Variation in supramolecular arrangements of hydrazones, o-H 2NC6H4CMeNNHC6H4X (XH, o-, m- and p-NO2), derived from o-aminoacetophenone and phenylhydrazines

Article abstract of DOI:10.1016/j.molstruc.2012.04.023

The crystal structures of four hydrazones, 1, derived from phenylhydrazines, XC₆H₄NHNH₂ (XH, o-NO ₂, m-NO₂ or p-NO₂) with 2-aminoacetophenone are reported, as is the mono hydrochloride, (2: Xm-NO₂), of (1: Xm-NO₂). Consistent strong intramolecular hydrogen bonds in 1 are of the type, NH_(amino)?N_(hydrazono), while (1: Xm-NO₂) portrays an additional NH_(hydrazono)?O _(nitro), intramolecular hydrogen bond. Of interest, different sets of strong intermolecular interactions are found even among the nitro derivatives, 1. In (1: Xo-NO₂), the strongest intermolecular interactions are NH_(amino)?O_(nitro) hydrogen bonds, while in (1: Xm-NO₂ and p-NO₂), both NH _(hydrazono)?O_(nitro) and NH _(amino)?N_(amino) are present. These strong intermolecular hydrogen bonds coupled with different combinations of some of CH?O, ππ stacking interactions and NO?π generate different supramolecular arrays for (1: X = nitro): 2-D, 2-D and 3-D, respectively for (1: Xo-NO₂), for (1: Xm-NO₂) and (1: Xp-NO₂). In (1: XH), the major intermolecular interactions are NH_(hydrazono)?N_(amino hydrogen bonds: these, supplemented by weaker NH?π and CH?π interactions, generate a two-dimensional array. While significant changes in the intermolecular interactions result on formation of the salt, (2: Xm-NO₂) from (1: Xm-NO₂), the strong NH_(amino)?N _(hydrazono) intramolecular hydrogen bonds persist. Strong intermolecular hydrogen bonds found in (2: Xm-NO₂) are of the types NH?Cl (both hydrazone and amine), NH_(amino)?O _(nitro): these coupled with weaker CH?O, NO?π, and ππ generate a three dimensional array.

Full text of DOI:10.1016/j.molstruc.2012.04.023

Journal of Molecular Structure 1020 (2012) 16–22
Contents lists available at SciVerse ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Variation in supramolecular arrangements of hydrazones,
o-H2NC6H4CMe@NNHC6H4X (X@H, o-, m- and p-NO2), derived
from o-aminoacetophenone and phenylhydrazines
c
R. Alan Howie a, Thomas C. Baddeley a, James L. Wardell b, , Solange M.S.V. Wardell
⇑
a Department of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen AB24 3UE, Scotland, United Kingdom
b Centro de Desenvolvimento Tecnológico em Saúde (CDTS), Fundação Oswaldo Cruz, (FIOCRUZ), Casa Amarela, Campus de Manguinhos, Av. Brazil 4365, 21040-900 Rio de Janeiro,
RJ, Brazil
c CHEMSOL,1 Harcourt Road, Aberdeen AB15 5NY, Scotland, United Kingdom
a r t i c l e i n f o
a b s t r a c t
Article history:
The crystal structures of four hydrazones, 1, derived from phenylhydrazines, XC6H4NHNH2 (X@H, o-NO2,
m-NO2 or p-NO2) with 2-aminoacetophenone are reported, as is the mono hydrochloride, (2: X@m-NO2),
of (1: X@m-NO2). Consistent strong intramolecular hydrogen bonds in 1 are of the type, NAH(amino)ꢀ ꢀ ꢀ
N(hydrazono), while (1: X@m-NO2) portrays an additional NAH(hydrazono)ꢀ ꢀ ꢀO(nitro), intramolecular hydrogen
bond. Of interest, different sets of strong intermolecular interactions are found even among the nitro
derivatives, 1. In (1: X@o-NO2), the strongest intermolecular interactions are NAH(amino)ꢀ ꢀ ꢀO(nitro) hydro-
gen bonds, while in (1: X@m-NO2 and p-NO2), both NAH(hydrazono)ꢀ ꢀ ꢀO(nitro) and NAH(amino)ꢀ ꢀ ꢀN(amino) are
present. These strong intermolecular hydrogen bonds coupled with different combinations of some of
Received 31 January 2012
Received in revised form 5 April 2012
Accepted 9 April 2012
Available online 20 April 2012
Keywords:
o-Aminophenyl ketones
Hydrazones
CAHꢀ ꢀ ꢀO,
p
Ap
stacking interactions and NAOꢀ ꢀ ꢀp generate different supramolecular arrays for (1:
Supramolecular arrangements
X = nitro): 2-D, 2-D and 3-D, respectively for (1: X@o-NO2), for (1: X@m-NO2) and (1: X@p-NO2). In (1:
X@H), the major intermolecular interactions are NAH(hydrazono)ꢀ ꢀ ꢀN(amino hydrogen bonds: these, supple-
mented by weaker NAHꢀ ꢀ ꢀ
p
and CAHꢀ ꢀ ꢀ
p interactions, generate a two-dimensional array.
While significant changes in the intermolecular interactions result on formation of the salt, (2: X@m-
NO2) from (1: X@m-NO2), the strong NAH(amino)ꢀ ꢀ ꢀN(hydrazono) intramolecular hydrogen bonds persist.
