Bis(2-amino­benzimidazolium) sulfate monohydrate

Peña Hueso, A.; Esparza Ruiz, A.; Flores Parra, A.

doi:10.1107/S2414314622001729

organic compounds

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ISSN: 2414-3146

Volume 7| Part 2| February 2022| x220172

https://doi.org/10.1107/S2414314622001729

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Bis(2-aminobenzimidazolium) sulfate monohydrate

Adrian Peña Hueso,^a Adriana Esparza Ruiz ^b and Angelina Flores Parra ^a ^*

^aDepartamento de Química, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 14-740, Ciudad de Mexico, CP 07000, Mexico, and ^bFacultad de Ingeniería Química, Universidad Autónoma de Yucatán, Periférico Norte Km 33.5, Tablaje Catastral 13615, Chuburna de Hidalgo Inn, Mérida, Yucatan, C.P 97203, Mexico
^*Correspondence e-mail: aflores@cinvestav.mx

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 15 December 2021; accepted 14 February 2022; online 22 February 2022)

In the title hydrated molecular salt, 2C₇H₈N₃⁺·SO₄²⁻·H₂O, the components are linked by numerous N—H⋯O and O—H⋯O hydrogen bonds.

Keywords: crystal structure; 2-aminobenzimidazolium; sulfate.

CCDC reference: 1810894

Structure description

2-Aminobenzimidazole has been used for the synthesis of a series of sulfur heterocycles such as 9H-3-thia-1,4a,9-triaza-fluorene-2,4-dithione (1): its potassium thiolate salt was used to prepare metal coordination compounds (Peña-Hueso et al., 2008 ), and is the precursor of the title compound. When compound 1 is dissolved in dimethyl sulfoxide and strong acids are added, instead of producing the protonated derivative, the thiadiazine ring breaks down, producing 2-aminobenzimidazolium sulfate (2): its crystal structural features are the subject of the present paper.

Compound 2 is formed by the transfer of two protons from sulfuric acid to the heterocycle: the crystal has two 2-aminobenzimidazolium cations, one sulfate anion and one water molecule in its asymmetric unit (Fig. 1). There is a small asymmetry in the S—O bond lengths of the SO₄^2– ion from 1.4596 (16) to 1.4723 (15) Å, probably caused by the hydrogen bonds around the anion (Gagné & Hawthorne, 2018 ). Two benzimidazolium cations are stacked in a head-to-tail way, with a distance between C9 of one molecule and C18 of another of 3.441 (3) Å.

Figure 1
The molecular structure of 2 showing displacement ellipsoids drawn at the 50% probability level

The sulfate ion accepts seven N—H⋯O hydrogen bonds from four adjacent benzimidazolium cations and one O—H⋯O link from a water molecule (Table 1, Fig. 2). The water molecule accepts one N—H⋯O hydrogen bond and forms two O—H⋯O links to two SO₄^2– ions (Fig. 3). In the extended structure, the benzimidazolium cations form parallel ribbons propagating in the [010] direction (Fig. 4).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O25ⁱ	0.81 (4)	2.25 (3)	2.946 (3)	144 (3)
N3—H3⋯O22ⁱⁱ	0.83 (3)	1.93 (3)	2.749 (3)	172 (3)
N11—H11⋯O23	0.85 (4)	1.96 (4)	2.786 (4)	166 (3)
N13—H13⋯O24ⁱⁱⁱ	0.83 (4)	1.91 (4)	2.720 (3)	165 (3)
N10—H101⋯O23ⁱ	0.87 (4)	2.03 (4)	2.894 (5)	169 (3)
N10—H102⋯O25ⁱⁱ	0.89 (3)	2.00 (3)	2.890 (3)	175 (3)
N20—H201⋯O26ⁱⁱⁱ	0.84 (3)	2.04 (3)	2.853 (4)	165 (3)
N20—H202⋯O22ⁱⁱⁱ	0.93 (4)	2.09 (4)	2.973 (4)	157 (3)
O26—H261⋯O24^iv	0.80 (7)	2.22 (7)	2.983 (4)	160 (7)
O26—H262⋯O24^v	0.80 (7)	2.14 (7)	2.860 (4)	150 (6)
C17—H17⋯O22	0.95	2.56	3.272 (3)	132
Symmetry codes: (i) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (ii) ; (iii) $[-x+2, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iv) $[-x+2, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (v) $[x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]$ .

Figure 2
Hydrogen-bond environment around the sulfate anion.

