1,3-Bis(4-fluoro­benzene­sulfonyl)-5-methyl­ene-1,2,3,4,5,6-hexa­hydro­pyrimidine

The title mol­ecule, C₁₇H₁₆F₂N₂O₄S₂, contains a di­aza­cyclo­hexane ring with fluoro­benzene­sulfon­amide groups, and an exocyclic double bond. This poly­amine ring was synthesized to be a precursor for novel energetic analogs of 1,3,5-tri­nitro­tri­aza­cyclo­hexane (RDX), from a complex condensation reaction. The structure contains several weak intermolecular and intramolecular C—H...O contacts.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.045
• wR factor = 0.124
• Data-to-parameter ratio = 10.3

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           67.11
         From the CIF: _reflns_number_total               3177
         TEST2: Reflns within _diffrn_reflns_theta_max
         Count of symmetry unique reflns         3369
         Completeness (_total/calc)             94.30%
          Alert C: < 95% complete


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 1 Alert Level C = Please check

---

S1. Comment

Polyamine rings, or ring systems, are necessary precursors for several of the most potent energetic materials known, such as RDX, HMX, and CL20. The C—N bonds holding these molecules together are weaker than C—C bonds, and thus release more energy when they are dissociated and recombined to form gaseous products, such as N₂ and CO₂. The backbone rings in these molecules are first synthesized with no energetic substituents, often through fairly simple condensation reactions between amines and a reactive carbonyl compound (e.g. glyoxal or formaldehyde). However, (I) results from a more complex condensation wherein the two N atoms seen in the central ring of the product (I) are already linked together in reactant (a). This reaction produces a diazacyclohexane ring with the amino N atoms already protected or stabilized by fluorobenzenesulfonamide groups, and an exocyclic double bond. This particular `designed' product, (I), was targeted as a precursor for further synthetic addition of energetic groups to produce novel analogs of 1,3,5-trinitrotriazacyclohexane (RDX).

The structure of the molecule of (I) and its packing are not unusual in any way (Figs. 1 and 2). There are five short intramolecular C—H···O contacts (Table 1) but they are not very short and are quite bent, so they may not be even weak `hydrogen bonds' but just unavoidable contacts caused by substitution of two bulky groups on each sulfonyl group. The remaining two C—H···O intermolecular bonds shown in Table 1 are close to linear [C—H···O angles of 163 (2) and 173 (2)°], and so appear to be hydrogen bonds, but weak ones, since their H···O contact distances [2.53 (3) and 2.54 (3) Å] are very slightly less than the expected van der Waals H···O contact of 2.62 Å (Rowland & Taylor, 1996).

S2. Experimental

Potassium carbonate (0.1 g, 0.27 mmol) and methallyl dichloride (0.038 g, 0.30 mmol) were added to a solution of methylene bis(4-fluorobenzenesulfonamide) (0.1 g, 0.27 mmol) in acetonitrile. The reaction mixture was heated at reflux overnight and then the resulting mixture was cooled to room temperature, filtered and concentrated to obtain a crystalline residue, which was recrystallized from a mixture of absolute ethanol and dried to obtain (1) as colorless crystals with a melting point of 457–458 K.

S3. Refinement

All of the H atoms were refined freely. The C—H bond distances are 0.86 (4)–1.03 (3) Å.

Computing details

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXTL (Sheldrick, 1997); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures

Fig. 1. A view of (I) with 25% atomic displacement ellipsoids.

Fig. 2. A view of the packing of (I), viewed down a direction perpendicular to the (001) plane. Only half of the contents of the cell (from z = 0 to z = 1/2) are shown, for clarity. The other half of the cell is related to that shown above by the inversion center at (1/2, 1/2, 1/2). Short C—H···O contacts [H···O distance = 2.53 (3) Å and C—H···O angle = 173 (2)°] link the screw-axis-related molecules along b, the vertical axis.

