (Fig. 1) with a highly distorted octahedral environment around the copper center. Each metal ion is facially coordinated by meaaz-NO₂ through N₂O donors atoms, whereas two bridged and one terminal coordinated chlorines occupy the other face of the distorted octahedron. Two amine nitrogen atoms (N3 and N6) of the ligand and two exogenous chlorines (Cl1, Cl2) lie in the equatorial plane. The coordination sphere of Cu1 is completed by another chlorine (Cl2') and an oxygen atom (O2) from the NO₂ group, in the axial positions. In the equatorial plane, the Cu—N and Cu—Cl bond lengths are Cu1—N6 2.064 (2) Å, Cu1—N3 2.122 (2) Å, Cu1—Cl2 2.2686 (7) Å and Cu1—Cl1 2.2694 (7) Å), respectively. The longer bond lengths Cu1—Cl2' (2.7611 (8) Å) and Cu1—O2 (2.845 (2) Å) are associated with the two apical positions, as expected for a (4 + 2) distorted geometry, as is common for Cu^II. The Cu—N and the Cu—Cl bond lengths in the equatorial plane are comparable to those found for other copper complexes [Cu(tacn)Cl₂] (Cu—N2 2.063 (4) Å, Cu—N3 2.038 (4) Å, CU—Cl1 2.268 (1) Å and Cu—Cl2 2.312 (1) Å) (Schwindinger, et al., 1980), [Cu₂(µ-Cl)₂(Me-bpa)₂(ClO₄)₂] (Me-bpa = N-methyl-bis(2-pyridylmethyl)amine) (Cu1—N36 1.983 (2) Å, Cu1—N10 2.036 (2) Å, Cu1—N26 1.989 (2) Å and Cu1—Cl1 2.2587 (6) Å) (Astner et al., 2008) and [Cu(me₃tacn)Cl₂] (Cu1—N1 2.100 (2) Å, Cu1—N2 2.111 (2) Å, Cu1—Cl2 2.2558 (9) Å and Cu1—Cl1 2.3050 (8) Å) (Steed et al., 2007). The seven-membered chelate ring of the meaaz-NO₂ ligand restricts the N—Cu—N angle to 77.35 (8)°, which is about 6° smaller than the respective angles formed by nine-membered ring in the Cu-tacn complexes.

As described in Rodriguez, et al. (1999), there are three kinds of configurations for copper complex containing the Cu-(µ-Cl)₂—Cu core: Type I, in which two square pyramids share one base-to-apex edge with the two bases nearly perpendicular to one another; Type II, square pyramids sharing one base-to-apex edge but with parallel basal planes and Type III, square pyramids sharing a basal edge with coplanar basal planes. The configuration of the Cu centers reported here are Type II given that the axial positions of one copper(II) center is directed toward the top and the same axis of the adjacent center is in the anti position. Although the Cu centers in the complex are hexacoordinate, it can be considered as type II, because the sixth coordination bond is very long (Cu—O2 = 2.845 (2)Å).

The packing is mainly governed by weak C—H···O and C—H···Cl interactions with average D···A distances of 2.99 Å and 3.74 Å, respectively. In addition, the packing analysis reveals that the molecules are accomodated in layers parallel to the (001) plane and are stacked along crystallographic a axis (Fig. 2).

Related literature top

For related literature, see: Belousoff et al. (2006); Deal & Burstyn (1996); Fry et al. (2005); Hegg & Burstyn (1998); Peralta et al. (2005); Rodriguez, et al. (1999); Romba et al. (2006). For the synthesis of the meaaz-NO₂ ligand see Ge et al. (2006). For related structures, see: Astner et al. (2008); Schwindinger et al. (1980); Steed et al. (2007).

Experimental top

The ligand 6-nitro-1,4,7-trimethyl-1,4-diazepine (meaaz-NO₂) was prepared as reported in the literature (Ge et al., 2006). The ligand was obtained with good yeld and was characterized by ¹H NMR [δ (p.p.m.) (CDCl3) 400 MHz: 1.46 (s, 3H); 2.36 (s, 6H); 2.48 (m, 2H); 2.56 (m, 2H); 2.66 and 3.36 (AB system, 4H)].

Copper complex was synthesized by adding 187 mg of the ligand meaaz-NO₂ (1.0 mmol) to a CH₃CN solution containing CuCl₂.2H₂O (171 mg, 1.0 mmol). The solution was then concentrated under magnetic stirring and was allowed to stand at room temperature for a few days, yielding a small number of dark green crystals which were suitable for the single-crystal X-ray analysis.