Figure 3
Network of hydrogen bonds (dashed lines) involving the water molecules and sulfate ions.

Figure 4
The unit-cell packing showing [010] ribbons of cations linked by sulfate anions.

The first crystal structure of a 2-aminobenzimidazolium salt was reported with the nitrate anion (Bats et al., 1999 ) and a related structure with hydrogen sulfate as the counter-ion is also known (You et al., 2009 ).

Synthesis and crystallization

The decomposition of 9H-3-thia-1,4a,9-triaza-fluorene-2,4-dithione with dilute aqueous H₂SO₄ in DMSO afforded the title compound 2, m.p. 287–289°C. IR (KBr), ν (cm⁻¹): 3285 (N—H), 1682 (C=N), 1520 (C=C), 1478 (C—N). NMR (DMSO-d₆, p.p.m.) δ ¹H: 7.27 (H4, H7); 7.09 (H5, H6); 13.18 (N1—H, N3—H); 8.70 (NH₂). δ ¹³C: 152.1 (C2); 111.8 (C4, C7); 123.4 (C5, C6); 130.4 (C8, C9). δ ¹⁵N: −257.1 (N1, N3); −312.9 (N10). Analysis calculated (%) for C₁₆H₁₆N₆SO₅: C, 43.97; H, 4.74; N, 21.98. Found: C, 43.50; H, 4.80; N, 21.80. The chemical shifts of C2 (152.1 p.p.m.), C8 and C9 (130.4 p.p.m.) in the ¹³C NMR spectrum indicate that the endocyclic nitrogen atoms are protonated, in agreement with the crystal structure.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	2C₇H₈N₃⁺·SO₄²⁻·H₂O
M_r	382.4
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	12.1115 (2), 10.6282 (2), 17.4772 (3)
β (°)	127.723 (1)
V (Å³)	1779.48 (6)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.22
Crystal size (mm)	0.25 × 0.25 × 0.17

Data collection
Diffractometer	Nonius KappaCCD
No. of measured, independent and observed [I > 3.0σ(I)] reflections	9132, 4563, 2429
R_int	0.04
(sin θ/λ)_max (Å⁻¹)	0.675

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.041, 0.050, 1.03
No. of reflections	2429
No. of parameters	265
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.25, −0.31
Computer programs: COLLECT (Nonius, 2001 ), DENZO/SCALEPACK (Otwinowski & Minor, 1997 ), SHELXS97 (Sheldrick, 2008 ), CRYSTALS (Betteridge et al., 2003 ) and CAMERON (Watkin et al., 1996 ).

Structural data

CCDC reference: 1810894

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314622001729/hb4397sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314622001729/hb4397Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314622001729/hb4397Isup3.cml

checkCIF report

Computing details top

Data collection: COLLECT (Nonius, 2001); cell refinement: DENZO/SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO/SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: CAMERON (Watkin et al., 1996); software used to prepare material for publication: CRYSTALS (Betteridge et al., 2003).

Bis(2-aminobenzimidazolium) sulfate monohydrate top

Crystal data top

2C₇H₈N₃⁺·SO₄²⁻·H₂O	F(000) = 800
M_r = 382.4	D_x = 1.427 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4784 reflections
a = 12.1115 (2) Å	θ = 1–29°
b = 10.6282 (2) Å	µ = 0.22 mm⁻¹
c = 17.4772 (3) Å	T = 293 K
β = 127.723 (1)°	Prism, colourless
V = 1779.48 (6) Å³	0.25 × 0.25 × 0.17 mm
Z = 4

Data collection top

Nonius KappaCCD diffractometer	2429 reflections with I > 3.0σ(I)
Radiation source: Enraf Nonius FR590	R_int = 0.04
Graphite monochromator	θ_max = 28.7°, θ_min = 2.1°
Detector resolution: 9 pixels mm^-1	h = −15→16
φ & ω scans	k = −14→14
9132 measured reflections	l = −23→23
4563 independent reflections

Refinement top

Refinement on F	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.041	Hydrogen site location: difference Fourier map
wR(F²) = 0.050	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	Method, part 1, Chebychev polynomial, (Watkin, 1994, Prince, 1982) [weight] = 1.0/[A₀T₀(x) + A₁T₁(x) ··· + A_n-1]T_n-1(x)] where A_i are the Chebychev coefficients listed below and x = F /Fmax Method = Robust Weighting (Prince, 1982) W = [weight] [1-(deltaF/6*sigmaF)²]² A_i are: 0.914 0.838 0.564 0.170 0.849E-01
2429 reflections	(Δ/σ)_max = 0.0002
265 parameters	Δρ_max = 0.25 e Å⁻³
0 restraints	Δρ_min = −0.31 e Å⁻³

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.