Strong intermolecular hydrogen bonds found in (2: X@m-NO2) are of the types NAHꢀ ꢀ ꢀCl (both hydrazone
and amine), NAH(amino)ꢀ ꢀ ꢀO(nitro): these coupled with weaker CAHꢀ ꢀ ꢀO, NAOꢀ ꢀ ꢀ
p, and pAp generate a
three dimensional array.
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
in addition the structure of the hydrochloride, (2: X@m-NO2), of
(1: X@m-NO2) is also reported, see Fig. 1. Among the aims of this
study were an investigation of the changes arising from the posi-
tioning of the nitro group substituents in 1 and a comparison of
the influence of the o-amino and o-hydroxyl groups in 1 and
o-HOC6H4NHAN@CMeC6H4X (3) on the supramolecular arrays
generated.
Our group, over a period of time, has investigated the influence
of substituents upon the supramolecular structures in several ser-
ies of hydrazones. These series include hydrazones formed from
substituted phenylhydrazines, including phenylhydrazine itself,
and acetone [1], substituted benzaldehydes [2] and 2-hydroxyace-
tophenone [3]. (Pyrazinecarbonyl)hydrazones of substituted benz-
aldehydes [4], arylaldehyde 7-chloroquinoline-4-hydrazones [5]
and N-isonicotinoyl arylaldehyde hydrazones [6] have also been
investigated along with L-serinyl derivatives, (S)-2-hydroxy-1-[N-
(benzylidene)-hydrazinylcarbonyl]ethylcarbamate esters [7]. We
now report the structures of four hydrazones, 1, generated from
XC6H4NHNH2 (X@H, o-, m- or p-NO2) and 2-aminoacetophenone:
2. Results and discussion
2.1. Synthesis
The syntheses involved reactions of an arylhydrazine or its
hydrochloride with an aryl ketone. NMR spectroscopy indicated
that in some cases two species, probably the (E)- and (Z)-isomers,
were present in solution, but only the (E) isomers were found in
the solid state.
⇑
Corresponding author. Tel./fax: +55 2125520435.
E-mail address: j.wardell@abdn.ac.uk (J.L. Wardell).
0022-2860/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.molstruc.2012.04.023

R. Alan Howie et al. / Journal of Molecular Structure 1020 (2012) 16–22
17
Me
Me
Me
X
X
X
NH
NH
NH
N
N
N
+
Cl-
NH3
OH
NH2
1
2
3
Fig. 1. Compounds whose structures are discussed in this paper.
Table 1
2.2. Crystal structures
Dihedral angles (°) between least squares planes in 1–2. R(1) and R(2) denote the
benzene rings in 1–2 defined by C(1)AC(6) and C(9)A(14), respectively. The
orientation of the benzene rings is relative to a reference plane, RP, defined by
C(7)/C(8)/N(1)/N(2), for which the root mean square displacement of the atoms from
the least squares plane lies in the range 0.0024–0.0116 Å.
2.2.1. Molecular geometry
The labelling scheme and connectivity of the atoms are shown
for 1 and 2 in Fig. 2. The bond lengths and bond angles in 1–2
are in the normal ranges for such compounds and are not discussed
further except to note that it is the o-amino group of (1: X@m-NO2)
which is protonated on formation of the corresponding hydrochlo-
ride, (2: X@m-NO2).
Table 1 lists the dihedral angles between the phenyl rings
[C(1)AC(6) and C(9)A(14), rings 1 and 2, respectively] with a refer-
ence plane (RP), defined by C(7), C(8), N(1), N(2). The largest shifts
from overall planarity are exhibited by (1: X@p-NO2) and (2: X@m-
NO2). As indicated by the geometric parameters listed in Table 2,
such a result is not a consequence of the differences in the intra-
molecular hydrogen bonding present in the molecules. Each of
R(1)/RP
R(2)/RP
R(2)/NO2
(1: X@H)
25.2(2)
3.99(14)
6.7(3)
14.3(3)
17.40(6)
20.5(2)
5.75(14)
5.0(3)
9.0(3)
8.77(7)
(1: X@o-NO2)
(1: X@m-NO2)
(1: X@p-NO2)
(2: X@m-NO2)
1.15(17)
7.3(5)
5.8(6)
4.46(15)
the molecules (1: X@H, m-NO2 and p-NO2) exhibit solely a strong
NAH(amino)ꢀ ꢀ ꢀN(hydrazono) intramolecular hydrogen bonds, whereas
(1: X@o-NO2) portrays an additional strong NAH(hydrazono)ꢀ ꢀ ꢀO(nitro)
(1: X = o-NO2)
(1: X = H)
(1: X = p-NO2)
(1: X = m-NO2)
(2: X = m-NO2)
Fig. 2. The labelling and connectivity of the atoms in 1 and 2. Dashed lines represent hydrogen-bonds.

18
R. Alan Howie et al. / Journal of Molecular Structure 1020 (2012) 16–22
Table 2
Parameters (Å, °) for intramolecular hydrogen-bonds in 1–2.
