Crystal structure of benzyl 2-naphthyl ether, a sensitiser for thermal paper

Kikuchi, T.; Gontani, S.; Miyanaga, K.; Kurata, T.; Akatani, Y.; Matsumoto, S.

doi:10.1107/S2056989019000690

research communications

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 75| Part 2| February 2019| Pages 242-245

https://doi.org/10.1107/S2056989019000690

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Crystal structure of benzyl 2-naphthyl ether, a sensitiser for thermal paper

Takuya Kikuchi,^a Saori Gontani,^a Kyohei Miyanaga,^b Takaaki Kurata,^b Yoshiki Akatani ^c and Shinya Matsumoto ^a ^*

^aGraduate School of Environment and Information Sciences, Yokohama National University, Tokiwadai 79-7, Hodogaya-ku, Yokohama 240-8501, Japan, ^bFunctional Chemicals R&D Laboratories, Nippon Kayaku Corporation Limited, Shimo 3-31-2, Kita-ku, Tokyo 115-8588, Japan, and ^cColor Materials Division in Functional Chemicals Group, Nippon Kayaku Corporation Limited, Shimo 3-31-2, Kita-ku, Tokyo 115-8588, Japan
^*Correspondence e-mail: matsumoto-shinya-py@ynu.ac.jp

Edited by H. Ishida, Okayama University, Japan (Received 3 December 2018; accepted 15 January 2019; online 18 January 2019)

The title compound [systematic name: 2-(benzyloxy)naphthalene], C₁₇H₁₄O, which is used as a sensitiser for thermal paper, has a twisted conformation with a dihedral angle of 48.71 (12)° between the phenyl ring and the naphthyl ring system. In the crystal, one molecule interacts with six neighbouring molecules via intermolecular C—H⋯π interactions to form a herringbone molecular arrangement.

Keywords: crystal structure; thermal paper; sensitiser; C—H⋯π intermolecular interaction.

CCDC reference: 1890872

1. Chemical context

Thermal printing is a rapid and inexpensive printing technology widely used in commercial applications such as receipts, faxes and tickets (Gregory, 1991 ; Mendum et al., 2011 ). Many structural reports are available for thermosensitive dyes and developers (Matsumoto et al., 2010 ; Kodama et al., 2013 ; Gontani et al., 2017 ; Ohashi et al., 2017 ). On the other hand, we found only one report on the crystal structure of a compound commonly used as a sensitiser for the thermosensitive layer (Rudolph et al., 2010 ), which can facilitate the dye coloration process by lowering the melting point of the dye/developer composite on thermal paper (US EPA, 2014 ). The title compound, benzyl 2-naphthyl ether, 1, is known as another commonly used sensitiser. Herein, we report the crystal structure of 1 as fundamental data for the investigation of its influence on the solid-state physicochemical properties of the thermosensitive layer of the thermal paper.

2. Structural commentary

The title compound (Fig. 1) is a simple ether compound in which a benzyl group is connected to a naphthyl group via an ether bond. The two aromatic rings are twisted, which is mainly attributable to the rotation about the C11—C12 bond. The dihedral angle between the mean planes of the naphthyl ring system (C1–C10) and the phenyl ring (C12–C17) is 48.71 (12)°. The related torsion angles for this dihedral angle are −44.9 (3)° (O1—C11—C12—C17), 178.7 (2)° (C1—O1—C11—C12) and −5.6 (3)° (C6—C1—O1—C11).

Figure 1
The molecular structure of the title compound, 1, with displacement ellipsoids drawn at the 50% probability level.

3. Supramolecular features

In the crystal, one molecule interacts with six neighbouring molecules via intermolecular C—H⋯π interactions (Table 1; Fig. 2). The molecules are linked by a C—H⋯π interaction between the benzene C1–C6 rings (C3—H3⋯Cg1ⁱ; symmetry code as in Table 1), forming a zigzag chain along the a-axis direction. The chains are connected into a layer structure parallel to the ab plane via a C—H⋯π interaction between the benzene C4/C5/C7–C10 ring and the methylene hydrogen atom (C11—H11A⋯Cg2ⁱⁱ; Table 1). A weak C—H⋯π interaction between the C12–C17 phenyl rings (C16—H16⋯Cg3ⁱⁱⁱ; Table 1) links the layers and thus the molecules form a herringbone arrangement when viewed along the a axis, as shown in Fig. 3.

