Characterization of fluorine-centred `F...O' σ-hole interactions in the solid state

In the current study, the crystal structure of 1-(3-nitrophenyl)-2,2,2-trifluoro­ethanone (A1) and (E)-4-((4-fluorophenyl) diazenyl)phenol (A2) has been analyzed for the characterization of the presence of a `unique' and `rare' intermolecular C(sp³/sp²)—F...O contact, which has been observed to play a significant role in the crystal packing. Theoretical charge-density calculations have been performed to study the nature and strength associated with the existence of this intermolecular F...O contact, wherein the F atom is attached to an sp³-hybridized C atom in the case of A1 and to an sp² hybridized carbon in the case of A2. The crystal packing of the former contains two `electronically different' Csp<sup>3</sup>—F...O contacts which are present across and in between the layers of molecules. In the latter case, it is characterized by the presence of a very `short' (2.708 Å) and `highly directional' (168° at ∠C4—F1...O1 and 174° at ∠C10—O1...F1) Csp²—F...O contact. According to the Cambridge Structural Database (CSD) study, it is a rare example in molecular crystals. Topological features of F...O contacts in the solid state were compared with the gas-phase models. The two-dimensional and three-dimensional static deformation density obtained from theoretical multipole modeling confirm the presence of a charge depleted region on the F atoms. Minimization of the electrostatic repulsion between like charges are observed through subtle arrangements in the electronic environment in two of the short intermolecular F...O contacts. These contacts were investigated using inputs from pair energy decomposition analysis, Bader's quantum theory of atoms in molecules (QTAIM), Hirshfeld surface analysis, delocalization index, reduced density gradient (RDG) plot, electrostatic potential surface and distributed atomic polarizability. The intermolecular energy decomposition (PIXEL) and RDG–NCI (non-covalent interaction) analysis of the F...O contacts establish the interaction to be dispersive in nature. The mutual polarization of an O atom by fluorine and vice versa provides real physical insights into the role of atomic polarizability in interacting atoms in molecules in crystals.

Computing details

Program(s) used to refine structure: SHELXL2014/7 (Sheldrick, 2014).

(I)

Crystal data

C12H9FN2O	F(000) = 448
Mr = 216.21	Dx = 1.446 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 9.7681 (7) Å	Cell parameters from 1894 reflections
b = 10.5358 (7) Å	θ = 2.4–27.0°
c = 10.5740 (8) Å	µ = 0.11 mm^−1
β = 114.134 (4)°	T = 100 K
V = 993.10 (13) Å^3	Plate, yellow
Z = 4	0.20 × 0.10 × 0.03 mm

Data collection

Bruker APEX-II CCD diffractometer	1385 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.058
Absorption correction: multi-scan SADABS	θmax = 27.1°, θmin = 2.4°
Tmin = 0.609, Tmax = 0.746	h = −11→12
6854 measured reflections	k = −13→13
2194 independent reflections	l = −13→9

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.056	H-atom parameters constrained
wR(F^2) = 0.161	w = 1/[σ^2(Fo^2) + (0.0489P)^2 + 0.217P] where P = (Fo^2 + 2Fc^2)/3
S = 1.11	(Δ/σ)max < 0.001
2194 reflections	Δρmax = 0.42 e Å^−3
146 parameters	Δρmin = −0.26 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.

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

	x	y	z	Uiso*/Ueq
O1	0.97315 (17)	0.21736 (14)	0.40883 (15)	0.0294 (4)
H1	0.9587	0.1883	0.3304	0.044*
F1	0.19694 (14)	1.04951 (13)	0.44854 (14)	0.0348 (4)
N1	0.5729 (2)	0.65103 (17)	0.46831 (19)	0.0266 (5)
N2	0.5703 (2)	0.60640 (18)	0.35838 (19)	0.0297 (5)
C4	0.2860 (2)	0.95074 (19)	0.4487 (2)	0.0207 (5)
C5	0.2679 (2)	0.8957 (2)	0.3242 (2)	0.0217 (5)
H5	0.1927	0.9258	0.2397	0.026*
C6	0.3599 (2)	0.7970 (2)	0.3240 (2)	0.0230 (5)
H6	0.3495	0.7588	0.2392	0.028*
C1	0.4696 (2)	0.7530 (2)	0.4505 (2)	0.0229 (5)
C7	0.6750 (2)	0.5049 (2)	0.3782 (2)	0.0246 (5)
C8	0.7878 (3)	0.4709 (2)	0.5063 (2)	0.0299 (6)
H8	0.7968	0.5147	0.5878	0.036*
C9	0.8857 (2)	0.3738 (2)	0.5146 (2)	0.0287 (6)
H9	0.9615	0.3501	0.6018	0.034*
C10	0.8731 (2)	0.3107 (2)	0.3946 (2)	0.0230 (5)
C3	0.3918 (2)	0.9082 (2)	0.5743 (2)	0.0247 (5)
H3	0.4013	0.9464	0.6589	0.030*
C2	0.4825 (2)	0.8092 (2)	0.5734 (2)	0.0248 (5)
H2	0.5558	0.7786	0.6587	0.030*
C12	0.6636 (3)	0.4416 (2)	0.2595 (2)	0.0273 (5)
H12	0.5881	0.4653	0.1722	0.033*
C11	0.7613 (2)	0.3442 (2)	0.2674 (2)	0.0259 (5)
H11	0.7520	0.3002	0.1859	0.031*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0341 (9)	0.0270 (9)	0.0210 (8)	0.0159 (7)	0.0051 (7)	−0.0044 (7)
F1	0.0325 (7)	0.0335 (8)	0.0347 (8)	0.0111 (6)	0.0100 (6)	−0.0055 (6)
N1	0.0289 (10)	0.0258 (11)	0.0266 (10)	−0.0043 (8)	0.0129 (8)	−0.0034 (8)
N2	0.0352 (11)	0.0302 (11)	0.0243 (10)	0.0039 (9)	0.0127 (8)	0.0018 (8)
C4	0.0175 (10)	0.0174 (11)	0.0278 (11)	0.0024 (9)	0.0098 (9)	−0.0011 (9)
C5	0.0213 (10)	0.0218 (12)	0.0204 (10)	0.0004 (9)	0.0068 (8)	0.0013 (9)
C6	0.0244 (11)	0.0219 (12)	0.0251 (11)	−0.0028 (9)	0.0126 (9)	−0.0050 (9)
C1	0.0198 (10)	0.0165 (11)	0.0321 (12)	0.0015 (9)	0.0102 (9)	0.0017 (9)
C7	0.0258 (11)	0.0180 (11)	0.0334 (12)	0.0025 (10)	0.0155 (10)	0.0041 (9)
C8	0.0348 (13)	0.0288 (13)	0.0311 (12)	−0.0012 (11)	0.0184 (10)	−0.0078 (10)
C9	0.0282 (12)	0.0320 (13)	0.0224 (11)	0.0028 (10)	0.0068 (9)	−0.0037 (10)
C10	0.0256 (11)	0.0175 (11)	0.0269 (11)	0.0034 (9)	0.0116 (9)	0.0011 (9)
C3	0.0236 (11)	0.0286 (13)	0.0209 (11)	0.0004 (10)	0.0080 (9)	−0.0019 (9)
C2	0.0224 (11)	0.0252 (12)	0.0233 (11)	0.0036 (9)	0.0059 (9)	0.0047 (9)
C12	0.0301 (12)	0.0279 (13)	0.0240 (11)	0.0063 (10)	0.0112 (9)	0.0055 (9)
C11	0.0286 (12)	0.0255 (12)	0.0228 (11)	0.0042 (10)	0.0097 (9)	0.0002 (9)