Computing details top

Data collection: APEX2, BIS and COSMO (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. A view of the molecular structure of copper complex showing the atom-labelling scheme. Ellipsoids are drawn at the 30% probability level. H atoms are omitted for clarity.
	Fig. 2. View down the a axis of the packing of copper complex.

Di-µ-chlorido-bis[chlorido(1,4,6-trimethyl-6-nitro-1,4-diazepine)copper(II)] top

Crystal data top

[Cu₂Cl₄(C₈H₁₇N₃O₂)₂]	F(000) = 660
M_r = 643.37	D_x = 1.658 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 6584 reflections
a = 10.5478 (2) Å	θ = 2.6–29.9°
b = 10.9251 (2) Å	µ = 2.10 mm⁻¹
c = 11.4430 (2) Å	T = 296 K
β = 102.297 (1)°	Block, dark green
V = 1288.39 (4) Å³	0.31 × 0.14 × 0.09 mm
Z = 2

Data collection top

Bruker APEXII CCD area-detector diffractometer	2528 independent reflections
Radiation source: fine-focus sealed tube	2080 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.036
ϕ and ω scans	θ_max = 26.0°, θ_min = 2.7°
Absorption correction: multi-scan (SADABS; Bruker, 2006)	h = −13→12
T_min = 0.562, T_max = 0.833	k = −13→13
25284 measured reflections	l = −14→14

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)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.083	H-atom parameters constrained
S = 1.07	w = 1/[σ²(F_o²) + (0.0432P)² + 0.7796P] where P = (F_o² + 2F_c²)/3
2528 reflections	(Δ/σ)_max = 0.001
148 parameters	Δρ_max = 0.76 e Å⁻³
0 restraints	Δρ_min = −0.37 e Å⁻³

Crystal data top

[Cu₂Cl₄(C₈H₁₇N₃O₂)₂]	V = 1288.39 (4) Å³
M_r = 643.37	Z = 2
Monoclinic, P2₁/n	Mo Kα radiation
a = 10.5478 (2) Å	µ = 2.10 mm⁻¹
b = 10.9251 (2) Å	T = 296 K
c = 11.4430 (2) Å	0.31 × 0.14 × 0.09 mm
β = 102.297 (1)°

Data collection top

Bruker APEXII CCD area-detector diffractometer	2528 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2006)	2080 reflections with I > 2σ(I)
T_min = 0.562, T_max = 0.833	R_int = 0.036
25284 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.030	0 restraints
wR(F²) = 0.083	H-atom parameters constrained
S = 1.07	Δρ_max = 0.76 e Å⁻³
2528 reflections	Δρ_min = −0.37 e Å⁻³
148 parameters

Special details top

Experimental. Absorption correction: SADABS (Bruker, 2006) was used to scale the data and to perform the multi-scan semi-empirical absorption correction.

