Double Bond Distance Research Articles

Quantum computational, spectroscopic investigation, molecular docking, and in vitro pharmacological studies of sulfonamide Schiff base

A new Schiff base, (E)-4-((3,5-dibromo-2-hydroxybenzylidene)amino)-N-(5-methylisoxazol-3-yl)benzenesulfonamide was synthesized and characterized by various physico-chemical, X-ray crystallography and DFT methods. The experimental findings were compared with the computed data. The characteristic azomethine band was found at 1616 cm−1 in the experimental FTIR spectrum. The double bond distance between C7=N1 was 1.277(5) Å. Single X-ray crystallography data indicated that the crystal system of the compound was monoclinic with space group P21/c. The experimental values were well correlated with the computed ones. The kinetic stability of the compound was high due to the larger HOMO-LUMO energy gap. Molecular docking and POM (Petra/Osiris/Molinspiration) investigation of the compound were also performed. POM analysis identified one antibacterial and two antitumor pharmacophore sites in the compound. It exhibited higher binding energy than the reference drug in molecular docking study. The compound followed Lipinski's rule of five and exhibited promising drug-like character and drug score. Moreover, in vitro anticancer, antibacterial, antifungal, anti-inflammatory and antioxidant properties of the compound were also carried out. It showed good antibacterial effects against S. aureus and S. typhi strains. In case of antifungal activity, the compound showed moderate inhibitory activity against both A. niger and A. flavus strains. Besides, it has the capability to stabilize the human red blood cell membrane in hypotonic solution and protect hemolysis. The highest cytotoxic activity of the compound with IC50 value of 65.344 μg/mL was observed against A549 lung cancer cells. Finally, the compound showed moderate antioxidant activity with IC50 value of 4.25 μM.

A Cyclic Iminoborane-NHC Adduct: Synthesis, Reactivity, and Bonding Analysis.

Lewis-base coordinated iminoborane adducts, in contrast to their isoelectronic analogue imines, remain largely unexplored given the lack of efficient synthetic strategies for generating robust compounds. Herein, we report the preparation of a cyclic amino iminoborane carbene complex 2 obtained in quantitative yield by adding NHC to the 1,8-(trimethylsilyl)aminonaphthalene complex of boron 1 to induce the elimination of trimethylsilyl chloride (TMSCl). The iminoborane-NHC adduct 2 shows unprecedented thermal stability both in the solid and solution phases, due to the rigid, pre-established geometry of the 1,8-diaminonaphthalene scaffold. Theoretical calculations reveal an exceptionally strong iminoborane-NHC bond as a consequence of the enhanced boron-center acidity in combination with the lower steric and electronic shielding. We show that the chemical bond can be understood as donor-acceptor interaction, leading to a different kind of electronic situation of the B═N π-bond. The high conjugation between the pz-lone pair of the tricoordinated sp2 hybridized N atom and the B═N π-system results in a particularly long B═N double bond distance. Taking advantage of the pendant lone pair of the dicoordinated sp2 hybridized N atom, the iminoborane-NHC adduct gives access to NHC-stabilized borenium cation 3 through the reaction with trimethylsilyl triflate (Me3SiOTf) or to the gallium adduct 4 by reacting with GaCl3. Incorporating an iminoborane functional group into a π-conjugated system brings a new bonding situation for broadening the scope of BN-containing polyaromatic systems.

Crystal structure, hydrogen bonding, Hirshfeld surface analysis and inhibition efficiency of a Schiff base 2-methoxy-6-(naphthalene-2-yliminomethyl)-phenol

Abstract The asymmetric unit of Schiff base of the title molecule, C18H15NO2, was synthesized from naphthalen-2-ylamine and 2‑hydroxyl-3‑methoxy-benzaldehyde. The two phenyl rings (naphthyl and salicylaldehyde) and the azomethine group are practically co-planar, the dihedral angle between the benzenaldehyde moiety and amino phenyl plane is 14.36(9)°. An interamolecular O2−H1A•••N2 hydrogen bond generates the S(6) ring motif. The double bond distance (N2−C11; 1.281(2)A) and the bond angle (C2−N2−C11;122.86(15)°) of the title Schiff base agreed with similar azomethines derivatives. Title crystal structure is mainly stabilized by the C − H•••O and π•••π interactions. The rings are parallelly displaced in which that π−stacking interaction is an offset or slipped stacking. The ring normal and the vector between the ring centroids form an angle of about 15.63° up to centroid-centroid distance of 3.9982(11)A. The intermolecular interactions were quantified using PIXEL and Hirshfeld surface analysis. The quantum chemical calculations were performed to understand their electronic properties and to elucidate the chemical reactivity.

