Crystal structure of N,N′-bis­(diiso­propyl­phosphan­yl)-4-methyl­pyridine-2,6-di­amine

Stöger, B.; Weil, M.; Bichler, B.; Eder, W.; Kirchner, K.

doi:10.1107/S1600536814010976

organic compounds

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ISSN: 2056-9890

Volume 70| Part 9| September 2014| Pages o889-o890

doi:10.1107/S1600536814010976

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Crystal structure of N,N′-bis(diisopropylphosphanyl)-4-methylpyridine-2,6-diamine

Berthold Stöger,^a Matthias Weil,^a ^* Bernhard Bichler,^b Wolfgang Eder ^b and Karl Kirchner ^b

^aInstitute for Chemical Technologies and Analytics, Division of Structural Chemistry, Vienna University of Technology, Getreidemarkt 9/164-SC, A-1060 Vienna, Austria, and ^bInstitute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163, A-1060 Vienna, Austria
^*Correspondence e-mail: mweil@mail.zserv.tuwien.ac.at

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 12 April 2014; accepted 13 April 2014; online 1 August 2014)

In the molecule of the title compound, C₁₈H₃₅N₃P₂, the methylpyridine-2,6-diamine moiety is almost planar, with a maximum deviation of 0.0129 (9) Å for one of the amine N atoms. Whereas one of the P atoms is co-planar with this mean plane [deviation = 0.0158 (10) Å], the other P atom is considerably displaced out of the mean plane by 0.5882 (10) Å. In the crystal, no directional intermolecular interactions beyond van der Waals contacts could be identified.

Keywords: crystal structure; PNP pincer ligand; methylpyridine-2,6-diamine.

CCDC reference: 1004282

1. Related literature

The title compound belongs to the family of PNP pincer ligands that are capable of forming complexes with various transition metals, leading to interesting properties and applications, see: Benito-Garagorri & Kirchner (2008 ); Langer et al. (2011 ); Bichler et al. (2013 ). For general aspects of pincer ligands and derived complexes, see: Morales-Morales & Jensen (2007 ).

2. Experimental

2.1. Crystal data

C₁₈H₃₅N₃P₂
M_r = 355.4
Orthorhombic, P b c a
a = 14.3394 (12) Å
b = 10.0089 (16) Å
c = 29.562 (3) Å
V = 4242.9 (9) Å³
Z = 8
Mo Kα radiation
μ = 0.21 mm⁻¹
T = 100 K
0.70 × 0.28 × 0.04 mm

2.2. Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2013 ) T_min = 0.93, T_max = 0.99
149837 measured reflections
6241 independent reflections
4614 reflections with I > 3σ(I)
R_int = 0.066

2.3. Refinement

R[F² > 2σ(F²)] = 0.031
wR(F²) = 0.046
S = 1.39
6241 reflections
216 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.29 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (Bruker, 2013); cell refinement: SAINT-Plus (Bruker, 2013); data reduction: SAINT-Plus; program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007 ); program(s) used to refine structure: JANA2006 (Petříček, et al., 2014 ); molecular graphics: Mercury (Macrae et al., 2008 ); software used to prepare material for publication: publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 1004282

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536814010976/su0004sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536814010976/su0004Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536814010976/su0004Isup3.cml

checkCIF report

Related literature top

The title compound belongs to the family of PNP pincer ligands that are capable of forming complexes with various transition metals, leading to interesting properties and applications, see: Benito-Garagorri & Kirchner (2008); Langer et al. (2011); Bichler et al. (2013). For general aspects of pincer ligands and derived complexes, see: Morales-Morales & Jensen (2007).