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

	x	y	z	U_iso*/U_eq
Cu1	0.41672 (3)	0.13540 (3)	1.03616 (3)	0.03146 (12)
Cl1	0.45369 (7)	0.11762 (7)	1.23819 (6)	0.0467 (2)
Cl2	0.62792 (6)	0.10672 (6)	1.02889 (7)	0.04311 (19)
N1	0.4017 (2)	0.4025 (2)	1.0951 (2)	0.0379 (5)
C1	0.2738 (2)	0.3853 (2)	0.9997 (2)	0.0328 (6)
C2	0.3105 (2)	0.3551 (2)	0.8818 (2)	0.0323 (5)
H2A	0.2344	0.3665	0.8182	0.039*
H2B	0.3752	0.4138	0.8689	0.039*
N3	0.3623 (2)	0.22930 (18)	0.87072 (18)	0.0305 (5)
C4	0.2543 (3)	0.1488 (2)	0.8105 (2)	0.0385 (6)
H4A	0.2887	0.0705	0.7919	0.046*
H4B	0.2099	0.1862	0.7361	0.046*
C5	0.1594 (3)	0.1294 (2)	0.8915 (2)	0.0384 (6)
H5A	0.0839	0.1809	0.8647	0.046*
H5B	0.1307	0.0448	0.8860	0.046*
N6	0.2196 (2)	0.15908 (19)	1.01947 (18)	0.0318 (5)
C7	0.1930 (3)	0.2888 (3)	1.0467 (2)	0.0392 (6)
H7A	0.2071	0.2978	1.1329	0.047*
H7B	0.1021	0.3056	1.0139	0.047*
C8	0.2051 (3)	0.5099 (3)	0.9930 (3)	0.0437 (7)
H8A	0.2607	0.5721	0.9723	0.065*
H8B	0.1857	0.5286	1.0693	0.065*
H8C	0.1260	0.5068	0.9333	0.065*
O2	0.5045 (2)	0.38177 (18)	1.0687 (2)	0.0487 (5)
O1	0.3919 (3)	0.4391 (3)	1.1928 (2)	0.0739 (8)
C11	0.4596 (3)	0.2357 (3)	0.7947 (3)	0.0458 (7)
H11A	0.4905	0.1548	0.7834	0.069*
H11B	0.5310	0.2860	0.8330	0.069*
H11C	0.4204	0.2703	0.7185	0.069*
C12	0.1585 (3)	0.0810 (3)	1.0982 (3)	0.0480 (7)
H12A	0.1948	0.1003	1.1803	0.072*
H12B	0.1745	−0.0036	1.0837	0.072*
H12C	0.0667	0.0957	1.0815	0.072*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cu1	0.02805 (18)	0.03469 (19)	0.02830 (19)	0.00043 (12)	−0.00153 (12)	0.00140 (13)
Cl1	0.0457 (4)	0.0598 (5)	0.0286 (3)	−0.0011 (3)	−0.0057 (3)	0.0030 (3)
Cl2	0.0305 (3)	0.0414 (4)	0.0548 (4)	0.0014 (3)	0.0034 (3)	−0.0005 (3)
N1	0.0431 (14)	0.0303 (12)	0.0341 (13)	0.0022 (10)	−0.0052 (10)	−0.0050 (10)
C1	0.0286 (13)	0.0343 (14)	0.0307 (13)	0.0012 (10)	−0.0043 (10)	−0.0038 (10)
C2	0.0350 (13)	0.0290 (13)	0.0291 (13)	−0.0018 (10)	−0.0014 (10)	0.0010 (10)
N3	0.0340 (11)	0.0295 (11)	0.0264 (10)	−0.0021 (8)	0.0026 (8)	−0.0009 (9)
C4	0.0474 (16)	0.0340 (15)	0.0280 (13)	−0.0064 (11)	−0.0059 (11)	−0.0032 (11)
C5	0.0362 (14)	0.0385 (15)	0.0339 (14)	−0.0074 (11)	−0.0071 (11)	−0.0005 (11)
N6	0.0291 (11)	0.0348 (12)	0.0290 (11)	−0.0026 (9)	0.0004 (9)	0.0036 (9)
C7	0.0367 (14)	0.0420 (16)	0.0389 (15)	0.0005 (11)	0.0080 (12)	−0.0009 (12)
C8	0.0431 (16)	0.0391 (15)	0.0450 (16)	0.0096 (12)	0.0008 (13)	−0.0041 (13)
O2	0.0340 (11)	0.0482 (12)	0.0561 (13)	−0.0006 (8)	−0.0078 (9)	−0.0021 (10)
O1	0.0730 (17)	0.095 (2)	0.0429 (13)	0.0211 (14)	−0.0124 (11)	−0.0325 (13)
C11	0.0544 (18)	0.0485 (17)	0.0381 (15)	0.0034 (14)	0.0176 (13)	0.0033 (13)
C12	0.0418 (16)	0.0530 (18)	0.0499 (18)	−0.0078 (13)	0.0114 (13)	0.0137 (15)

Geometric parameters (Å, º) top

Cu1—N6	2.064 (2)	C4—H4A	0.9700
Cu1—N3	2.122 (2)	C4—H4B	0.9700
Cu1—Cl2	2.2686 (7)	C5—N6	1.502 (3)
Cu1—Cl1	2.2694 (7)	C5—H5A	0.9700
Cu1—Cl2ⁱ	2.7611 (8)	C5—H5B	0.9700
Cu1—O2	2.845 (2)	N6—C12	1.484 (3)
Cl2—Cu1ⁱ	2.7611 (8)	N6—C7	1.491 (3)
N1—O2	1.207 (3)	C7—H7A	0.9700
N1—O1	1.212 (3)	C7—H7B	0.9700
N1—C1	1.556 (3)	C8—H8A	0.9600
C1—C2	1.517 (4)	C8—H8B	0.9600
C1—C7	1.524 (4)	C8—H8C	0.9600
C1—C8	1.536 (4)	C11—H11A	0.9600
C2—N3	1.495 (3)	C11—H11B	0.9600
C2—H2A	0.9700	C11—H11C	0.9600
C2—H2B	0.9700	C12—H12A	0.9600
N3—C11	1.482 (3)	C12—H12B	0.9600
N3—C4	1.487 (3)	C12—H12C	0.9600
C4—C5	1.517 (4)

