N-Oxide–N-oxide inter­actions and Cl...Cl halogen bonds in penta­chloro­pyridine N-oxide: the many-body approach to inter­actions in the crystal state

Penta­chloro­pyridine N-oxide, C₅Cl₅NO, crystallizes in the monoclinic space group P2₁/c. In the crystal structure, mol­ecules are linked by C—Cl...Cl halogen bonds into infinite ribbons extending along the crystallographic [100] direction. These mol­ecular aggregates are further stabilized by very short inter­molecular N-oxide–N-oxide inter­actions into herringbone motifs. Computations based on quantum chemistry methods allowed for a more detailed description of the N-oxide–N-oxide inter­actions and Cl...Cl halogen bonds. For this purpose, Hirshfeld surface analysis and the many-body approach to interaction energy were applied.

Computing details

Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: Structure solution software; please supply; program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010), PLATON (Spek, 2009) and WinGX (Farrugia, 2012).

Pentachloropyridine N-oxide

Crystal data

C5Cl5NO	F(000) = 520
Mr = 267.31	Dx = 2.116 Mg m^−3
Monoclinic, P21/c	Cu Kα radiation, λ = 1.54184 Å
a = 8.5852 (2) Å	Cell parameters from 3739 reflections
b = 17.0639 (4) Å	θ = 5.4–76.2°
c = 5.9883 (2) Å	µ = 15.31 mm^−1
β = 106.936 (3)°	T = 100 K
V = 839.22 (4) Å^3	Plate, colourless
Z = 4	0.34 × 0.08 × 0.02 mm

Data collection

Agilent SuperNova DualSource diffractometer	1391 reflections with I > 2σ(I)
Detector resolution: 10.4052 pixels mm^-1	Rint = 0.046
CrysAlisPro 1.171.39.15e (Rigaku Oxford Diffraction, 2015) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. scans	θmax = 68.5°, θmin = 5.2°
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011)	h = −10→10
Tmin = 0.100, Tmax = 1.000	k = −17→20
8310 measured reflections	l = −7→7
1548 independent reflections

Refinement

Refinement on F^2	109 parameters
Least-squares matrix: full	0 restraints
R[F^2 > 2σ(F^2)] = 0.032	w = 1/[σ^2(Fo^2) + (0.0591P)^2 + 0.0274P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.085	(Δ/σ)max = 0.001
S = 1.04	Δρmax = 0.40 e Å^−3
1548 reflections	Δρmin = −0.44 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
Cl4	0.66813 (6)	0.46937 (3)	0.91688 (9)	0.01612 (17)
Cl3	0.32783 (7)	0.41016 (3)	0.60185 (10)	0.01635 (17)
Cl2	0.31457 (7)	0.31363 (3)	0.14987 (10)	0.01768 (17)
Cl6	0.94101 (7)	0.32091 (4)	0.32595 (11)	0.02151 (18)
Cl5	0.98100 (7)	0.42141 (4)	0.78199 (10)	0.02224 (18)
O1	0.6181 (2)	0.29071 (10)	0.0775 (3)	0.0196 (4)
N1	0.6295 (2)	0.32790 (11)	0.2679 (3)	0.0137 (4)
C3	0.5028 (3)	0.38880 (13)	0.5324 (4)	0.0136 (5)
C5	0.7925 (3)	0.39268 (13)	0.6128 (4)	0.0150 (5)
C4	0.6539 (3)	0.41299 (13)	0.6757 (4)	0.0131 (5)
C2	0.4926 (3)	0.34654 (13)	0.3314 (4)	0.0140 (5)
C6	0.7787 (3)	0.34953 (14)	0.4118 (4)	0.0150 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl4	0.0184 (3)	0.0165 (3)	0.0140 (3)	−0.00124 (19)	0.0056 (2)	−0.00348 (18)
Cl3	0.0132 (3)	0.0187 (3)	0.0188 (3)	0.00076 (18)	0.0071 (2)	−0.0008 (2)
Cl2	0.0155 (3)	0.0199 (3)	0.0157 (3)	−0.00312 (19)	0.0015 (2)	−0.00179 (19)
Cl6	0.0166 (3)	0.0280 (3)	0.0228 (3)	0.0019 (2)	0.0104 (2)	−0.0042 (2)
Cl5	0.0128 (3)	0.0333 (4)	0.0197 (3)	−0.0038 (2)	0.0033 (2)	−0.0063 (2)
O1	0.0275 (9)	0.0177 (8)	0.0148 (9)	−0.0022 (7)	0.0079 (7)	−0.0061 (6)
N1	0.0168 (10)	0.0120 (9)	0.0128 (9)	−0.0011 (7)	0.0051 (8)	−0.0008 (7)
C3	0.0141 (11)	0.0126 (11)	0.0150 (11)	0.0024 (8)	0.0054 (8)	0.0024 (8)
C5	0.0152 (11)	0.0141 (11)	0.0146 (11)	−0.0019 (9)	0.0028 (9)	0.0003 (8)
C4	0.0154 (11)	0.0112 (11)	0.0128 (11)	0.0015 (8)	0.0042 (9)	0.0005 (8)
C2	0.0161 (11)	0.0105 (10)	0.0148 (11)	0.0003 (8)	0.0036 (9)	0.0021 (8)
C6	0.0159 (11)	0.0148 (11)	0.0166 (11)	0.0008 (8)	0.0083 (9)	0.0021 (9)