Crystallographic and spectroscopic characterization of a mixed actinide-lanthanide carbide cluster stabilized inside an Ih(7)-C80 fullerene cage.

A mixed actinide-lanthanide cluster fullerene, Sc2UC@Ih(7)-C80, was isolated and fully characterized. For the first time, the single crystal X-ray crystallographic analysis confirms a novel actinide-lanthanide cluster Sc2UC stabilized inside an Ih(7)-C80 cage. Moreover, the U[double bond, length as m-dash]C double bond distance is 2.01 Å, the shortest U[double bond, length as m-dash]C bond confirmed by crystallography so far.

NHC-Stabilized Silicon-Carbon Mixed Cumulene.

The NHC-stabilized silicon-carbon mixed cumulene (Me3Si)2C═Si(IPr)═Si(IPr)═C(SiMe3)2 (3, IPr = 1,3-diisopropyl-4,5-dimethyl-imidazol-2-ylidene) has been prepared by reaction of Ar(SiMe3)NK with the NHC-stabilized silene (Me3Si)2C═Si(SiMe3)Cl(IPr) (2) in toluene at low temperature via the elimination of trimethylsilyl and chloride groups from 2. X-ray crystal analysis of 3 indicated the formal C═Si═Si═C cumulene skeleton with the short Si-Si double bond distance of 2.1896(10) Å. DFT calculations disclosed its zwitterionic character. Reaction of 3 with diphenylacetylene resulted in the formation of a silatriafulvene with an exocyclic NHC-stabilized silene moiety.

Single-Step Substitution of all the α, β-Positions in Pyrrole: Choice of Binuclear versus Multinuclear Complex of the Novel Polydentate Ligand

The α and β-positions of pyrrole were substituted with 3,5-dimethylpyrazolylmethyl groups in a single step that involved the reaction between 2,5-dimethylaminomethylpyrrole and 3,5-dimethylpyrazole-1-carbinol, affording 2,3,4,5-tetrakis(3,5-dimethylpyrazol-1-ylmethyl)pyrrole LH in 40% yield. The coordination chemistry of this new polydentate ligand LH was explored by synthesizing several Pd(II), Cu(I), and Ag(I) complexes. When LH was used as a neutral ligand with [Pd(COD)Cl2], AgBF4, and CuX (X = Cl and I), compartmental type binuclear Pd(II) and Ag(I) complexes such as [Pd2Cl4(μ-C4HN-2,3,4,5-(CH2Me2pz)4-N,N,N,N)] and [Ag2(μ-C4HN-2,3,4,5-(CH2Me2pz)4-N,N,N,N)(CH3CN)2](2+)[BF4(-)]2 and cage-like copper(I) complexes [Cu2(μ-X)(μ-C4HN-2,3,4,5-(CH2Me2pz)4-N,N,N,N)](+)[CuX2](-) (X = Cl and I) containing a halide ion bridging in a bent fashion were obtained, respectively. Conversely, when the same metal precursors were treated with LH in the presence of n-BuLi, the multinuclear complexes [Pd2Cl3(μ-C4N-2,3,4,5-(CH2Me2pz)4-N,N,N,N,N)], [(Cu2(μ-I){μ-C4N-2,3,4,5-(CH2Me2pz)4-N,N,N,N,N})2Cu](+)I(-), and [Ag4(μ-C4N-2,3,4,5-(CH2Me2pz)4-N,N,N,N)2](2+)[BF4(-)]2 were obtained. In addition, the treatment of LH with [Pd(OAc)2] gave the mononuclear complex, [Pd(OAc)(C4N-2,3,4,5-(CH2Me2pz)4-N,N,N)]. The chloride analogue of this complex was obtained by the reaction of LH with [Pd(COD)Cl2] in the presence of triethylamine. The structures of all complexes were determined by single-crystal X-ray diffraction analyses, which revealed interesting structural features, including pyrazole arms adopting different conformations with respect to the pyrrole ring plane and linear two- and three-coordinated copper(I) and silver(I) atoms exhibiting weak interactions between the metal and the pyrrolic carbon atoms and Ag(I)···Ag(I) interactions. The observed shorter metal pyrrolide nitrogen (M-N) bond distances and the elongation of the C-C double and single bond distances of the pyrrole ring in these complexes probably indicates the presence of π-donation/π-back bonding between the metal and the pyrrole ring. These multinuclear complexes are novel, and their formations are favored by the multidentating nature of the ligand LH.

