¹³C and ¹⁹F solid-state NMR and X-ray crystallographic study of halogen-bonded frameworks featuring nitro­gen-containing heterocycles

Halogen bonding is a noncovalent inter­action between the electrophilic region of a halogen (σ-hole) and an electron donor. We report a crystallographic and structural analysis of halogen-bonded compounds by applying a combined X-ray diffraction (XRD) and solid-state nuclear magnetic resonance (SSNMR) approach. Single-crystal XRD was first used to characterize the halogen-bonded cocrystals formed between two fluorinated halogen-bond donors (1,4-di­iodo­tetra­fluoro­benzene and 1,3,5-tri­fluoro-2,4,6-tri­iodo­benzene) and several nitro­gen-containing heterocycles (acridine, 1,10-phenanthroline, 2,3,5,6-tetra­methyl­pyrazine, and hexa­methyl­ene­tetra­mine). New structures are reported for the following three cocrystals, all in the P2₁/c space group: acridine–1,3,5-tri­fluoro-2,4,6-tri­iodo­benzene (1/1), C₆F₃I₃·C₁₃H₉N, 1,10-phenanthroline–1,3,5-tri­fluoro-2,4,6-tri­iodo­benzene (1/1), C₆F₃I₃·C₁₂H₈N₂, and 2,3,5,6-tetra­methyl­pyrazine–1,3,5-tri­fluoro-2,4,6-tri­iodo­benzene (1/1), C₆F₃I₃·C₈H₁₂N₂. ¹³C and ¹⁹F solid-state magic-angle spinning (MAS) NMR is shown to be a convenient method to characterize the structural features of the halogen-bond donor and acceptor, with chemical shifts attributable to cocrystal formation observed in the spectra of both nuclides. Cross polarization (CP) from ¹⁹F to ¹³C results in improved spectral sensitivity in characterizing the perfluorinated halogen-bond donor when compared to conventional ¹H CP. Gauge-including projector-augmented wave density functional theory (GIPAW DFT) calculations of magnetic shielding constants, along with optimization of the XRD structures, provide a final set of structures in best agreement with the experimental ¹³C and ¹⁹F chemical shifts. Data for carbons bonded to iodine remain outliers due to well-known relativistic effects.

Computing details

For all compounds, data collection: APEX2 (Bruker, 2012); cell refinement: APEX2 (Bruker, 2012); data reduction: SAINT and XPREP (Bruker, 2009); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b) and WinGX (Farrugia, 2012); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: CIFTAB (Sheldrick, 1997).

(db146) 2,3,5,6-Tetramethylpyrazine–1,3,5-trifluoro-2,4,6-triiodobenzene (1/1)

Crystal data

C6F3I3·C8H12N2	Dx = 2.416 Mg m^−3
Mr = 645.96	Melting point: 398 K
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 7.9818 (3) Å	Cell parameters from 9977 reflections
b = 26.7046 (9) Å	θ = 2.6–27.8°
c = 9.2220 (3) Å	µ = 5.31 mm^−1
β = 115.398 (2)°	T = 200 K
V = 1775.69 (11) Å^3	Rod, colorless
Z = 4	0.52 × 0.26 × 0.11 mm
F(000) = 1184

Data collection

Bruker APEXII CCD diffractometer	3892 reflections with I > 2σ(I)
Detector resolution: 8.33 pixels mm^-1	Rint = 0.042
φ and ω scans	θmax = 27.9°, θmin = 1.5°
Absorption correction: multi-scan (SADABS; Bruker, 2003)	h = −10→10
Tmin = 0.443, Tmax = 0.746	k = −34→35
29591 measured reflections	l = −11→12
4238 independent reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.029	H-atom parameters constrained
wR(F^2) = 0.067	w = 1/[σ^2(Fo^2) + (0.0295P)^2 + 1.8982P] where P = (Fo^2 + 2Fc^2)/3
S = 1.19	(Δ/σ)max = 0.003
4238 reflections	Δρmax = 0.59 e Å^−3
203 parameters	Δρmin = −1.64 e Å^−3

Special details

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. Data were collected on a Bruker AXS Kappa-single crystal diffractometer equipped with a sealed Mo tube source (wavelength 0.71073 Å) APEX II CCD detector. Raw data collection and processing were performed with the APEX II software package from BRUKER AXS (Bruker, 2012). Semi-empirical absorption corrections based on equivalent reflections were applied (Bruker, 2001). Systematic absences in the diffraction dataset and unit cell parameters were consistent with monoclinic P2₁/c (No. 14) for compounds A2, B2, and C2. The structures were solved by direct methods and refined with full-matrix least-squares procedures based on F², procedures using SHELXL2014 (Sheldrick, 2015) and WinGX (Farrugia 1999). All non-hydrogen atoms were refined anisotropically.

