A series of N-(2-phenylethyl)nitroaniline derivatives as precursors for slow and sustained nitric oxide release agents

organic compounds

Acta Crystallographica Section C

Crystal Structure

symmetry, the molecules pack in a herringbone pattern with

fewer face-to-face interactions between the rings. The closest

˚

such interactions are about 3.5 A between rings that are

Communications

ISSN 0108-2701

largely slipped past one another. 4-Methylsulfonyl-2-nitro-N-

(2-phenylethyl)aniline, C₁₅H₁₆N₂O₄S, (IV), differs from (I) in

having a methylsulfonyl group in place of the 4-nitro group.

The intramolecular N—Hꢀ ꢀ ꢀO hydrogen bond is present as in

(I). However, unlike (I), the conformation about the ethyl

group is gauche, so the two arene rings are nearly perpen-

A series of N-(2-phenylethyl)nitro-

aniline derivatives as precursors for

slow and sustained nitric oxide release dicular rather than parallel. The packing is signiﬁcantly

different from the other three structures in that there are no

agents

intermolecular hydrogen bonds involving the N—H groups.

The molecules are arranged in tetragonal columns running

along the c axis, with the aniline rings mostly parallel and

Colin B. Wade,^aDillip K. Mohanty,^a* Philip J. Squattrito,^a*

Nicholas J. Amato^band Kristin Kirschbaum^b

˚

separated by ca 3.7 A. Taken together, these structures

demonstrate that modest changes in functional groups cause

^aDepartment of Chemistry, Central Michigan University, Mount Pleasant, MI 48859,

USA, and ^bDepartment of Chemistry, University of Toledo, Toledo, OH 43606, USA

signiﬁcant differences in molecular conformation, inter-

molecular interactions and packing.

Correspondence e-mail: mohan1dk@cmich.edu, p.squattrito@cmich.edu

Keywords: crystal structure; N-(2-phenylethyl)nitroaniline

Received 6 September 2013

derivatives; secondary amines; nitric oxide release agents.

Accepted 18 September 2013

2,4-Dinitro-N-(2-phenylethyl)aniline, C₁₄H₁₃N₃O₄, (I), crys-

tallizes with one independent molecule in the asymmetric unit.

The adjacent amine and nitro groups form an intramolecular

N—Hꢀ ꢀ ꢀO hydrogen bond. The anti conformation about the

ethyl C—C bond leads to the phenyl and aniline rings being

essentially parallel. Molecules are linked into dimers by

intermolecular N—Hꢀ ꢀ ꢀO hydrogen bonds, such that each

amine H atom participates in a three-centre interaction with

two nitro O atoms. Though the dimers pack so that the arene

rings of adjacent molecules are parallel, the rings are

staggered and ꢀ–ꢀ interactions do not appear to be favoured.

4,6-Dinitro-N,N⁰-bis(2-phenylethyl)benzene-1,3-diamine,

C₂₂H₂₂N₄O₄, (II), differs from (I) in the presence of a second

2-phenylethylamine group on the substituted ring. Compound

(II) also crystallizes with one unique molecule in the

asymmetric unit. Both amine groups are involved in intra-

molecular N—Hꢀ ꢀ ꢀO hydrogen bonds with adjacent nitro

groups. Although one ethyl group adopts an anti conformation

as in (I), the other is gauche, with the result that the pendant

phenyl rings are not parallel. The amine group that is part of

the gauche conformation participates in a three-centre N—

Hꢀ ꢀ ꢀO hydrogen bond with the nitro group of a neighbouring

molecule, leading to dimers as in (I). The other amine H atom

does not form any intermolecular hydrogen bonds. The

1. Introduction

Nitric oxide (NO) is known for its signiﬁcance as a messenger

molecule in essentially every organ system across many life

forms: mammals, plants, ﬁsh and insects (Giles, 2006). In

humans, NO has important functions in the cardiovascular,

nervous, respiratory and immune systems. It plays vital roles in

protecting the heart, brain and kidneys. NO activities within

these systems include facilitating endothelium-dependent

vasodilation; regulating blood pressure, vascular tone and

compliance; and inhibiting platelet aggregation, vascular

inﬂammatory factors, leukocyte adhesion and smooth muscle

cell proliferation (Mason & Cockcroft, 2006). Metabolic

activity, sexual response, insulin release and the peripheral

nervous system are affected by NO as well (Giles, 2006).

Numerous factors (including aging, hypercholesterolaemia,

smoking and diabetes mellitus) can contribute to the loss of

NO bioavailability and/or lack of NO production, resulting in

endothelial dysfunction (Cai et al., 2005). Diseases and dis-

orders based on NO malfunction include hypertension,

atherosclerosis, cardiovascular disease, asthma, pulmonary

hypertension, erectile dysfunction, preeclampsia and insulin

resistance (Giles, 2006).

In order to ameliorate deleterious conditions arising out of

NO shortfall, numerous NO donors have been developed,

most of which release NO in a single high-concentration burst

(Cai et al., 2005). We have reported a series of N-nitrosated

secondary amines which release NO in a slow, sustained and

rate-tunable manner (Wang et al., 2009; Yu et al., 2011; Curtis

et al., 2013). Furthermore, the released NO has been shown to

inhibit the proliferation of human aortic smooth muscle cells, a

contributing factor to the progression of atherosclerosis (Yu et

al., 2011; Curtis et al., 2013). As part of this continuing study,

we report herein the syntheses and X-ray crystal structures of

four secondary amines that are precursors to slow and

˚

packing leads to separations of ca 3.4 A of the parallel anti

phenyl and aminobenzene rings. 2-Cyano-4-nitro-N-(2-

phenylethyl)aniline, C₁₅H₁₃N₃O₂, (III), differs from (I) only

in having a cyano group in place of the 2-nitro group. The

absence of the adjacent nitro group eliminates the intra-

molecular N—Hꢀ ꢀ ꢀO hydrogen bond. Molecules of (III) adopt

the same anti conformation about the ethyl group as in (I), but

crystallize in the higher-symmetry monoclinic space group

P2₁/n. The molecules are linked into dimers via N—Hꢀ ꢀ ꢀN

amine–cyano hydrogen bonds, while the nitro groups are not

involved in any N—Hꢀ ꢀ ꢀO interactions. Owing to the different

Acta Cryst. (2013). C69, 1383–1389

doi:10.1107/S0108270113025869

# 2013 International Union of Crystallography 1383

organic compounds

sustained NO-releasing agents. These secondary amines, 2,4-

dinitro-N-(2-phenylethyl)aniline, (I), 4,6-dinitro-N,N⁰-bis(2-

phenylethyl)benzene-1,3-diamine, (II), 2-cyano-4-nitro-N-(2-

phenylethyl)aniline, (III), and 4-methylsulfonyl-2-nitro-N-(2-

phenylethyl)aniline, (IV), were prepared by the reactions of 2-

phenylethylamine and four different activated aromatic

mono- and diﬂuorides, namely 2,4-dinitroﬂuorobenzene for

(I), 1,5-diﬂuoro-2,4-dinitrobenzene for (II), 2-cyano-4-nitro-

ﬂuorobenzene for (III) and (3-nitro-4-ﬂuorophenyl)methyl

sulfone for (IV).