Geometric parameters (Å, º)

O1—C10	1.351 (2)	C7—C12	1.385 (3)
O1—H1	0.8400	C7—C8	1.399 (3)
F1—C4	1.356 (2)	C8—C9	1.378 (3)
N1—N2	1.245 (3)	C8—H8	0.9500
N1—C1	1.432 (3)	C9—C10	1.393 (3)
N2—C7	1.435 (3)	C9—H9	0.9500
C4—C5	1.382 (3)	C10—C11	1.387 (3)
C4—C3	1.382 (3)	C3—C2	1.371 (3)
C5—C6	1.375 (3)	C3—H3	0.9500
C5—H5	0.9500	C2—H2	0.9500
C6—C1	1.407 (3)	C12—C11	1.380 (3)
C6—H6	0.9500	C12—H12	0.9500
C1—C2	1.386 (3)	C11—H11	0.9500
C10—O1—H1	109.5	C7—C8—H8	119.9
N2—N1—C1	114.60 (19)	C8—C9—C10	119.7 (2)
N1—N2—C7	113.85 (18)	C8—C9—H9	120.2
F1—C4—C5	119.25 (18)	C10—C9—H9	120.2
F1—C4—C3	118.48 (19)	O1—C10—C11	122.7 (2)
C5—C4—C3	122.26 (19)	O1—C10—C9	117.09 (19)
C6—C5—C4	119.31 (19)	C11—C10—C9	120.2 (2)
C6—C5—H5	120.3	C2—C3—C4	118.1 (2)
C4—C5—H5	120.3	C2—C3—H3	121.0
C5—C6—C1	119.5 (2)	C4—C3—H3	121.0
C5—C6—H6	120.3	C3—C2—C1	121.4 (2)
C1—C6—H6	120.3	C3—C2—H2	119.3
C2—C1—C6	119.5 (2)	C1—C2—H2	119.3
C2—C1—N1	114.09 (18)	C11—C12—C7	120.4 (2)
C6—C1—N1	126.42 (19)	C11—C12—H12	119.8
C12—C7—C8	119.6 (2)	C7—C12—H12	119.8
C12—C7—N2	116.01 (19)	C12—C11—C10	119.9 (2)
C8—C7—N2	124.4 (2)	C12—C11—H11	120.1
C9—C8—C7	120.2 (2)	C10—C11—H11	120.1
C9—C8—H8	119.9
C1—N1—N2—C7	179.63 (16)	C8—C9—C10—O1	179.3 (2)
F1—C4—C5—C6	178.89 (18)	C8—C9—C10—C11	−0.8 (3)
C3—C4—C5—C6	−1.5 (3)	F1—C4—C3—C2	−179.27 (19)
C4—C5—C6—C1	0.7 (3)	C5—C4—C3—C2	1.1 (3)
C5—C6—C1—C2	0.4 (3)	C4—C3—C2—C1	0.1 (3)
C5—C6—C1—N1	179.44 (19)	C6—C1—C2—C3	−0.8 (3)
N2—N1—C1—C2	−174.6 (2)	N1—C1—C2—C3	−179.95 (19)
N2—N1—C1—C6	6.3 (3)	C8—C7—C12—C11	0.9 (3)
N1—N2—C7—C12	172.2 (2)	N2—C7—C12—C11	178.7 (2)
N1—N2—C7—C8	−10.1 (3)	C7—C12—C11—C10	−0.9 (3)
C12—C7—C8—C9	−0.8 (3)	O1—C10—C11—C12	−179.2 (2)
N2—C7—C8—C9	−178.4 (2)	C9—C10—C11—C12	0.9 (3)
C7—C8—C9—C10	0.7 (3)