Structural phase transition in a charge-transfer compound: tropylium hexa­fluorido­anti­monate(V)–1,4-di­methyl­naphthalene (1/1)

Mol­ecular motion in crystals has attracted much attention for the development of stimuli-responsive materials. The most studied are mol­ecules with few atoms or highly symmetrical mol­ecules. To develop mol­ecules with new motion characteristics, we synthesized a charge-transfer compound, namely, tropylium hexa­fluorido­anti­monate(V)–1,4-di­methyl­naphthalene (1/1), (C₇H₇)[SbF₆]·C₁₂H₁₂, and studied its structural phase transition. In this compound, the tropylium cation and the 1,4-di­methyl­naphthalene mol­ecule have planar geometry, but the latter has low symmetry. They are stacked as a one-dimensional chain structure through π–π charge-transfer inter­actions. Weak inter­molecular inter­actions and planar mol­ecular geometry result in a large degree of freedom of in-plane motion. Upon heating, due to the in-plane rotation of the mol­ecules, the com­pound undergoes an order–disorder structural phase transition (phase-transition tem­per­ature = 334 K). The space group of the room-tem­per­ature phase is P2₁/m and the space group of the high-tem­per­ature phase is P4/mmm. This phase transition is accompanied by significant dielectric anomalies. The current investigation shows that the structural features of the title compound can be used to construct functional materials with phase transitions, such as mol­ecular ferroelectrics.

Computing details

For both structures, data collection: CrysAlis PRO (Rigaku OD, 2019); cell refinement: CrysAlis PRO (Rigaku OD, 2019); data reduction: CrysAlis PRO (Rigaku OD, 2019); program(s) used to solve structure: SHELXT2018 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009). Software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009) for 1_302K.

Tropylium hexafluoridoantimonate(V)–1,4-dimethylnaphthalene (1/1) (1_302K)

Crystal data

(C7H7)[SbF6]·C12H12	F(000) = 476
Mr = 483.09	Dx = 1.673 Mg m^−3
Monoclinic, P121/m1	Mo Kα radiation, λ = 0.71073 Å
a = 6.8156 (4) Å	Cell parameters from 4421 reflections
b = 17.1703 (7) Å	θ = 2.4–27.2°
c = 8.3590 (4) Å	µ = 1.49 mm^−1
β = 101.331 (5)°	T = 302 K
V = 959.15 (8) Å^3	Block, clear yellowish yellow
Z = 2	0.22 × 0.15 × 0.12 mm

Data collection

Rigaku XtaLAB Synergy diffractometer with a Dualflex HyPix detector	2712 independent reflections
Radiation source: micro-focus sealed X-ray tube, Mova (Mo) X-ray Source	1765 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.021
Detector resolution: 10.0000 pixels mm^-1	θmax = 31.6°, θmin = 2.4°
ω scans	h = −8→9
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2019)	k = −23→23
Tmin = 0.801, Tmax = 1.000	l = −9→11
9700 measured reflections

Refinement

Refinement on F^2	Primary atom site location: dual
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.034	H-atom parameters constrained
wR(F^2) = 0.104	w = 1/[σ^2(Fo^2) + (0.0499P)^2 + 0.178P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max < 0.001
2712 reflections	Δρmax = 0.51 e Å^−3
122 parameters	Δρmin = −0.50 e Å^−3
60 restraints