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

	x	y	z	Uiso*/Ueq
C1	0.6742 (5)	0.45071 (13)	0.3810 (4)	0.0233 (7)
C2	0.5309 (5)	0.45006 (13)	0.2272 (4)	0.0236 (7)
C3	0.4763 (5)	0.40684 (13)	0.1356 (4)	0.0246 (7)
C4	0.5684 (5)	0.36328 (13)	0.2032 (4)	0.0247 (7)
C5	0.7107 (5)	0.36093 (13)	0.3568 (4)	0.0237 (7)
C6	0.7595 (5)	0.40557 (13)	0.4397 (4)	0.0246 (7)
C7	1.1004 (6)	0.56055 (15)	0.9216 (5)	0.0374 (9)
H7A	1.0631	0.5365	0.8330	0.056*
H7B	1.0620	0.5482	1.0028	0.056*
H7C	1.2354	0.5646	0.9699	0.056*
C8	1.0090 (5)	0.61026 (14)	0.8586 (5)	0.0269 (7)
C9	1.0623 (5)	0.65410 (13)	0.9482 (4)	0.0256 (7)
C10	1.2160 (7)	0.65493 (16)	1.1139 (5)	0.0400 (10)
H10A	1.3342	0.6608	1.1081	0.060*
H10B	1.2208	0.6227	1.1664	0.060*
H10C	1.1939	0.6818	1.1759	0.060*
C11	0.6320 (6)	0.65340 (16)	0.4831 (5)	0.0354 (9)
H11A	0.6801	0.6659	0.4084	0.053*
H11B	0.5297	0.6748	0.4776	0.053*
H11C	0.5871	0.6190	0.4537	0.053*
C12	0.7844 (5)	0.65404 (13)	0.6512 (4)	0.0238 (7)
C13	0.8365 (5)	0.69778 (13)	0.7418 (4)	0.0262 (7)
C14	0.7447 (6)	0.74686 (15)	0.6771 (6)	0.0416 (10)
H14A	0.7944	0.7725	0.7610	0.062*
H14B	0.6107	0.7437	0.6425	0.062*
H14C	0.7688	0.7566	0.5853	0.062*
N1	0.8696 (4)	0.61067 (11)	0.7105 (4)	0.0250 (6)
N2	0.9762 (5)	0.69739 (11)	0.8890 (4)	0.0266 (6)
F1	0.8978 (3)	0.40462 (9)	0.5893 (3)	0.0370 (5)
F2	0.4432 (3)	0.49317 (8)	0.1650 (3)	0.0356 (5)
F3	0.5167 (4)	0.32068 (8)	0.1168 (3)	0.0376 (6)
I1	0.75461 (3)	0.51659 (2)	0.51617 (3)	0.02766 (7)
I2	0.26993 (4)	0.40876 (2)	−0.09761 (3)	0.03493 (8)
I3	0.84031 (4)	0.29339 (2)	0.45734 (3)	0.03048 (8)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0234 (17)	0.0213 (16)	0.0227 (17)	−0.0031 (13)	0.0076 (14)	−0.0036 (13)
C2	0.0256 (17)	0.0201 (16)	0.0214 (17)	0.0030 (13)	0.0066 (14)	0.0040 (13)
C3	0.0248 (17)	0.0271 (17)	0.0164 (16)	−0.0029 (14)	0.0035 (14)	0.0011 (13)
C4	0.0278 (18)	0.0242 (17)	0.0202 (17)	−0.0045 (14)	0.0083 (14)	−0.0054 (13)
C5	0.0256 (17)	0.0209 (16)	0.0221 (17)	0.0030 (13)	0.0078 (14)	0.0037 (13)
C6	0.0215 (16)	0.0285 (18)	0.0168 (16)	−0.0033 (14)	0.0016 (13)	−0.0014 (13)
C7	0.043 (2)	0.0242 (18)	0.037 (2)	0.0072 (17)	0.0093 (19)	0.0021 (16)
C8	0.0286 (18)	0.0246 (17)	0.0266 (18)	0.0004 (14)	0.0110 (15)	0.0026 (14)
C9	0.0290 (18)	0.0235 (17)	0.0218 (17)	−0.0017 (14)	0.0085 (15)	0.0006 (14)
C10	0.048 (3)	0.034 (2)	0.026 (2)	−0.0022 (19)	0.0041 (19)	0.0010 (17)
C11	0.034 (2)	0.034 (2)	0.027 (2)	−0.0010 (17)	0.0024 (17)	−0.0043 (16)
C12	0.0229 (16)	0.0238 (17)	0.0209 (17)	−0.0002 (13)	0.0058 (14)	−0.0017 (13)
C13	0.0286 (18)	0.0218 (16)	0.0243 (18)	0.0011 (14)	0.0076 (15)	−0.0010 (14)
C14	0.044 (2)	0.0245 (19)	0.040 (2)	0.0053 (17)	0.0019 (19)	−0.0006 (17)
N1	0.0256 (15)	0.0216 (14)	0.0259 (15)	−0.0009 (12)	0.0093 (13)	−0.0030 (12)
N2	0.0320 (16)	0.0212 (14)	0.0222 (15)	−0.0017 (12)	0.0075 (13)	−0.0022 (12)
F1	0.0348 (12)	0.0343 (12)	0.0231 (11)	−0.0008 (10)	−0.0055 (10)	0.0000 (9)
F2	0.0386 (13)	0.0240 (11)	0.0330 (12)	0.0079 (9)	0.0047 (10)	0.0040 (9)
F3	0.0461 (14)	0.0226 (11)	0.0329 (12)	−0.0043 (10)	0.0062 (11)	−0.0087 (9)
I1	0.02873 (13)	0.02442 (12)	0.02914 (13)	−0.00499 (9)	0.01176 (10)	−0.00770 (9)
I2	0.03110 (14)	0.04383 (16)	0.01930 (12)	−0.00144 (11)	0.00075 (10)	−0.00015 (10)
I3	0.03278 (14)	0.02334 (12)	0.03413 (14)	0.00554 (9)	0.01321 (11)	0.00662 (9)

Geometric parameters (Å, º)