temperature of the reaction mixture reached 343 K. The

reaction was allowed to proceed with stirring for 12 h, after

which the DMAC was removed by distillation at reduced

pressure. The crude product was dissolved in dichloromethane

(75 ml) and washed with a saturated sodium chloride solution

(200 ml), followed by two washes with deionized water

(200 ml). The organic layer was separated and anhydrous

magnesium sulfate was added to dry the product. The resulting

mixture was ﬁltered and the ﬁltrate was evaporated at reduced

pressure using a rotary evaporator. Crystals of (I) suitable for

X-ray diffraction were obtained by recrystallization from a

dichloromethane–hexane solution (4:1 v/v) (yield 69%; m.p.

425–427 K). Spectroscopic analysis for (I): ¹H NMR

(300 MHz, DMSO-d₆): ꢁ 8.8 (overlapping peaks, 2H), 8.2 (dd,

J₁= 10.00, J₂= 3.33 Hz, 1H), 7.3–7.2 (overlapping peaks, 6H),

3.7 (q, J = 6.36 Hz, 2H), 2.9 (t, J = 7.58 Hz, 2H); IR (NaCl, ꢂ,

cm^ꢁ1): 3361, 3124, 3070, 3036, 2969, 2938, 2860, 1622, 1592,

1550, 1525, 1501, 1452, 1418, 1380, 1337, 1313.

Compounds (II)–(IV) were prepared in a similar manner,

using 1,5-diﬂuoro-2,4-dinitrobenzene for (II) (yield 62%; m.p.

408–409 K), 2-cyano-4-nitroﬂuorobenzene for (III) (yield

73%; m.p. 427–429 K) and (3-nitro-4-ﬂuorophenyl)methyl

sulfone for (IV) (yield 63%; m.p. 414–416 K) in place of 2,4-

dinitroﬂuorobenzene. Spectroscopic analysis for (II): ¹H NMR

(300 MHz, DMSO-d₆): ꢁ 8.9 (s, 1H), 8.4 (t, J = 5.45 Hz, 2H),

7.3–7.2 (overlapping peaks, 10H), 5.8 (s, 1H), 3.6 (q, J =

6.97 Hz, 4H), 3.0 (t, J = 7.27 Hz, 4H); IR (NaCl, ꢂ, cm^ꢁ1): 3360,

1617, 1540, 1474, 1456, 1348, 1308. Spectroscopic analysis for

1

(III): H NMR (300 MHz, DMSO-d₆): ꢁ 8.4 (d, J = 3.33 Hz,

1H), 8.1 (dd, J₁= 9.70, J₂= 2.73 Hz, 1H), 7.6 (t, J = 5.76 Hz,

1H), 7.3–7.2 (overlapping peaks, 5H), 6.9 (d, J = 9.39 Hz, 1H),

3.5 (q, J = 6.36 Hz, 2H), 2.9 (t, J = 7.58 Hz, 2H); IR (NaCl, ꢂ,

cm^ꢁ1): 3353, 2222, 1610, 1587, 1541, 1507, 1497, 1456, 1337,

1

1321. Spectroscopic analysis for (IV): H NMR (300 MHz,

DMSO-d₆): ꢁ 8.6 (t, J = 5.78 Hz, 1H), 8.5 (d, J = 2.42 Hz, 1H),

7.9 (dd, J₁= 7.58, J₂= 2.12 Hz, 1H), 7.3–7.2 (overlapping

peaks, 6H), 3.7 (q, J = 5.78 Hz, 2H), 3.2 (s, 3H), 2.9 (t, J =

7.58 Hz, 2H); IR (NaCl, ꢂ, cm^ꢁ1): 3369, 3088, 3063, 3023, 2927,

2869, 1616, 1569, 1521, 1466, 1456, 1431, 1411, 1359, 1307.

2.2. Refinement

Crystal data, data collection and structure reﬁnement

details are summarized in Table 1. All H atoms were located

from difference Fourier syntheses and reﬁned isotropically

2. Experimental

˚

without any restraints [N—H = 0.866 (15)–0.900 (17) A and

˚

C—H = 0.898 (13)–1.006 (16) A].

2.1. Synthesis and crystallization

For the synthesis of 2,4-dinitro-N-(2-phenylethyl)aniline,

(I), a 100 ml three-necked round-bottomed ﬂask, equipped

with a magnetic stirrer bar, nitrogen inlet, air condenser and

thermometer, was charged with 2-phenylethylamine (PEA;

0.6370 g, 5.26 mmol), 2,4-dinitroﬂuorobenzene (0.9775 g,

5.25 mmol), potassium carbonate (1.4489 g, 10.48 mmol) and

dimethylacetamide (DMAC, 50 ml). The vials used to weigh

PEA and 2,4-dinitroﬂuorobenzene were washed with DMAC

(5 ml) and the washes were transferred to the reaction vessel.

The reaction vessel was heated using an oil bath until the

3. Results and discussion

2,4-Dinitro-N-(2-phenylethyl)aniline, (I), crystallizes in the

triclinic space group P1 with one independent molecule in the

asymmetric unit (Fig. 1). As we (Payne et al., 2010) and others

(Panunto et al., 1987; Clegg et al., 1994) have observed pre-

viously, the adjacent amine and nitro groups form an intra-

molecular N—Hꢀ ꢀ ꢀO hydrogen bond (Table 2). The ethyl

group adopts an anti conformation [N1—C7—C8—C9 =

ꢂ

1384 Wade et al. C₁₄H₁₃N₃O₄and three analogues

Acta Cryst. (2013). C69, 1383–1389

organic compounds

Table 1

Experimental details.