Special details

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

Refinement. Crystal structure data were collected on a Rigaku Synergy X-ray diffraction instrument using Mo—Kα (λ=0.71073 Å) radiation. The structure was solved by direct methods and continuous Fourier synthesis, and the full-matrix least-squares refinement of F² was performed using the SHELXLTL-2018 software package. Non-hydrogen atoms were anisotropically refined using all reflections with I>2σ(I).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Sb1	0.500000	0.500000	1.000000	0.06346 (14)
F1	0.4603 (6)	0.50401 (10)	0.7725 (3)	0.1019 (9)
F3	0.4120 (5)	0.39670 (13)	0.9886 (2)	0.1095 (8)
F2	0.7606 (4)	0.4657 (2)	1.0139 (3)	0.1245 (8)
C7	−0.0904 (4)	0.29146 (16)	0.4980 (3)	0.0548 (5)
C6	−0.1302 (5)	0.3304 (2)	0.3445 (4)	0.0698 (7)
H6	−0.131985	0.384508	0.341751	0.084*
C8	−0.0522 (5)	0.3329 (2)	0.6475 (4)	0.0719 (7)
C5	−0.1652 (5)	0.2904 (2)	0.2034 (4)	0.0805 (9)
H5	−0.189661	0.317171	0.104773	0.097*
C9	−0.0134 (5)	0.2897 (2)	0.7890 (4)	0.0855 (10)
H9	0.013784	0.315756	0.888510	0.103*
C10	−0.0533 (7)	0.4202 (2)	0.6545 (6)	0.1108 (14)
H10A	0.051625	0.440362	0.604735	0.166*
H10B	−0.032303	0.436779	0.766265	0.166*
H10C	−0.180045	0.439318	0.597015	0.166*
C2	0.4159 (7)	0.3371 (3)	0.5311 (8)	0.1268 (15)
H2	0.417468	0.389911	0.555580	0.152*
C1	0.4474 (6)	0.2890 (3)	0.6583 (5)	0.127 (2)
H1	0.472662	0.312636	0.760442	0.152*
C3	0.3822 (7)	0.3191 (3)	0.3724 (7)	0.1207 (15)
H3	0.367650	0.361267	0.301202	0.145*
C4	0.3669 (8)	0.250000	0.3033 (7)	0.1103 (18)
H4	0.341712	0.250001	0.189889	0.132*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sb1	0.0839 (2)	0.05559 (19)	0.05024 (18)	−0.00541 (12)	0.01163 (14)	−0.00258 (10)
F1	0.158 (3)	0.0933 (18)	0.0530 (13)	−0.0122 (11)	0.0166 (14)	−0.0005 (8)
F3	0.164 (2)	0.0728 (14)	0.0868 (15)	−0.0340 (16)	0.0128 (13)	−0.0055 (9)
F2	0.1009 (19)	0.144 (2)	0.133 (2)	0.0239 (19)	0.0340 (16)	0.015 (2)
C7	0.0397 (13)	0.0714 (14)	0.0565 (12)	0.0004 (12)	0.0174 (9)	−0.0006 (10)
C6	0.0579 (18)	0.0839 (19)	0.0715 (14)	0.0079 (14)	0.0223 (14)	0.0164 (12)
C8	0.0501 (17)	0.0980 (18)	0.0723 (14)	−0.0071 (15)	0.0238 (14)	−0.0211 (13)
C5	0.065 (2)	0.124 (2)	0.0570 (15)	0.0099 (17)	0.0212 (14)	0.0170 (14)
C9	0.061 (2)	0.147 (3)	0.0523 (14)	−0.0067 (17)	0.0188 (14)	−0.0214 (14)
C10	0.103 (3)	0.100 (2)	0.138 (4)	−0.017 (2)	0.046 (3)	−0.044 (2)
C2	0.074 (3)	0.084 (3)	0.230 (4)	−0.014 (2)	0.050 (4)	−0.048 (3)
C1	0.056 (2)	0.229 (6)	0.097 (3)	−0.009 (3)	0.015 (2)	−0.081 (3)
C3	0.084 (3)	0.125 (3)	0.170 (3)	0.021 (3)	0.064 (3)	0.072 (2)
C4	0.050 (3)	0.216 (5)	0.068 (3)	0.000	0.017 (2)	0.000

Geometric parameters (Å, º)