Experimental top

4-Methylpyridine-2,6-diamine (500 mg, 4 mmol, 1 eq) was diluted in toluene and triethylamine (1.2 ml, 8.6 mmol, 2.1 eq) was added. The mixture was cooled to 273 K using an ice bath and chlorodiisopropylphosphine (1.3 ml, 8.2 mmol, 2.05 eq) was added drop wise using a syringe. The cooling bath was removed, and after reaching room temperature, the reaction mixture was stirred at 353 K for another 12 h. The precipitate was filtered off and the solvent was evaporated. Yield: 69% off-white powder. For further purification, the compound was recrystallized using a toluene/hexane 1:1 (v/v) mixture. Spectroscopic data for the title compound are available in the archived CIF.

Computing details top

Data collection: APEX2 (Bruker, 2013); cell refinement: SAINT-Plus (Bruker, 2013); data reduction: SAINT-Plus (Bruker, 2013); program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: JANA2006 (Petříček, et al., 2014); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top

Fig. 1. The molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 80% probability level.

N,N'-Bis(diisopropylphosphanyl)-4-methylpyridine-2,6-diamine top

Crystal data top

C₁₈H₃₅N₃P₂	F(000) = 1552
M_r = 355.4	D_x = 1.113 Mg m⁻³
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 9974 reflections
a = 14.3394 (12) Å	θ = 2.5–30°
b = 10.0089 (16) Å	µ = 0.21 mm⁻¹
c = 29.562 (3) Å	T = 100 K
V = 4242.9 (9) Å³	Plate, translucent colourless
Z = 8	0.70 × 0.28 × 0.04 mm

Data collection top

Bruker APEXII CCD diffractometer	6241 independent reflections
Radiation source: X-ray tube	4614 reflections with I > 3σ(I)
Graphite monochromator	R_int = 0.066
ω and ϕ scans	θ_max = 30.1°, θ_min = 1.4°
Absorption correction: multi-scan (SADABS; Bruker, 2013)	h = −20→20
T_min = 0.93, T_max = 0.99	k = −14→14
149837 measured reflections	l = −41→41

Refinement top

Refinement on F	Primary atom site location: iterative
R[F² > 2σ(F²)] = 0.031	Secondary atom site location: none
wR(F²) = 0.046	Hydrogen site location: geom,difmap
S = 1.39	H atoms treated by a mixture of independent and constrained refinement
6241 reflections	Weighting scheme based on measured s.u.'s w = 1/(σ²(F) + 0.0004F²)
216 parameters	(Δ/σ)_max = 0.014
2 restraints	Δρ_max = 0.29 e Å⁻³
132 constraints	Δρ_min = −0.21 e Å⁻³

Crystal data top

C₁₈H₃₅N₃P₂	V = 4242.9 (9) Å³
M_r = 355.4	Z = 8
Orthorhombic, Pbca	Mo Kα radiation
a = 14.3394 (12) Å	µ = 0.21 mm⁻¹
b = 10.0089 (16) Å	T = 100 K
c = 29.562 (3) Å	0.70 × 0.28 × 0.04 mm

Data collection top

Bruker APEXII CCD diffractometer	6241 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2013)	4614 reflections with I > 3σ(I)
T_min = 0.93, T_max = 0.99	R_int = 0.066
149837 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.031	2 restraints
wR(F²) = 0.046	H atoms treated by a mixture of independent and constrained refinement
S = 1.39	Δρ_max = 0.29 e Å⁻³
6241 reflections	Δρ_min = −0.21 e Å⁻³
216 parameters

Special details top

Experimental. Spectroscopic data for the title compound:

¹H-NMR (400 MHz, CDCl₃) 6.34 (s, 2H), 4.88 (bs, 2H), 2.18 (s, 3H), 1.87–1.60 (m, 4H), 1.15–0.92 (m, 24H). ³¹P NMR (162 MHz, CDCl₃) 55.65. ¹³C-NMR (63 MHz, CDCl₃) 156.59 (d, J = 21.9 Hz), 153.94 (s), 99.14 (d, J = 19.7 Hz), 26.27 (d, J = 11.4 Hz), 21.80 (d, J = 15.3 Hz), 18.46 (d, J = 19.7 Hz), 17.18 (d, J = 7.9 Hz).