(I)

(II)

(III)

(IV)

Crystal data

Chemical formula

M_r

C₁₄H₁₃N₃O₄

287.27

C₂₂H₂₂N₄O₄

406.44

C₁₅H₁₃N₃O₂

267.28

C₁₅H₁₆N₂O₄S

320.36

Crystal system, space group

Temperature (K)

Triclinic, P1

100

Triclinic, P1

100

Monoclinic, P2₁/n

100

7.4871 (5), 16.270 (1),

10.8432 (7)

90, 94.384 (1), 90

Tetragonal, I4₁/a

100

20.4639 (13), 20.4639 (13),

14.3952 (14)

90, 90, 90

˚

a, b, c (A)

7.235 (2), 7.282 (2),

13.512 (4)

88.714 (5), 85.131 (5),

67.239 (5)

654.0 (4)

8.1121 (7), 10.1819 (8),

13.1018 (11)

93.466 (1), 106.595 (1),

106.932 (1)

979.88 (14)

2

Mo Kꢃ

0.10

0.20 ꢄ 0.10 ꢄ 0.05

ꢃ, ꢄ, ꢅ (^ꢃ)

3

˚

V (A )

1317.00 (15)

4

Mo Kꢃ

0.09

6028.3 (10)

16

Mo Kꢃ

0.24

Z

Radiation type

2

Mo Kꢃ

0.11

0.20 ꢄ 0.10 ꢄ 0.02

ꢆ (mm^ꢁ1

Crystal size (mm)

)

0.40 ꢄ 0.20 ꢄ 0.10

0.40 ꢄ 0.20 ꢄ 0.20

Data collection

Diffractometer

Bruker APEX DUO

CCD area-detector

diffractometer

Bruker APEX DUO

CCD area-detector

diffractometer

Bruker APEX DUO

CCD area-detector

diffractometer

Bruker APEX DUO

CCD area-detector

diffractometer

Absorption correction

Multi-scan (SADABS;

Sheldrick, 1996)

0.978, 0.998

Multi-scan (SADABS;

Sheldrick, 1996)

0.981, 0.995

Multi-scan (SADABS;

Sheldrick, 1996)

0.964, 0.991

Multi-scan (SADABS;

Sheldrick, 1996)

0.912, 0.955

T_min, T_max

No. of measured, indepen-

dent and observed

[I > 2ꢇ(I)] reﬂections

R_int

9039, 3158, 2288

17364, 6868, 5289

23007, 4732, 4189

52424, 5524, 5155

0.027

0.661

0.018

0.767

0.018

0.765

0.018

0.765

ꢁ1

˚

(sin ꢈ/ꢉ)_max(A

)

Reﬁnement

R[F²> 2ꢇ(F²)], wR(F²), S

No. of reﬂections

No. of parameters

0.040, 0.104, 1.03

3158

242

0.043, 0.121, 1.03

6868

359

0.038, 0.113, 1.04

4732

233

0.029, 0.086, 1.06

5524

263

H-atom treatment

All H-atom parameters

reﬁned

0.29, ꢁ0.26

All H-atom parameters

reﬁned

0.57, ꢁ0.21

All H-atom parameters

reﬁned

All H-atom parameters

reﬁned

0.51, ꢁ0.31

ꢁ3

˚

Áꢊ_max, Áꢊ_min(e A

)

0.56, ꢁ0.20

Computer programs: APEX2 (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008) and CrystalMaker (Palmer, 2013).

ꢁ173.75 (12)^ꢃ], with the result that the phenyl and aniline

rings are nearly parallel. This is the same overall molecular

conformation that was observed in the related compound

N-[2-(2-formylphenyl)ethyl]-2-nitroaniline (Clegg et al., 1994).

Neighbouring molecules of (I) are linked into dimers across

centres of inversion by an intermolecular N—Hꢀ ꢀ ꢀO hydrogen

bond between the amine group of one molecule and the nitro

group of the other (Fig. 2). The amine H1 atom thus partici-

pates in a three-centre hydrogen bond with two nitro O21

atoms, and each O21 atom serves as an acceptor for both intra-

and intermolecular hydrogen bonds (Table 2). The inter-

i

˚

molecular H1ꢀ ꢀ ꢀO21 distance of 2.381 (19) A [symmetry

code: (i) ꢁx + 1, ꢁy, ꢁz + 1] is within the typical range for this

type of N—Hꢀ ꢀ ꢀO amine–nitro interaction (Panunto et al.,

1987). The absence of a more extended hydrogen-bond

network (i.e. chains) is a departure from what we had found in

an earlier study of a related set of arenes with similar func-

tional groups (Payne et al., 2010). Owing to the triclinic

symmetry of (I), all of the arene rings in the crystal structure

are parallel to one another and they are approximately

parallel to the (110) plane. Although the plane-to-plane

˚

distance (ca 3.4 A) is short enough for ꢀ–ꢀ interactions, the

rings are staggered rather than face-to-face, suggesting that

such interactions are not important in this structure.

4,6-Dinitro-N,N⁰-bis(2-phenylethyl)benzene-1,3-diamine,

(II), differs from (I) only in having a second 2-phenylethyl-

amine group in the 5-position on the nitro ring. As in (I), both

amine H atoms form intramolecular N—Hꢀ ꢀ ꢀO hydrogen

Table 2

Hydrogen-bond geometry (A, ) for (I).

ꢃ

˚

D—Hꢀ ꢀ ꢀA

D—H

Hꢀ ꢀ ꢀA

Dꢀ ꢀ ꢀA

D—Hꢀ ꢀ ꢀA

Figure 1

N1—H1ꢀ ꢀ ꢀO21

0.867 (19)

1.983 (19)

2.381 (19)

2.6377 (16)

3.0823 (18)

131.5 (16)

138.3 (16)

The molecular structure of (I), showing atom labels and 70% probability

displacement ellipsoids for non-H atoms. The intramolecular hydrogen

bond is shown as a dashed line.

N1—H1ꢀ ꢀ ꢀO21ⁱ

Symmetry code: (i) ꢁx þ 1; ꢁy; ꢁz þ 1.

ꢂ

Acta Cryst. (2013). C69, 1383–1389

Wade et al.

C₁₄H₁₃N₃O₄and three analogues 1385

organic compounds

Table 3

Hydrogen-bond geometry (A, ) for (II).