C1—C6	1.376 (5)	C8—C9	1.390 (5)
C1—C2	1.389 (5)	C9—N2	1.336 (5)
C1—I1	2.092 (3)	C9—C10	1.495 (5)
C2—F2	1.342 (4)	C10—H10A	0.9800
C2—C3	1.386 (5)	C10—H10B	0.9800
C3—C4	1.375 (5)	C10—H10C	0.9800
C3—I2	2.074 (3)	C11—C12	1.505 (5)
C4—F3	1.348 (4)	C11—H11A	0.9800
C4—C5	1.386 (5)	C11—H11B	0.9800
C5—C6	1.379 (5)	C11—H11C	0.9800
C5—I3	2.088 (3)	C12—N1	1.336 (5)
C6—F1	1.347 (4)	C12—C13	1.392 (5)
C7—C8	1.506 (5)	C13—N2	1.337 (5)
C7—H7A	0.9800	C13—C14	1.495 (5)
C7—H7B	0.9800	C14—H14A	0.9800
C7—H7C	0.9800	C14—H14B	0.9800
C8—N1	1.342 (5)	C14—H14C	0.9800
C6—C1—C2	116.3 (3)	N2—C9—C10	117.2 (3)
C6—C1—I1	121.9 (3)	C8—C9—C10	121.9 (3)
C2—C1—I1	121.8 (3)	C9—C10—H10A	109.5
F2—C2—C3	118.9 (3)	C9—C10—H10B	109.5
F2—C2—C1	118.4 (3)	H10A—C10—H10B	109.5
C3—C2—C1	122.6 (3)	C9—C10—H10C	109.5
C4—C3—C2	117.5 (3)	H10A—C10—H10C	109.5
C4—C3—I2	121.6 (3)	H10B—C10—H10C	109.5
C2—C3—I2	120.9 (3)	C12—C11—H11A	109.5
F3—C4—C3	118.5 (3)	C12—C11—H11B	109.5
F3—C4—C5	118.4 (3)	H11A—C11—H11B	109.5
C3—C4—C5	123.1 (3)	C12—C11—H11C	109.5
C6—C5—C4	116.1 (3)	H11A—C11—H11C	109.5
C6—C5—I3	122.1 (3)	H11B—C11—H11C	109.5
C4—C5—I3	121.7 (3)	N1—C12—C13	120.9 (3)
F1—C6—C1	118.0 (3)	N1—C12—C11	117.2 (3)
F1—C6—C5	117.6 (3)	C13—C12—C11	122.0 (3)
C1—C6—C5	124.4 (3)	N2—C13—C12	120.5 (3)
C8—C7—H7A	109.5	N2—C13—C14	117.7 (3)
C8—C7—H7B	109.5	C12—C13—C14	121.8 (3)
H7A—C7—H7B	109.5	C13—C14—H14A	109.5
C8—C7—H7C	109.5	C13—C14—H14B	109.5
H7A—C7—H7C	109.5	H14A—C14—H14B	109.5
H7B—C7—H7C	109.5	C13—C14—H14C	109.5
N1—C8—C9	120.4 (3)	H14A—C14—H14C	109.5
N1—C8—C7	116.9 (3)	H14B—C14—H14C	109.5
C9—C8—C7	122.6 (3)	C12—N1—C8	118.6 (3)
N2—C9—C8	120.9 (3)	C9—N2—C13	118.7 (3)
C6—C1—C2—F2	179.8 (3)	C4—C5—C6—F1	−179.8 (3)
I1—C1—C2—F2	0.2 (5)	I3—C5—C6—F1	1.1 (5)
C6—C1—C2—C3	−0.6 (6)	C4—C5—C6—C1	1.5 (6)
I1—C1—C2—C3	179.7 (3)	I3—C5—C6—C1	−177.7 (3)
F2—C2—C3—C4	−179.7 (3)	N1—C8—C9—N2	0.0 (6)
C1—C2—C3—C4	0.7 (6)	C7—C8—C9—N2	−179.1 (4)
F2—C2—C3—I2	2.6 (5)	N1—C8—C9—C10	179.6 (4)
C1—C2—C3—I2	−177.0 (3)	C7—C8—C9—C10	0.5 (6)
C2—C3—C4—F3	179.5 (3)	N1—C12—C13—N2	1.5 (6)
I2—C3—C4—F3	−2.8 (5)	C11—C12—C13—N2	−178.0 (4)
C2—C3—C4—C5	0.3 (6)	N1—C12—C13—C14	179.2 (4)
I2—C3—C4—C5	178.0 (3)	C11—C12—C13—C14	−0.3 (6)
F3—C4—C5—C6	179.5 (3)	C13—C12—N1—C8	−1.1 (5)
C3—C4—C5—C6	−1.4 (6)	C11—C12—N1—C8	178.4 (4)
F3—C4—C5—I3	−1.4 (5)	C9—C8—N1—C12	0.4 (6)
C3—C4—C5—I3	177.8 (3)	C7—C8—N1—C12	179.5 (4)
C2—C1—C6—F1	−179.3 (3)	C8—C9—N2—C13	0.4 (6)
I1—C1—C6—F1	0.4 (5)	C10—C9—N2—C13	−179.2 (4)
C2—C1—C6—C5	−0.5 (6)	C12—C13—N2—C9	−1.1 (6)
I1—C1—C6—C5	179.1 (3)	C14—C13—N2—C9	−178.9 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7A···I1	0.98	2.95	3.758 (4)	140
C10—H10C···I3^i	0.98	3.19	3.749 (4)	118
C11—H11C···I1	0.98	2.99	3.760 (4)	136
C14—H14A···I3^i	0.98	3.01	3.782 (4)	137

Symmetry code: (i) −x+2, y+1/2, −z+3/2.

(db152) Dibenzo[b,e]pyridine–1,3,5-trifluoro-2,4,6-triiodobenzene (1/1)

Crystal data

C6F3I3·C13H9N	Dx = 2.343 Mg m^−3
Mr = 688.97	Melting point: 443 K
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 10.5079 (4) Å	Cell parameters from 9922 reflections
b = 12.5632 (5) Å	θ = 2.2–28.3°
c = 15.1563 (6) Å	µ = 4.83 mm^−1
β = 102.490 (2)°	T = 200 K
V = 1953.47 (13) Å^3	Block, yellow
Z = 4	0.42 × 0.24 × 0.23 mm
F(000) = 1264

Data collection

Bruker APEX-II CCD diffractometer	4541 reflections with I > 2σ(I)
Detector resolution: 8.33 pixels mm^-1	Rint = 0.022
φ and ω scans	θmax = 28.3°, θmin = 2.0°
Absorption correction: multi-scan SADABS, Bruker (2003)	h = −14→13
Tmin = 0.500, Tmax = 0.746	k = −16→16
43868 measured reflections	l = −20→20
4835 independent reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.022	H-atom parameters constrained
wR(F^2) = 0.054	w = 1/[σ^2(Fo^2) + (0.0232P)^2 + 3.1972P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max = 0.001
4835 reflections	Δρmax = 1.10 e Å^−3
235 parameters	Δρmin = −1.47 e Å^−3

Special details

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. Data were collected on a Bruker AXS Kappa-single crystal diffractometer equipped with a sealed Mo tube source (wavelength 0.71073 Å) APEX II CCD detector. Raw data collection and processing were performed with the APEX II software package from BRUKER AXS (Bruker, 2012). Semi-empirical absorption corrections based on equivalent reflections were applied (Bruker, 2001). Systematic absences in the diffraction dataset and unit cell parameters were consistent with monoclinic P2₁/c (No. 14) for compounds A2, B2, and C2. The structures were solved by direct methods and refined with full-matrix least-squares procedures based on F², procedures using SHELXL2014 (Sheldrick, 2015) and WinGX (Farrugia 1999). All non-hydrogen atoms were refined anisotropically.