N6—Cu1—N3	77.35 (8)	N3—C4—H4B	109.7
N6—Cu1—Cl2	172.72 (6)	C5—C4—H4B	109.7
N3—Cu1—Cl2	96.62 (6)	H4A—C4—H4B	108.2
N6—Cu1—Cl1	93.22 (6)	N6—C5—C4	111.6 (2)
N3—Cu1—Cl1	154.87 (6)	N6—C5—H5A	109.3
Cl2—Cu1—Cl1	93.93 (3)	C4—C5—H5A	109.3
N6—Cu1—Cl2ⁱ	89.11 (6)	N6—C5—H5B	109.3
N3—Cu1—Cl2ⁱ	102.97 (6)	C4—C5—H5B	109.3
Cl2—Cu1—Cl2ⁱ	88.29 (2)	H5A—C5—H5B	108.0
Cl1—Cu1—Cl2ⁱ	100.08 (3)	C12—N6—C7	107.1 (2)
N6—Cu1—O2	100.77 (7)	C12—N6—C5	108.6 (2)
N3—Cu1—O2	71.22 (7)	C7—N6—C5	110.5 (2)
Cl2—Cu1—O2	80.84 (5)	C12—N6—Cu1	115.53 (16)
Cl1—Cu1—O2	88.12 (5)	C7—N6—Cu1	109.30 (15)
Cl2ⁱ—Cu1—O2	166.84 (5)	C5—N6—Cu1	105.75 (16)
Cu1—Cl2—Cu1ⁱ	91.71 (2)	N6—C7—C1	116.1 (2)
O2—N1—O1	123.4 (2)	N6—C7—H7A	108.3
O2—N1—C1	119.5 (2)	C1—C7—H7A	108.3
O1—N1—C1	117.1 (2)	N6—C7—H7B	108.3
C2—C1—C7	115.6 (2)	C1—C7—H7B	108.3
C2—C1—C8	110.8 (2)	H7A—C7—H7B	107.4
C7—C1—C8	109.7 (2)	C1—C8—H8A	109.5
C2—C1—N1	107.6 (2)	C1—C8—H8B	109.5
C7—C1—N1	107.6 (2)	H8A—C8—H8B	109.5
C8—C1—N1	104.9 (2)	C1—C8—H8C	109.5
N3—C2—C1	116.3 (2)	H8A—C8—H8C	109.5
N3—C2—H2A	108.2	H8B—C8—H8C	109.5
C1—C2—H2A	108.2	N1—O2—Cu1	85.76 (15)
N3—C2—H2B	108.2	N3—C11—H11A	109.5
C1—C2—H2B	108.2	N3—C11—H11B	109.5
H2A—C2—H2B	107.4	H11A—C11—H11B	109.5
C11—N3—C4	108.3 (2)	N3—C11—H11C	109.5
C11—N3—C2	108.6 (2)	H11A—C11—H11C	109.5
C4—N3—C2	109.0 (2)	H11B—C11—H11C	109.5
C11—N3—Cu1	117.18 (17)	N6—C12—H12A	109.5
C4—N3—Cu1	99.36 (15)	N6—C12—H12B	109.5
C2—N3—Cu1	113.78 (15)	H12A—C12—H12B	109.5
N3—C4—C5	109.8 (2)	N6—C12—H12C	109.5
N3—C4—H4A	109.7	H12A—C12—H12C	109.5
C5—C4—H4A	109.7	H12B—C12—H12C	109.5

Symmetry code: (i) −x+1, −y, −z+2.

Experimental details

Crystal data
Chemical formula	[Cu₂Cl₄(C₈H₁₇N₃O₂)₂]
M_r	643.37
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	296
a, b, c (Å)	10.5478 (2), 10.9251 (2), 11.4430 (2)
β (°)	102.297 (1)
V (Å³)	1288.39 (4)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	2.10
Crystal size (mm)	0.31 × 0.14 × 0.09

Data collection
Diffractometer	Bruker APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2006)
T_min, T_max	0.562, 0.833
No. of measured, independent and observed [I > 2σ(I)] reflections	25284, 2528, 2080
R_int	0.036
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.030, 0.083, 1.07
No. of reflections	2528
No. of parameters	148
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.76, −0.37

Computer programs: APEX2, BIS and COSMO (Bruker, 2006), SAINT (Bruker, 2006), SHELXTL (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2003).

Acknowledgements

The authors thank the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and the Financiadora de Estudos e Projetos (FINEP) for financial support. The authors also thank to Dr Manfredo Hörner and Dr Robert A. Burrow at Universidade Federal de Santa Maria for the crystallographic facilities.

References

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