The positions of all NH and OH hydrogen atoms were refined, and all CH were placed at ideal positions.

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

	x	y	z	U_iso*/U_eq
C2	0.5660 (3)	0.1533 (2)	−0.12552 (17)	0.0484
C4	0.5449 (3)	0.1836 (2)	0.0688 (2)	0.0626
C5	0.6271 (4)	0.1200 (3)	0.1556 (2)	0.0725
C6	0.7293 (3)	0.0372 (3)	0.1756 (2)	0.0728
C7	0.7524 (3)	0.0132 (3)	0.1090 (2)	0.0682
C8	0.6705 (3)	0.0761 (2)	0.02241 (18)	0.0503
C9	0.5691 (2)	0.1616 (2)	0.00250 (16)	0.047
C12	0.9604 (2)	0.2887 (2)	0.21087 (16)	0.047
C14	0.8306 (3)	0.3839 (3)	−0.0275 (2)	0.0719
C15	0.7199 (4)	0.4642 (3)	−0.0859 (2)	0.0819
C16	0.6467 (4)	0.5164 (3)	−0.0557 (2)	0.0786
C17	0.6837 (3)	0.4930 (3)	0.03457 (18)	0.0617
C18	0.7951 (2)	0.4131 (2)	0.09334 (16)	0.0479
C19	0.8659 (3)	0.3583 (2)	0.06268 (17)	0.0521
H1	0.700 (3)	0.023 (3)	−0.073 (2)	0.0781*
H3	0.440 (3)	0.256 (3)	−0.122 (2)	0.0603*
H4	0.476	0.2396	0.0553	0.0818*
H5	0.6134	0.1333	0.2013	0.0945*
H6	0.7819	−0.0041	0.2343	0.0851*
H7	0.82	−0.0425	0.1215	0.0843*
H11	0.830 (3)	0.384 (3)	0.220 (2)	0.0595*
H13	1.021 (3)	0.235 (3)	0.136 (2)	0.0682*
H14	0.8797	0.3482	−0.0463	0.0925*
H15	0.6943	0.4849	−0.1462	0.0986*
H16	0.5679	0.568	−0.0992	0.0857*
H17	0.6367	0.5309	0.0569	0.0697*
H101	0.580 (3)	0.137 (3)	−0.227 (2)	0.0811*
H102	0.472 (3)	0.237 (3)	−0.247 (2)	0.0806*
H201	1.041 (3)	0.247 (3)	0.339 (2)	0.07*
H202	1.115 (3)	0.183 (3)	0.301 (2)	0.0698*
H261	0.979 (7)	0.918 (6)	0.069 (5)	0.1811*
H262	0.925 (6)	0.838 (6)	0.005 (5)	0.1804*
N1	0.6657 (2)	0.0745 (2)	−0.05947 (16)	0.0562
N3	0.5078 (2)	0.20819 (19)	−0.08953 (14)	0.0477
N10	0.5301 (3)	0.1737 (2)	−0.21296 (17)	0.0601
N11	0.85749 (19)	0.3685 (2)	0.18649 (14)	0.0479
N13	0.9688 (2)	0.2826 (2)	0.13810 (14)	0.0539
N20	1.0417 (2)	0.2263 (2)	0.29315 (16)	0.0582
O22	0.72767 (16)	0.64914 (16)	0.21275 (11)	0.0506
O23	0.72874 (19)	0.44104 (15)	0.26788 (13)	0.0584
O24	0.8960 (2)	0.5933 (2)	0.37860 (12)	0.0746
O25	0.6554 (2)	0.61476 (17)	0.31313 (14)	0.0657
O26	0.9603 (4)	0.8443 (3)	0.06107 (18)	0.1136
S21	0.75054 (6)	0.57563 (5)	0.29273 (4)	0.0431