ꢃ

˚

D—Hꢀ ꢀ ꢀA

D—H

Hꢀ ꢀ ꢀA

Dꢀ ꢀ ꢀA

D—Hꢀ ꢀ ꢀA

N1—H1ꢀ ꢀ ꢀO21

N5—H5ꢀ ꢀ ꢀO41

N5—H5ꢀ ꢀ ꢀO41ⁱ

0.891 (15)

0.900 (17)

1.935 (15)

1.967 (16)

2.800 (17)

2.6318 (11)

2.6358 (11)

3.5877 (11)

133.8 (13)

129.8 (14)

146.8 (13)

Symmetry code: (i) ꢁx þ 2; ꢁy þ 2; ꢁz þ 1.

ecules are linked into dimers across centres of inversion via

three-centre N—Hꢀ ꢀ ꢀO amine–nitro hydrogen bonds (Fig. 4

and Table 3). The intermolecular H5ꢀ ꢀ ꢀO41ⁱdistance of

˚

2.800 (17) A in (II) [symmetry code: (i) ꢁx + 2, ꢁy + 2, ꢁz + 1]

is signiﬁcantly longer than that in (I), but it is still in the

observed range for a second amine–nitro contact (Panunto et

al., 1987). Although there are two amine groups in (II), only

that involving the gauche 2-phenylethyl group participates in

intermolecular hydrogen bonds. Therefore, as was the case in

(I), there are no hydrogen-bonded chains in (II). The mol-

ecules pack with the nitro and anti-phenyl rings approximately

Figure 2

Molecules of (I) are linked into dimers across centres of inversion by N—

Hꢀ ꢀ ꢀO amine–nitro hydrogen bonds (dashed lines). The view is onto the

(100) plane. [Symmetry codes: (#) x, y + 1, z; ($) ꢁx + 1, ꢁy + 1, ꢁz + 1.]

˚

parallel to (110). Neighbouring rings are ca 3.5 A apart and

overlap more than in (I), suggesting greater ꢀ–ꢀ interaction.

2-Cyano-4-nitro-N-(2-phenylethyl)aniline, (III), differs from

(I) only in having a cyano group in place of the 2-nitro group.

Since the 2-nitro group adjacent to the amine is absent, there

is no intramolecular hydrogen bond in (III). The molecule

adopts the same anti conformation seen in (I) [N1—C7—C8—

C9 = ꢁ171.53 (6)^ꢃ] (Fig. 5). Molecules of (III) are linked into

dimers across centres of inversion by N—Hꢀ ꢀ ꢀN amine–cyano

hydrogen bonds (Fig. 6 and Table 4). The nitro groups are not

involved in any hydrogen bonds. A similar amine–cyano

dimerization was observed in 2,6-bis(ethylamino)-3-nitro-

benzonitrile (Payne et al., 2010), though in that case the

molecules were also joined by three-centre N—Hꢀ ꢀ ꢀO amine–

nitro hydrogen bonds involving the other amine group. In

bonds with the adjacent nitro groups (Table 3). Although the

two halves of the molecule through the central ring are

chemically identical, in the crystal structure the molecule

possesses no internal symmetry (Fig. 3) because the two

2-phenylethyl groups adopt different conformations. One, as

in (I), is anti [N1—C7—C8—C9 = 172.60 (8)^ꢃ], while the other

is gauche [N5—C15—C16—C17 = ꢁ66.94 (10)^ꢃ]. As a result,

the C1–C6 and C9–C14 rings are nearly parallel, but the C17–

C22 ring is approximately orthogonal to the other rings.

The packing of (II) has features in common with that of (I).

Compound (II) also crystallizes in the P1 space group with one

independent molecule in the asymmetric unit, and the mol-

Figure 4

Figure 3

Molecules of (II) are linked into dimers across centres of inversion by

weak N—Hꢀ ꢀ ꢀO amine–nitro hydrogen bonds (dashed lines). The view is

onto the (100) plane. [Symmetry codes: (#) x, y ꢁ 1, z; ($) ꢁx + 2, ꢁy + 1,

ꢁz + 1.]

The molecular structure of (II), showing atom labels and 70% probability

displacement ellipsoids for non-H atoms. Intramolecular hydrogen bonds

are shown as dashed lines.

ꢂ

1386 Wade et al. C₁₄H₁₃N₃O₄and three analogues

Acta Cryst. (2013). C69, 1383–1389

organic compounds

Figure 5

The molecular structure of (III), showing atom labels and 70%

probability displacement ellipsoids for non-H atoms.

Figure 7

The molecular structure of (IV), showing atom labels and 70%

probability displacement ellipsoids for non-H atoms. The intramolecular

hydrogen bond is shown as a dashed line.

nearby arene rings are not parallel to each other. The closest

˚

contacts between the aniline rings (ca 3.4 A) involve rings that

are mostly slipped past each other. In this, i.e. the apparent

lack of strong ꢀ–ꢀ interactions, the structure of (III) is

consistent with (I) and (II).

4-Methylsulfonyl-2-nitro-N-(2-phenylethyl)aniline, (IV), is

modiﬁed from (I) in having a methylsulfonyl group in place of

the 4-nitro group. The amine and 2-nitro groups form the

expected intramolecular hydrogen bond but, unlike (I) and

(III), the 2-phenylethyl group adopts a gauche conformation

[N1—C7—C8—C9 = ꢁ61.20 (8)^ꢃ] (Fig. 7). Such an arrange-

ment was also observed in a 2,4-dinitroaniline derivative in

which the 2-phenylethyl group is functionalized at the ꢃ-ethyl

C atom (Williams et al., 2011). Unlike the other compounds

studied here, there are no intermolecular hydrogen bonds of

any signiﬁcance in the structure of (IV). The closest Hꢀ ꢀ ꢀO

5

4

1

4

1

4

˚

contact, H1ꢀ ꢀ ꢀO22(ꢁy + , x ꢁ , z ꢁ ) [3.26 (2) A], is well

beyond a reasonable Hꢀ ꢀ ꢀA distance for a normal two-centre

hydrogen bond. The absence of amine–sulfone interactions is

surprising, as such hydrogen bonds have been shown to be

favoured in similar systems (Glidewell et al., 2001; Glidewell &

Ferguson, 1996; Bertolasi et al., 1993).

Figure 6

Molecules of (III) are linked into dimers across centres of inversion by

N—Hꢀ ꢀ ꢀN hydrogen bonds (dashed lines) between the amine H and

cyano N atom. [Symmetry code: (#) ꢁx + 1, ꢁy, ꢁz + 2.]