1,3-Bis(4-fluorobenzenesulfonyl)-5-methylene-1,2,3,4,5,6-hexahydropyrimidine

Crystal data

C17H16F2N2O4S2	F(000) = 856
Mr = 414.44	Dx = 1.455 Mg m^−3
Monoclinic, P21/n	Melting point = 457–458 K
Hall symbol: -P 2yn	Cu Kα radiation, λ = 1.54178 Å
a = 13.8591 (2) Å	Cell parameters from 7044 reflections
b = 10.8218 (1) Å	θ = 3.8–67.0°
c = 13.8946 (2) Å	µ = 2.97 mm^−1
β = 114.751 (1)°	T = 294 K
V = 1892.48 (5) Å^3	Plate, colorless
Z = 4	0.18 × 0.16 × 0.05 mm

Data collection

Bruker SMART CCD area-detector diffractometer	3177 independent reflections
Radiation source: fine-focus sealed tube	2783 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.032
ϕ and ω scans	θmax = 67.1°, θmin = 3.8°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −15→16
Tmin = 0.686, Tmax = 0.862	k = −11→12
9044 measured reflections	l = −15→15

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.045	All H-atom parameters refined
wR(F^2) = 0.124	w = 1/[σ^2(Fo^2) + (0.0828P)^2 + 0.1403P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max < 0.001
3177 reflections	Δρmax = 0.24 e Å^−3
309 parameters	Δρmin = −0.35 e Å^−3
0 restraints	Extinction correction: SHELXTL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0116 (7)

