DMF Molecules Research Articles

Low-dimensional compounds containing bioactive ligands. Part VI: Synthesis, structures, in vitro DNA binding, antimicrobial and anticancer properties of first row transition metal complexes with 5-chloro-quinolin-8-ol

A series of new 3d metal complexes with 5-chloro-quinolin-8-ol (ClQ), [Mn(ClQ)2] (1), [Fe(ClQ)3] (2), [Co(ClQ)2(H2O)2] (3), [Ni(ClQ)2(H2O)2] (4), [Cu(ClQ)2] (5), [Zn(ClQ)2(H2O)2] (6), [Mn(ClQ)3]·DMF (7) and [Co(ClQ)3]·DMF·(EtOH)0.35 (8) (DMF=N,N-dimethylformamide), has been synthesized and characterized by elemental analysis, IR spectroscopy and TG–DTA thermal analysis. X-ray structure analysis of 7 and 8 revealed that these molecular complexes contain three chelate ClQ molecules coordinated to the central atoms in a deformed octahedral geometry and free space between the complex units is filled by solvated DMF and ethanol molecules. Antimicrobial activity of 1–6 was tested by determining the minimum inhibitory concentration and minimum microbicidal concentration against 12 strains of bacteria and 5 strains of fungi. The intensity of antimicrobial action varies depending on the group of microorganism and can be sorted: 1>ClQ>6>3/4>2>5. Complexes 1–6 exhibit high cytotoxic activity against MDA-MB, HCT-116 and A549 cancer cell lines. Among them, complex 2 is significantly more cytotoxic against MDA-MB cells than cisplatin at all tested concentrations and is not cytotoxic against control mesenchymal stem cells indicating that this complex seems to be a good candidate for future pharmacological evaluation. Interaction of 1–6 with DNA was investigated using UV–VIS spectroscopy, fluorescence spectroscopy and agarose gel electrophoresis. The binding studies indicate that 1–6 can interact with CT-DNA through intercalation; complex 2 has the highest binding affinity. Moreover, complexes 1–6 inhibit the catalytic activity of topoisomerase I.

Fast Interchange of Coordinated and Guest Dimethylformamide Molecules in the Zinc(II) Lactate Terephthalate Metal–Organic Framework

Mobility of N,N-dimethylformamide (dmf) molecules in a homochiral metal–organic framework [Zn2(bdc)(S-lac)(dmf)]·dmf (bdc = 1,4-benzenedicarboxylate; S-lac = L-(−)-lactate) has been studied using 13C, 1H, and 2H solid-state NMR and DSC experiments. The compound exhibits a phase transition in the vicinity of 240 K, associated with disordering of the dmf molecules. In the high-temperature phase, the dmf molecules undergo intense diffusion accompanied by the exchange between the molecules coordinated with Zn and guest molecules in the framework pores. The activation energy of the molecular migration including exchange between coordinated and guest molecules was estimated to be 37 kJ/mol.

A double complex Cd(II) salt containing the Keggin polyoxoanion and the supramolecular cation of the [amide…H…amide]+ type

The complex [H(DMFA)2]2[Cd(DMFA)6][SiW12O40] (I) was obtained by a reaction between H4[SiW12O40], CdI2, and AgNO3 in N,N-dimethylformamide (DMF) and characterized by X-ray diffraction (CIF file CCDC No. 1041227). Structure I is made up of the complex cations [Cd(DMF)6]2+, the Keggin polyoxoanions [SiW12O40]4–, and the dimeric cations [DMF...H...DMF]+, in which two DMF molecules are linked by a short hydrogen bond (O...O, 2.39(2) A). The cations of this type were compared with similar dimeric cations containing the fragment {amide...H...amide}.

Synthesis of mixed-ligand cobalt complexes and their applications in high cis-1,4-selective butadiene polymerization

Incomplete oxidation of (N-di-tert-butylphosphino)-6-(2-methyl-2′H-benzoimidazole)-2-aminepyridine dichlorocobalt (PN3CoCl2) in DMF results in a unique co-crystal I formed with three parts including DMF, unit A and unit B complex with Co1 and Co2, respectively (PN3 ligand in unit A: (N-di-tert-butylphosphino)-6-(2′-methyl-2′H-benzoimidazole)-2-aminepyridine, and OPN3 ligand in unit B: (N-di-tert-butylphosphinoxide)-6-(2′-methyl-2′H-benzoimidazole)-2-aminepyridine), with 1:1:1 molar ratio. Co1 and Co2 complexes both display a five-coordinated distorted-square-pyramidal geometry around the metal center. The Co1 center is coordinated with PN3 ligand via two N atoms from pyridine, benzoimidazole moiety as well as one P atom, and the Co2 center is coordinated with the oxidized ligand OPN3 via two N atoms from pyridine, benzoimidazole moiety as well as one O atom from DMF molecule, while the oxidized phosphine moiety (OP) being excluded from the coordination sphere. Activated with AlEt2Cl, the co-crystallized complexes I are able to actively convert butadiene to polybutadiene, affording cis-1,4 polybutadiene with cis-1,4 unit up to 95.5–97.8% and number average molecular weight of cal. 105g/mol. The high cis-1,4 selectivity and monomodal GPC curve of resultant polymer imply that the identical active species generated from two distinctive cobalt centers.