In addition to the lack of intermolecular hydrogen bonding,

the crystal packing in (IV) is substantially different from that

in (I)–(III). First, the compound crystallizes in the tetragonal

system, space group I4₁/a (Z = 16). According to a previous

study of over 29000 organic compounds (Mighell et al., 1983),

only ca 2.9% are tetragonal. Of the 68 tetragonal space groups,

I4₁/a is the second most popular among organic compounds,

with over 11% of the occurrences being in that system.

(III), the single amine H atom is not available for additional

interactions.

The packing in (III) shows some notable differences from

that seen in (I). The compound crystallizes in the monoclinic

space group P2₁/n (Z = 4), which does not require all of the

rings to be oriented in the same direction. Instead, we see

more of a herringbone pattern (Fig. 6) in which most of the

Table 4

Hydrogen-bond geometry (A, ) for (III).

ꢃ

˚

Table 5

Hydrogen-bond geometry (A, ) for (IV).

ꢃ

˚

D—Hꢀ ꢀ ꢀA

D—H

Hꢀ ꢀ ꢀA

Dꢀ ꢀ ꢀA

D—Hꢀ ꢀ ꢀA

D—H

Hꢀ ꢀ ꢀA

Dꢀ ꢀ ꢀA

D—Hꢀ ꢀ ꢀA

N1—H1ꢀ ꢀ ꢀN2ⁱ

0.866 (15)

2.300 (15)

3.0287 (10)

141.9 (12)

N1—H1ꢀ ꢀ ꢀO21

0.882 (16)

1.951 (16)

2.6364 (9)

133.4 (14)

Symmetry code: (i) ꢁx þ 1; ꢁy; ꢁz þ 2.

ꢂ

Acta Cryst. (2013). C69, 1383–1389

Wade et al.

C₁₄H₁₃N₃O₄and three analogues 1387

organic compounds

key factor in making this motif possible, as the phenyl rings are

positioned conveniently around the periphery of the columns.

4. Conclusions

The results of this study, taken together with those of a

previous study of amine- and nitro-substituted arenes (Payne

et al., 2010), indicate that the introduction of changes in

functionalization at a single point in the molecule can result in

substantial changes in the molecular and crystal structures. In

the earlier work, molecules with two amine groups and one

nitro group formed hydrogen-bonded chains, while in the

present work we ﬁnd that molecules with a single amine group

and one or two nitro groups form at most hydrogen-bonded

dimers. In general, it appears that reducing the number of

amine groups from two to one correlates with a reduction in

the dimensionality of the hydrogen-bonding network from

two (chains) to one (dimers). It is true, though, that the

addition of the phenyl rings to the 2-phenylethyl groups could

have played a role in this tendency towards reduced dimen-

sionality. The structure of (III) demonstrates that N—Hꢀ ꢀ ꢀN

amine–cyano hydrogen bonds are preferred over N—Hꢀ ꢀ ꢀO

amine–nitro hydrogen bonds, so the introduction of a cyano

group in these systems will result in a completely different set

of intermolecular interactions. Structures (I) and (IV) show

that changing a single functional group, in this case in the

4-position on the main ring, can lead to a change in the

preferred conformation of the molecule, a disruption in the

hydrogen-bonding pattern and a dramatically different

packing structure.

Transformation of the precursors into NO release agents

involves nitrosation of the amine groups, which would elim-

inate the intramolecular hydrogen bonding. Also, NO release

agents are expected to function in an aqueous solution

environment (i.e. in vivo). Thus, it is probably unlikely that

inter- and intramolecular interactions in the solid-state struc-

tures of the precursors would correlate with the NO release

behaviour. Our recent ﬁndings suggest that the characteristics

of the organic group (length of alkyl chain, presence of alkyl

or aryl substituents) on the former amine N atom bearing the

NO group have the primary effect on the NO release rate (Yu

et al., 2011; Curtis et al., 2013). Given this observation, it would

be interesting to see how the NO release rate changes when

one uses aliphatic cyclic amines of different ring sizes. Since

NO leaves as a radical, it will also be of interest to see how the

release rate changes when one moves from benzene deriva-

tives to aromatic heterocycles and to larger naphthalene and

anthracene-based compounds.

Figure 8

(a) A packing diagram for (IV), showing half of the 16 molecules

belonging to the I-centred tetragonal unit cell. Note the absence of any

intermolecular N—Hꢀ ꢀ ꢀO hydrogen-bonding interactions. (b) The same

eight molecules shown in part (a) form columns along [001] with fourfold

symmetry.

However, this is still only ca 0.34% of the total number of

surveyed organic structures. As required by the 4₁axis, mol-

ecules of (IV) are arranged in columns along the c axis, with

successive molecules rotated by 90^ꢃwith respect to each other

(Fig. 8). The aniline rings are approximately parallel and

slipped somewhat. The separation between the planes is ca

DKM acknowledges ﬁnancial support from the National

Institutes of Health (NIH) through Award No. R15HL106600

from the National Heart, Lung, and Blood Institute (NHLBI).

The content is solely the responsibility of the authors and does

not represent the ofﬁcial views of NHLBI or NIH. The authors

thank the College of Natural Science and Mathematics of the

˚

3.7 A, but this is apparently sufﬁciently favourable to take

precedence over hydrogen bonding. As the views in Fig. 8

suggest, the gauche conformation of the ethyl group may be a

ꢂ

1388 Wade et al. C₁₄H₁₃N₃O₄and three analogues

Acta Cryst. (2013). C69, 1383–1389

organic compounds

Glidewell, C. & Ferguson, G. (1996). Acta Cryst. C 52 , 2528–2530.

Glidewell, C., Harrison, W . T. A ., Low, J. N., Sime, J. G. & Wardell, J. L. (2001).

Acta Cryst. B 57 , 190–200.

University of Toledo for generous ﬁnancial support of the

X-ray diffraction facility.

Mason, R. P . & C ockcroft, J. R. (2006). J. Clin. Hypertens. 8 (Suppl. s12), 40–

52.

Mighell, A. D., Himes, V . L . & Rodgers, J. R. (1983). Acta Cryst. A 39 , 737–740.

Palmer, D. (2013). CrystalMaker . CrystalMaker Software Ltd, Yarnton,

Oxfordshire, England.

Supplementary data for this paper are available from the IUCr electronic

archives (Reference: CU3041). Services for accessing these data are

described at the back of the journal.

Panunto, T. W ., Urbanczyk-Lipkowska, Z., Johnson, R. & Etter, M. C. (1987).

