Nitro functionalized dibromodiazadiene dyes were prepared and fully characterized including X-ray single crystal analysis. Electron deficient dibromodiazadienes were found to be able to act as donors ...of halogen bonding (XB), while the nitro group acted as an acceptor of the XB. Depending on the substituents, the Br···O XB competed with other weak interactions, and for some of the dyes, they even outcompeted the XB involving the nitro group. However, the nitro functionalized dibromoalkenes 6a and 10a, which had only the nitro moiety as the most plausible acceptor of the XB, reliably formed 1D chains via Br⋯O XB. Experimental work was supported by the DFT calculations and topological analysis of the electron density distribution within the framework of Bader’s theory (QTAIM method).
In the title compound, C16H13N7O2, the 3,5-di-methyl-phenyl and 4-nitro-phenyl rings are inclined to the central 2H-1,2,3-triazole ring by 1.80 (7) and 1.79 (7)°, respectively, and to one another by ...2.16 (7)°. In the crystal, the mol-ecules are linked by C-H⋯N hydrogen bonds and π-π stacking inter-actions centroid-to-centroid distances = 3.7295 (9) and 3.7971 (9) Å, forming ribbons along the b-axis direction. These ribbons are connected to each other by weak van der Waals inter-actions and the stability of the crystal structure is ensured. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (31.5%), N⋯H/H⋯N (19.2%), O⋯H/H⋯O (14.5%), N⋯C/C⋯C (10.9%) and C⋯H/H⋯C (10.2%) contacts.
The crystal structures and Hirshfeld surface analyses of three similar azo compounds are reported. Methyl 4-{2,2-di-chloro-1-(
)-phenyl-diazen-ylethen-yl}benzoate, C
H
Cl
N
O
, (
), and methyl ...4-{2,2-di-chloro-1-(
)-(4-methyl-phen-yl)diazen-ylethen-yl}benzoate, C
H
Cl
N
O
, (
), crystallize in the space group
2
/
with
= 4, and methyl 4-{2,2-di-chloro-1-(
)-(3,4-di-methyl-phen-yl)diazen-ylethen-yl}benzoate, C
H
Cl
N
O
, (
), in the space group
with
= 2. In the crystal of (
), mol-ecules are linked by C-H⋯N hydrogen bonds, forming chains with
(6) motifs parallel to the
axis. Short inter-molecular Cl⋯O contacts of 2.8421 (16) Å and weak van der Waals inter-actions between these chains stabilize the crystal structure. In (
), mol-ecules are linked by C-H⋯O hydrogen bonds and C-Cl⋯π inter-actions, forming layers parallel to (010). Weak van der Waals inter-actions between these layers consolidate the mol-ecular packing. In (
), mol-ecules are linked by C-H⋯π and C-Cl⋯π inter-actions forming chains parallel to 011. Furthermore, these chains are connected by C-Cl⋯π inter-actions parallel to the
axis, forming (01) layers. The stability of the mol-ecular packing is ensured by van der Waals forces between these layers.
The copper catalyzed reaction of N-monosubstituted hydrazones with carbon tetrabromide leads to formation of expected dibromodiazadienes and unexpected dibromostyrenes. The experimental and ...theoretical study of the reaction revealed a key role of N-centered radicals, which can eliminate aryl radicals to form the corresponding dibromostyrenes. Alternatively, the oxidation of intermediate N-centered radicals by Cu(II) results in the corresponding diazadienes. These two reaction pathways are competitive directions of the reaction. Consequently, the reaction can be useful for the synthesis of both dibromostyrenes and rare dibromodiazadienes.
C—H⋯π and C—Cl⋯π interactions are the most important intermolecular interactions in the crystal structures of the title compounds.