Table 1
Hydrogen-bond geometry (Å, °)

Cg1, Cg2 and Cg3 are the centroids of the C1–C6, C4/C5/C7–C10 and C12–C17 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯Cg1ⁱ	0.93	2.71	3.439 (2)	135
C11—H11A⋯Cg2ⁱⁱ	0.97	2.63	3.512 (3)	150
C16—H16⋯Cg3ⁱⁱⁱ	0.93	2.87	3.586 (3)	135
Symmetry codes: (i) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]$ ; (ii) $[x-{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+1]$ ; (iii) $[-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Figure 2
A packing diagram of the title compound, 1, showing intermolecular C—H⋯π interactions (dashed lines). [Symmetry codes: (A) −x + 1, y + $[{1\over 2}]$ , −z + $[{1\over 2}]$ ; (B) −x + 1, y − $[{1\over 2}]$ , −z + $[{1\over 2}]$ ; (C) x + $[{1\over 2}]$ , −y + $[{3\over 2}]$ , −z + 1; (D) x − $[{1\over 2}]$ , −y + $[{3\over 2}]$ , −z + 1; (E) x + $[{1\over 2}]$ , −y + $[{1\over 2}]$ , −z + 1; (F) x − $[{1\over 2}]$ , −y + $[{1\over 2}]$ , −z + 1.]

Figure 3
A packing diagram of the title compound, 1, viewed along the a axis, showing a herringbone arrangement. H atoms have been omitted for clarity.

4. Database survey

Three analogous compounds of 1, namely, 2-benzyloxy-1-naphthaldehyde, 2 [CSD (Groom et al., 2016 ) refcode SOLVUL; Gao et al., 2009 ], 2-benzyloxy-3-methoxynaphthalene, 3 (MEBYIC; Huang et al., 2004 ) and 2-benzyloxy-3-hydroxynaphthalene, 4 (SICGEQ; Peters et al., 1998 ), have been reported. Compounds, 2, 3 and 4, crystallize in the centrosymmetric space groups P2₁/c, P2₁/c and P $[\overline{1}]$ , respectively. Fig. 4 shows an overlay of the molecular geometries of compounds 1–4, which indicates significant geometrical differences in the conformation of the benzyl unit caused by the rotations around the C1—O1 and C11—C12 bonds. Fig. 5 shows packing diagrams for compounds 2–4. In the crystals of 2–4, the molecules form zigzag chains via C—H⋯O interactions. In 2, the chains are linked by π–π interactions into a three-dimensional network, whereas C—H⋯π interactions contribute to the arrangement of the chains in 3 and 4.

Figure 4
An overlay of the molecular conformation of four analogous benzyl-2-naphthyl ether derivatives, 1 (blue), 2 (red), 3 (yellow) and 4 (green). All H atoms have been omitted for clarity.

Figure 5
Packing diagrams of compounds 2 (a), 3 (b) and 4 (c). The dotted lines indicate intermolecular C—H⋯O and C—H⋯π interactions.

5. Synthesis and crystallization

The title compound was purchased from Tokyo Kasei Kogyo Co., Ltd., and used without further purification. X-ray diffraction quality colourless platelets were obtained using a liquid–liquid diffusion method, with combination of chloroform and ethanol at 278 K.

6. Refinement

The crystal data, data collection and structure refinement details are summarized in Table 2. All H atoms were positioned geometrically (C—H = 0.93 Å) and refined using a riding model with U_iso(H) = 1.2U_eq(C).

Table 2
Experimental details

Crystal data
Chemical formula	C₁₇H₁₄O
M_r	234.30
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	298
a, b, c (Å)	6.10537 (10), 7.58687 (13), 26.8196 (5)
V (Å³)	1242.30 (4)
Z	4
Radiation type	Cu Kα
μ (mm⁻¹)	0.59
Crystal size (mm)	0.61 × 0.42 × 0.04

Data collection
Diffractometer	Rigaku XtaLAB PRO
Absorption correction	Multi-scan (CrysAlis PRO; Rigaku OD, 2015 $[Rigaku Oxford Diffraction (2015). CrysAlis PRO. Rigaku Corporation, Tokyo, Japan.]$ )
T_min, T_max	0.396, 0.976
No. of measured, independent and observed [F² > 2.0σ(F²)] reflections	3724, 2017, 1841
R_int	0.033
(sin θ/λ)_max (Å⁻¹)	0.594

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.042, 0.107, 1.01
No. of reflections	2017
No. of parameters	163
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.12, −0.20
Absolute structure	Flack x determined using 601 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )
Absolute structure parameter	−0.3 (3)
Computer programs: CrysAlis PRO (Rigaku OD, 2015 $[Rigaku Oxford Diffraction (2015). CrysAlis PRO. Rigaku Corporation, Tokyo, Japan.]$ ), SHELXT (Sheldrick, 2015a ), SHELXL2014 (Sheldrick, 2015b ) and CrystalStructure (Rigaku, 2018 ).