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

	x	y	z	U_iso*/U_eq
P1	0.781952 (19)	0.61761 (3)	0.277629 (10)	0.01628 (8)
P2	0.62798 (2)	0.33177 (3)	0.045775 (10)	0.01837 (8)
N1	0.70180 (6)	0.42925 (9)	0.16952 (3)	0.0149 (2)
N2	0.73728 (7)	0.50053 (10)	0.24153 (3)	0.0176 (3)
N3	0.66959 (7)	0.33964 (10)	0.10001 (3)	0.0200 (3)
C1	0.69814 (7)	0.52954 (11)	0.19953 (4)	0.0146 (3)
C2	0.65663 (7)	0.65213 (11)	0.19012 (4)	0.0166 (3)
C3	0.61705 (7)	0.67148 (11)	0.14781 (4)	0.0164 (3)
C4	0.62017 (8)	0.56884 (11)	0.11637 (4)	0.0180 (3)
C5	0.66312 (7)	0.44882 (11)	0.12890 (4)	0.0158 (3)
C6	0.57228 (8)	0.80360 (11)	0.13652 (4)	0.0220 (3)
C7	0.76791 (8)	0.52642 (12)	0.33135 (4)	0.0211 (3)
C8	0.66449 (9)	0.50783 (15)	0.34168 (5)	0.0326 (4)
C9	0.81669 (11)	0.60387 (14)	0.36929 (4)	0.0321 (4)
C10	0.90932 (8)	0.60456 (12)	0.26658 (4)	0.0207 (3)
C11	0.92671 (9)	0.64908 (13)	0.21773 (4)	0.0280 (4)
C12	0.95354 (8)	0.46787 (12)	0.27535 (4)	0.0251 (3)
C13	0.71074 (8)	0.20717 (12)	0.02331 (4)	0.0196 (3)
C14	0.80702 (9)	0.27110 (14)	0.01819 (4)	0.0304 (4)
C15	0.67652 (9)	0.15302 (14)	−0.02210 (4)	0.0288 (4)
C16	0.51998 (8)	0.23173 (12)	0.05297 (4)	0.0218 (3)
C17	0.44882 (9)	0.31763 (15)	0.07830 (5)	0.0322 (4)
C18	0.53214 (9)	0.09667 (13)	0.07581 (4)	0.0285 (4)
H1c2	0.655417	0.721798	0.212436	0.0199*
H1c4	0.593587	0.579767	0.086795	0.0216*
H1c6	0.531526	0.829737	0.160715	0.0264*
H2c6	0.619791	0.870155	0.132575	0.0264*
H3c6	0.536997	0.795035	0.109071	0.0264*
H1c7	0.795933	0.439591	0.328992	0.0253*
H1c8	0.634885	0.463114	0.316796	0.0392*
H2c8	0.657585	0.4551	0.368598	0.0392*
H3c8	0.635919	0.593558	0.346145	0.0392*
H1c9	0.88155	0.614221	0.362035	0.0386*
H2c9	0.788416	0.690318	0.372402	0.0386*
H3c9	0.810676	0.555582	0.397193	0.0386*
H1c10	0.939505	0.661523	0.288221	0.0248*
H1c11	0.897622	0.734181	0.212703	0.0336*
H2c11	0.992597	0.656607	0.212556	0.0336*
H3c11	0.900823	0.584359	0.197319	0.0336*
H1c12	0.950231	0.447657	0.307053	0.0302*
H2c12	0.920525	0.400794	0.258548	0.0302*
H3c12	1.017612	0.469408	0.265948	0.0302*
H1c13	0.714996	0.133665	0.044067	0.0235*
H1c14	0.823637	0.315444	0.045839	0.0365*
H2c14	0.852243	0.203124	0.011583	0.0365*
H3c14	0.805635	0.334884	−0.006051	0.0365*