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. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
S1	0.38019 (4)	0.57707 (4)	0.10099 (4)	0.0575 (2)
S2	0.66270 (4)	0.83976 (5)	0.14058 (4)	0.0642 (2)
O1B	0.38055 (12)	0.56931 (15)	−0.00144 (12)	0.0697 (4)
N1	0.50458 (13)	0.56938 (15)	0.18668 (13)	0.0564 (4)
O2B	0.59433 (12)	0.83484 (16)	0.02996 (12)	0.0767 (5)
O1A	0.32549 (13)	0.48619 (14)	0.13395 (13)	0.0748 (4)
N3	0.60807 (13)	0.75132 (15)	0.19882 (13)	0.0575 (4)
C15	0.2208 (2)	0.8453 (3)	0.1708 (2)	0.0831 (7)
C14	0.2440 (2)	0.9444 (2)	0.1244 (2)	0.0783 (7)
C2	0.58612 (16)	0.62316 (19)	0.15980 (18)	0.0576 (5)
O2A	0.68482 (14)	0.95557 (16)	0.19455 (15)	0.0869 (5)
C6	0.5301 (2)	0.5748 (2)	0.30056 (19)	0.0691 (6)
C11	0.32773 (15)	0.72206 (19)	0.11110 (15)	0.0555 (5)
F14	0.20086 (17)	1.05554 (16)	0.12776 (15)	0.1136 (6)
F24	1.05857 (14)	0.5984 (2)	0.1956 (2)	0.1407 (9)
C21	0.78362 (16)	0.7691 (2)	0.15712 (17)	0.0633 (5)
C12	0.35262 (17)	0.8246 (2)	0.06658 (17)	0.0612 (5)
C16	0.26276 (19)	0.7321 (3)	0.1640 (2)	0.0709 (6)
C22	0.7887 (2)	0.7031 (3)	0.0756 (2)	0.0753 (6)
C13	0.3096 (2)	0.9379 (2)	0.07304 (19)	0.0726 (6)
C26	0.87125 (19)	0.7789 (3)	0.2547 (2)	0.0773 (7)
C5	0.56452 (18)	0.7019 (2)	0.34479 (16)	0.0702 (6)
C4	0.6470 (2)	0.7585 (3)	0.31561 (18)	0.0744 (6)
C25	0.9646 (2)	0.7199 (3)	0.2675 (3)	0.0917 (9)
C23	0.8814 (2)	0.6455 (3)	0.0879 (3)	0.0934 (8)
C24	0.9669 (2)	0.6562 (3)	0.1841 (3)	0.0946 (9)
C5A	0.5268 (3)	0.7570 (4)	0.4059 (3)	0.1002 (10)
H4A	0.713 (2)	0.710 (3)	0.348 (2)	0.087 (8)*
H12	0.397 (2)	0.819 (2)	0.0300 (19)	0.076 (7)*
H2A	0.5646 (16)	0.622 (2)	0.0857 (18)	0.058 (6)*
H4B	0.662 (2)	0.847 (3)	0.342 (2)	0.098 (9)*
H6A	0.593 (2)	0.516 (3)	0.339 (2)	0.092 (8)*
H16	0.248 (2)	0.664 (3)	0.194 (2)	0.082 (8)*
H22	0.733 (2)	0.699 (2)	0.013 (2)	0.078 (7)*
H6B	0.468 (2)	0.551 (3)	0.304 (2)	0.081 (8)*
H2B	0.648 (2)	0.574 (2)	0.194 (2)	0.077 (7)*
H5A	0.476 (3)	0.729 (3)	0.420 (3)	0.116 (12)*
H25	1.024 (3)	0.726 (3)	0.327 (3)	0.104 (10)*
H5B	0.551 (2)	0.839 (3)	0.428 (2)	0.092 (9)*
H13	0.324 (2)	1.006 (3)	0.049 (2)	0.083 (8)*
H26	0.865 (2)	0.826 (3)	0.312 (2)	0.087 (8)*
H23	0.888 (3)	0.593 (4)	0.033 (3)	0.128 (13)*
H15	0.177 (3)	0.858 (3)	0.211 (2)	0.104 (9)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0571 (3)	0.0574 (3)	0.0572 (3)	−0.00605 (19)	0.0233 (2)	−0.00788 (19)
S2	0.0603 (3)	0.0622 (3)	0.0608 (4)	−0.0069 (2)	0.0163 (2)	0.0040 (2)
O1B	0.0724 (9)	0.0808 (10)	0.0540 (9)	−0.0029 (7)	0.0245 (7)	−0.0171 (7)
N1	0.0596 (9)	0.0554 (9)	0.0539 (10)	−0.0002 (7)	0.0237 (8)	0.0002 (6)
O2B	0.0659 (9)	0.0918 (12)	0.0600 (10)	−0.0024 (8)	0.0143 (7)	0.0185 (7)
O1A	0.0756 (9)	0.0660 (9)	0.0859 (11)	−0.0168 (7)	0.0370 (8)	−0.0069 (7)
N3	0.0579 (9)	0.0605 (10)	0.0486 (9)	−0.0056 (7)	0.0167 (7)	−0.0054 (7)
C15	0.0921 (17)	0.0924 (18)	0.0793 (18)	0.0216 (13)	0.0503 (14)	0.0053 (13)
C14	0.0887 (16)	0.0752 (15)	0.0704 (15)	0.0203 (13)	0.0326 (12)	−0.0036 (11)
C2	0.0564 (11)	0.0580 (11)	0.0587 (13)	0.0015 (9)	0.0244 (9)	−0.0021 (9)
O2A	0.0881 (11)	0.0622 (10)	0.1022 (14)	−0.0114 (8)	0.0316 (10)	−0.0060 (8)
C6	0.0734 (14)	0.0752 (14)	0.0568 (13)	0.0012 (11)	0.0255 (11)	0.0095 (10)
C11	0.0531 (10)	0.0634 (11)	0.0474 (10)	0.0017 (8)	0.0183 (8)	−0.0011 (8)
F14	0.1472 (16)	0.0877 (11)	0.1173 (13)	0.0434 (10)	0.0665 (12)	0.0034 (9)
F24	0.0777 (11)	0.162 (2)	0.185 (2)	0.0313 (12)	0.0582 (12)	0.0364 (16)
C21	0.0563 (11)	0.0649 (12)	0.0624 (13)	−0.0136 (9)	0.0187 (9)	0.0031 (9)
C12	0.0585 (11)	0.0707 (13)	0.0541 (12)	−0.0015 (9)	0.0234 (9)	0.0000 (9)
C16	0.0751 (14)	0.0802 (15)	0.0675 (14)	0.0080 (11)	0.0398 (11)	0.0079 (11)
C22	0.0636 (13)	0.0877 (17)	0.0702 (16)	−0.0085 (12)	0.0237 (12)	−0.0008 (12)
C13	0.0814 (15)	0.0664 (14)	0.0654 (14)	0.0034 (11)	0.0263 (12)	0.0054 (10)
C26	0.0651 (13)	0.0838 (16)	0.0676 (15)	−0.0141 (11)	0.0128 (11)	0.0031 (12)
C5	0.0717 (13)	0.0864 (15)	0.0456 (12)	−0.0044 (11)	0.0176 (10)	−0.0026 (10)
C4	0.0726 (14)	0.0898 (17)	0.0499 (13)	−0.0127 (12)	0.0150 (10)	−0.0083 (11)
C25	0.0593 (14)	0.107 (2)	0.087 (2)	−0.0087 (14)	0.0090 (13)	0.0186 (16)
C23	0.0815 (18)	0.106 (2)	0.100 (2)	−0.0009 (15)	0.0451 (16)	0.0015 (17)
C24	0.0600 (14)	0.105 (2)	0.120 (3)	0.0056 (13)	0.0396 (15)	0.0253 (18)
C5A	0.112 (2)	0.115 (3)	0.084 (2)	−0.018 (2)	0.0510 (18)	−0.0276 (17)