Compound
DAHꢀ ꢀ ꢀA
DAH
Hꢀ ꢀ ꢀA
Dꢀ ꢀ ꢀA
DAHꢀ ꢀ ꢀA
(1: X@H)
N(3)AH(3O)ꢀ ꢀ ꢀN(1)
N(2)AH(2 N)ꢀ ꢀ ꢀO(1)
N(3)AH(3O)ꢀ ꢀ ꢀN(1)
C(11)AH(11)ꢀ ꢀ ꢀO(2)
N(3)AH(3O)ꢀ ꢀ ꢀN(1)
N(3)AH(3O)ꢀ ꢀ ꢀN(1)
N(3)AH(3B)ꢀ ꢀ ꢀN(1)
0.908(19)
0.88
0.81(7)
0.95
0.86(4)
0.95(5)
0.91
2.04(3)
1.95
2.04(7)
2.36
2.01(5)
2.00(5)
1.99
2.711(4)
2.601(7)
2.643(8)
2.692(8)
2.675(6)
2.705(5)
2.6740(17)
130(3)
129
131(6)
100
134(4)
129(3)
131
(1: X@o-NO2)
(1: X@o-NO2)
(1: X@o-NO2)
(1: X@m-NO2)
(1: X@p-NO2)
(2: X@m-NO2)
as well as a weaker CAHꢀ ꢀ ꢀO(nitro) intramolecular hydrogen bond,
see Table 2 and Fig. 2. In the cases of the nitro derivatives of 1,
the nitro group is only slightly out of the plane of the attached phe-
nyl ring, see Table 1. The strong NAH(ammomio)ꢀ ꢀ ꢀN(hydrazono) intra-
molecular hydrogen bonds persists on formation of the salt, (2:
X@m-NO2) from (1: X@m-NO2).
as that at the centre of the unit cell as shown in Fig. 4a. The face
to face dimers, related to one another by unit cell translation, form
stacks, for the choice of origin used in the refinement, propagated
along the 1, 0, z and 1/2, 1/2, z rows. As can be seen in Fig. 4b,
where the dimers are seen approximately end on, connectivity
within and between the stacks, completing two-dimensional con-
nectivity in layers of molecules parallel to (101), is provided by
hydrogen-bonds of the form N(3)AH(3 N)ꢀ ꢀ ꢀN(3’) where N(3) of
the o-NH2 group is both donor and acceptor.
In (1: X@p-NO2), as seen in Fig. 4c, it is the individual molecules,
not dimers, which are related to one another by unit cell transla-
tion in the direction of c to form stacks. There are now two forms
of connection both operating between and within the stacks as
indicated in Fig. 4d. The first is the same N(3)AH(3 N)ꢀ ꢀ ꢀN(3’) as
before. The second consists of two intermolecular hydrogen-bonds
which are of the form N(2)AH(2 N)ꢀ ꢀ ꢀO(1) and C(14)AH(14)ꢀ ꢀ ꢀO(1)
which both utilise the same nitro group oxygen atom as acceptor.
Overall, complete three-dimensional connectivity is attained.
As noted above in Section 2.2.1, the hydrochloride, (2: X@m-
NO2), is formed from (1: X@m-NO2) on protonation of the o-amino
group. The ammonium group acts as a three time donor in inter-
molecular hydrogen-bonding with two chloride ions and to a nitro
oxygen as acceptor, see Table 3. Additionally N(2) in (2: X@m-NO2)
acts as donor for an intermolecular hydrogen-bond now with
another Cl. These four intermolecular hydrogen-bonds together
2.2.2. Supramolecular connectivity
All of the structures exhibit strong intermolecular (or inter-
ionic) hydrogen-bonds of the form XAHꢀ ꢀ ꢀY, where X@O or N
and Y@O, N, Cl and some show weaker interactions, such as
CAHꢀ ꢀ ꢀY (Y@O or
p), listed in Table 3. The cut-off values taken
for the CAHꢀ ꢀ ꢀO weak hydrogen bonds are d(Hꢀ ꢀ ꢀO) < the sum of
the van der Waals radii, 2.72 Å, and CAHꢀ ꢀ ꢀO < 100° [8]. The latter
interactions while weaker still play important roles in the supra-
molecular arrays generated [9]. In (1: X@H) intermolecular hydro-
gen-bonds of the form N(2)AH(2N)ꢀ ꢀ ꢀN(3) link molecules, related
to one another by unit cell translation, to form chains propagated
in the direction of a, which can be seen at y = 0 and 1/2 in
Fig. 3a. Links between the chains to complete two-dimensional
connectivity in layers of molecules parallel to (001) are provided
by weaker CAHꢀ ꢀ ꢀ
p
interactions of the form N(3)AH(3 N)ꢀ ꢀ ꢀCg(1)
and C(5)AH(5)ꢀ ꢀ ꢀCg(2).
The situation in (1: X@o-NO2), shown in Fig. 3b, is generally
similar except that the connectivity in the chains of molecules
related to one another by unit cell translation, now in the direction
of b, is accomplished by hydrogen-bonds of the form
N(3)AH(3 N)ꢀ ꢀ ꢀO(1) and connectivity between the chains complet-
ing two-dimensional connectivity in layers of molecules, again par-
with the weak
p
ꢀ ꢀ ꢀ
p
[Cg(1)ꢀ ꢀ ꢀCg(2), Table 4a] and NAOꢀ ꢀ ꢀ
p
[N(4)AO(2)ꢀ ꢀ ꢀCg(2), Table 4b] contacts create one dimensional
connectivity in double chains propagated in the direction of c as
shown in Fig. 5. The chains are packed side by side in a C-face cen-
tred arrangement which induces the C(5)AH(5)ꢀ ꢀ ꢀO(1) (Table 3)
allel to (001), is provided by a combination of
(Table 4a) and NAOꢀ ꢀ ꢀ contacts [10] (Table 4b). The cut off values
accepted for the NAOꢀ ꢀ ꢀ contacts are d(Oꢀ ꢀ ꢀCg) < 4.0 Å and
< 30.0° [8].