Supporting information

CCDC reference: 1890872

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2056989019000690/is5508sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989019000690/is5508Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2056989019000690/is5508Isup3.cml

checkCIF report

Computing details top

Data collection: CrysAlis PRO (Rigaku OD, 2015); cell refinement: CrysAlis PRO (Rigaku OD, 2015); data reduction: CrysAlis PRO (Rigaku OD, 2015); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: CrystalStructure (Rigaku, 2018); software used to prepare material for publication: CrystalStructure (Rigaku, 2018).

2-(Benzyloxy)naphthalene top

Crystal data top

C₁₇H₁₄O	D_x = 1.253 Mg m⁻³
M_r = 234.30	Cu Kα radiation, λ = 1.54184 Å
Orthorhombic, P2₁2₁2₁	Cell parameters from 2523 reflections
a = 6.10537 (10) Å	θ = 6.1–71.1°
b = 7.58687 (13) Å	µ = 0.59 mm⁻¹
c = 26.8196 (5) Å	T = 298 K
V = 1242.30 (4) Å³	Plate, colourless
Z = 4	0.61 × 0.42 × 0.04 mm
F(000) = 496.00

Data collection top

Rigaku XtaLAB PRO diffractometer	1841 reflections with F² > 2.0σ(F²)
Detector resolution: 5.811 pixels mm^-1	R_int = 0.033
ω scans	θ_max = 66.4°, θ_min = 3.3°
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2015)	h = −3→7
T_min = 0.396, T_max = 0.976	k = −9→8
3724 measured reflections	l = −31→31
2017 independent reflections

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.042	H-atom parameters constrained
wR(F²) = 0.107	w = 1/[σ²(F_o²) + (0.0559P)²] where P = (F_o² + 2F_c²)/3
S = 1.01	(Δ/σ)_max < 0.001
2017 reflections	Δρ_max = 0.12 e Å⁻³
163 parameters	Δρ_min = −0.20 e Å⁻³
0 restraints	Absolute structure: Flack x determined using 601 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.3 (3)
Secondary atom site location: difference Fourier map

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 was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F². R-factor (gt) are based on F. The threshold expression of F² > 2.0 sigma(F²) is used only for calculating R-factor (gt).