Geometric parameters (Å, º)

S1—O1B	1.4277 (16)	C11—C16	1.385 (3)
S1—O1A	1.4292 (16)	F24—C24	1.365 (3)
S1—N1	1.6364 (17)	C21—C22	1.366 (4)
S1—C11	1.760 (2)	C21—C26	1.395 (3)
S2—O2A	1.4264 (18)	C12—C13	1.383 (3)
S2—O2B	1.4296 (16)	C12—H12	0.95 (3)
S2—N3	1.6300 (18)	C16—H16	0.91 (3)
S2—C21	1.767 (2)	C22—C23	1.373 (4)
N1—C2	1.452 (3)	C22—H22	0.89 (3)
N1—C6	1.471 (3)	C13—H13	0.87 (3)
N3—C2	1.474 (3)	C26—C25	1.386 (4)
N3—C4	1.482 (3)	C26—H26	0.98 (3)
C15—C14	1.358 (4)	C5—C5A	1.312 (4)
C15—C16	1.376 (4)	C5—C4	1.495 (3)
C15—H15	1.00 (3)	C4—H4A	0.98 (3)
C14—F14	1.353 (3)	C4—H4B	1.02 (3)
C14—C13	1.372 (4)	C25—C24	1.360 (5)
C2—H2A	0.95 (2)	C25—H25	0.89 (3)
C2—H2B	0.95 (3)	C23—C24	1.369 (5)
C6—C5	1.500 (3)	C23—H23	0.99 (4)
C6—H6A	1.03 (3)	C5A—H5A	0.86 (4)
C6—H6B	0.92 (3)	C5A—H5B	0.95 (3)
C11—C12	1.383 (3)
O1B—S1—O1A	120.18 (10)	C22—C21—C26	121.3 (2)
O1B—S1—N1	106.27 (9)	C22—C21—S2	119.56 (18)
O1A—S1—N1	105.69 (9)	C26—C21—S2	119.1 (2)
O1B—S1—C11	107.82 (10)	C13—C12—C11	119.2 (2)
O1A—S1—C11	107.20 (10)	C13—C12—H12	119.3 (16)
N1—S1—C11	109.38 (8)	C11—C12—H12	121.5 (16)
O2A—S2—O2B	119.85 (11)	C15—C16—C11	119.6 (2)
O2A—S2—N3	107.29 (11)	C15—C16—H16	120.5 (17)
O2B—S2—N3	105.99 (9)	C11—C16—H16	119.9 (17)
O2A—S2—C21	109.16 (10)	C21—C22—C23	120.3 (3)
O2B—S2—C21	106.82 (11)	C21—C22—H22	120.8 (17)
N3—S2—C21	107.09 (9)	C23—C22—H22	118.9 (17)
C2—N1—C6	113.48 (17)	C14—C13—C12	118.5 (2)
C2—N1—S1	119.26 (14)	C14—C13—H13	118.1 (19)
C6—N1—S1	119.07 (15)	C12—C13—H13	123.4 (19)
C2—N3—C4	112.12 (18)	C25—C26—C21	118.4 (3)
C2—N3—S2	115.92 (14)	C25—C26—H26	122.5 (17)
C4—N3—S2	118.75 (14)	C21—C26—H26	119.1 (17)
C14—C15—C16	118.7 (2)	C5A—C5—C4	123.1 (3)
C14—C15—H15	118.7 (19)	C5A—C5—C6	122.5 (3)
C16—C15—H15	122.6 (19)	C4—C5—C6	114.4 (2)
F14—C14—C15	119.3 (2)	N3—C4—C5	107.86 (18)
F14—C14—C13	117.5 (3)	N3—C4—H4A	108.4 (17)
C15—C14—C13	123.2 (2)	C5—C4—H4A	109.1 (16)
N1—C2—N3	110.22 (16)	N3—C4—H4B	111.5 (16)
N1—C2—H2A	110.6 (13)	C5—C4—H4B	111.1 (17)
N3—C2—H2A	109.4 (14)	H4A—C4—H4B	109 (2)
N1—C2—H2B	106.9 (15)	C24—C25—C26	118.5 (3)
N3—C2—H2B	109.7 (15)	C24—C25—H25	119 (2)
H2A—C2—H2B	110 (2)	C26—C25—H25	122 (2)
N1—C6—C5	111.67 (18)	C24—C23—C22	117.8 (3)