In (1: X@m-NO2) intermolecular hydrogen-bonds of the form
p
ꢀ ꢀ ꢀ
p interactions
intermolecular hydrogen-bond and the Cg(1)ꢀ ꢀ ꢀCg(10)
pꢀ ꢀ ꢀp con-
p
tact (Table 4a) to complete the three-dimensional connectivity of
p
the structure.
c
In the series of hydrazones, 3, derived from 2-hydroxyacetophe-
none and XC6H4NHNH2, previously reported [2], the o-hydroxy
N(2)AH(2 N)ꢀ ꢀ ꢀO(2) and C(10)AH(10)ꢀ ꢀ ꢀO(2) create dimers such
Table 3
Parameters (Å, °) for intermolecular (or interionic) hydrogen-bonds in 1–2. Entries of the form XAHꢀ ꢀ ꢀCg (X@N or C) under the column heading DAHꢀ ꢀ ꢀA indicate XAHꢀ ꢀ ꢀ
p
contacts where Cg(1) and Cg(2) are the centroids of the rings defined by C(1)AC(6) and C(9)AC(14), respectively.
Compound
DAHꢀ ꢀ ꢀA
DAH
Hꢀ ꢀ ꢀA
2.46(4)
2.91(3)
2.69
2.35(7)
2.30
2.19(5)
2.44
2.52
2.32(4)
2.57
2.59
2.25
Dꢀ ꢀ ꢀA
3.177(4)
3.651(3)
3.602(3)
3.112(7)
3.093(6)
3.107(7)
3.247(7)
3.036(5)
3.230(5)
3.375(6)
3.3379(13)
3.1375(13)
2.9519(17)
3.1288(14)
3.1646(19)
DAHꢀ ꢀ ꢀA
138(3)
142(2)
160
143(6)
150
157(4)
143
118
168(4)
142
144
164
(1: X@H)
(1: X@H)
(1: X@H)
N(2)AH(2 N)ꢀ ꢀ ꢀN(3i)
0.89(4)
0.889(19)
0.95
0.90(8)
0.88
0.97(5)
0.95
0.88
0.92(4)
0.95
0.88
0.91
0.91
N(3)AH(3 N)ꢀ ꢀ ꢀCg(1ii)
C(5)AH(5)ꢀ ꢀ ꢀCg(2iii
)
(1: X@o-NO2)
(1: X@m-NO2)
(1: X@m-NO2)
(1: X@m-NO2)
(1: X@p-NO2)
(1: X@p-NO2)
(1: X@p-NO2)
(2: X@m-NO2)
(2: X@m-NO2)
(2: X@m-NO2)
(2: X@m-NO2)
(2: X@m-NO2)
N(3)AH(3 N)ꢀ ꢀ ꢀO(1iv
)
N(2)AH(2 N)ꢀ ꢀ ꢀO(2v)
N(3)AH(3 N)ꢀ ꢀ ꢀN(3vi
C(10)AH(10)ꢀ ꢀ ꢀO(2v)
N(2)AH(2 N)ꢀ ꢀ ꢀO(1vii
)
)
N(3)AH(3 N)ꢀ ꢀ ꢀN(3viii
)
C(14)AH(14)ꢀ ꢀ ꢀO(1ix)
N(2)AH(2 N)ꢀ ꢀ ꢀCl(1)
N(3)AH(3A)ꢀ ꢀ ꢀCl(1x)
)
N(3)AH(3B)ꢀ ꢀ ꢀO(1xi
)
2.30
2.22
2.49
128
176
128
N(3)AH(3C)ꢀ ꢀ ꢀCl(1xii
)
0.91
0.95
C(5)AH(5)ꢀ ꢀ ꢀO(1xiii
)
Symmetry codes: (i) x ꢁ 1, y, z; (ii) ꢁx + 2, y + 1/2, ꢁz + 1; (iii) ꢁx + 1, y ꢁ 1/2, ꢁz + 1; (iv) x, y + 1, z; (v) ꢁx + 1, ꢁy + 2, ꢁz + 1; (vi) ꢁx + 1/2, y ꢁ 1/2, ꢁz + 3/2; (vii) ꢁx + 3/2,
y ꢁ 1/2, z ꢁ 1/2; (viii) ꢁx + 1, ꢁy + 1, z ꢁ 1/2; (ix) ꢁx + 3/2, y ꢁ 1/2, z + 1/2; (x) x, ꢁy + 1, zꢁ1/2; (xi) ꢁx + 1, y, ꢁz + 1/2; (xii) ꢁx + 1, ꢁy + 1, ꢁz + 1; and (xiii) x + 1/2, ꢁy + 1/2,
z + ½.

R. Alan Howie et al. / Journal of Molecular Structure 1020 (2012) 16–22
19
Fig. 3. Intermolecular connectivity (dashed lines) in (a) (1: X@H) and (b) (1: X@o-NO2). The unit cell outlines are shown and selected atoms are labelled.