H1c15	0.620148	0.103025	−0.0176	0.0345*
H2c15	0.664577	0.226133	−0.042306	0.0345*
H3c15	0.723356	0.095883	−0.034922	0.0345*
H1c16	0.498808	0.208867	0.023147	0.0262*
H1c17	0.440136	0.400466	0.062477	0.0386*
H2c17	0.390461	0.270903	0.080008	0.0386*
H3c17	0.471218	0.335423	0.108302	0.0386*
H1c18	0.569613	0.039846	0.056995	0.0343*
H2c18	0.562348	0.108617	0.104509	0.0343*
H3c18	0.472136	0.056297	0.080352	0.0343*
H1n3	0.6939 (10)	0.2689 (9)	0.1124 (5)	0.042 (4)*
H1n2	0.7548 (9)	0.4176 (4)	0.2438 (5)	0.027 (4)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
P1	0.01745 (13)	0.01506 (14)	0.01634 (13)	0.00115 (10)	−0.00312 (10)	−0.00393 (11)
P2	0.02390 (15)	0.01747 (15)	0.01375 (13)	0.00096 (11)	−0.00236 (10)	−0.00068 (11)
N1	0.0140 (4)	0.0141 (4)	0.0165 (4)	−0.0004 (3)	−0.0013 (3)	−0.0016 (3)
N2	0.0208 (5)	0.0137 (4)	0.0182 (4)	0.0012 (4)	−0.0056 (4)	−0.0025 (4)
N3	0.0287 (5)	0.0153 (5)	0.0160 (4)	0.0045 (4)	−0.0058 (4)	−0.0028 (4)
C1	0.0112 (4)	0.0159 (5)	0.0167 (5)	−0.0022 (4)	−0.0006 (4)	−0.0010 (4)
C2	0.0156 (5)	0.0141 (5)	0.0199 (5)	0.0001 (4)	−0.0007 (4)	−0.0034 (4)
C3	0.0139 (5)	0.0135 (5)	0.0217 (5)	−0.0003 (4)	0.0000 (4)	0.0010 (4)
C4	0.0207 (5)	0.0163 (5)	0.0170 (5)	0.0016 (4)	−0.0031 (4)	0.0002 (4)
C5	0.0156 (5)	0.0155 (5)	0.0162 (5)	−0.0014 (4)	0.0003 (4)	−0.0020 (4)
C6	0.0239 (6)	0.0168 (5)	0.0253 (6)	0.0045 (4)	−0.0025 (4)	0.0002 (5)
C7	0.0249 (6)	0.0211 (6)	0.0171 (5)	0.0032 (4)	−0.0013 (4)	−0.0022 (4)
C8	0.0296 (6)	0.0423 (8)	0.0260 (6)	0.0022 (6)	0.0067 (5)	0.0028 (6)
C9	0.0461 (8)	0.0318 (7)	0.0185 (6)	0.0040 (6)	−0.0077 (5)	−0.0039 (5)
C10	0.0177 (5)	0.0183 (6)	0.0260 (6)	−0.0018 (4)	−0.0031 (4)	−0.0044 (5)
C11	0.0260 (6)	0.0249 (6)	0.0332 (7)	−0.0011 (5)	0.0065 (5)	0.0012 (5)
C12	0.0182 (5)	0.0240 (6)	0.0332 (7)	0.0018 (4)	−0.0041 (5)	−0.0020 (5)
C13	0.0227 (5)	0.0198 (5)	0.0161 (5)	−0.0014 (4)	0.0030 (4)	−0.0015 (4)
C14	0.0269 (6)	0.0341 (8)	0.0301 (7)	−0.0059 (5)	0.0072 (5)	−0.0027 (6)
C15	0.0374 (7)	0.0300 (7)	0.0189 (6)	−0.0014 (6)	0.0031 (5)	−0.0060 (5)
C16	0.0192 (5)	0.0272 (6)	0.0191 (5)	0.0018 (5)	−0.0018 (4)	−0.0049 (5)
C17	0.0242 (6)	0.0400 (8)	0.0323 (7)	0.0051 (6)	0.0006 (5)	−0.0097 (6)
C18	0.0271 (6)	0.0282 (7)	0.0303 (7)	−0.0062 (5)	0.0044 (5)	−0.0002 (5)