J. Am. Chem. Soc. 109 , 7786–7797.

Payne, T. J., Thurman, C. R., Yu, H., Sun, Q., Mohanty, D. K., Squattrito, P . J .,

Giolando, M.-R., Brue, C. R. & Kirschbaum, K. (2010). Acta Cryst. C 66 ,

o369–o373.

References

Bertolasi, V ., Ferretti, V ., Gilli, P . & B enedetti, P . G. (1993). J. Chem. Soc.

Perkin Trans. 2 , pp. 213–219.

Bruker (2005). APEX2 . Bruker AXS Inc., Madison, Wisconsin, USA.

Cai, T. B., Wang, P . J. & H older, A. A. (2005). Nitric Oxide Donors for

Pharmaceutical and Biological Applications , edited by P . G. W a ng, T. B. Cai

& N. Taniguchi, pp. 3–31 and 59–60. Weinheim: Wiley-VCH.

Clegg, W ., Stanforth, S. P ., Hedley, K. A., Raper, E. S. & Creighton, J. R.

(1994). Acta Cryst. C 50 , 583–585.

Curtis, B., Payne, T. J., Ash, D. E. & Mohanty, D. K. (2013). Bioorg. Med.

Chem. 21 , 1123–1135.

Giles, T. D. (2006). J. Clin. Hypertens. 8 (Suppl. s12), 2–16.

Sheldrick, G. M. (1996). SADABS . University of G o ¨t tingen, Germany.

Sheldrick, G. M. (2008). Acta Cryst. A 64 , 112–122.

Wang, J., Teng, Y.-H., Yu, H., Oh-Lee, J. & Mohanty, D. K. (2009). Polym. J. 41 ,

715–725.

Williams, D. E., Dalisay, D. S., Patrick, B. O., Matainaho, T., Andrusiak, K.,

Deshpande, R., Myers, C. L., Piotrowski, J. S., Boone, C., Yoshida, M. &

Andersen, R. J. (2011). Org. Lett. 13 , 3936–3939.

Yu, H., Payne, T. J. & Mohanty, D. K. (2011). Chem. Biol. Drug Des. 78 , 527–

534.

ꢂ

Acta Cryst. (2013). C69, 1383–1389

Wade et al.

C₁₄H₁₃N₃O₄and three analogues 1389

supplementary materials

Acta Cryst. (2013). C69, 1383-1389 [doi:10.1107/S0108270113025869]

A series of N-(2-phenylethyl)nitroaniline derivatives as precursors for slow and

sustained nitric oxide release agents

Colin B. Wade, Dillip K. Mohanty, Philip J. Squattrito, Nicholas J. Amato and Kristin

Kirschbaum

Computing details

For all compounds, data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (Bruker, 2005); data reduction:

APEX2 (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine

structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalMaker (Palmer, 2013); software used to prepare

material for publication: APEX2 (Bruker, 2005).

(C14H13N3O4) 2,4-Dinitro-N-(2-phenylethyl)aniline

Crystal data

C₁₄H₁₃N₃O₄

Z = 2

M_r= 287.27

Triclinic, P1

F(000) = 300

D_x= 1.459 Mg m⁻³

Melting point: 425 K

Mo Kα radiation, λ = 0.71073 Å

Cell parameters from 11611 reflections

θ = 3.0–32.1°

Hall symbol: -P 1

a = 7.235 (2) Å

b = 7.282 (2) Å

c = 13.512 (4) Å

α = 88.714 (5)°

β = 85.131 (5)°

γ = 67.239 (5)°

V = 654.0 (4) Å³

µ = 0.11 mm⁻¹

T = 100 K

Plate, orange

0.20 × 0.10 × 0.02 mm

Data collection

Bruker APEX DUO CCD area-detector

diffractometer

Radiation source: sealed tube

Graphite monochromator

ω scans

9039 measured reflections

3158 independent reflections

2288 reflections with I > 2σ(I)

R_int= 0.027

θ

_max= 28.0°, θ_min= 3.0°

Absorption correction: multi-scan

(SADABS; Sheldrick, 1996)

h = −9→9

k = −9→9

l = −17→17

T

_min= 0.978, T_max= 0.998

Refinement

Refinement on F²

Least-squares matrix: full

R[F²> 2σ(F²)] = 0.040

wR(F²) = 0.104

242 parameters

0 restraints

Primary atom site location: structure-invariant

direct methods

S = 1.03

3158 reflections

Secondary atom site location: difference Fourier

map

Acta Cryst. (2013). C69, 1383-1389

sup-1

supplementary materials

Hydrogen site location: difference Fourier map

All H-atom parameters refined

w = 1/[σ²(F_o²) + (0.0523P)²+ 0.1059P]

where P = (F_o²+ 2F_c²)/3

(Δ/σ)_max< 0.001

Δρ_max= 0.28 e Å⁻³

Δρ_min= −0.25 e Å⁻³

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 F²against 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 (Å²)

x

y

z

U_iso*/U_eq

O21

O22

O41

O42

N1

0.47421 (16)

0.30058 (15)

0.35861 (18)

0.17704 (17)

0.69604 (18)

0.654 (3)

0.19492 (14)

0.48827 (14)

0.39571 (17)

0.61028 (16)

−0.09321 (17)

−0.062 (3)

0.31155 (16)

0.44961 (18)

0.04072 (19)

0.23875 (19)

0.3712 (2)

0.46231 (7)

0.40811 (8)

−0.04202 (8)

0.07262 (8)

0.33654 (9)

0.3982 (14)

0.39279 (8)

0.04614 (9)

0.26771 (10)

0.29173 (10)

0.21903 (10)

0.2391 (11)

0.12088 (10)

0.09314 (11)

0.0257 (13)

0.16413 (11)

0.1449 (13)

0.31717 (12)

0.2580 (12)

0.3754 (12)

0.30299 (12)

0.3592 (12)

0.2453 (12)

0.29443 (10)

0.37972 (11)

0.4453 (13)

0.37235 (13)

0.4326 (14)

0.27972 (13)

0.2770 (12)

0.19510 (12)

0.1310 (14)

0.20191 (11)

0.0226 (3)

0.0218 (2)

0.0288 (3)

0.0304 (3)

0.0162 (3)

0.032 (5)*

0.0150 (3)

0.0212 (3)

0.0137 (3)

0.0132 (3)

0.0141 (3)

0.018 (4)*

0.0166 (3)

0.0179 (3)

0.021 (4)*

0.0167 (3)

0.027 (4)*

0.0178 (3)

0.018 (4)*

0.021 (4)*

0.0169 (3)

0.015 (4)*

0.014 (4)*

0.0151 (3)