Table 4
Parameters (Å, °) for further, comparatively weak
respectively.
pꢀ ꢀ ꢀp
and NAOꢀ ꢀ ꢀ
Cgꢀ ꢀ ꢀCg
p intermolecular contacts Cg(1) and Cg(2) are the centroids of the rings defined by C(1)AC(6) and C(9)AC(14),
Compound
Cg(I)ꢀ ꢀ ꢀCg(J)
a
b
c
Cg(I)perp
Cg(J)perp
a.
pꢀ ꢀ ꢀp intermolecular contacts
(1: X@o-NO2
(2: X@m-NO2
(2: X@m-NO2
Cg(1)ꢀ ꢀ ꢀCg(2i)
Cg(1)ꢀ ꢀ ꢀCg(1ii)
Cg(1)ꢀ ꢀ ꢀCg(2i)
3.720(7)
3.6722(10)
3.9019(11)
1.28
0.0
16.19
23.84
17.40
31.10
24.76
17.40
17.53
3.378
3.504
3.721
3.402
3.504
3.341
NAOꢀ ꢀ ꢀCg
Oꢀ ꢀ ꢀCg
Operp
c
NAOꢀ ꢀ ꢀCg
Nꢀ ꢀ ꢀCg
b. NAOꢀ ꢀ ꢀ
p intermolecular contacts
(1: X@o-NO2
N(4)AO(1)ꢀ ꢀ ꢀCg(1i)
3.787(8)
3.6330(19)
3.475
3.456
23.42
17.94
68.1(3)
74.96(11)
3.517(8)
3.5199(17)
(2: X@m-NO2
N(4)AO(2)ꢀ ꢀ ꢀCg(2ii)
Symmetry codes: (i) ꢁx + 1, ꢁy + 1, ꢁz + 1; and (ii) ꢁx + 3/2, ꢁy + 1/2, ꢁz + 1.
Alpha is the dihedral angle between the least squares planes of the overlapping rings. Beta is the angle between the vectors Cgꢀ ꢀ ꢀCg and Cg(I)perp where Cg(I)perp is the
prependicular distance of Cg(I) from the plane of ring J. Similarly
is the angle between the vectors Cgꢀ ꢀ ꢀCg and Cg(J)perp
Symmetry codes: (i) ꢁx, ꢁy + 1, ꢁz + 1; and (ii) ꢁx + 1, y, ꢁz + 1/2.
Operp is the perpendicular distance of the oxygen atom from the ring plane and
c
.
c
is the angle between the vectors Operp and Oꢀ ꢀ ꢀCg.
group, as does the o-amino group in series 1, is involved in strong
hydrogen bonding. Generally, the o-hydroxy group acts as a donor
in forming intramolecular OAHꢀ ꢀ ꢀN(H) hydrogen bonds, and as an
acceptor in forming NAHꢀ ꢀ ꢀO intermolecular hydrogen bonds in
(3: X@H and 4-NO2): interestingly, such intermolecular NAHꢀ ꢀ ꢀO
hydrogen bonds are absent in (3: X@2-NO2 and 3-NO2). As
with the compounds studied in this article, supramolecular
arrangements varied for the individual members of series 3 as a

20
R. Alan Howie et al. / Journal of Molecular Structure 1020 (2012) 16–22
(a)
(b)
(c)
(d)
Fig. 4. Intermolecular connectivity (dashed lines) in (a) and (b) (1: X@m-NO2) and (c) and (d) (1: X@p-NO2). The unit cell outlines are shown and selected atoms are labelled.
MeOH solutions, with source T = 100 °C and desolvation T = 150 °C
and cone voltage 15 V. Daughter peaks were obtained with a colli-
sion voltage of 10 V.
3.2. Synthesis
3.2.1. General procedure
Solutions of an arylhydrazine, or its hydrochloride, and the ke-
tone (1–3 mmol each) in either ethanol or methanol (15–25 ml)
were refluxed for 1 h, rotary evaporated and the residue recrystal-
lised from ethanol, methanol or acetone.
3.2.2. (E)-2-Aminoacetophenone phenylhydrazone (1: X@H)
Fig. 5. Double chain in (2: X@m-NO2). Selected atoms are labelled.
Reagents:
2-Aminoacetophenone
and
phenylhydrazine
(2 mmol) in EtOH (20 ml). Recrystallised from EtOH, m.p.
consequence of different combinations of intermolecular interac-
206–8 °C.
tions, which included NAHꢀ ꢀ ꢀO(H), NAHꢀ ꢀ ꢀO(NO), CAHꢀ ꢀ ꢀO(H),
IR (KBr, cmꢁ1):
m: 3450, 3319, 1615, 1600, 1580.
CAHꢀ ꢀ ꢀO(NO) and CAHꢀ ꢀ ꢀ
p
hydrogen bonds, as well as
pꢀ ꢀ ꢀp stack-
Anal. Found: C, 74.51; H, 6.92; N, 18.38. Calculated for C14H15N3:
C, 74.63; H, 6.71; N, 18.64%.
ing interactions.
3.2.3. (E)-2-Aminoacetophenone 2-nitrophenylhydrazone
(1: X@o-NO2)
3. Experimental
3.1. General
Reagents: 2-Aminoacetophenone and 2-nitrophenylhydr-
azine (2 mmol) in EtOH (20 ml). Recrystallised from EtOH,
m.p. 158–160 °C.
IR spectra were recorded on a Nicolet Magna 760 FTIR instru-
ment. Melting points were measured on a Griffin melting point
apparatus. Elemental analyses were performed with a Perkin Elmer
2400 apparatus. Mass spectra were obtained using a Waters Quattro
Premier Triple quadruple instrument, in ES + mode, with samples in
IR (KBr, cmꢁ1):
m: 3456, 3318, 1620, 1576.
