4-(1H-2,3-Dihydro­naphtho­[1,8-de][1,3,2]di­aza­borinin-2-yl)-1-ethylpyridin-1-ium iodide

Hashimoto, S.; Okuno, T.

doi:10.1107/S2414314624003626

organic compounds

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ISSN: 2414-3146

Volume 9| Part 4| April 2024| x240362

https://doi.org/10.1107/S2414314624003626

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4-(1H-2,3-Dihydronaphtho[1,8-de][1,3,2]diazaborinin-2-yl)-1-ethylpyridin-1-ium iodide

Shu Hashimoto ^a and Tsunehisa Okuno ^a ^*

^aDepartment of Systems Engineering, Wakayama University, Sakaedani, Wakayama, 640-8510, Japan
^*Correspondence e-mail: okuno@wakayama-u.ac.jp

Edited by I. Brito, University of Antofagasta, Chile (Received 13 March 2024; accepted 22 April 2024; online 26 April 2024)

4-EtPyBdanI.

The title compound, C₁₇H₁₇BN₃I, is a type of diazaborinane featuring substitution at the 1, 2, and 3 positions of the nitrogen–boron six-membered heterocycle. The organic molecule has a planar structure, the dihedral angle between the pyridyl ring and the fused ring system being 3.46 (4)°. In the crystal, molecules are stacked in a head-to-tail manner. The iodide ion makes close contacts with three organic molecules and supports the alternating stack.

Keywords: crystal structure; pyridinium ion; Bdan.

CCDC reference: 2349942

Structure description

The title compound (Fig. 1) is a type of diazaborinane featuring substitution at 1, 2, and 3 positions in the nitrogen-boron six-membered heterocycle. Diazaborinanes have been found to stabilize organic radicals (LaPorte et al., 2023 ). The hydrated polymorph of the title compound was reported by Hashimoto et al. (2024 ).

Figure 1
The title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.

The organic unit has a planar structure, with a dihedral angle between the N1/C1—C5 pyridyl ring and the N2/N3/C6–C15/B1 ring system of 3.46 (4)°. The organic unit has the similar structure to those previously reported (Akerman et al., 2011 ; Slabber et al., 2011 ). The ethyl group on the nitrogen atom has an out-of-plane conformation. In the crystal, the organic unit forms alternating stacks in a head-to-tail manner along the a axis, as shown in Fig. 2, where the B1⋯·B1ⁱ and B1⋯·B1ⁱⁱⁱ distances are 3.380 (3) and 3.793 (3) Å, respectively [symmetry codes:(i) −x + 1, −y + 1, −z + 1; (iii) −x, −y + 1, −z + 1]. Three kinds of hydrogen bonds occur between the organic unit and the iodide ions, as summarized in Table 1, the with iodide ion being surrounded by three organic units. It supports the alternating stacking and connects neighboring stacks.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H5⋯I1	0.81 (2)	2.96 (2)	3.7260 (13)	157.2 (18)
C2—H2⋯I1	0.93	3.16 (1)	4.0483 (14)	161 (1)
N3—H12⋯I1ⁱ	0.82 (2)	3.02 (2)	3.7453 (12)	148.7 (18)
C16—H14⋯I1ⁱⁱ	0.97	3.07 (1)	3.8981 (15)	144 (1)
Symmetry codes: (i) ; (ii) .

Figure 2
Intermolecular interactions in the title compound [symmetry codes: (i) −x + 1, −y + 1, −z + 1; (ii) x, y − 1, z; (iii) −x, −y + 1, −z + 1].

Synthesis and crystallization

The precursor of the title compound, 2-(pyridin-4-yl)-2,3-dihydro-1H-naphtho[1,8-de][1,3,2] diazaborinine, 4PyBdan, was prepared by condensation of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine and 1,8-diaminonaphthalene. A solution of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (0.20 g, 0.98 mmol) and 1,8-diaminonaphthalene (0.20 g, 1.3 mmol) in dry toluene (50 ml) was refluxed for 24 h under an argon atmosphere. The solution was concentrated under reduced pressure. The residual solid was purified by column chromatography (SiO₂, ethyl acetate) to give a yellow solid of 4PyBdan (0.23 g) in 96% yield. ¹H NMR (400 MHz, CDCl₃): δ 6.44 (br s, 2H), 6.44 (d, J = 8.2 Hz, 2H), 7.09 (d, J = 8.2 Hz, 2H), 7.15 (t, J = 8.2 Hz, 2H), 7.50 (d, J = 6.0 Hz, 2H), 8.69 (d, J = 6.0 Hz, 2H).