0.0185 (3)

0.025 (4)*

0.0221 (3)

0.034 (5)*

0.0237 (3)

0.026 (4)*

0.0225 (3)

0.031 (5)*

0.0182 (3)

H1

N2

0.41095 (17)

0.31213 (19)

0.61056 (19)

0.46755 (19)

0.3740 (2)

0.280 (2)

N4

C1

C2

C3

H3

0.497 (2)

C4

0.4213 (2)

0.5681 (2)

0.599 (2)

0.3149 (2)

C5

0.1266 (2)

H5

0.092 (2)

C6

0.6582 (2)

0.756 (3)

−0.0059 (2)

−0.133 (3)

−0.2971 (2)

−0.299 (2)

−0.336 (2)

−0.4436 (2)

−0.429 (2)

−0.411 (2)

H6

C7

0.8410 (2)

0.932 (2)

H7A

H7B

C8

0.920 (2)

0.7394 (2)

0.641 (2)

H8B

H8A

C9

0.662 (2)

0.8931 (2)

0.9689 (2)

0.917 (2)

−0.65607 (19)

−0.7611 (2)

−0.699 (2)

−0.9552 (2)

−1.025 (3)

−1.0461 (2)

−1.178 (3)

−0.9442 (2)

−1.014 (3)

−0.7496 (2)

C10

H10

C11

H11

C12

H12

C13

H13

C14

1.1134 (2)

1.161 (3)

1.1825 (2)

1.277 (3)

1.1069 (2)

1.155 (3)

0.9635 (2)

Acta Cryst. (2013). C69, 1383-1389

sup-2

supplementary materials

H14

0.914 (2)

−0.682 (2)

0.1425 (13)

0.025 (4)*

Atomic displacement parameters (Å²)

U¹¹

U²²

U³³

U¹²

U¹³

U²³

O21

O22

O41

O42

N1

0.0317 (6)

0.0234 (6)

0.0441 (7)

0.0346 (7)

0.0168 (6)

0.0154 (6)

0.0282 (7)

0.0113 (6)

0.0140 (7)

0.0129 (6)

0.0182 (7)

0.0217 (7)

0.0152 (7)

0.0135 (7)

0.0130 (7)

0.0119 (6)

0.0188 (7)

0.0190 (8)

0.0138 (7)

0.0172 (7)

0.0177 (7)

0.0159 (5)

0.0124 (5)

0.0303 (6)

0.0196 (6)

0.0101 (6)

0.0131 (6)

0.0195 (7)

0.0122 (6)

0.0112 (6)

0.0108 (6)

0.0151 (7)

0.0183 (7)

0.0127 (7)

0.0108 (7)

0.0121 (7)

0.0126 (7)

0.0167 (7)

0.0156 (7)

0.0110 (7)

0.0196 (7)

0.0188 (7)

0.0157 (5)

−0.0043 (4)

0.0007 (4)

−0.0026 (4)

0.0012 (4)

−0.0063 (5)

−0.0069 (5)

−0.0014 (5)

−0.0004 (5)

−0.0052 (5)

−0.0008 (5)

0.0010 (5)

0.0002 (5)

−0.0021 (6)

0.0029 (6)

0.0028 (6)

−0.0042 (6)

−0.0018 (6)

−0.0002 (5)

−0.0003 (6)

−0.0052 (6)

0.0009 (6)

0.0068 (6)

−0.0007 (6)

0.0024 (4)

−0.0048 (4)

0.0025 (4)

0.0043 (5)

−0.0008 (5)

−0.0009 (5)

0.0036 (5)

−0.0012 (5)

−0.0027 (5)

−0.0014 (5)

0.0020 (5)

−0.0045 (6)

−0.0047 (5)

−0.0003 (6)

−0.0014 (5)

−0.0017 (5)

0.0010 (6)

0.0062 (6)

−0.0032 (6)

−0.0120 (6)

−0.0021 (6)

0.0224 (5)

0.0144 (5)

0.0282 (6)

0.0190 (6)

0.0154 (6)

0.0180 (6)

0.0191 (7)

0.0143 (7)

0.0186 (7)

0.0180 (7)

0.0155 (7)

0.0214 (7)

0.0263 (8)

0.0235 (8)

0.0214 (7)

0.0203 (8)

0.0326 (9)

0.0451 (10)

0.0311 (9)

0.0200 (7)

−0.0161 (5)

−0.0002 (5)

−0.0023 (5)

−0.0046 (5)

−0.0109 (6)

−0.0061 (5)

−0.0050 (5)

−0.0047 (5)

−0.0080 (6)

−0.0104 (6)

−0.0049 (6)

−0.0011 (5)

−0.0024 (5)

−0.0055 (5)

−0.0077 (6)

−0.0073 (6)

−0.0040 (6)

−0.0088 (6)

−0.0091 (6)

N2

N4

C1

C2

C3

C4

C5

C6

C7

C8

C9

C10

C11

C12

C13

C14

Geometric parameters (Å, º)

O21—N2

O22—N2

O41—N4

O42—N4

N1—C1

N1—C7

N1—H1

N2—C2

N4—C4

C1—C6

C1—C2

C2—C3

C3—C4

C3—H3

C4—C5

C5—C6

C5—H5

C6—H6

1.2448 (15)

C7—C8

1.534 (2)

1.2350 (14)

1.2398 (16)

1.2356 (16)

1.3374 (18)

1.4622 (17)

0.867 (19)

1.4433 (17)

1.4482 (18)

1.429 (2)

C7—H7A

C7—H7B

C8—C9

0.989 (16)

0.984 (16)

1.5161 (19)

0.974 (16)

0.967 (16)

1.396 (2)

1.399 (2)

1.395 (2)

0.980 (17)

1.389 (2)

0.966 (19)

1.382 (2)

0.938 (17)

1.395 (2)

0.979 (18)

0.955 (17)

C8—H8B

C8—H8A

C9—C14

C9—C10

C10—C11

C10—H10

C11—C12

C11—H11

C12—C13

C12—H12

C13—C14

C13—H13

C14—H14

1.4369 (18)

1.3850 (19)

1.372 (2)

0.932 (16)

1.406 (2)

1.362 (2)

0.937 (17)

0.948 (17)

C1—N1—C7

C1—N1—H1

125.87 (13)

117.6 (12)

C8—C7—H7A

N1—C7—H7B

110.3 (9)

106.3 (9)