Manganese(II) and zinc(II) complexes of 4-phenyl(2-methoxybenzoyl)-3-thiosemicarbazide: Synthesis, spectral, structural characterization, thermal behavior and DFT study

The ligand 4-phenyl(2-methoxybenzoyl)-3-thiosemicarbazide (Hpmt), forms isostructural [Mn(pmt)2(o-phen)] (1) and [Zn(pmt)2(o-phen)] (2) complexes containing o-phen as coligand which have been characterized by analytical, spectroscopic (IR, UV–Vis, NMR), magnetic susceptibility, TGA and single crystal X-ray data. Both complexes crystallize in monoclinic systems with the space group P2/n. The complexes have distorted octahedral geometry around the metal center. The ligand in the complexes is coordinated through the deprotonated hydrazinic nitrogen and carbonyl oxygen. The hydrazinic nitrogen coordinates with a shorter M–N distance than the o-phen nitrogen and bond lengths in the chelate ring systems are intermediate between single and double bond distances, suggesting considerable delocalization of charge. There is a good agreement between the geometrical parameters obtained by X-ray crystallography to those generated by DFT method. The thermal degradations of complexes 1 and 2 have been investigated by thermogravimetric analyses which indicate that the final residues left are Mn(NCO)2 and Zn(NCSNH)2. The small HOMO–LUMO energy gap suggests low excitation energy for the complexes.

(5Z,7Z,9Z)-5,10-Dibromobenzo[8]annulene

In the structure of the title compound, C12H8Br2, the two bromine substituents are oriented exo to the boat-shaped cyclo­octa­tetra­ene at the two ring sites that are β to the ring fusion positions. The average Br—C bond distance is 1.919 (2) Å, the average distance for C=C double bonds that are Br substituted is 1.328 (2) Å, while the other two double-bond distances are 1.327 (2) and 1.398 (2) Å for the non-fused and fused bonds, respectively. Each type of ring inter­atomic distance is within s.u. of the average values for the four known structures, including the title compound, of benzo-fused cyclo­ocata­tetra­enes that are not coordinated to a metal atom. The crystal structure features short Br⋯Br [3.6620 (3) Å] and C⋯H [2.834 (2) and 2.841 (2) Å] contacts.

Binuclear butadiene chromium carbonyls: Comparison with their trimethylenemethane isomers

Butadiene is known to form a chromium carbonyl complex (η4-C4H6)Cr(CO)4, which has been structurally characterized by X-ray crystallography. The structures and energetics of the butadiene chromium carbonyl complexes (C4H6)Cr(CO)m (m=5, 4, 3, 2) and (C4H6)2Cr2(CO)n (n=7, 6, 5) have now been investigated by density functional theory. The lowest energy (C4H6)2Cr2(CO)7 structure is a singlet singly bridged structure with a Cr–Cr single bond distance of ∼3.1Å. This structure is predicted to be disfavored with respect to dissociation into mononuclear fragments. The lowest energy singlet (C4H6)2Cr2(CO)6 structure is an unbridged structure with a CrCr double bond distance of ∼2.7Å. However, a doubly bridged isomeric singlet (C4H6)2Cr2(CO)4(μ-CO)2 structure with two bridging CO groups and a similar CrCr double bond lies only slightly higher in energy. Related triplet (C4H6)2Cr2(CO)6 structures with longer Cr–Cr distances of ∼3.0Å corresponding to formal single bonds are comparable in energy to the singlet structures. The hexacarbonyl (C4H6)2Cr2(CO)6 is predicted to be energetically disfavored with respect to disproportionation into (C4H6)2Cr2(CO)7+(C4H6)2Cr2(CO)5. The lowest energy (C4H6)2Cr2(CO)5 structure has all terminal CO groups and a short CrCr triple bond distance of ∼2.4Å. A higher energy (C4H6)2Cr2(CO)5 structure by ∼4kcal/mol has a four-electron donor η2-μ-CO group and a CrCr double bond distance of ∼2.7Å. These (C4H6)2Cr2(CO)n (n=7, 6, 5) structures are similar to the isomeric [(CH2)3C]2Cr2(CO)n structures that are previously reported except for some differences in the arrangements of the bridging carbonyl groups.