A mixture of 4PyBdan (0.15 g, 0.61 mmol) and iodoethane (3.0 ml, 37.7 mmol) in acetonitrile (24 ml) was stirred for 14 h under an argon atmosphere. The precipitate was filtered off and dried under vacuum to give the title compound (0.14 g) in 57% yield as a red solid. Single crystals of sufficient quality were obtained by recrystallization from acetonitrile.

Refinement

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

Table 2
Experimental details

Crystal data
Chemical formula	C₁₇H₁₇BN₃⁺·I⁻
M_r	401.04
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	293
a, b, c (Å)	7.0800 (3), 10.6304 (3), 11.0650 (3)
α, β, γ (°)	89.715 (2), 79.711 (3), 89.598 (2)
V (Å³)	819.37 (5)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	1.95
Crystal size (mm)	0.1 × 0.05 × 0.03

Data collection
Diffractometer	XtaLAB AFC10 (RCD3): fixed-χ single
Absorption correction	Multi-scan (CrysAlis PRO; Rigaku OD, 2020 )
T_min, T_max	0.942, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	12190, 4404, 4088
R_int	0.016
(sin θ/λ)_max (Å⁻¹)	0.737

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.020, 0.052, 1.07
No. of reflections	4404
No. of parameters	208
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.78, −0.29
Computer programs: CrysAlis PRO (Rigaku OD, 2020), SHELXT2014/4 (Sheldrick, 2015a ), SHELXL2014/7 (Sheldrick, 2015b ) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 2349942

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314624003626/bx4026sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314624003626/bx4026Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314624003626/bx4026Isup3.cml

checkCIF report

Computing details top

4-(1H-2,3-Dihydronaphtho[1,8-de][1,3,2]diazaborinin-2-yl)-1-ethylpyridin-1-ium iodide top

Crystal data top

C₁₇H₁₇BN₃⁺·I⁻	Z = 2
M_r = 401.04	F(000) = 396
Triclinic, P1	D_x = 1.626 Mg m⁻³
a = 7.0800 (3) Å	Mo Kα radiation, λ = 0.71073 Å
b = 10.6304 (3) Å	Cell parameters from 7826 reflections
c = 11.0650 (3) Å	θ = 3.8–31.4°
α = 89.715 (2)°	µ = 1.95 mm⁻¹
β = 79.711 (3)°	T = 293 K
γ = 89.598 (2)°	Plate, clear red
V = 819.37 (5) Å³	0.1 × 0.05 × 0.03 mm

Data collection top

XtaLAB AFC10 (RCD3): fixed-χ single diffractometer	4404 independent reflections
Radiation source: Rotating-anode X-ray tube, Rigaku (Mo) X-ray Source	4088 reflections with I > 2σ(I)
Mirror monochromator	R_int = 0.016
Detector resolution: 10.0000 pixels mm^-1	θ_max = 31.6°, θ_min = 3.7°
ω scans	h = −7→10
Absorption correction: multi-scan (CrysAlisPro; Rigaku OD, 2020)	k = −14→14
T_min = 0.942, T_max = 1.000	l = −15→15
12190 measured reflections

Refinement top

Refinement on F²	Primary atom site location: dual
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.020	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.052	w = 1/[σ²(F_o²) + (0.0288P)² + 0.2552P] where P = (F_o² + 2F_c²)/3
S = 1.07	(Δ/σ)_max = 0.004
4404 reflections	Δρ_max = 0.78 e Å⁻³
208 parameters	Δρ_min = −0.29 e Å⁻³
0 restraints

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. The positions of the N-bound and the O-bound H atoms were obtained from difference Fourier maps and were refined isotropically. The C-bound H atoms were placed at ideal positions and were refined as riding on their parent C atoms. U_iso(H) values of the H atoms were set at 1.2U_eq(parent atom for C_sp2) and 1.5U_eq(parent atom for C_sp3).