Geometric parameters (Å, º) top

P1—N2	1.7094 (10)	C9—H2c9	0.96
P1—C7	1.8426 (12)	C9—H3c9	0.96
P1—C10	1.8599 (12)	C10—C11	1.5319 (18)
P2—N3	1.7125 (11)	C10—C12	1.5300 (17)
P2—C13	1.8452 (12)	C10—H1c10	0.96
P2—C16	1.8564 (12)	C11—H1c11	0.96
N1—C1	1.3408 (14)	C11—H2c11	0.96
N1—C5	1.3372 (14)	C11—H3c11	0.96
N2—C1	1.3932 (14)	C12—H1c12	0.96
N2—H1n2	0.870 (6)	C12—H2c12	0.96
N3—C5	1.3901 (15)	C12—H3c12	0.96
N3—H1n3	0.870 (11)	C13—C14	1.5292 (18)
C1—C2	1.3918 (16)	C13—C15	1.5286 (17)
C2—C3	1.3872 (16)	C13—H1c13	0.96
C2—H1c2	0.96	C14—H1c14	0.96
C3—C4	1.3861 (16)	C14—H2c14	0.96
C3—C6	1.5074 (16)	C14—H3c14	0.96
C4—C5	1.3998 (16)	C15—H1c15	0.96
C4—H1c4	0.96	C15—H2c15	0.96
C6—H1c6	0.96	C15—H3c15	0.96
C6—H2c6	0.96	C16—C17	1.5301 (18)
C6—H3c6	0.96	C16—C18	1.5212 (18)
C7—C8	1.5256 (17)	C16—H1c16	0.96
C7—C9	1.5324 (18)	C17—H1c17	0.96
C7—H1c7	0.96	C17—H2c17	0.96
C8—H1c8	0.96	C17—H3c17	0.96
C8—H2c8	0.96	C18—H1c18	0.96
C8—H3c8	0.96	C18—H2c18	0.96
C9—H1c9	0.96	C18—H3c18	0.96