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

	x	y	z	Uiso*/Ueq
I1	0.69981 (2)	0.63350 (2)	0.37844 (2)	0.03415 (5)
I5	0.42931 (2)	0.69475 (2)	0.68888 (2)	0.03950 (6)
I3	0.80099 (2)	0.32884 (2)	0.69125 (2)	0.05225 (7)
F6	0.51611 (17)	0.72439 (13)	0.50306 (11)	0.0408 (4)
F4	0.60499 (17)	0.49209 (15)	0.75078 (11)	0.0433 (4)
F2	0.80976 (18)	0.44332 (15)	0.50880 (12)	0.0464 (4)
N7	0.7728 (2)	0.68282 (17)	0.20061 (15)	0.0309 (4)
C5	0.5559 (2)	0.6094 (2)	0.62765 (16)	0.0285 (5)
C1	0.6644 (2)	0.5855 (2)	0.50297 (15)	0.0281 (5)
C2	0.7260 (2)	0.4975 (2)	0.54717 (17)	0.0306 (5)
C20	0.8618 (2)	0.7599 (2)	0.19944 (18)	0.0322 (5)
C4	0.6218 (2)	0.5212 (2)	0.66889 (17)	0.0305 (5)
C3	0.7061 (2)	0.4626 (2)	0.62976 (17)	0.0312 (5)
C6	0.5793 (2)	0.63910 (19)	0.54474 (17)	0.0282 (5)
C15	0.9335 (3)	0.7667 (3)	0.1297 (2)	0.0392 (6)
C8	0.7511 (3)	0.6105 (2)	0.13388 (18)	0.0348 (5)
C19	0.8857 (3)	0.8353 (2)	0.2708 (2)	0.0419 (6)
H19	0.8374	0.8320	0.3169	0.050*
C9	0.6577 (3)	0.5286 (3)	0.1354 (2)	0.0463 (7)
H9	0.6102	0.5279	0.1821	0.056*
C13	0.8199 (3)	0.6111 (3)	0.06216 (19)	0.0442 (7)
C16	1.0269 (3)	0.8510 (3)	0.1350 (3)	0.0607 (10)
H16	1.0743	0.8585	0.0886	0.073*
C14	0.9107 (3)	0.6910 (3)	0.0622 (2)	0.0508 (8)
H14	0.9576	0.6938	0.0152	0.061*
C18	0.9777 (3)	0.9123 (3)	0.2734 (3)	0.0564 (9)
H18	0.9941	0.9615	0.3221	0.068*
C10	0.6358 (4)	0.4519 (3)	0.0715 (2)	0.0638 (10)
H10	0.5741	0.3973	0.0740	0.077*
C12	0.7920 (5)	0.5289 (4)	−0.0041 (2)	0.0677 (11)
H12	0.8362	0.5281	−0.0526	0.081*
C17	1.0486 (3)	0.9198 (3)	0.2049 (3)	0.0649 (11)
H17	1.1124	0.9740	0.2079	0.078*
C11	0.7045 (5)	0.4525 (4)	0.0007 (3)	0.0768 (13)
H11	0.6884	0.3982	−0.0439	0.092*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.04110 (10)	0.03481 (9)	0.02732 (8)	−0.00377 (7)	0.00911 (7)	0.00187 (6)
I5	0.03726 (10)	0.03943 (10)	0.04554 (10)	0.00062 (7)	0.01718 (8)	−0.00627 (7)
I3	0.04325 (11)	0.04561 (12)	0.06837 (14)	0.01305 (9)	0.01309 (10)	0.02722 (10)
F6	0.0463 (9)	0.0334 (8)	0.0429 (8)	0.0117 (7)	0.0103 (7)	0.0097 (7)
F4	0.0429 (9)	0.0563 (11)	0.0333 (8)	0.0025 (8)	0.0141 (7)	0.0141 (7)
F2	0.0526 (10)	0.0456 (10)	0.0469 (9)	0.0175 (8)	0.0237 (8)	0.0037 (8)
N7	0.0298 (10)	0.0312 (11)	0.0325 (10)	−0.0003 (8)	0.0081 (8)	0.0057 (8)
C5	0.0249 (11)	0.0308 (12)	0.0302 (11)	−0.0020 (9)	0.0067 (9)	−0.0026 (9)
C1	0.0310 (11)	0.0285 (11)	0.0245 (10)	−0.0034 (9)	0.0058 (9)	0.0004 (9)
C2	0.0291 (12)	0.0314 (12)	0.0327 (12)	0.0024 (10)	0.0095 (9)	−0.0004 (10)
C20	0.0237 (11)	0.0353 (13)	0.0359 (12)	0.0024 (10)	0.0029 (9)	0.0113 (10)
C4	0.0262 (11)	0.0356 (13)	0.0294 (11)	−0.0040 (10)	0.0055 (9)	0.0049 (10)
C3	0.0281 (12)	0.0295 (12)	0.0353 (12)	0.0015 (9)	0.0053 (10)	0.0075 (10)
C6	0.0271 (11)	0.0253 (11)	0.0304 (11)	−0.0004 (9)	0.0026 (9)	0.0019 (9)
C15	0.0278 (12)	0.0486 (16)	0.0423 (14)	0.0037 (11)	0.0098 (11)	0.0198 (13)
C8	0.0376 (13)	0.0355 (13)	0.0301 (12)	0.0041 (11)	0.0048 (10)	0.0062 (10)
C19	0.0388 (15)	0.0385 (15)	0.0459 (15)	−0.0057 (12)	0.0037 (12)	0.0054 (12)
C9	0.0583 (19)	0.0401 (16)	0.0385 (15)	−0.0084 (14)	0.0057 (13)	0.0014 (12)
C13	0.0553 (18)	0.0482 (17)	0.0300 (13)	0.0141 (14)	0.0109 (12)	0.0087 (12)
C16	0.0360 (16)	0.076 (3)	0.072 (2)	−0.0073 (16)	0.0161 (16)	0.035 (2)
C14	0.0508 (18)	0.068 (2)	0.0389 (15)	0.0159 (16)	0.0212 (14)	0.0204 (15)
C18	0.0506 (19)	0.0448 (18)	0.065 (2)	−0.0151 (15)	−0.0066 (16)	0.0080 (16)
C10	0.087 (3)	0.048 (2)	0.0497 (19)	−0.0125 (19)	−0.0011 (18)	−0.0065 (16)
C12	0.099 (3)	0.072 (3)	0.0354 (16)	0.018 (2)	0.0212 (19)	−0.0037 (16)
C17	0.0397 (17)	0.064 (2)	0.085 (3)	−0.0210 (16)	−0.0005 (17)	0.026 (2)
C11	0.123 (4)	0.057 (2)	0.045 (2)	0.005 (3)	0.005 (2)	−0.0167 (17)