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

	x	y	z	U_iso*/U_eq
I1	0.41685 (2)	0.80629 (2)	0.76854 (2)	0.03537 (5)
N1	0.38277 (16)	0.22734 (11)	0.80569 (10)	0.0189 (2)
N2	0.22902 (17)	0.60900 (11)	0.53955 (11)	0.0206 (2)
N3	0.24819 (18)	0.43530 (12)	0.39835 (11)	0.0220 (2)
C6	0.19028 (19)	0.69330 (13)	0.45019 (12)	0.0202 (2)
C4	0.3287 (2)	0.25792 (13)	0.60271 (13)	0.0221 (3)
H3	0.3186	0.2239	0.5269	0.026*
C3	0.30663 (18)	0.38741 (12)	0.62082 (12)	0.0181 (2)
C2	0.3276 (2)	0.43318 (13)	0.73619 (13)	0.0217 (3)
H2	0.3151	0.5189	0.7522	0.026*
C1	0.3666 (2)	0.35186 (13)	0.82613 (13)	0.0219 (3)
H1	0.3820	0.3835	0.9019	0.026*
C5	0.3656 (2)	0.17955 (13)	0.69587 (13)	0.0222 (3)
H4	0.3785	0.0934	0.6826	0.027*
C16	0.4153 (2)	0.14270 (14)	0.90731 (13)	0.0233 (3)
H13	0.4977	0.1841	0.9559	0.028*
H14	0.4801	0.0667	0.8733	0.028*
C15	0.18123 (18)	0.64498 (13)	0.33129 (12)	0.0197 (2)
C14	0.2089 (2)	0.51456 (14)	0.30483 (13)	0.0218 (3)
C7	0.1655 (2)	0.82045 (14)	0.47347 (14)	0.0267 (3)
H6	0.1693	0.8515	0.5514	0.032*
C10	0.14939 (19)	0.73002 (14)	0.23651 (13)	0.0232 (3)
C11	0.1474 (2)	0.68118 (17)	0.11772 (14)	0.0292 (3)
H9	0.1297	0.7353	0.0543	0.035*
C9	0.1257 (2)	0.85948 (15)	0.26407 (14)	0.0275 (3)
H8	0.1040	0.9157	0.2033	0.033*
C8	0.1343 (2)	0.90312 (15)	0.37892 (16)	0.0299 (3)
H7	0.1193	0.9888	0.3949	0.036*
C13	0.2006 (2)	0.47006 (16)	0.18876 (14)	0.0296 (3)
H11	0.2143	0.3845	0.1721	0.035*
C12	0.1712 (2)	0.55533 (18)	0.09582 (14)	0.0327 (3)
H10	0.1680	0.5250	0.0175	0.039*
C17	0.2286 (2)	0.10846 (19)	0.98868 (17)	0.0362 (4)
H17	0.1531	0.0588	0.9431	0.054*
H15	0.1592	0.1838	1.0168	0.054*
H16	0.2543	0.0610	1.0580	0.054*
B1	0.2602 (2)	0.47939 (14)	0.51714 (14)	0.0189 (3)
H5	0.246 (3)	0.639 (2)	0.604 (2)	0.035 (6)*
H12	0.280 (3)	0.365 (2)	0.373 (2)	0.035 (5)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
I1	0.06050 (9)	0.01998 (6)	0.02905 (6)	0.00500 (4)	−0.01733 (5)	−0.00322 (4)
N1	0.0171 (5)	0.0176 (5)	0.0217 (5)	0.0001 (4)	−0.0027 (4)	0.0065 (4)
N2	0.0239 (6)	0.0190 (5)	0.0187 (5)	0.0031 (4)	−0.0037 (4)	0.0041 (4)
N3	0.0252 (6)	0.0176 (5)	0.0238 (6)	0.0014 (4)	−0.0063 (4)	0.0032 (4)
C6	0.0177 (6)	0.0196 (6)	0.0224 (6)	0.0025 (5)	−0.0016 (5)	0.0066 (5)
C4	0.0259 (7)	0.0191 (6)	0.0216 (6)	−0.0010 (5)	−0.0053 (5)	0.0034 (5)
C3	0.0148 (6)	0.0175 (6)	0.0210 (6)	−0.0001 (4)	−0.0007 (4)	0.0056 (4)
C2	0.0251 (7)	0.0160 (6)	0.0232 (6)	0.0015 (5)	−0.0028 (5)	0.0037 (5)
C1	0.0261 (7)	0.0186 (6)	0.0210 (6)	0.0018 (5)	−0.0041 (5)	0.0019 (5)
C5	0.0256 (7)	0.0148 (6)	0.0264 (6)	0.0002 (5)	−0.0049 (5)	0.0035 (5)
C16	0.0238 (7)	0.0212 (6)	0.0259 (7)	0.0008 (5)	−0.0076 (5)	0.0099 (5)
C15	0.0146 (6)	0.0225 (6)	0.0210 (6)	0.0010 (5)	−0.0008 (4)	0.0067 (5)
C14	0.0187 (6)	0.0241 (7)	0.0225 (6)	0.0007 (5)	−0.0041 (5)	0.0047 (5)
C7	0.0313 (8)	0.0207 (6)	0.0281 (7)	0.0047 (5)	−0.0056 (6)	0.0039 (5)
C10	0.0152 (6)	0.0293 (7)	0.0242 (6)	0.0017 (5)	−0.0012 (5)	0.0107 (5)
C11	0.0222 (7)	0.0418 (9)	0.0233 (7)	0.0048 (6)	−0.0037 (5)	0.0107 (6)
C9	0.0224 (7)	0.0278 (7)	0.0309 (7)	0.0028 (6)	−0.0012 (5)	0.0154 (6)
C8	0.0304 (8)	0.0211 (7)	0.0372 (8)	0.0047 (6)	−0.0041 (6)	0.0097 (6)
C13	0.0326 (8)	0.0308 (8)	0.0270 (7)	0.0049 (6)	−0.0100 (6)	−0.0013 (6)
C12	0.0317 (8)	0.0459 (10)	0.0218 (7)	0.0072 (7)	−0.0084 (6)	0.0005 (6)
C17	0.0270 (8)	0.0448 (10)	0.0364 (8)	−0.0022 (7)	−0.0053 (6)	0.0246 (7)
B1	0.0158 (6)	0.0184 (6)	0.0221 (7)	−0.0008 (5)	−0.0026 (5)	0.0060 (5)