EI+ MS: 293 [1% (M + Na)+], 271 [100% (M + Na)+], 133 [26%
(C8H9N2)+, (2-H2NC6H4CMeN)].

R. Alan Howie et al. / Journal of Molecular Structure 1020 (2012) 16–22
21
Table 5
Crystal data and structure refinement for 1 and 2.
(1: X@H)
(1: X@o-NO2)
(1: X@m-NO2)
(1: X@p-NO2)
(2: X@m-NO2)
Empirical formula
Formula weight
C
14H15N3
C14H14N4O2
270.29
C14H14N4O2
270.29
C14H14N4O2
270.29
C14H15ClN4O2
306.75
225.29
Crystal system, space group
Monoclinic, P21
Triclinic, P-1
Monoclinic, P21/n
Orthorhombic, Pna21
Monoclinic, C2/c
Unit cell dimensions:
a (Å)
b (Å)
c (Å)
5.9544(3)
9.4214(5)
10.8369(6)
90
99.746(3)
90
599.16(6)
2, 1.249
0.076
6.8201(10)
8.633(13)
11.326(18)
81.76(3)
88.29(4)
75.99(4)
640.3(14)
2, 1.402
0.098
14.91(2)
3.898(6)
22.89(4)
90
105.906(15)
90
1279(3)
4, 1.403
0.098
21.666(1)
13.8168(6)
4.1612(1)
90
90
90
1245.68(8)
4, 1.441
0.101
18.3030(4)
10.4042(3)
16.4597(3)
90
114.998 (1)
90
2840.77(12)
8, 1.434
0.279
a
(o)
b (o)
c
(o)
Volume (Å3)
Z, Calculated density (Mg/m3)
Absorpt. coefficient (mmꢁ1
F(000)
)
240
284
568
568
1280
Crystal size (mm)
0.10 ꢂ 0.08 ꢂ 0.04
0.05 ꢂ 0.04 ꢂ 0.01
2.38–26.82
ꢁ8 6 h 6 6
ꢁ11 6 k 6 11
ꢁ14 6 l 6 14
6300/2815
[R(int) = 0.039]
1467
0.08 ꢂ 0.03 ꢂ 0.005
1.79–22.50
ꢁ16 6 h 6 16
ꢁ3 6 k 6 4
ꢁ25 6 l 6 25
7669/1840
[R(int) = 0.103]
925
0.38 ꢂ 0.02 ꢂ 0.02
2.95–27.52
ꢁ28 6 h 6 27
ꢁ9 6 k 6 17
ꢁ5 6 l 6 4
7130/1617
[R(int) = 0.066]
1289
0.36 ꢂ 0.34 ꢂ 0.15
3.16–27.50
ꢁ23 6 h 6 23
ꢁ13 6 k 6 12
ꢁ21 6 l 6 21
17.579/3257
[R(int) = 0.046]
2685
Theta range for data collection (o) 3.47–27.69
Index ranges
ꢁ7 6 h 6 7
ꢁ12 6 k 6 12
ꢁ14 6 l 6 14
7822/1469
[R(int) = 0.088]
1070
Reflections collected/unique
Reflections observed [I > 2r(I)]
Max. and min. transmission
Data/restraints/parameters
Goodness-of-fit on F2
0.9969 and 0.8680
1469/3/165
1.049
0.9990 and 0.6893
2815/0/190
1.107
0.9995 and 0.9922
1840/0/188
0.972
0.9980 and 0.8312
1617/1/188
1.177
0.9593 and 0.8800
3257/0/192
1.060
Final R indices [I > 2
r
(I)]
R1 = 0.055, wR2 = 0.113 R1 = 0.107, wR2 = 0.350 R1 = 0.061, wR2 = 0.157
R1 = 0.090, wR2 = 0.129 R1 = 0.155, wR2 = 0.373 R1 = 0. 129, wR2 = 0.197 R1 = 0.091, wR2 = 0.130 R1 = 0.049, wR2 = 0.099
0.20 and ꢁ0.21 0.40 and ꢁ0.43 0.23 and ꢁ0.24 0.27 and ꢁ0.24 0.27 and ꢁ0.27
R1 = 0.065, wR2 = 0.117 R1 = 0.038, wR2 = 0.093
R indices (all data)
Largest diff. peak and hole (e/Å3)
MSMS on m/z = 271: m/z = 271 [19% (M + H)+], 133 [100%,
(C8H9N2)+].
3.2.6. (E)-2-Aminoacetophenone 3-nitrophenylhydrazone
hydrochloride (2: X@m-NO2)
Anal. Found: C, 62.45; H, 5.01; N, 20.54. Calculated for
C
14H14N4O2: C, 62.21; H, 5.22; N, 20.72%.
Reagents: 2-Aminoacetophenone and 3-nitrophenylhydr-
azine.hydrochloride (2 mmol) in EtOH (20 ml). Recrystal-
lised from Me2CO.
3.2.4. (E)-2-Aminoacetophenone 3-nitrophenylhydrazone (1: X@m-
IR (KBr, cmꢁ1):
m: 3300–2300(v.br), 3258, 1618, 1580, 1535,
NO2)
1515.
Anal. Found: C, 54.97; H, 5.14; N, 18.02. Calculated for
14H15ClN4O2: C, 54.81; H, 4.94; N, 18.26%.