Geometric parameters (Å, º)

I1—C1	2.090 (2)	C8—C13	1.430 (4)
I5—C5	2.077 (2)	C19—C18	1.362 (4)
I3—C3	2.070 (2)	C19—H19	0.9500
F6—C6	1.344 (3)	C9—C10	1.351 (5)
F4—C4	1.342 (3)	C9—H9	0.9500
F2—C2	1.340 (3)	C13—C14	1.385 (5)
N7—C8	1.342 (4)	C13—C12	1.427 (5)
N7—C20	1.350 (3)	C16—C17	1.347 (6)
C5—C4	1.382 (4)	C16—H16	0.9500
C5—C6	1.383 (3)	C14—H14	0.9500
C1—C6	1.378 (3)	C18—C17	1.406 (6)
C1—C2	1.379 (4)	C18—H18	0.9500
C2—C3	1.384 (3)	C10—C11	1.417 (6)
C20—C19	1.418 (4)	C10—H10	0.9500
C20—C15	1.428 (4)	C12—C11	1.342 (7)
C4—C3	1.381 (4)	C12—H12	0.9500
C15—C14	1.379 (5)	C17—H17	0.9500
C15—C16	1.435 (5)	C11—H11	0.9500
C8—C9	1.426 (4)
C8—N7—C20	118.8 (2)	C18—C19—H19	119.9
C4—C5—C6	117.2 (2)	C20—C19—H19	119.9
C4—C5—I5	121.21 (18)	C10—C9—C8	120.9 (3)
C6—C5—I5	121.54 (19)	C10—C9—H9	119.5
C6—C1—C2	116.9 (2)	C8—C9—H9	119.5
C6—C1—I1	122.25 (18)	C14—C13—C12	124.2 (3)
C2—C1—I1	120.89 (18)	C14—C13—C8	117.7 (3)
F2—C2—C1	118.7 (2)	C12—C13—C8	118.1 (3)
F2—C2—C3	118.3 (2)	C17—C16—C15	121.0 (3)
C1—C2—C3	123.1 (2)	C17—C16—H16	119.5
N7—C20—C19	118.6 (2)	C15—C16—H16	119.5
N7—C20—C15	122.1 (3)	C15—C14—C13	120.6 (3)
C19—C20—C15	119.3 (3)	C15—C14—H14	119.7
F4—C4—C3	118.5 (2)	C13—C14—H14	119.7
F4—C4—C5	118.9 (2)	C19—C18—C17	120.8 (4)
C3—C4—C5	122.6 (2)	C19—C18—H18	119.6
C4—C3—C2	117.1 (2)	C17—C18—H18	119.6
C4—C3—I3	122.07 (18)	C9—C10—C11	120.2 (4)
C2—C3—I3	120.78 (19)	C9—C10—H10	119.9
F6—C6—C1	118.5 (2)	C11—C10—H10	119.9
F6—C6—C5	118.4 (2)	C11—C12—C13	121.2 (4)
C1—C6—C5	123.1 (2)	C11—C12—H12	119.4
C14—C15—C20	118.2 (3)	C13—C12—H12	119.4
C14—C15—C16	123.9 (3)	C16—C17—C18	120.7 (3)
C20—C15—C16	117.8 (3)	C16—C17—H17	119.6
N7—C8—C9	118.8 (3)	C18—C17—H17	119.6
N7—C8—C13	122.6 (3)	C12—C11—C10	120.9 (4)
C9—C8—C13	118.7 (3)	C12—C11—H11	119.6
C18—C19—C20	120.3 (3)	C10—C11—H11	119.6
C6—C1—C2—F2	−179.9 (2)	C19—C20—C15—C14	178.5 (3)
I1—C1—C2—F2	0.2 (3)	N7—C20—C15—C16	−179.4 (3)
C6—C1—C2—C3	−0.2 (4)	C19—C20—C15—C16	−0.4 (4)
I1—C1—C2—C3	179.9 (2)	C20—N7—C8—C9	179.6 (2)
C8—N7—C20—C19	−179.1 (2)	C20—N7—C8—C13	0.8 (4)
C8—N7—C20—C15	−0.1 (4)	N7—C20—C19—C18	178.0 (3)
C6—C5—C4—F4	177.8 (2)	C15—C20—C19—C18	−1.0 (4)
I5—C5—C4—F4	−1.3 (3)	N7—C8—C9—C10	−177.7 (3)
C6—C5—C4—C3	−1.2 (4)	C13—C8—C9—C10	1.1 (5)
I5—C5—C4—C3	179.7 (2)	N7—C8—C13—C14	−0.9 (4)
F4—C4—C3—C2	−177.1 (2)	C9—C8—C13—C14	−179.7 (3)
C5—C4—C3—C2	1.9 (4)	N7—C8—C13—C12	178.4 (3)
F4—C4—C3—I3	2.4 (3)	C9—C8—C13—C12	−0.4 (4)
C5—C4—C3—I3	−178.67 (19)	C14—C15—C16—C17	−177.1 (3)
F2—C2—C3—C4	178.5 (2)	C20—C15—C16—C17	1.7 (5)
C1—C2—C3—C4	−1.1 (4)	C20—C15—C14—C13	0.3 (4)
F2—C2—C3—I3	−1.0 (3)	C16—C15—C14—C13	179.2 (3)
C1—C2—C3—I3	179.4 (2)	C12—C13—C14—C15	−178.9 (3)
C2—C1—C6—F6	−179.1 (2)	C8—C13—C14—C15	0.3 (4)
I1—C1—C6—F6	0.8 (3)	C20—C19—C18—C17	1.2 (5)
C2—C1—C6—C5	1.0 (4)	C8—C9—C10—C11	−0.9 (6)
I1—C1—C6—C5	−179.10 (19)	C14—C13—C12—C11	178.8 (4)
C4—C5—C6—F6	179.8 (2)	C8—C13—C12—C11	−0.5 (6)
I5—C5—C6—F6	−1.1 (3)	C15—C16—C17—C18	−1.6 (6)
C4—C5—C6—C1	−0.3 (4)	C19—C18—C17—C16	0.1 (6)
I5—C5—C6—C1	178.78 (19)	C13—C12—C11—C10	0.7 (7)
N7—C20—C15—C14	−0.5 (4)	C9—C10—C11—C12	0.0 (7)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C19—H19···I1	0.95	3.12	3.779 (3)	128
C9—H9···I1	0.95	3.21	3.846 (3)	126
C19—H19···I1	0.95	3.12	3.779 (3)	128
C9—H9···I1	0.95	3.21	3.846 (3)	126