Geometric parameters (Å, º) top

N1—C1	1.3446 (18)	C16—H14	0.9700
N1—C5	1.3452 (19)	C16—C17	1.506 (2)
N1—C16	1.4855 (16)	C15—C14	1.423 (2)
N2—C6	1.3930 (16)	C15—C10	1.4283 (18)
N2—B1	1.4100 (19)	C14—C13	1.382 (2)
N2—H5	0.81 (2)	C7—H6	0.9300
N3—C14	1.3961 (17)	C7—C8	1.409 (2)
N3—B1	1.415 (2)	C10—C11	1.418 (2)
N3—H12	0.81 (2)	C10—C9	1.413 (2)
C6—C15	1.427 (2)	C11—H9	0.9300
C6—C7	1.381 (2)	C11—C12	1.365 (3)
C4—H3	0.9300	C9—H8	0.9300
C4—C3	1.3957 (19)	C9—C8	1.367 (2)
C4—C5	1.3816 (18)	C8—H7	0.9300
C3—C2	1.4012 (19)	C13—H11	0.9300
C3—B1	1.5808 (19)	C13—C12	1.410 (2)
C2—H2	0.9300	C12—H10	0.9300
C2—C1	1.3786 (18)	C17—H17	0.9600
C1—H1	0.9300	C17—H15	0.9600
C5—H4	0.9300	C17—H16	0.9600
C16—H13	0.9700