Reagents: 2-Aminoacetophenone and 3-nitrophenylhydr-
azine (2 mmol) in EtOH (25 ml). Recrystallised from EtOH,
m.p. 178–181 °C.
C
3.3. Crystallography
IR (KBr, cmꢁ1):
m: 3460, 3339, 1620, 1605, 1587.
EI+ MS: m/z = 563 [4% (2 M + Na)+], 541 [17% (2 M + H)+, 293
[3% (M + Na)+], 271 [100% (M + Na)+].
In all cases the intensity data were collected at 120(2) K. For (1:
X@o-NO2) and (1: X@m-NO2) the data were obtained with syn-
chrotron radiation [11] (k = 0.6889 Å) at beamline I19 of the EPSRC
Diamond Light Source at the Harwell Science and Innovation Cam-
pus, Didcot, UK, by staff of the National X-ray crystallographic ser-
vice utilising a Rigaku Saturn 724 + detector on a Crystal Logics
diffractometer. Data collection, cell refinement and data reduction
were accomplished with the CrystalClear [12] software package.
For (1: X@o-NO2) only, correction for absorption, by comparison
of the intensities of equivalent reflections, was applied by means
of the programme, SADABS [13].
MSMS on m/z = 271: m/z = 271 [100% (M + H)+], 254 [12%
(M ꢁ 16)+], 208 [22% (M ꢁ 62)+], 134 [47%, (C8H10N2)+], 133
[8%, (C8H9N2)+], 120 [31%], 106 [4%].
Anal. Found: C, 62.39; H, 5.32; N, 20.48. Calculated for
C14H14N4O2: C, 62.21; H, 5.22; N, 20.72%.
3.2.5. (E)-2-Aminoacetophenone 4-nitrophenylhydrazone (1: X@p-
NO2)
Reagents: 2-Aminoacetophenone and 4-nitrophenylhydr-
azine (2 mmol) in EtOH (25 ml). Recrystallised from EtOH,
m.p. 195–6 °C.
For all other cases the data were obtained with Mo Ka radiation
(k = 0.71073 Å) on a Bruker-Nonius KappaCCD area detector dif-
fractometer of the EPSRC X-ray crystallographic service at the Uni-
versity of Southampton, UK. Data collection was carried out under
the control of the program COLLECT [14] and data reduction and
unit cell refinement were achieved with the COLLECT and DENZO
[15] software combination. Correction for absorption was applied
by means of the program SADABS [16]. The structures were solved
by direct methods in SHELXS97 [17] and refined, by full-matrix
least-squares on F2, in SHELXL97 [17], both within the OSCAIL
[18] suite of programs.
IR (KBr, cmꢁ1):
m: 3375, 3328, 1597(br).
EI+ MS: m/z = 563 [2% (2 M + Na)+], 541 [2% (2 M + H)+],, 293
[1% (M + Na)+], 271 [100% (M + Na)+], 133 [7%, (C8H9N2)+].
MSMS on m/z = 271: m/z = 271 [100% (M + H)+], 254 [9%
(M ꢁ 16)+], 208 [5% (M ꢁ 62)+], 206 [16% (M ꢁ 62)+134
[60%, (C8H10N2)+], 133 [14%, (C8H9N2)+], 120 [41%], 106 [3%].
Anal. Found: C, 62.35; H, 5.17; N, 20.57. Calculated for
C14H14N4O2: C, 62.21; H, 5.22; N, 20.72%.

22
R. Alan Howie et al. / Journal of Molecular Structure 1020 (2012) 16–22
Coordinates of the hydrogen atoms of all of the NH2 groups in 1,
CAHꢀ ꢀ ꢀO(NO), NAHꢀ ꢀ ꢀO(H), NAHꢀ ꢀ ꢀO(NO) and CAHꢀ ꢀ ꢀ
bonds, as well as stacking interactions.
ꢀ ꢀ ꢀ
p hydrogen
the NH group in (1: X@H) were obtained from difference maps and
refined freely. All other hydrogen atoms were placed in calculated
positions with XAH distances (X@O, N or C) of Å 0.84, 0.88, 0.91,
0.95 or 0.98 Å for OH, NH or NH3 groups or aryl or methyl hydrogen,
respectively, and refined with a riding model. For all hydrogen
atoms Uiso(H) was set to kUeq(X) with k = 1.5 for NH3 and methyl
groups and H2O and 1.2 otherwise. The rotational orientations of
the methyl and NH3 groups were also refined. The refinements of
(1: X@H) and (1: X@p-NO2) were carried out, as is the normal
practice for non-centrosymmetric structures containing no atom
of higher atomic number than that of oxygen, with merged inten-
sity data so that the absolute structures are indeterminate and
p p
Acknowledgements
The use of the EPSRC X-ray crystallographic service at South-
ampton and the valuable assistance of the staff there is gratefully
acknowledged. We thank CAPES for financial support.