(db201) 1,10-Phenanthroline–1,3,5-trifluoro-2,4,6-triiodobenzene (1/1)

Crystal data

C6F3I3·C12H8N2	Dx = 2.408 Mg m^−3
Mr = 689.96	Melting point: 453 K
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 8.6445 (3) Å	Cell parameters from 9717 reflections
b = 14.0472 (6) Å	θ = 2.8–28.3°
c = 15.8147 (6) Å	µ = 4.96 mm^−1
β = 97.662 (2)°	T = 200 K
V = 1903.25 (13) Å^3	Block, colourless
Z = 4	0.51 × 0.37 × 0.37 mm
F(000) = 1264

Data collection

Bruker APEXII CCD diffractometer	4397 reflections with I > 2σ(I)
Detector resolution: 8.33 pixels mm^-1	Rint = 0.024
φ and ω scans	θmax = 28.4°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2003)	h = −10→11
Tmin = 0.468, Tmax = 0.746	k = −18→18
28519 measured reflections	l = −21→21
4752 independent reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.025	H-atom parameters constrained
wR(F^2) = 0.059	w = 1/[σ^2(Fo^2) + (0.0213P)^2 + 4.2879P] where P = (Fo^2 + 2Fc^2)/3
S = 1.15	(Δ/σ)max = 0.002
4752 reflections	Δρmax = 1.23 e Å^−3
235 parameters	Δρmin = −0.60 e Å^−3

Special details

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. Data were collected on a Bruker AXS Kappa-single crystal diffractometer equipped with a sealed Mo tube source (wavelength 0.71073 Å) APEX II CCD detector. Raw data collection and processing were performed with the APEX II software package from BRUKER AXS (Bruker, 2012). Semi-empirical absorption corrections based on equivalent reflections were applied (Bruker, 2001). Systematic absences in the diffraction dataset and unit cell parameters were consistent with monoclinic P2₁/c (No. 14) for compounds A2, B2, and C2. The structures were solved by direct methods and refined with full-matrix least-squares procedures based on F², procedures using SHELXL2014 (Sheldrick, 2015) and WinGX (Farrugia 1999). All non-hydrogen atoms were refined anisotropically.