New Isolable Dialkylsilylene and Its Isolable Dimer That Equilibrate in Solution

The new isolable dialkylsilylene 3 bearing a bidentate alkyl substituent was synthesized. Recrystallization of silylene 3 gave yellow crystals of 3 and orange-red crystals of tetraalkyldisilene 4, a dimer of 3. In the solid state, 3 exists as a monomer with a closest distance of 6.745 Å between dicoordinate silicon atoms, while disilene 4 has a remarkably long Si═Si double bond distance of 2.252 Å. An equilibrium between 3 and 4 in solution was observed by NMR and UV-vis spectroscopies, and the thermodynamic parameters of the equilibrium were estimated to be ΔH = -36 ± 3 kJ mol(-1) and ΔS = -170 ± 15 J mol(-1) K(-1). Analysis of the percent buried volume, a measure of the steric demand around the divalent silicon, showed that the flexible steric bulkiness of the alkyl substituent of 3 and 4 allows the reversible dimerization of silylene 3 to disilene 4 and the isolation of both species.

Open chains versus closed rings: Comparison of binuclear butadiene cobalt carbonyls with cyclic hydrocarbon analogs

The reaction of Co2(CO)8 with butadiene has long been known to give the binuclear (C4H6)2Co2(CO)2(μ-CO)2. In addition, other (diene)2Co2(CO)2(μ-CO)2 derivatives have been synthesized. In this connection the binuclear butadiene cobalt carbonyls (C4H6)2Co2(CO)n (n=4, 3, 2, 1) have now been investigated by density functional theory. For (C4H6)2Co2(CO)4 several doubly carbonyl bridged stereoisomers were found differing only in the arrangements of the butadiene ligands and with predicted Co–Co single bond distances in the range 2.53–2.61Å. A similar multiplicity of stereoisomers is not possible for the corresponding cyclobutadiene derivative (C4H4)2Co2(CO)4. The lone unbridged (C4H6)2Co2(CO)4 structure lies ∼13kcal/mol above the lowest energy doubly bridged isomer with a significantly longer Co–Co distance of 2.74Å. For (C4H6)2Co2(CO)3 the lowest energy structures are doubly carbonyl bridged structures with CoCo double bond distances in the range 2.45–2.51Å. However, triply carbonyl bridged (C4H6)2Co2(μ-CO)3 structures with significantly shorter CoCo distances of 2.24–2.30Å are also found. For (C4H6)2Co2(CO)2 several structures with bridging butadiene ligands and terminal carbonyl groups are energetically competitive with those with bridging carbonyl groups and terminal butadiene ligands, unlike the corresponding cyclobutadiene complexes. The lowest energy singlet (C4H6)2Co2(CO) has a two-electron donor bridging carbonyl group and an extremely short Co–Co distance of 2.13Å suggesting the formal quadruple bond required to give each cobalt atom the favored 18-electron configuration. This differs from the cyclobutadiene analog (C4H4)2Co2(CO) in which the bridging carbonyl group is a four-electron donor η2-μ-CO group and the cobalt-cobalt distance is much longer at ∼2.5Å.

Unsaturation in binuclear cyclopentadienylrhodium carbonyls: Comparison with their cobalt analogs

The Cp 2Rh 2(CO) n ( n = 4, 3, 2, 1) derivatives have been examined by density functional theory using the BP86 and MPW1PW91 functionals. The known tricarbonyl Cp 2Rh 2(CO) 3 is predicted to have a singly bridged structure with a predicted Rh–Rh single bond distance of ∼2.70 Å in close agreement with the experimental value of 2.68 Å, determined by X-ray crystallography. In contrast to the cobalt analog, no evidence for a triply bridged Cp 2Rh 2(μ-CO) 3 structure was found. The known dicarbonyl Cp 2Rh 2(CO) 2 is predicted to have a doubly bridged structure with a predicted Rh Rh double bond distance of 2.58 Å in close agreement with the experimental Rh Rh double bond distance of 2.564 Å, found by X-ray crystallography for the permethylated derivative (η 5-Me 5C 5) 2Rh 2(μ-CO) 2. The monocarbonyl Cp 2Rh 2(CO) is predicted to have a four-electron donor bridging carbonyl group with a Rh–O distance of ∼2.5 Å and a Rh Rh double bond distance of ∼2.54 Å. This differs from Cp 2Co 2(CO) which was previously predicted to have only a two-electron donor bridging carbonyl group with a long Co⋯O distance and a short Co Co distance of ∼2.0 Å suggesting a formal triple bond. For Cp 2Rh 2(CO) 4 doubly bridged trans and cis isomers were found within ∼1.0 kcal/mol in energy with non-bonding Rh⋯Rh distances of ∼3.2 Å. However, these Cp 2Rh 2(CO) 4 isomers are predicted to be unstable with respect both to CO loss to give Cp 2Rh 2(CO) 3 and to fragmentation into two CpRh(CO) 2 units.