Appendix A. Supplementary data
Full details of the crystal structure determinations in cif format
are available in the online version, at doi: (to be inserted), and have
also been deposited with the Cambridge Crystallographic Data
Centre with deposition numbers 852597–852600 and 852602 for
refinements of (1: X@H), (1: X@o-NO2), (1: X@m-NO2), (1: X@p-
NO2) and (2: X@m-NO2) respectively. Copies of these can be ob-
tained free of charge on written application to CCDC, 12 Union
Road, Cambridge, CB2 1EZ, UK (fax: +44 1223 336033); on request
by e-mail to deposit@ccdc.cam.ac.uk or by access to http://
www.ccdc.cam.ac.uk. Supplementary data associated with this
article can be found, in the online version, at http://dx.doi.org/
10.1016/j.molstruc.2012.04.023.
the Flack
x parameters [19] meaningless and therefore not
reported. In the case of (1: X@H) correction for extinction was ap-
plied where the coefficient k in the correction of the form
Fcꢃ = kFc[1 + 0.001 ꢂ Fc2k3/sin(2h)]ꢁ1/4 was refined to the value of
0.047(12). The program ORTEP-3 for Windows [20] has been used
in the preparation of the Figures in which ellipsoids are drawn at
the 50% probability level and hydrogen atoms, where shown, are
represented as small spheres of arbitrary radii. Where colour
coding is used C, Cl, N and O are shown as open, green, blue and
red ellipsoids, respectively. Programs SHELXL97 [17] and PLATON
[8] were used in the calculation of molecular geometry. Hydrogen
bonds of the form CAHꢀ ꢀ ꢀX (X@Cl or O) were identified by PLATON
but their geometric parameters were calculated by SHELXL97.
Crystal data and structure refinement details are listed in Table 5
for 1 and 2.
References
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4. Conclusions
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Consistant strong intramolecular hydrogen bonds present in 1
are of the type, NAH(amine)ꢀ ꢀ ꢀN(hydrazone), while (1: X@o-NO2) por-
trays an additional NAH(hydrazone)ꢀ ꢀ ꢀO(nitro) intramolecular hydro-
gen bond. Different sets of strong intermolecular interactions are
found even among the nitro derivatives, 1. In (1: X@o-NO2), the
strongest intermolecular interactions are NAH(amine)ꢀ ꢀ ꢀO(nitro)
hydrogen bonds, while in (1: X@m-NO2 and p-NO2), both
NAH(hydrazone)ꢀ ꢀ ꢀO(nitro) and NAH(amine)ꢀ ꢀ ꢀN(amino) are present. These
strong intermolecular hydrogen bonds coupled with different com-
[8] A.L. Spek, J. Appl. Crystallogr. 36 (2003) 7–13.
[9] K. Merz, V. Vasylyeva, CrystEngComm. 12 (2010) 3989-4002; D.M.P. Mingos
(Ed.), Supramolecular Assembly via Hydrogen Bonds I and II (Structure and
Bonding, vols. 108 and 111), Springer, Berlin/Heidelberg, 2004; G.R. Desiraju, T.
Steiner, The Weak Hydrogen Bond, Oxford University Press, New York, 1999;
M. Nishio, CrystEngComm.6 (2004) 130–158.
[10] L. Huang, L. Massa, J. Karle, Proc. Natl. Acad. Sci. 105 (2008) 13720–13723.
[11] W. Clegg, J. Chem. Soc., Dalton Trans. (2000) 3223–3232.
[12] CrystalClear, Rigaku Inc., The Woodlands, Texas, USA, 2010.
[13] SADABS, Bruker AXS Inc., Madison, USA, 2008.
[14] R.W.W. Hooft, COLLECT, Data Collection Software. Nonius BV, Delft, The
Netherlands, 1998.
[15] Z. Otwinowski, W. Minor, Processing of X-ray diffraction data collected in
oscillation mode, in: C.W. Carter Jr, R.M. Sweet (Eds.), Methods in Enzymology,
Macromolecular Crystallography, Part A, vol. 276, Academic Press, New York,
1997, pp. 307–326.
binations of some of CAHꢀ ꢀ ꢀO,
p
ꢀ ꢀ ꢀ
p stacking interactions and
NAO— generate different supramolecular arrays. In (1: X@H),
p
the major intermolecular interactions are NAH(hydrazone)ꢀ ꢀ ꢀN(amine)
hydrogen bonds. While significant changes in the intermolecular
interactions result on formation of the salt, (2: X@m-NO2) from
(1: X@m-NO2), the strong NAH(ammonio)ꢀ ꢀ ꢀN(hydrazone) intramolecu-
lar hydrogen bonds persist. Strong intermolecular hydrogen bonds
found in (2: X@m-NO2) are of the types NAHꢀ ꢀ ꢀCl (both hydrazone
and amine), NAH(amine)ꢀ ꢀ ꢀO(nitro).
In the series of hydrazones, 3, derived from 2-hydroxyacetophe-
none and XC6H4NHNH2, previously reported [2], the hydroxy
groups formed strong intramolecular OAHꢀ ꢀ ꢀN(H) hydrogen
bonds for all compounds. As with the compounds studied in this
article, supramolecular arrangements varied for the individual
members of series 3 as a consequence of different combinations
of intermolecular interactions, which included CAHꢀ ꢀ ꢀO(H) and
[16] G.M. Sheldrick, SADABS Version 2007/2, Bruker AXS Inc., Madison, Wisconsin,
USA, 2007.
[17] G.M. Sheldrick, Acta Crystallogr. A 64 (2008) 112–122.
[18] P. McArdle, P. OSCAIL for Windows, Version 1.0.12, Crystallography Centre,
Chemistry Department, NUI Galway, Ireland, 2006.
[19] H.D. Flack, Acta Crystallogr. A 39 (1983) 876–881.
[20] L. Farrugia, J. Appl. Crystallogr. 30 (1997) 565.