The crystal structures and Hirshfeld surface analyses of four ...similar azo compounds are reported. (
E
)-1-1-(4-
tert
-Butylphenyl)-2,2-dichloroethenyl-2-phenyldiazene, C
18
H
18
Cl
2
N
2
, (
I
), and (
E
)-1-1-(4-
tert
-butylphenyl)-2,2-dichloroethenyl-2-(4-methylphenyl)diazene, C
19
H
20
Cl
2
N
2
, (
II
), crystallize in the monoclinic space group
C
2/
c
with
Z
= 8, and (
E
)-1-1-(4-
tert
-butylphenyl)-2,2-dichloroethenyl-2-(4-methoxyphenyl)diazene, C
19
H
20
Cl
2
N
2
O, (
III
), in the monoclinic space group
P
2
1
/
c
with
Z
= 4. (
E
)-1-1-(4-
tert
-Butylphenyl)-2,2-dichloroethenyl-2-(3-methylphenyl)diazene, C
19
H
20
Cl
2
N
2
, (
IV
), crystallizes in the triclinic space group
P
with
Z
= 4 and comprises two molecules (
A
and
B
) in the asymmetric unit. In the crystal structures of (
I
) and (
II
), molecules are linked by C—H⋯π and C—Cl⋯π interactions, forming layers parallel to (
02), while molecules of (
III
) are linked by C—H⋯O contacts, C—H⋯π and C—Cl⋯π interactions forming layers parallel to (
02). The stability of the molecular packing is ensured by van der Waals forces between these layers. In the crystal structure of (
IV
), molecules are linked by C—H⋯π and C—Cl⋯π interactions, forming a tri-periodic network.
The crystal structures and Hirshfeld surface analyses of four similar azo compounds are reported. (
E
)-1-1-(4-
tert
-Butylphenyl)-2,2-dichloroethenyl-2-phenyldiazene, C
18
H
18
Cl
2
N
2
, (
I
), and ...(
E
)-1-1-(4-
tert
-butylphenyl)-2,2-dichloroethenyl-2-(4-methylphenyl)diazene, C
19
H
20
Cl
2
N
2
, (
II
), crystallize in the monoclinic space group
C
2/
c
with
Z
= 8, and (
E
)-1-1-(4-
tert
-butylphenyl)-2,2-dichloroethenyl-2-(4-methoxyphenyl)diazene, C
19
H
20
Cl
2
N
2
O, (
III
), in the monoclinic space group
P
2
1
/
c
with
Z
= 4. (
E
)-1-1-(4-
tert
-Butylphenyl)-2,2-dichloroethenyl-2-(3-methylphenyl)diazene, C
19
H
20
Cl
2
N
2
, (
IV
), crystallizes in the triclinic space group
P
\overline{1} with
Z
= 4 and comprises two molecules (
A
and
B
) in the asymmetric unit. In the crystal structures of (
I
) and (
II
), molecules are linked by C—H...π and C—Cl...π interactions, forming layers parallel to (\overline{2}02), while molecules of (
III
) are linked by C—H...O contacts, C—H...π and C—Cl...π interactions forming layers parallel to (\overline{3}02). The stability of the molecular packing is ensured by van der Waals forces between these layers. In the crystal structure of (
IV
), molecules are linked by C—H...π and C—Cl...π interactions, forming a tri-periodic network.
In the title compound, C
16
H
13
N
7
O
2
, the 3,5-dimethylphenyl and 4-nitrophenyl rings are inclined to the central 2
H
-1,2,3-triazole ring by 1.80 (7) and 1.79 (7)°, respectively, and to one ...another by 2.16 (7)°. In the crystal, the molecules are linked by C—H...N hydrogen bonds and π–π stacking interactions centroid-to-centroid distances = 3.7295 (9) and 3.7971 (9) Å, forming ribbons along the
b
-axis direction. These ribbons are connected to each other by weak van der Waals interactions and the stability of the crystal structure is ensured. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H...H (31.5%), N...H/H...N (19.2%), O...H/H...O (14.5%), N...C/C...C (10.9%) and C...H/H...C (10.2%) contacts.
The copper catalyzed reaction of N-monosubstituted hydrazones with carbon tetrabromide leads to formation of expected dibromodiazadienes and unexpected dibromostyrenes. The experimental and ...theoretical study of the reaction revealed a key role of N-centered radicals, which can eliminate aryl radicals to form the corresponding dibromostyrenes. Alternatively, the oxidation of intermediate N-centered radicals by Cu(II) results in the corresponding diazadienes. These two reaction pathways are competitive directions of the reaction. Consequently, the reaction can be useful for the synthesis of both dibromostyrenes and rare dibromodiazadienes.