Triple-Decker Sandwiches and Related Compounds of the First-Row Transition Metals Containing Cyclopentadienyl and Benzene Rings

The triple-decker sandwich compound trans-Cp(2)V(2)(eta(6):eta(6)-mu-C(6)H(6)) has been synthesized, as well as "slipped" sandwich compounds of the type trans-Cp(2)Co(2)(eta(4):eta(4)-mu-arene) and the cis-Cp(2)Fe(2)(eta(4):eta(4)-mu-C(6)R(6)) derivatives with an Fe-Fe bond (Cp = eta(5)-cyclopentadienyl). Theoretical studies show that the symmetrical triple-decker sandwich structures trans-Cp(2)M(2)(eta(6):eta(6)-mu-C(6)H(6)) are the global minima for M = Ti, V, and Mn but lie approximately 10 kcal/mol above the global minimum for M = Cr. The nonbonding M...M distances and spin states in these triple decker sandwich compounds can be related to the occupancies of the frontier bonding molecular orbitals. The global minimum for the chromium derivative is a singlet spin state cis-Cp(2)Cr(2)(eta(4):eta(4)-mu-C(6)H(6)) structure with a very short CrCr distance of 2.06 A, suggesting a formal quadruple bond. A triplet state cis-Cp(2)Cr(2)(eta(4):eta(4)-mu-C(6)H(6)) structure with a predicted Cr[triple bond]Cr distance of 2.26 A lies only approximately 3 kcal/mol above this global minimum. For the later transition metals the global minima are predicted to be cis-Cp(2)M(2)(eta(6):eta(6)-mu-C(6)H(6)) structures with a metal-metal bond, rather than triple decker sandwiches. These include singlet cis-Cp(2)Fe(2)(eta(4):eta(4)-mu-C(6)H(6)) with a predicted Fe=Fe double bond distance of 2.43 A, singlet cis-Cp(2)Co(2)(eta(3):eta(3)-mu-C(6)H(6)) with a predicted Co-Co single bond distance of 2.59 A, and triplet cis-Cp(2)Ni(2)(eta(3):eta(3)-mu-C(6)H(6)) with a predicted Ni-Ni distance of 2.71 A.

From silicon(II)-based dioxygen activation to adducts of elusive dioxasiliranes and sila-ureas stable at room temperature

Dioxygen activation for the subsequent oxygenation of organic substrates that involves cheap and environmentally friendly chemical elements is at the cutting edge of chemical research. As silicon is a non-toxic and highly oxophilic element, the use of silylenes could be attractive for facile dioxygen activation to give dioxasiliranes with a SiO(2)-peroxo ring as versatile oxo-transfer reagents. However, the latter are elusive species, and have been generated and studied only in argon matrices at -233 degrees C. Recently, it was demonstrated that unstable silicon species can be isolated by applying the concept of donor-acceptor stabilization. We now report the first synthesis and crystallographic characterization of dioxasiliranes stabilized by N-heterocyclic carbenes that feature a three-membered SiO(2)-peroxide ring, isolable at room temperature. Unexpectedly, these can undergo internal oxygen transfer in toluene solution at ambient temperature to give a unique complex of cyclic sila-urea with C=O --> Si=O interaction and the shortest Si=O double-bond distance reported to date.