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

	x	y	z	U_iso*/U_eq
O1	0.5853 (3)	0.5557 (2)	0.39703 (5)	0.0492 (4)
C1	0.6358 (4)	0.5250 (3)	0.44606 (8)	0.0394 (5)
C5	0.5738 (4)	0.5198 (3)	0.53498 (7)	0.0380 (5)
C3	0.9115 (3)	0.4027 (3)	0.50010 (8)	0.0432 (5)
H3	1.0488	0.3518	0.5045	0.052*
C4	0.7789 (4)	0.4363 (3)	0.54226 (8)	0.0393 (5)
C12	0.3435 (4)	0.6519 (3)	0.33234 (8)	0.0446 (5)
C6	0.5058 (3)	0.5652 (3)	0.48601 (8)	0.0405 (5)
H6	0.3728	0.6223	0.4811	0.049*
C7	0.8415 (4)	0.3848 (3)	0.59097 (9)	0.0494 (6)
H7	0.9760	0.3300	0.5960	0.059*
C2	0.8426 (4)	0.4432 (3)	0.45349 (9)	0.0447 (5)
H2	0.9310	0.4173	0.4262	0.054*
C10	0.4399 (4)	0.5505 (3)	0.57705 (8)	0.0466 (5)
H10	0.3060	0.6072	0.5731	0.056*
C11	0.3713 (4)	0.6215 (4)	0.38720 (8)	0.0491 (6)
H11A	0.3492	0.7313	0.4051	0.059*
H11B	0.2628	0.5374	0.3987	0.059*
C8	0.7069 (5)	0.4148 (4)	0.63052 (9)	0.0561 (6)
H8	0.7496	0.3798	0.6623	0.067*
C9	0.5047 (5)	0.4980 (3)	0.62363 (9)	0.0547 (6)
H9	0.4136	0.5177	0.6509	0.066*
C13	0.1486 (4)	0.6077 (4)	0.30972 (9)	0.0572 (6)
H13	0.0402	0.5509	0.3280	0.069*
C17	0.5030 (5)	0.7337 (4)	0.30452 (9)	0.0557 (6)
H17	0.6365	0.7617	0.3192	0.067*
C16	0.4669 (6)	0.7750 (4)	0.25472 (10)	0.0650 (8)
H16	0.5752	0.8315	0.2363	0.078*
C14	0.1122 (5)	0.6472 (5)	0.25993 (10)	0.0721 (9)
H14	−0.0195	0.6162	0.2449	0.086*
C15	0.2717 (5)	0.7322 (4)	0.23289 (10)	0.0706 (9)
H15	0.2467	0.7607	0.1996	0.085*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0436 (8)	0.0647 (10)	0.0394 (8)	0.0042 (7)	0.0028 (7)	0.0050 (7)
C1	0.0388 (11)	0.0405 (11)	0.0387 (11)	−0.0026 (9)	0.0009 (9)	0.0015 (8)
C5	0.0394 (11)	0.0352 (10)	0.0393 (11)	−0.0026 (8)	0.0009 (9)	−0.0017 (9)
C3	0.0325 (9)	0.0461 (11)	0.0510 (13)	0.0024 (9)	0.0007 (11)	−0.0012 (10)
C4	0.0366 (10)	0.0367 (10)	0.0448 (11)	−0.0015 (9)	−0.0019 (10)	−0.0017 (9)
C12	0.0473 (12)	0.0465 (11)	0.0401 (11)	0.0038 (10)	−0.0003 (10)	−0.0054 (9)
C6	0.0342 (10)	0.0439 (11)	0.0435 (11)	0.0035 (8)	0.0025 (10)	0.0006 (9)
C7	0.0474 (12)	0.0489 (12)	0.0517 (13)	0.0047 (11)	−0.0082 (12)	0.0020 (10)
C2	0.0342 (10)	0.0509 (12)	0.0490 (12)	−0.0003 (9)	0.0086 (10)	−0.0012 (10)
C10	0.0438 (12)	0.0505 (12)	0.0454 (12)	0.0058 (10)	0.0058 (11)	−0.0035 (10)
C11	0.0433 (12)	0.0619 (14)	0.0423 (12)	0.0026 (11)	0.0017 (10)	0.0014 (10)
C8	0.0682 (16)	0.0590 (14)	0.0411 (12)	0.0024 (13)	−0.0041 (13)	0.0023 (11)
C9	0.0633 (15)	0.0595 (14)	0.0414 (12)	0.0015 (13)	0.0100 (12)	−0.0025 (11)
C13	0.0472 (12)	0.0702 (16)	0.0542 (14)	−0.0016 (12)	−0.0033 (12)	−0.0035 (12)
C17	0.0600 (14)	0.0602 (15)	0.0470 (13)	−0.0119 (12)	−0.0011 (13)	−0.0033 (11)
C16	0.085 (2)	0.0626 (16)	0.0473 (14)	−0.0058 (16)	0.0077 (15)	0.0040 (12)
C14	0.0624 (17)	0.099 (2)	0.0545 (16)	0.0074 (17)	−0.0178 (15)	−0.0066 (16)
C15	0.092 (2)	0.0753 (19)	0.0444 (13)	0.0178 (18)	−0.0101 (16)	0.0030 (13)

Geometric parameters (Å, º) top

O1—C1	1.370 (2)	C2—H2	0.9300
O1—C11	1.423 (3)	C10—C9	1.370 (3)
C1—C6	1.368 (3)	C10—H10	0.9300
C1—C2	1.421 (3)	C11—H11A	0.9700
C5—C10	1.413 (3)	C11—H11B	0.9700
C5—C4	1.417 (3)	C8—C9	1.399 (4)
C5—C6	1.420 (3)	C8—H8	0.9300
C3—C2	1.354 (3)	C9—H9	0.9300
C3—C4	1.414 (3)	C13—C14	1.387 (4)
C3—H3	0.9300	C13—H13	0.9300
C4—C7	1.416 (3)	C17—C16	1.390 (4)
C12—C17	1.374 (3)	C17—H17	0.9300
C12—C13	1.377 (3)	C16—C15	1.367 (4)
C12—C11	1.499 (3)	C16—H16	0.9300
C6—H6	0.9300	C14—C15	1.375 (4)
C7—C8	1.361 (4)	C14—H14	0.9300
C7—H7	0.9300	C15—H15	0.9300