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

	x	y	z	Uiso*/Ueq
C1	0.7597 (3)	0.4407 (2)	0.64308 (18)	0.0242 (6)
C2	0.8391 (4)	0.3616 (2)	0.67737 (18)	0.0245 (6)
C3	0.9211 (4)	0.3016 (2)	0.62997 (19)	0.0252 (6)
C4	0.9182 (4)	0.3230 (2)	0.5443 (2)	0.0266 (6)
C5	0.8392 (4)	0.3997 (2)	0.50567 (18)	0.0261 (6)
C6	0.7615 (4)	0.4573 (2)	0.55748 (19)	0.0258 (6)
C8	0.2109 (5)	0.4212 (3)	0.8125 (2)	0.0395 (8)
H8	0.1886	0.3878	0.7601	0.047*
C9	0.1598 (5)	0.3816 (3)	0.8841 (3)	0.0490 (10)
H9	0.1062	0.3224	0.8807	0.059*
C10	0.1881 (5)	0.4294 (3)	0.9593 (3)	0.0488 (10)
H10	0.1524	0.4046	1.0091	0.059*
C11	0.2708 (4)	0.5157 (3)	0.9628 (2)	0.0368 (8)
C12	0.3029 (5)	0.5706 (3)	1.0397 (2)	0.0483 (10)
H12	0.2673	0.5484	1.0904	0.058*
C13	0.3825 (5)	0.6532 (3)	1.0411 (2)	0.0472 (10)
H13	0.4017	0.6885	1.0927	0.057*
C14	0.4385 (4)	0.6881 (2)	0.9659 (2)	0.0320 (7)
C15	0.5223 (5)	0.7734 (3)	0.9655 (3)	0.0420 (9)
H15	0.5450	0.8098	1.0163	0.050*
C16	0.5712 (5)	0.8037 (3)	0.8911 (3)	0.0411 (8)
H16	0.6274	0.8616	0.8892	0.049*
C17	0.5367 (4)	0.7478 (2)	0.8183 (2)	0.0356 (7)
H17	0.5701	0.7700	0.7670	0.043*
C19	0.4093 (3)	0.6367 (2)	0.88943 (19)	0.0247 (6)
C20	0.3219 (4)	0.5486 (2)	0.88732 (19)	0.0273 (6)
N7	0.2884 (3)	0.5021 (2)	0.81209 (17)	0.0301 (6)
N18	0.4609 (3)	0.6661 (2)	0.81583 (17)	0.0298 (6)
F2	0.8371 (2)	0.34209 (15)	0.76014 (12)	0.0352 (4)
F4	0.9960 (3)	0.26562 (16)	0.49663 (13)	0.0401 (5)
F6	0.6834 (3)	0.53257 (16)	0.52202 (13)	0.0412 (5)
I1	0.63114 (2)	0.52779 (2)	0.71479 (2)	0.02812 (6)
I3	1.04561 (3)	0.18576 (2)	0.68479 (2)	0.03167 (6)
I5	0.81615 (3)	0.42273 (2)	0.37432 (2)	0.03450 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0241 (14)	0.0291 (15)	0.0200 (13)	0.0008 (12)	0.0044 (10)	−0.0042 (11)
C2	0.0251 (14)	0.0288 (15)	0.0201 (12)	−0.0020 (12)	0.0049 (10)	0.0007 (11)
C3	0.0261 (14)	0.0258 (14)	0.0240 (13)	0.0035 (12)	0.0042 (11)	0.0036 (11)
C4	0.0269 (15)	0.0281 (15)	0.0256 (14)	0.0041 (12)	0.0062 (11)	−0.0054 (12)
C5	0.0281 (15)	0.0316 (15)	0.0200 (13)	0.0027 (12)	0.0087 (11)	0.0022 (11)
C6	0.0268 (15)	0.0279 (15)	0.0226 (13)	0.0052 (12)	0.0030 (11)	0.0016 (11)
C8	0.045 (2)	0.0353 (18)	0.0388 (18)	−0.0113 (16)	0.0070 (16)	−0.0006 (15)
C9	0.057 (3)	0.048 (2)	0.042 (2)	−0.023 (2)	0.0054 (18)	0.0117 (18)
C10	0.058 (3)	0.057 (3)	0.0326 (18)	−0.013 (2)	0.0107 (17)	0.0161 (17)
C11	0.0402 (19)	0.047 (2)	0.0240 (15)	−0.0001 (16)	0.0064 (13)	0.0055 (14)
C12	0.061 (3)	0.065 (3)	0.0196 (15)	−0.005 (2)	0.0089 (15)	0.0046 (16)
C13	0.063 (3)	0.056 (2)	0.0219 (15)	0.003 (2)	0.0033 (16)	−0.0080 (16)
C14	0.0360 (17)	0.0318 (16)	0.0272 (15)	0.0068 (14)	0.0006 (13)	−0.0039 (13)
C15	0.050 (2)	0.0336 (18)	0.0409 (19)	0.0030 (16)	−0.0008 (16)	−0.0133 (15)
C16	0.043 (2)	0.0242 (16)	0.056 (2)	−0.0018 (14)	0.0049 (17)	−0.0058 (15)
C17	0.0404 (19)	0.0246 (15)	0.0436 (19)	−0.0008 (14)	0.0124 (15)	−0.0005 (14)
C19	0.0231 (14)	0.0265 (14)	0.0246 (13)	0.0063 (11)	0.0033 (11)	−0.0001 (11)
C20	0.0298 (15)	0.0296 (15)	0.0223 (13)	0.0034 (12)	0.0031 (11)	0.0030 (12)
N7	0.0353 (15)	0.0306 (14)	0.0253 (12)	−0.0039 (12)	0.0078 (11)	−0.0019 (11)
N18	0.0339 (15)	0.0263 (13)	0.0306 (13)	−0.0013 (11)	0.0101 (11)	−0.0021 (11)
F2	0.0433 (11)	0.0429 (11)	0.0205 (8)	0.0084 (9)	0.0085 (8)	0.0046 (8)
F4	0.0497 (12)	0.0418 (11)	0.0314 (10)	0.0183 (10)	0.0148 (9)	−0.0039 (9)
F6	0.0571 (14)	0.0397 (12)	0.0282 (10)	0.0231 (10)	0.0102 (9)	0.0077 (8)
I1	0.03073 (11)	0.03111 (11)	0.02333 (10)	0.00403 (8)	0.00654 (7)	−0.00551 (7)
I3	0.03452 (12)	0.02701 (11)	0.03367 (11)	0.00512 (8)	0.00526 (8)	0.00532 (8)
I5	0.04263 (13)	0.04277 (13)	0.01953 (9)	0.00434 (10)	0.00940 (8)	0.00139 (8)

Geometric parameters (Å, º)