N1—C6—H6A	107.4 (15)	C24—C23—H23	119 (2)
C5—C6—H6A	107.2 (16)	C22—C23—H23	123 (2)
N1—C6—H6B	104.1 (16)	C25—C24—F24	119.0 (3)
C5—C6—H6B	112.0 (17)	C25—C24—C23	123.7 (3)
H6A—C6—H6B	114 (2)	F24—C24—C23	117.3 (4)
C12—C11—C16	120.9 (2)	C5—C5A—H5A	125 (2)
C12—C11—S1	119.42 (15)	C5—C5A—H5B	116.5 (19)
C16—C11—S1	119.63 (18)	H5A—C5A—H5B	118 (3)
O1B—S1—N1—C2	33.61 (17)	N3—S2—C21—C22	100.78 (19)
O1A—S1—N1—C2	162.35 (15)	O2A—S2—C21—C26	38.6 (2)
C11—S1—N1—C2	−82.54 (16)	O2B—S2—C21—C26	169.55 (17)
O1B—S1—N1—C6	−179.89 (15)	N3—S2—C21—C26	−77.25 (19)
O1A—S1—N1—C6	−51.15 (17)	C16—C11—C12—C13	−1.6 (3)
C11—S1—N1—C6	63.96 (17)	S1—C11—C12—C13	178.80 (17)
O2A—S2—N3—C2	−175.59 (14)	C14—C15—C16—C11	0.4 (4)
O2B—S2—N3—C2	55.26 (16)	C12—C11—C16—C15	1.2 (4)
C21—S2—N3—C2	−58.51 (16)	S1—C11—C16—C15	−179.2 (2)
O2A—S2—N3—C4	−37.5 (2)	C26—C21—C22—C23	−0.6 (4)
O2B—S2—N3—C4	−166.65 (18)	S2—C21—C22—C23	−178.6 (2)
C21—S2—N3—C4	79.59 (19)	F14—C14—C13—C12	−178.6 (2)
C16—C15—C14—F14	178.1 (2)	C15—C14—C13—C12	1.2 (4)
C16—C15—C14—C13	−1.6 (5)	C11—C12—C13—C14	0.5 (3)
C6—N1—C2—N3	−55.2 (2)	C22—C21—C26—C25	0.0 (4)
S1—N1—C2—N3	93.03 (18)	S2—C21—C26—C25	178.0 (2)
C4—N3—C2—N1	60.7 (2)	N1—C6—C5—C5A	133.0 (3)
S2—N3—C2—N1	−158.48 (14)	N1—C6—C5—C4	−48.4 (3)
C2—N1—C6—C5	49.1 (3)	C2—N3—C4—C5	−58.2 (3)
S1—N1—C6—C5	−99.2 (2)	S2—N3—C4—C5	162.25 (17)
O1B—S1—C11—C12	−37.86 (19)	C5A—C5—C4—N3	−129.2 (3)
O1A—S1—C11—C12	−168.57 (16)	C6—C5—C4—N3	52.2 (3)
N1—S1—C11—C12	77.29 (18)	C21—C26—C25—C24	0.7 (4)
O1B—S1—C11—C16	142.56 (17)	C21—C22—C23—C24	0.4 (4)
O1A—S1—C11—C16	11.9 (2)	C26—C25—C24—F24	179.5 (2)
N1—S1—C11—C16	−102.29 (18)	C26—C25—C24—C23	−0.9 (5)
O2A—S2—C21—C22	−143.37 (19)	C22—C23—C24—C25	0.3 (5)
O2B—S2—C21—C22	−12.4 (2)	C22—C23—C24—F24	179.9 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2A···O1B	0.95 (2)	2.39 (2)	2.852 (3)	109 (2)
C22—H22···O2B	0.89 (3)	2.51 (3)	2.873 (3)	105 (1)
C16—H16···O1A	0.91 (3)	2.51 (3)	2.884 (3)	105 (2)
C4—H4B···O2A	1.02 (3)	2.49 (3)	2.897 (3)	103 (2)
C2—H2A···O2B	0.95 (2)	2.52 (2)	2.947 (3)	108 (2)
C13—H13···O2B^i	0.87 (3)	2.54 (3)	3.386 (3)	163 (2)
C2—H2B···O2A^ii	0.95 (3)	2.53 (3)	3.476 (3)	173 (2)

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