Ni(II) and Mn(II) complexes of NNS tridentate ligand N′-[(2-methoxyphenyl)carbonothioyl]pyridine-2-carbohydrazide (H 2mcph): Synthesis, spectral and structural characterization

The ligand N′-[(2-methoxyphenyl)carbonothioyl]pyridine-2-carbohydrazide (H 2mcph), having NNS donor sequence, has been found to form [Ni(Hmcph) 2]·CH 2Cl 2·0.5C 6H 6 and [Mn(Hmcph) 2]·2H 2O which have been characterized by spectroscopic and spectrometric techniques including magnetic susceptibility measurements and single crystal X-ray of both complexes. The compounds crystallize in the triclinic and monoclinic systems with the space group P 1 ¯ and P2(1)/ c, respectively with a distorted octahedral geometry about the M(II) center . The ligand is coordinated through the ring nitrogen, hydrazinic N and thione sulfur. The hydrazinic nitrogen coordinates with a shorter M–N distance than the ring nitrogen and the bond lengths in the chelate ring systems are intermediate between single and double bond distances, suggesting considerable delocalization of charge.

Crystal and Molecular Structures of Di-1-Adamantylthiophosphinic Chloride, P,P-Diphenyl-N-Benzyl Phosphinothioic- and Selenoic- Amides

Synthesis and X-ray structural determination of three phosphorus compounds are reported. (3b) is monoclinic P2(1)/c with a = 11.852(1), b = 12.825(1), c = 12.445(1) A, β = 103.693(1)o; (4a) and (4b) are monoclinic P2(1)/n with a = 12.1422(16), b = 9.0860(12), c = 14.845(2) A, β = 96.498(3)o for (4a), and a = 12.2714(16), b = 9.2812(12), c = 14.800(2) A, β = 97.176(2)o for (4b). They all exhibit distorted tetrahedral geometry about the P atom. Ph2P(X)NHC7H7 (X=S (4a) and X=Se (4b)) show typical P–S and P–Se double bond distances and P–N single bonds, while P–S bond in 1-Ad2P(S)Cl (3b) is comparable to P–S single bonded probably due to the largeness of 1-adamantyl groups. Synthesis and X-ray structural determination of 1-Ad2P(S)Cl (3b), Ph2P(S)NHC7H7 (4a) and Ph2P(Se)NHC7H7 (4b) are reported.

Synthesis, characterization and spectroscopic studies of a new ligand [N′-(2-methoxybenzoyl)hydrazinecarbodithioate] ethyl ester and its Mn(II) and Cd(II) complexes: X-ray structural study of Mn(II) complex

A new dithioligand [N′-(2-methoxybenzoyl)hydrazinecarbodithioate] ethyl ester (H 2mbhce, 1) formed complexes [M(Hmbhce) 2] n {M = Mn(II), Cd(II)} which have been characterized with the help of elemental analyses, magnetic susceptibility measurements, IR, UV–Vis, 1H and 13C NMR and mass spectrometry. [Mn(Hmbhce) 2] n ( 2) crystallized in monoclinic system with space group P 21/ n. In the polymeric structure of 2, the ligand acts as an uninegative tridentate N(1), O(1), S(3) donor and forms a five membered chelate ring with N(1), C(2) and O(1). The intermediate bond lengths (between single and double bond distances) O(1)–C(2) = 1.241(3), N(2)–C(2) = 1.325(3), N(1)–N(2) = 1.393(2), N(1)–C(8) = 1.311(3) Ǻ and C(8)–S(3) = 1.704(2) Å suggest considerable delocalization of charge which develops slightly aromatic character in the chelate ring.

Diethylmethyleniminium chloride

The title compound, C5H12N+·Cl−, contains [Et2N=CH2]+ and Cl− ions. The C=N double-bond distance is 1.2729 (13) Å and the sum of the angles around the central N atom is 359.92°. There are short contacts [2.973 (1) Å] between the iminium C atom and the Cl− ion and between five of the C—H H atoms and the Cl− ion, of which the shortest is 2.623 (11) Å.

Tripotassium carboxylatomethylenebis(diazeniumdiolate) 2.5-hydrate

The title compound, 3K+·C2HN4O63−·2.5H2O, contains two diazeniumdiolate substituents which are nearly planar, with observed N—O and N—N double-bond distances in the range 1.276 (3)–1.309 (3) A, revealing extensive double-bond delocalization over the four-atom groups. One water molecule lies on a twofold rotation axis.

4-{5-(Dimethylamino)-2-[4-(dimethylamino)-2-iodophenylmethyl]phenyl}-(3E)-3-buten-2-one

The title compound, C21H25BrN2O, was synthesized by the Heck reaction. Its crystal structure shows that there are π–π-stacking interactions between the two aromatic rings of the two neighboring mol­ecules in the unit cell. The C—I bond distance is 2.108 (4) A and the butene double-bond distance is 1.311 (4) A.