Sb1—F1^i	1.869 (3)	C5—H5	0.9300
Sb1—F1	1.869 (3)	C9—C9^ii	1.364 (7)
Sb1—F3^i	1.869 (2)	C9—H9	0.9300
Sb1—F3	1.869 (2)	C10—H10A	0.9600
Sb1—F2^i	1.853 (3)	C10—H10B	0.9600
Sb1—F2	1.853 (3)	C10—H10C	0.9600
C7—C7^ii	1.424 (5)	C2—H2	0.9300
C7—C6	1.425 (4)	C2—C1	1.330 (6)
C7—C8	1.417 (4)	C2—C3	1.336 (7)
C6—H6	0.9300	C1—C1^ii	1.340 (10)
C6—C5	1.345 (4)	C1—H1	0.9300
C8—C9	1.377 (5)	C3—H3	0.9300
C8—C10	1.501 (5)	C3—C4	1.315 (6)
C5—C5^ii	1.387 (7)	C4—H4	0.9300
F1—Sb1—F1^i	180.0	C6—C5—C5^ii	120.7 (2)
F3—Sb1—F1	90.13 (8)	C6—C5—H5	119.6
F3—Sb1—F1^i	89.86 (8)	C5^ii—C5—H5	119.6
F3^i—Sb1—F1^i	90.14 (8)	C8—C9—H9	118.7
F3^i—Sb1—F1	89.87 (8)	C9^ii—C9—C8	122.6 (2)
F3—Sb1—F3^i	180.0 (2)	C9^ii—C9—H9	118.7
F2^i—Sb1—F1	88.80 (15)	C8—C10—H10A	109.5
F2—Sb1—F1^i	88.80 (15)	C8—C10—H10B	109.5
F2—Sb1—F1	91.20 (15)	C8—C10—H10C	109.5
F2^i—Sb1—F1^i	91.20 (15)	H10A—C10—H10B	109.5
F2—Sb1—F3	89.77 (15)	H10A—C10—H10C	109.5
F2^i—Sb1—F3	90.23 (15)	H10B—C10—H10C	109.5
F2—Sb1—F3^i	90.23 (15)	C1—C2—H2	115.8
F2^i—Sb1—F3^i	89.77 (15)	C1—C2—C3	128.3 (5)
F2—Sb1—F2^i	180.0	C3—C2—H2	115.8
C7^ii—C7—C6	117.96 (18)	C2—C1—C1^ii	128.3 (3)
C8—C7—C7^ii	120.12 (18)	C2—C1—H1	115.8
C8—C7—C6	121.9 (3)	C1^ii—C1—H1	115.8
C7—C6—H6	119.3	C2—C3—H3	115.6
C5—C6—C7	121.3 (3)	C4—C3—C2	128.8 (5)
C5—C6—H6	119.3	C4—C3—H3	115.6
C7—C8—C10	122.3 (3)	C3—C4—C3^ii	129.0 (6)
C9—C8—C7	117.3 (3)	C3^ii—C4—H4	115.5
C9—C8—C10	120.4 (3)	C3—C4—H4	115.5
C7^ii—C7—C6—C5	−0.5 (4)	C6—C7—C8—C10	0.8 (5)
C7^ii—C7—C8—C9	0.8 (4)	C8—C7—C6—C5	179.6 (3)
C7^ii—C7—C8—C10	−179.1 (3)	C10—C8—C9—C9^ii	179.1 (2)
C7—C6—C5—C5^ii	0.5 (4)	C2—C3—C4—C3^ii	−0.6 (11)
C7—C8—C9—C9^ii	−0.8 (4)	C1—C2—C3—C4	1.9 (9)
C6—C7—C8—C9	−179.4 (3)	C3—C2—C1—C1^ii	−2.1 (7)

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

Tropylium hexafluoridoantimonate(V)–1,4-dimethylnaphthalene (1/1) (1_363K)

Crystal data

(C7H7)[SbF6]·C12H12	Dx = 1.583 Mg m^−3
Mr = 483.09	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P4/mmm	Cell parameters from 467 reflections
a = 8.5249 (7) Å	θ = 2.4–30.5°
c = 6.9744 (17) Å	µ = 1.41 mm^−1
V = 506.86 (15) Å^3	T = 363 K
Z = 1	Block, yellow
F(000) = 238	0.22 × 0.15 × 0.12 mm

Data collection

Rigaku XtaLAB Synergy diffractometer with a Dualflex HyPix detector	258 reflections with I > 2σ(I)
ω scans	Rint = 0.044
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2019)	θmax = 31.1°, θmin = 2.4°
Tmin = 0.029, Tmax = 1.000	h = −10→9
2185 measured reflections	k = −7→10
441 independent reflections	l = −7→9

Refinement

Refinement on F^2	20 restraints
Least-squares matrix: full	H-atom parameters not defined
R[F^2 > 2σ(F^2)] = 0.086	w = 1/[σ^2(Fo^2) + (0.1603P)^2 + 0.0184P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.253	(Δ/σ)max < 0.001
S = 1.06	Δρmax = 0.77 e Å^−3
441 reflections	Δρmin = −0.52 e Å^−3
33 parameters

Special details

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

Refinement. Crystal structure data were collected on a Rigaku Synergy X-ray diffraction instrument using Mo—Kα (λ=0.71073 Å) radiation. The structure was solved by direct methods and continuous Fourier synthesis, and the full-matrix least-squares refinement of F² was performed using the SHELXLTL-2018 software package. Non-hydrogen atoms were anisotropically refined using all reflections with I>2σ(I).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Sb1	0.500000	0.500000	0.000000	0.1390 (12)
F1	0.500000	0.2831 (14)	0.000000	0.242 (9)
F2	0.500000	0.500000	0.259 (6)	0.34 (2)
C1	0.073 (3)	0.166 (2)	0.091 (3)	0.171 (11)	0.43750 (10)
C3	0.000000	0.175 (9)	0.431 (3)	0.46 (5)	0.7500 (1)
C2	0.196 (5)	0.196 (5)	0.404 (7)	0.43 (4)	0.7500 (1)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sb1	0.1030 (11)	0.1030 (11)	0.211 (2)	0.000	0.000	0.000
F1	0.145 (9)	0.098 (5)	0.48 (3)	0.000	0.000	0.000
F2	0.38 (4)	0.38 (4)	0.26 (3)	0.000	0.000	0.000
C1	0.25 (3)	0.117 (10)	0.147 (8)	−0.045 (14)	−0.010 (11)	0.000 (8)
C3	0.53 (9)	0.78 (10)	0.078 (10)	0.000	0.000	0.048 (18)
C2	0.53 (6)	0.53 (6)	0.22 (3)	−0.16 (7)	0.09 (2)	0.09 (2)