C1—C6	1.376 (4)	C10—H10	0.9500
C1—C2	1.378 (4)	C11—C20	1.405 (4)
C1—I1	2.086 (3)	C11—C12	1.435 (5)
C2—F2	1.340 (3)	C12—C13	1.348 (6)
C2—C3	1.384 (4)	C12—H12	0.9500
C3—C4	1.385 (4)	C13—C14	1.429 (5)
C3—I3	2.076 (3)	C13—H13	0.9500
C4—F4	1.344 (3)	C14—C15	1.401 (5)
C4—C5	1.374 (4)	C14—C19	1.403 (4)
C5—C6	1.388 (4)	C15—C16	1.370 (6)
C5—I5	2.085 (3)	C15—H15	0.9500
C6—F6	1.337 (4)	C16—C17	1.393 (5)
C8—N7	1.319 (4)	C16—H16	0.9500
C8—C9	1.385 (5)	C17—N18	1.319 (4)
C8—H8	0.9500	C17—H17	0.9500
C9—C10	1.359 (6)	C19—N18	1.365 (4)
C9—H9	0.9500	C19—C20	1.448 (5)
C10—C11	1.405 (6)	C20—N7	1.354 (4)
C6—C1—C2	117.0 (3)	C10—C11—C12	122.5 (3)
C6—C1—I1	120.8 (2)	C20—C11—C12	119.7 (4)
C2—C1—I1	122.1 (2)	C13—C12—C11	121.2 (3)
F2—C2—C1	118.6 (3)	C13—C12—H12	119.4
F2—C2—C3	118.6 (3)	C11—C12—H12	119.4
C1—C2—C3	122.8 (3)	C12—C13—C14	120.7 (3)
C2—C3—C4	117.0 (3)	C12—C13—H13	119.7
C2—C3—I3	121.7 (2)	C14—C13—H13	119.7
C4—C3—I3	121.3 (2)	C15—C14—C19	118.0 (3)
F4—C4—C5	118.5 (3)	C15—C14—C13	122.0 (3)
F4—C4—C3	118.3 (3)	C19—C14—C13	119.9 (3)
C5—C4—C3	123.2 (3)	C16—C15—C14	119.3 (3)
C4—C5—C6	116.5 (3)	C16—C15—H15	120.4
C4—C5—I5	122.7 (2)	C14—C15—H15	120.4
C6—C5—I5	120.5 (2)	C15—C16—C17	118.5 (3)
F6—C6—C1	118.4 (3)	C15—C16—H16	120.7
F6—C6—C5	118.1 (3)	C17—C16—H16	120.7
C1—C6—C5	123.5 (3)	N18—C17—C16	124.5 (3)
N7—C8—C9	124.6 (4)	N18—C17—H17	117.8
N7—C8—H8	117.7	C16—C17—H17	117.8
C9—C8—H8	117.7	N18—C19—C14	122.5 (3)
C10—C9—C8	118.5 (4)	N18—C19—C20	117.9 (3)
C10—C9—H9	120.8	C14—C19—C20	119.5 (3)
C8—C9—H9	120.8	N7—C20—C11	122.2 (3)
C9—C10—C11	119.5 (3)	N7—C20—C19	118.8 (3)
C9—C10—H10	120.3	C11—C20—C19	118.9 (3)
C11—C10—H10	120.3	C8—N7—C20	117.4 (3)
C10—C11—C20	117.8 (3)	C17—N18—C19	117.1 (3)
C6—C1—C2—F2	−178.6 (3)	C10—C11—C12—C13	179.9 (4)
I1—C1—C2—F2	−2.1 (4)	C20—C11—C12—C13	−0.5 (6)
C6—C1—C2—C3	1.5 (5)	C11—C12—C13—C14	−0.5 (7)
I1—C1—C2—C3	178.1 (2)	C12—C13—C14—C15	−179.7 (4)
F2—C2—C3—C4	178.8 (3)	C12—C13—C14—C19	0.6 (6)
C1—C2—C3—C4	−1.3 (5)	C19—C14—C15—C16	0.5 (5)
F2—C2—C3—I3	−2.0 (4)	C13—C14—C15—C16	−179.2 (4)
C1—C2—C3—I3	177.9 (2)	C14—C15—C16—C17	−0.5 (6)
C2—C3—C4—F4	−179.6 (3)	C15—C16—C17—N18	−0.8 (6)
I3—C3—C4—F4	1.1 (4)	C15—C14—C19—N18	0.9 (5)
C2—C3—C4—C5	0.2 (5)	C13—C14—C19—N18	−179.4 (3)
I3—C3—C4—C5	−179.0 (3)	C15—C14—C19—C20	−179.5 (3)
F4—C4—C5—C6	−179.5 (3)	C13—C14—C19—C20	0.2 (5)
C3—C4—C5—C6	0.7 (5)	C10—C11—C20—N7	2.8 (5)
F4—C4—C5—I5	6.5 (4)	C12—C11—C20—N7	−176.8 (4)
C3—C4—C5—I5	−173.3 (3)	C10—C11—C20—C19	−179.1 (3)
C2—C1—C6—F6	178.9 (3)	C12—C11—C20—C19	1.3 (5)
I1—C1—C6—F6	2.3 (4)	N18—C19—C20—N7	−3.3 (4)
C2—C1—C6—C5	−0.6 (5)	C14—C19—C20—N7	177.0 (3)
I1—C1—C6—C5	−177.2 (3)	N18—C19—C20—C11	178.5 (3)
C4—C5—C6—F6	−180.0 (3)	C14—C19—C20—C11	−1.2 (5)
I5—C5—C6—F6	−5.9 (4)	C9—C8—N7—C20	0.9 (6)
C4—C5—C6—C1	−0.4 (5)	C11—C20—N7—C8	−3.0 (5)
I5—C5—C6—C1	173.7 (2)	C19—C20—N7—C8	178.9 (3)
N7—C8—C9—C10	1.3 (7)	C16—C17—N18—C19	2.1 (5)
C8—C9—C10—C11	−1.4 (7)	C14—C19—N18—C17	−2.1 (5)
C9—C10—C11—C20	−0.5 (6)	C20—C19—N18—C17	178.2 (3)
C9—C10—C11—C12	179.1 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8···I3^i	0.95	3.26	4.037 (4)	141
C9—H9···F4^ii	0.95	2.50	3.182 (4)	128
C16—H16···F6^iii	0.95	2.57	3.159 (4)	121
C8—H8···I3^i	0.95	3.26	4.037 (4)	141
C9—H9···F4^ii	0.95	2.50	3.182 (4)	128
C16—H16···F6^iii	0.95	2.57	3.159 (4)	121

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