N2—P1—C7	99.06 (5)	P1—C10—C12	116.11 (8)
N2—P1—C10	102.14 (5)	P1—C10—H1c10	106.5
C7—P1—C10	102.93 (5)	C11—C10—C12	110.63 (10)
N3—P2—C13	98.28 (5)	C11—C10—H1c10	112.45
N3—P2—C16	102.02 (5)	C12—C10—H1c10	103.38
C13—P2—C16	102.31 (5)	C10—C11—H1c11	109.47
C1—N1—C5	117.93 (9)	C10—C11—H2c11	109.47
P1—N2—C1	124.36 (8)	C10—C11—H3c11	109.47
P1—N2—H1n2	119.8 (9)	H1c11—C11—H2c11	109.47
C1—N2—H1n2	112.7 (9)	H1c11—C11—H3c11	109.47
P2—N3—C5	126.02 (8)	H2c11—C11—H3c11	109.47
P2—N3—H1n3	119.7 (9)	C10—C12—H1c12	109.47
C5—N3—H1n3	114.1 (9)	C10—C12—H2c12	109.47
N1—C1—N2	114.71 (9)	C10—C12—H3c12	109.47
N1—C1—C2	122.99 (10)	H1c12—C12—H2c12	109.47
N2—C1—C2	122.29 (10)	H1c12—C12—H3c12	109.47
C1—C2—C3	118.57 (10)	H2c12—C12—H3c12	109.47
C1—C2—H1c2	120.71	P2—C13—C14	109.48 (9)
C3—C2—H1c2	120.71	P2—C13—C15	110.44 (8)
C2—C3—C4	119.21 (10)	P2—C13—H1c13	109.19
C2—C3—C6	119.76 (10)	C14—C13—C15	110.57 (10)
C4—C3—C6	121.02 (10)	C14—C13—H1c13	109.06
C3—C4—C5	118.21 (10)	C15—C13—H1c13	108.06
C3—C4—H1c4	120.89	C13—C14—H1c14	109.47
C5—C4—H1c4	120.89	C13—C14—H2c14	109.47
N1—C5—N3	114.13 (9)	C13—C14—H3c14	109.47
N1—C5—C4	123.08 (10)	H1c14—C14—H2c14	109.47
N3—C5—C4	122.78 (10)	H1c14—C14—H3c14	109.47
C3—C6—H1c6	109.47	H2c14—C14—H3c14	109.47
C3—C6—H2c6	109.47	C13—C15—H1c15	109.47
C3—C6—H3c6	109.47	C13—C15—H2c15	109.47
H1c6—C6—H2c6	109.47	C13—C15—H3c15	109.47
H1c6—C6—H3c6	109.47	H1c15—C15—H2c15	109.47
H2c6—C6—H3c6	109.47	H1c15—C15—H3c15	109.47
P1—C7—C8	109.83 (8)	H2c15—C15—H3c15	109.47
P1—C7—C9	109.29 (8)	P2—C16—C17	108.02 (9)
P1—C7—H1c7	109.89	P2—C16—C18	115.76 (8)
C8—C7—C9	111.03 (10)	P2—C16—H1c16	106.69
C8—C7—H1c7	108.11	C17—C16—C18	111.01 (10)
C9—C7—H1c7	108.66	C17—C16—H1c16	111.87
C7—C8—H1c8	109.47	C18—C16—H1c16	103.42
C7—C8—H2c8	109.47	C16—C17—H1c17	109.47
C7—C8—H3c8	109.47	C16—C17—H2c17	109.47
H1c8—C8—H2c8	109.47	C16—C17—H3c17	109.47
H1c8—C8—H3c8	109.47	H1c17—C17—H2c17	109.47
H2c8—C8—H3c8	109.47	H1c17—C17—H3c17	109.47
C7—C9—H1c9	109.47	H2c17—C17—H3c17	109.47
C7—C9—H2c9	109.47	C16—C18—H1c18	109.47
C7—C9—H3c9	109.47	C16—C18—H2c18	109.47
H1c9—C9—H2c9	109.47	C16—C18—H3c18	109.47
H1c9—C9—H3c9	109.47	H1c18—C18—H2c18	109.47
H2c9—C9—H3c9	109.47	H1c18—C18—H3c18	109.47
P1—C10—C11	107.76 (8)	H2c18—C18—H3c18	109.47

Experimental details

Crystal data
Chemical formula	C₁₈H₃₅N₃P₂
M_r	355.4
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	100
a, b, c (Å)	14.3394 (12), 10.0089 (16), 29.562 (3)
V (Å³)	4242.9 (9)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.21
Crystal size (mm)	0.70 × 0.28 × 0.04

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2013)
T_min, T_max	0.93, 0.99
No. of measured, independent and observed [I > 3σ(I)] reflections	149837, 6241, 4614
R_int	0.066
(sin θ/λ)_max (Å⁻¹)	0.706

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.031, 0.046, 1.39
No. of reflections	6241
No. of parameters	216
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.29, −0.21

Computer programs: APEX2 (Bruker, 2013), SAINT-Plus (Bruker, 2013), SUPERFLIP (Palatinus & Chapuis, 2007), JANA2006 (Petříček, et al., 2014), Mercury (Macrae et al., 2008), publCIF (Westrip, 2010).

Acknowledgements

The X-ray centre of the Vienna University of Technology is acknowledged for providing access to the single-crystal diffractometer.

References

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