Geometric parameters (Å, º)

Cl4—C4	1.710 (2)	N1—C6	1.370 (3)
Cl3—C3	1.711 (2)	N1—C2	1.374 (3)
Cl2—C2	1.693 (2)	C3—C2	1.384 (3)
Cl6—C6	1.692 (2)	C3—C4	1.393 (3)
Cl5—C5	1.712 (2)	C5—C6	1.386 (3)
O1—N1	1.284 (3)	C5—C4	1.393 (3)
Cl4···Cl5^i	3.555 (1)	O1···N1^v	2.766 (2)
Cl3···Cl4^ii	3.532 (1)	Cl4···N1^vi	3.281 (1)
Cl4···Cl4^ii	3.477 (1)	Cl2···Cl5^vii	3.572 (1)
Cl3···Cl5^iii	3.455 (1)	Cl5···Cl2^viii	3.572 (1)
Cl3···Cl6^iii	3.589 (1)	Cl2···Cl2^v	3.699 (1)
Cl6···Cl2^iv	3.658 (1)	Cl2···Cl2^ix	3.699 (1)
O1—N1—C6	120.5 (2)	C5—C4—C3	118.4 (2)
O1—N1—C2	120.7 (2)	C5—C4—Cl4	120.80 (18)
C6—N1—C2	118.8 (2)	C3—C4—Cl4	120.79 (18)
C2—C3—C4	120.1 (2)	N1—C2—C3	121.2 (2)
C2—C3—Cl3	118.99 (18)	N1—C2—Cl2	115.51 (18)
C4—C3—Cl3	120.86 (18)	C3—C2—Cl2	123.25 (19)
C6—C5—C4	120.2 (2)	N1—C6—C5	121.1 (2)
C6—C5—Cl5	119.55 (19)	N1—C6—Cl6	115.69 (18)
C4—C5—Cl5	120.24 (18)	C5—C6—Cl6	123.18 (19)
C6—C5—C4—C3	0.1 (3)	C4—C3—C2—N1	−0.4 (3)
Cl5—C5—C4—C3	179.63 (17)	Cl3—C3—C2—N1	179.99 (17)
C6—C5—C4—Cl4	−177.46 (18)	C4—C3—C2—Cl2	178.99 (17)
Cl5—C5—C4—Cl4	2.1 (3)	Cl3—C3—C2—Cl2	−0.7 (3)
C2—C3—C4—C5	−0.8 (3)	O1—N1—C6—C5	177.2 (2)
Cl3—C3—C4—C5	178.82 (17)	C2—N1—C6—C5	−3.0 (3)
C2—C3—C4—Cl4	176.73 (17)	O1—N1—C6—Cl6	−2.3 (3)
Cl3—C3—C4—Cl4	−3.6 (3)	C2—N1—C6—Cl6	177.52 (17)
O1—N1—C2—C3	−177.9 (2)	C4—C5—C6—N1	1.8 (4)
C6—N1—C2—C3	2.3 (3)	Cl5—C5—C6—N1	−177.69 (17)
O1—N1—C2—Cl2	2.7 (3)	C4—C5—C6—Cl6	−178.72 (17)
C6—N1—C2—Cl2	−177.13 (17)	Cl5—C5—C6—Cl6	1.7 (3)

Symmetry codes: (i) −x+2, −y+1, −z+2; (ii) −x+1, −y+1, −z+2; (iii) x−1, y, z; (iv) x+1, y, z; (v) x, −y−1/2, z−3/2; (vi) x, y, z+1; (vii) x−1, y, z−1; (viii) x+1, y, z+1; (ix) x, −y−1/2, z−1/2.