Geometric parameters (Å, º)

Sb1—F2	1.81 (4)	C1—C1^vii	1.69 (5)
Sb1—F2^i	1.81 (4)	C1—C1^viii	1.78 (4)
Sb1—F1^ii	1.849 (12)	C3—C3^ix	0.97 (4)
Sb1—F1^i	1.849 (12)	C3—C2^x	1.69 (5)
Sb1—F1^iii	1.849 (12)	C3—C2	1.69 (5)
Sb1—F1	1.849 (12)	C3—C2^ix	2.04 (4)
C1—C1^iv	1.12 (5)	C3—C2^xi	2.04 (4)
C1—C1^v	1.25 (5)	C2—C2^ix	1.34 (10)
C1—C1^vi	1.26 (4)
F2—Sb1—F2^i	180.0	C1^vi—C1—C1^viii	44.7 (16)
F2—Sb1—F1^ii	90.000 (3)	C1^vii—C1—C1^viii	78.3 (18)
F2^i—Sb1—F1^ii	90.000 (3)	C3^ix—C3—C2^x	96 (2)
F2—Sb1—F1^i	90.0	C3^ix—C3—C2	96 (2)
F2^i—Sb1—F1^i	90.0	C2^x—C3—C2	163 (4)
F1^ii—Sb1—F1^i	90.000 (1)	C3^ix—C3—C2^ix	55.4 (17)
F2—Sb1—F1^iii	90.000 (3)	C2^x—C3—C2^ix	150 (2)
F2^i—Sb1—F1^iii	90.000 (3)	C2—C3—C2^ix	41 (3)
F1^ii—Sb1—F1^iii	180.0	C3^ix—C3—C2^xi	55.4 (17)
F1^i—Sb1—F1^iii	90.000 (1)	C2^x—C3—C2^xi	41 (3)
F2—Sb1—F1	90.0	C2—C3—C2^xi	150 (2)
F2^i—Sb1—F1	90.0	C2^ix—C3—C2^xi	110 (3)
F1^ii—Sb1—F1	90.000 (1)	C2^ix—C2—C3^xii	84 (2)
F1^i—Sb1—F1	180.0	C2^ix—C2—C3	84 (2)
F1^iii—Sb1—F1	90.0	C3^xii—C2—C3	78 (5)
C1^iv—C1—C1^v	134.998 (2)	C2^ix—C2—C3^ix	55.4 (17)
C1^iv—C1—C1^vi	89.998 (1)	C3^xii—C2—C3^ix	77 (4)
C1^v—C1—C1^vi	89.999 (1)	C3—C2—C3^ix	28.2 (12)
C1^iv—C1—C1^vii	48.6 (15)	C2^ix—C2—C3^xiii	55.4 (17)
C1^v—C1—C1^vii	117.9 (9)	C3^xii—C2—C3^xiii	28.2 (12)
C1^vi—C1—C1^vii	41.4 (15)	C3—C2—C3^xiii	77 (4)
C1^iv—C1—C1^viii	119.8 (9)	C3^ix—C2—C3^xiii	63 (4)
C1^v—C1—C1^viii	45.3 (16)
C3^ix—C3—C2—C2^ix	0.000 (8)	C2^x—C3—C2—C3^ix	137 (19)
C2^x—C3—C2—C2^ix	137 (19)	C2^ix—C3—C2—C3^ix	0.000 (7)
C2^xi—C3—C2—C2^ix	19 (9)	C2^xi—C3—C2—C3^ix	19 (9)
C3^ix—C3—C2—C3^xii	84.8 (18)	C3^ix—C3—C2—C3^xiii	55.9 (14)
C2^x—C3—C2—C3^xii	−138 (17)	C2^x—C3—C2—C3^xiii	−167 (18)
C2^ix—C3—C2—C3^xii	84.8 (18)	C2^ix—C3—C2—C3^xiii	55.9 (14)
C2^xi—C3—C2—C3^xii	104 (10)	C2^xi—C3—C2—C3^xiii	75 (9)

Symmetry codes: (i) −x+1, −y+1, −z; (ii) y, −x+1, −z; (iii) −y+1, x, z; (iv) y, x, z; (v) −x, y, z; (vi) x, y, −z; (vii) y, x, −z; (viii) −x, y, −z; (ix) x, y, −z+1; (x) −y, x, z; (xi) −y, x, −z+1; (xii) y, −x, z; (xiii) y, −x, −z+1.