C1—O1—C11	116.36 (18)	O1—C11—C12	109.85 (19)
C6—C1—O1	125.7 (2)	O1—C11—H11A	109.7
C6—C1—C2	120.2 (2)	C12—C11—H11A	109.7
O1—C1—C2	114.1 (2)	O1—C11—H11B	109.7
C10—C5—C4	118.4 (2)	C12—C11—H11B	109.7
C10—C5—C6	122.0 (2)	H11A—C11—H11B	108.2
C4—C5—C6	119.61 (19)	C7—C8—C9	120.4 (2)
C2—C3—C4	121.3 (2)	C7—C8—H8	119.8
C2—C3—H3	119.4	C9—C8—H8	119.8
C4—C3—H3	119.4	C10—C9—C8	120.4 (2)
C3—C4—C7	122.2 (2)	C10—C9—H9	119.8
C3—C4—C5	118.47 (19)	C8—C9—H9	119.8
C7—C4—C5	119.3 (2)	C12—C13—C14	120.7 (3)
C17—C12—C13	118.9 (2)	C12—C13—H13	119.7
C17—C12—C11	121.5 (2)	C14—C13—H13	119.7
C13—C12—C11	119.5 (2)	C12—C17—C16	120.8 (3)
C1—C6—C5	120.1 (2)	C12—C17—H17	119.6
C1—C6—H6	120.0	C16—C17—H17	119.6
C5—C6—H6	120.0	C15—C16—C17	119.8 (3)
C8—C7—C4	120.6 (2)	C15—C16—H16	120.1
C8—C7—H7	119.7	C17—C16—H16	120.1
C4—C7—H7	119.7	C15—C14—C13	119.7 (3)
C3—C2—C1	120.3 (2)	C15—C14—H14	120.1
C3—C2—H2	119.8	C13—C14—H14	120.1
C1—C2—H2	119.8	C16—C15—C14	120.2 (3)
C9—C10—C5	120.9 (2)	C16—C15—H15	119.9
C9—C10—H10	119.5	C14—C15—H15	119.9
C5—C10—H10	119.5

C11—O1—C1—C6	−5.6 (3)	C4—C5—C10—C9	−1.2 (3)
C11—O1—C1—C2	174.04 (19)	C6—C5—C10—C9	176.9 (2)
C2—C3—C4—C7	175.9 (2)	C1—O1—C11—C12	178.72 (19)
C2—C3—C4—C5	−2.3 (3)	C17—C12—C11—O1	−44.9 (3)
C10—C5—C4—C3	178.9 (2)	C13—C12—C11—O1	139.5 (2)
C6—C5—C4—C3	0.8 (3)	C4—C7—C8—C9	−0.3 (4)
C10—C5—C4—C7	0.8 (3)	C5—C10—C9—C8	0.9 (4)
C6—C5—C4—C7	−177.4 (2)	C7—C8—C9—C10	−0.1 (4)
O1—C1—C6—C5	177.4 (2)	C17—C12—C13—C14	−0.8 (4)
C2—C1—C6—C5	−2.2 (3)	C11—C12—C13—C14	174.9 (3)
C10—C5—C6—C1	−176.7 (2)	C13—C12—C17—C16	1.4 (4)
C4—C5—C6—C1	1.4 (3)	C11—C12—C17—C16	−174.2 (2)
C3—C4—C7—C8	−178.1 (2)	C12—C17—C16—C15	−0.7 (4)
C5—C4—C7—C8	0.0 (3)	C12—C13—C14—C15	−0.4 (4)
C4—C3—C2—C1	1.6 (3)	C17—C16—C15—C14	−0.6 (5)
C6—C1—C2—C3	0.7 (3)	C13—C14—C15—C16	1.2 (5)
O1—C1—C2—C3	−178.9 (2)

Hydrogen-bond geometry (Å, º) top

Cg1, Cg2 and Cg3 are the centroids of the C1–C6, C4/C5/C7–C10 and C12–C17 rings, respectively.

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···Cg1ⁱ	0.93	2.71	3.439 (2)	135
C11—H11A···Cg2ⁱⁱ	0.97	2.63	3.512 (3)	150
C16—H16···Cg3ⁱⁱⁱ	0.93	2.87	3.586 (3)	135

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

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Volume 75| Part 2| February 2019| Pages 242-245

https://doi.org/10.1107/S2056989019000690

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