C1—N1—C5	120.68 (11)	C14—C15—C10	119.66 (13)
C1—N1—C16	118.97 (12)	N3—C14—C15	117.96 (13)
C5—N1—C16	120.33 (12)	C13—C14—N3	121.88 (14)
C6—N2—B1	122.92 (12)	C13—C14—C15	120.15 (13)
C6—N2—H5	116.8 (16)	C6—C7—H6	120.0
B1—N2—H5	119.9 (16)	C6—C7—C8	119.91 (15)
C14—N3—B1	122.71 (13)	C8—C7—H6	120.0
C14—N3—H12	112.2 (16)	C11—C10—C15	118.47 (14)
B1—N3—H12	124.4 (16)	C9—C10—C15	118.79 (14)
N2—C6—C15	117.93 (12)	C9—C10—C11	122.73 (13)
C7—C6—N2	121.80 (13)	C10—C11—H9	119.8
C7—C6—C15	120.25 (12)	C12—C11—C10	120.44 (14)
C3—C4—H3	119.5	C12—C11—H9	119.8
C5—C4—H3	119.5	C10—C9—H8	119.6
C5—C4—C3	120.92 (13)	C8—C9—C10	120.85 (13)
C4—C3—C2	116.81 (12)	C8—C9—H8	119.6
C4—C3—B1	122.23 (12)	C7—C8—H7	119.5
C2—C3—B1	120.96 (12)	C9—C8—C7	121.07 (15)
C3—C2—H2	119.8	C9—C8—H7	119.5
C1—C2—C3	120.39 (13)	C14—C13—H11	120.2
C1—C2—H2	119.8	C14—C13—C12	119.51 (15)
N1—C1—C2	120.87 (13)	C12—C13—H11	120.2
N1—C1—H1	119.6	C11—C12—C13	121.73 (15)
C2—C1—H1	119.6	C11—C12—H10	119.1
N1—C5—C4	120.31 (13)	C13—C12—H10	119.1
N1—C5—H4	119.8	C16—C17—H17	109.5
C4—C5—H4	119.8	C16—C17—H15	109.5
N1—C16—H13	109.4	C16—C17—H16	109.5
N1—C16—H14	109.4	H17—C17—H15	109.5
N1—C16—C17	111.19 (12)	H17—C17—H16	109.5
H13—C16—H14	108.0	H15—C17—H16	109.5
C17—C16—H13	109.4	N2—B1—N3	117.28 (12)
C17—C16—H14	109.4	N2—B1—C3	121.20 (12)
C6—C15—C10	119.13 (13)	N3—B1—C3	121.51 (12)
C14—C15—C6	121.19 (12)

N2—C6—C15—C14	0.62 (19)	C16—N1—C1—C2	−176.98 (12)
N2—C6—C15—C10	−177.51 (12)	C16—N1—C5—C4	177.77 (13)
N2—C6—C7—C8	177.40 (14)	C15—C6—C7—C8	−1.1 (2)
N3—C14—C13—C12	−176.41 (14)	C15—C14—C13—C12	2.2 (2)
C6—N2—B1—N3	−0.9 (2)	C15—C10—C11—C12	1.4 (2)
C6—N2—B1—C3	179.14 (12)	C15—C10—C9—C8	0.5 (2)
C6—C15—C14—N3	−0.94 (19)	C14—N3—B1—N2	0.5 (2)
C6—C15—C14—C13	−179.61 (13)	C14—N3—B1—C3	−179.49 (12)
C6—C15—C10—C11	177.85 (12)	C14—C15—C10—C11	−0.31 (19)
C6—C15—C10—C9	−0.70 (19)	C14—C15—C10—C9	−178.86 (13)
C6—C7—C8—C9	0.8 (2)	C14—C13—C12—C11	−1.1 (3)
C4—C3—C2—C1	−0.5 (2)	C7—C6—C15—C14	179.15 (13)
C4—C3—B1—N2	176.79 (13)	C7—C6—C15—C10	1.0 (2)
C4—C3—B1—N3	−3.2 (2)	C10—C15—C14—N3	177.18 (12)
C3—C4—C5—N1	−0.7 (2)	C10—C15—C14—C13	−1.5 (2)
C3—C2—C1—N1	−0.9 (2)	C10—C11—C12—C13	−0.7 (2)
C2—C3—B1—N2	−3.24 (19)	C10—C9—C8—C7	−0.5 (2)
C2—C3—B1—N3	176.80 (13)	C11—C10—C9—C8	−178.03 (15)
C1—N1—C5—C4	−0.7 (2)	C9—C10—C11—C12	179.89 (15)
C1—N1—C16—C17	84.82 (17)	B1—N2—C6—C15	0.33 (19)
C5—N1—C1—C2	1.6 (2)	B1—N2—C6—C7	−178.18 (13)
C5—N1—C16—C17	−93.72 (17)	B1—N3—C14—C15	0.3 (2)
C5—C4—C3—C2	1.3 (2)	B1—N3—C14—C13	178.99 (14)
C5—C4—C3—B1	−178.72 (13)	B1—C3—C2—C1	179.52 (13)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H5···I1	0.81 (2)	2.96 (2)	3.7260 (13)	157.2 (18)
C2—H2···I1	0.93	3.16 (1)	4.0483 (14)	161 (1)
N3—H12···I1ⁱ	0.82 (2)	3.02 (2)	3.7453 (12)	148.7 (18)
C16—H14···I1ⁱⁱ	0.97	3.07 (1)	3.8981 (15)	144 (1)

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

Acknowledgements

TO gratefully acknowledges the publication supporting fund of Wakayama University.

Funding information

Funding for this research was provided by: Wakayama University.

References

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