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C2	0.0604 (14)	0.0435 (12)	0.0537 (13)	0.0027 (10)	0.0411 (12)	−0.0021 (10)
C4	0.0850 (19)	0.0550 (15)	0.0668 (16)	0.0109 (13)	0.0563 (16)	0.0013 (12)
C5	0.109 (2)	0.0657 (17)	0.0641 (17)	0.0001 (17)	0.0640 (18)	0.0001 (14)
C6	0.087 (2)	0.0733 (18)	0.0555 (15)	0.0049 (16)	0.0420 (16)	0.0142 (14)
C7	0.0703 (17)	0.0651 (17)	0.0705 (17)	0.0194 (14)	0.0436 (15)	0.0185 (14)
C8	0.0577 (14)	0.0464 (12)	0.0551 (14)	0.0060 (11)	0.0388 (12)	0.0017 (11)
C9	0.0580 (13)	0.0411 (11)	0.0484 (12)	0.0015 (10)	0.0358 (11)	−0.0010 (10)
C12	0.0421 (11)	0.0541 (13)	0.0449 (12)	−0.0005 (10)	0.0266 (11)	−0.0062 (11)
C14	0.086 (2)	0.087 (2)	0.0555 (16)	0.0163 (16)	0.0498 (16)	−0.0027 (14)
C15	0.107 (3)	0.085 (2)	0.0498 (15)	0.0272 (19)	0.0461 (17)	0.0063 (14)
C16	0.090 (2)	0.0757 (19)	0.0485 (15)	0.0291 (17)	0.0315 (15)	−0.0001 (14)
C17	0.0615 (15)	0.0649 (16)	0.0475 (14)	0.0171 (13)	0.0277 (12)	−0.0065 (12)
C18	0.0467 (12)	0.0520 (13)	0.0425 (12)	0.0014 (10)	0.0261 (11)	−0.0085 (10)
C19	0.0542 (14)	0.0561 (14)	0.0480 (13)	0.0051 (11)	0.0322 (12)	−0.0054 (11)
N1	0.0716 (14)	0.0522 (12)	0.0658 (13)	0.0182 (11)	0.0527 (12)	0.0089 (10)
N3	0.0555 (11)	0.0470 (10)	0.0480 (11)	0.0102 (9)	0.0356 (10)	0.0018 (9)
N10	0.0807 (16)	0.0608 (13)	0.0583 (13)	0.0140 (11)	0.0525 (13)	0.0042 (10)
N11	0.0440 (10)	0.0592 (12)	0.0450 (10)	0.0050 (9)	0.0296 (9)	−0.0045 (9)
N13	0.0522 (12)	0.0660 (13)	0.0499 (11)	0.0139 (10)	0.0345 (10)	−0.0004 (10)
N20	0.0551 (12)	0.0685 (14)	0.0502 (12)	0.0098 (11)	0.0318 (11)	0.0020 (11)
O22	0.0481 (9)	0.0669 (10)	0.0421 (8)	0.0040 (7)	0.0302 (8)	0.0120 (7)
O23	0.0752 (12)	0.0507 (9)	0.0791 (12)	−0.0031 (8)	0.0624 (11)	−0.0046 (8)
O24	0.0619 (11)	0.1028 (15)	0.0410 (9)	−0.0251 (11)	0.0223 (9)	0.0111 (9)
O25	0.0948 (14)	0.0562 (10)	0.0907 (13)	0.0093 (9)	0.0796 (12)	0.0092 (9)
O26	0.144 (2)	0.148 (3)	0.0652 (14)	−0.069 (2)	0.0725 (17)	−0.0286 (16)
S21	0.0483 (3)	0.0508 (3)	0.0396 (3)	−0.0046 (3)	0.0317 (3)	0.0008 (2)

Geometric parameters (Å, º) top

C2—N1	1.336 (3)	C15—H15	0.925
C2—N3	1.333 (3)	C16—C17	1.374 (4)
C2—N10	1.326 (3)	C16—H16	0.95
C4—C5	1.380 (4)	C17—C18	1.379 (3)
C4—C9	1.377 (3)	C17—H17	0.955
C4—H4	0.931	C18—C19	1.387 (3)
C5—C6	1.379 (4)	C18—N11	1.393 (3)
C5—H5	0.92	C19—N13	1.389 (3)
C6—C7	1.378 (4)	H1—N1	0.80 (3)
C6—H6	0.922	H3—N3	0.83 (3)
C7—C8	1.373 (4)	H11—N11	0.85 (3)
C7—H7	0.921	H13—N13	0.83 (3)
C8—C9	1.390 (3)	H101—N10	0.87 (3)
C8—N1	1.396 (3)	H102—N10	0.89 (3)
C9—N3	1.386 (3)	H201—N20	0.83 (3)
C12—N11	1.343 (3)	H202—N20	0.93 (3)
C12—N13	1.338 (3)	H261—O26	0.81 (6)
C12—N20	1.321 (3)	H262—O26	0.79 (6)
C14—C15	1.376 (4)	O22—S21	1.4723 (15)
C14—C19	1.385 (4)	O23—S21	1.4711 (18)
C14—H14	0.919	O24—S21	1.4680 (19)
C15—C16	1.394 (4)	O25—S21	1.4596 (16)