Acta Cryst. (2013). C69, 1383-1389

sup-3

supplementary materials

C7—N1—H1

O22—N2—O21

O22—N2—C2

O21—N2—C2

O42—N4—O41

O42—N4—C4

O41—N4—C4

N1—C1—C6

N1—C1—C2

C6—C1—C2

C3—C2—C1

C3—C2—N2

C1—C2—N2

C4—C3—C2

C4—C3—H3

C2—C3—H3

C3—C4—C5

C3—C4—N4

C5—C4—N4

C6—C5—C4

C6—C5—H5

C4—C5—H5

C5—C6—C1

C5—C6—H6

C1—C6—H6

N1—C7—C8

N1—C7—H7A

116.2 (12)

121.63 (11)

119.07 (11)

119.30 (11)

123.20 (12)

119.13 (12)

117.66 (12)

121.24 (12)

123.14 (12)

115.62 (12)

121.89 (12)

115.84 (11)

122.28 (12)

119.61 (12)

122.3 (9)

C8—C7—H7B

H7A—C7—H7B

C9—C8—C7

109.5 (9)

108.7 (13)

111.05 (11)

110.6 (9)

C9—C8—H8B

C7—C8—H8B

C9—C8—H8A

C7—C8—H8A

H8B—C8—H8A

C14—C9—C10

C14—C9—C8

108.5 (9)

110.1 (9)

111.3 (9)

105.1 (12)

118.80 (13)

120.97 (13)

120.23 (13)

120.58 (14)

119.7 (10)

119.96 (15)

121.3 (11)

118.7 (11)

119.87 (14)

121.9 (11)

118.2 (11)

120.46 (14)

118.1 (10)

121.4 (10)

120.33 (14)

119.1 (10)

120.6 (10)

C10—C9—C8

C11—C10—C9

C11—C10—H10

C9—C10—H10

C12—C11—C10

C12—C11—H11

C10—C11—H11

C13—C12—C11

C13—C12—H12

C11—C12—H12

C12—C13—C14

C12—C13—H13

C14—C13—H13

C13—C14—C9

C13—C14—H14

C9—C14—H14

118.1 (9)

120.74 (13)

118.95 (12)

120.27 (12)

120.01 (13)

120.6 (10)

119.3 (10)

122.00 (13)

119.6 (10)

118.4 (10)

112.67 (12)

109.2 (9)

C7—N1—C1—C6

C7—N1—C1—C2

N1—C1—C2—C3

C6—C1—C2—C3

N1—C1—C2—N2

C6—C1—C2—N2

O22—N2—C2—C3

O21—N2—C2—C3

O22—N2—C2—C1

O21—N2—C2—C1

C1—C2—C3—C4

N2—C2—C3—C4

C2—C3—C4—C5

C2—C3—C4—N4

O42—N4—C4—C3

O41—N4—C4—C3

O42—N4—C4—C5

O41—N4—C4—C5

−0.9 (2)

C3—C4—C5—C6

N4—C4—C5—C6

C4—C5—C6—C1

N1—C1—C6—C5

C2—C1—C6—C5

C1—N1—C7—C8

N1—C7—C8—C9

3.2 (2)

179.47 (12)

−176.80 (13)

3.52 (19)

−174.48 (13)

−0.9 (2)

177.98 (13)

−2.33 (19)

−85.52 (17)

−173.75 (12)

2.6 (2)

−177.05 (12)

−6.70 (18)

173.22 (12)

173.85 (12)

−6.24 (18)

−1.4 (2)

C7—C8—C9—C14

C7—C8—C9—C10

C14—C9—C10—C11

C8—C9—C10—C11

C9—C10—C11—C12

C10—C11—C12—C13

C11—C12—C13—C14

C12—C13—C14—C9

C10—C9—C14—C13

C8—C9—C14—C13

−99.44 (16)

79.65 (16)

0.4 (2)

−178.69 (13)

−0.2 (2)

179.12 (12)

−2.0 (2)

−0.4 (2)

175.69 (12)

−1.2 (2)

0.9 (2)

−0.7 (2)

179.53 (13)

176.52 (13)

−2.7 (2)

0.0 (2)

179.15 (13)

Acta Cryst. (2013). C69, 1383-1389

sup-4

supplementary materials

Hydrogen-bond geometry (Å, º)

D—H···A

D—H

H···A

D···A

D—H···A

N1—H1···O21

N1—H1···O21ⁱ

0.867 (19)

1.983 (19)

2.381 (19)

2.6377 (16)

3.0823 (18)

131.5 (16)

138.3 (16)

Symmetry code: (i) −x+1, −y, −z+1.

(C22H22N4O4) 4,6-Dinitro-N,N′-bis(2-phenylethyl)benzene-1,3-diamine

Crystal data

C₂₂H₂₂N₄O₄

Z = 2

M_r= 406.44

Triclinic, P1

F(000) = 428

D_x= 1.378 Mg m⁻³

Melting point: 408 K

Hall symbol: -P 1

a = 8.1121 (7) Å

b = 10.1819 (8) Å

c = 13.1018 (11) Å

α = 93.466 (1)°

β = 106.595 (1)°

γ = 106.932 (1)°

V = 979.88 (14) Å³

Mo Kα radiation, λ = 0.71073 Å

Cell parameters from 17364 reflections

θ = 2.5–32.7°

µ = 0.10 mm⁻¹

T = 100 K

Parallelpiped, orange

0.20 × 0.10 × 0.05 mm

Data collection

Bruker APEX DUO CCD area-detector

diffractometer

Radiation source: sealed tube

Graphite monochromator

ω scans

17364 measured reflections

6868 independent reflections

5289 reflections with I > 2σ(I)

R_int= 0.018

θ

_max= 33.0°, θ_min= 1.6°

Absorption correction: multi-scan

(SADABS; Sheldrick, 1996)

h = −12→12

k = −15→15

l = −19→19

T

_min= 0.981, T_max= 0.995

Refinement

Refinement on F²

Least-squares matrix: full

R[F²> 2σ(F²)] = 0.043

wR(F²) = 0.121

S = 1.03

6868 reflections

Secondary atom site location: difference Fourier

map

Hydrogen site location: difference Fourier map

All H-atom parameters refined

w = 1/[σ²(F_o²) + (0.0693P)²+ 0.148P]

where P = (F_o²+ 2F_c²)/3

359 parameters

0 restraints

Primary atom site location: structure-invariant

direct methods

(Δ/σ)_max= 0.001

Δρ_max= 0.57 e Å⁻³

Δρ_min= −0.21 e Å⁻³