N1—C2—N3	109.0 (2)	C16—C17—H17	122.5
N1—C2—N10	125.7 (2)	C18—C17—H17	120.8
N3—C2—N10	125.2 (2)	C17—C18—C19	121.7 (2)
C5—C4—C9	117.5 (2)	C17—C18—N11	131.6 (2)
C5—C4—H4	121.5	C19—C18—N11	106.7 (2)
C9—C4—H4	121	C18—C19—C14	121.6 (2)
C4—C5—C6	121.5 (3)	C18—C19—N13	106.5 (2)
C4—C5—H5	119.2	C14—C19—N13	131.8 (2)
C6—C5—H5	119.3	C8—N1—C2	109.08 (19)
C5—C6—C7	121.3 (3)	C8—N1—H1	127 (2)
C5—C6—H6	119.3	C2—N1—H1	122 (2)
C7—C6—H6	119.4	C9—N3—C2	109.2 (2)
C6—C7—C8	117.2 (3)	C9—N3—H3	128.6 (19)
C6—C7—H7	122	C2—N3—H3	121.9 (19)
C8—C7—H7	120.8	H102—N10—C2	117 (2)
C7—C8—C9	121.8 (2)	H102—N10—H101	124 (3)
C7—C8—N1	132.3 (2)	C2—N10—H101	117 (2)
C9—C8—N1	106.0 (2)	C18—N11—C12	108.65 (18)
C8—C9—C4	120.7 (2)	C18—N11—H11	125.7 (19)
C8—C9—N3	106.76 (19)	C12—N11—H11	125.5 (19)
C4—C9—N3	132.5 (2)	C19—N13—C12	109.13 (19)
N11—C12—N13	109.0 (2)	C19—N13—H13	125 (2)
N11—C12—N20	126.2 (2)	C12—N13—H13	126 (2)
N13—C12—N20	124.8 (2)	H202—N20—C12	114.7 (18)
C15—C14—C19	116.6 (2)	H202—N20—H201	124 (3)
C15—C14—H14	122.8	C12—N20—H201	118 (2)
C19—C14—H14	120.7	H261—O26—H262	100 (6)
C14—C15—C16	121.6 (3)	O22—S21—O23	109.89 (10)
C14—C15—H15	119.2	O22—S21—O24	108.29 (10)
C16—C15—H15	119.3	O23—S21—O24	108.23 (12)
C15—C16—C17	121.7 (3)	O22—S21—O25	111.26 (10)
C15—C16—H16	119.2	O23—S21—O25	108.86 (10)
C17—C16—H16	119.1	O24—S21—O25	110.26 (13)
C16—C17—C18	116.8 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O25ⁱ	0.81 (4)	2.25 (3)	2.946 (3)	144 (3)
N3—H3···O22ⁱⁱ	0.83 (3)	1.93 (3)	2.749 (3)	172 (3)
N11—H11···O23	0.85 (4)	1.96 (4)	2.786 (4)	166 (3)
N13—H13···O24ⁱⁱⁱ	0.83 (4)	1.91 (4)	2.720 (3)	165 (3)
N10—H101···O23ⁱ	0.87 (4)	2.03 (4)	2.894 (5)	169 (3)
N10—H102···O25ⁱⁱ	0.89 (3)	2.00 (3)	2.890 (3)	175 (3)
N20—H201···O26ⁱⁱⁱ	0.84 (3)	2.04 (3)	2.853 (4)	165 (3)
N20—H202···O22ⁱⁱⁱ	0.93 (4)	2.09 (4)	2.973 (4)	157 (3)
O26—H261···O24^iv	0.80 (7)	2.22 (7)	2.983 (4)	160 (7)
O26—H262···O24^v	0.80 (7)	2.14 (7)	2.860 (4)	150 (6)
C17—H17···O22	0.95	2.56	3.272 (3)	132

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

Funding information

The authors thank Cinvestav for financial support.

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