From intra- to inter-molecular hydrogen bonds with the surroundings: steady-state and time-resolved behaviours.

We report on the photodynamics of 2-(2'-hydroxyphenyl)benzoxazole (HBO), compared to its amino derivatives, 6-amino-2-(2'-hydroxypheny)benzoxazole (6A-HBO) and 5-amino-2-(2'-hydroxypheny)benzoxazole (5A-HBO) in N,N-dimethylformamide (DMF) solutions. HBO at S0 shows a reversible deprotonation reaction leading to the production of anionic forms. However, for 6A-HBO and 5A-HBO, DMF containing KOH is necessary to produce the anions. Excited HBO in DMF exhibits intra- as well as inter-molecular proton transfer (ESIPT and ESPT) reactions. With excitation at 330 nm, we observed the open-enol, anti-enol and keto forms with different emission and lifetimes (620 ps, 1.5 ns, and 74 ps, respectively), while with the excitation at 433 nm, only the anionic species emission was detected (3.7 ns). Contrary to HBO, 6A-HBO and 5A-HBO do not exhibit any proton transfer process, and only the emissions of the open-enol charge-transferred forms (open-ECT) were observed, which are comparable to those of their methylated derivatives (6A-MBO and 5A-MBO). Femtosecond studies of 6A-MBO and 6A-HBO in DMF indicate that an intramolecular charge-transfer (ICT) reaction (∼80 fs) and solvent relaxation process (2 ps) take place at S1. Remarkably, the photoinduced breaking of the intramolecular hydrogen bond of 6A-HBO and the formation of an intermolecular hydrogen bond with DMF molecules occurs in 80 ps, while for 5A-HBO, this process occurs in less than 10 ps. In this study, we have demonstrated that the presence and position of the amino group in the HBO framework change both the S0 and S1 behaviours of the intramolecular H-bonds; a result which might be useful for the design and better understanding of supramolecular systems based on intra- and intermolecular H-bonds.

Synthesis, crystal structure of two new Zn(II), Cu(II) porphyrins and their catalytic activities to ethylbenzene oxidation

One novel porphyrin 5,10,15,20-tetra(4-(4-acetateethyl)phenoxy)phenylporphyrin (H2Pp), and its two corresponding zinc(II) and copper(II) porphyrins (ZnPp, CuPp) is synthesized and characterized by spectroscopic techniques. The single crystal structures of [ZnPp(DMF)]·DMF (1) and [CuPp(DMF)] (2) are also obtained and analyzed. Complex 1 crystallizes in monoclinic system compared to the triclinic system of complex 2, which may due to the influence of solvent DMF molecule in 1. The metal centers have similar coordination environments in the two structures, which are all five-coordinated pyramid geometry with four nitrogen atoms of porphyrin ring from equator and an axial oxygen atom of DMF molecule. 1 and 2 display 3D supramolecular structures constructed by π⋯π interactions of porphyrin rings and C–H⋯O hydrogen bonds. The catalytic activities of 1 and 2 to the ethylbenzene oxidation are examined. The results indicate that both of them exhibit highly selectivity to acetophenone (>99%) with the conversion of 23% (1) and 76% (2) respectively.

Solvothermal Synthesis of Tetravalent Uranium with Isophthalate or Pyromellitate Ligands

AbstractThree new coordination polymers bearing tetravalent uranium have been isolated with the O‐donor ligands such as isophthalate (1,3‐bdc) or pyromellitate (btec). The compounds 1 and 3 have been solvothermaly synthesized in N,N‐dimethylformamide (DMF). The crystal structure of U(1,3‐bdc)2(DMF) (1) is built up from discrete tricapped trigonal‐primastic UO9 units, for which one carbonyl oxygen atom from DMF is bound to uranium. The connection of the UO9 units with the isophthalate linkers occurs in a chelating and bidentate fashion and gives rise to the formation of a 3D framework, delimiting narrow channels running along the [101] direction. Upon heating, the DMF molecules are removed, generating the second phase U(1,3‐bdc)2 (2) compound, closely related to 1. Indeed, the coordination environment of uranium is reduced to eight with a distorted square‐antiprismatic geometry. This transition induces the relative shrinkage of the network (ΔV = 23 %). The structure of the compound U(btec)(DMF)2 (3) also exhibits a 3D framework composed of an isolated bicapped square‐antiprismatic UO10 unit, for which two carbonyl oxygen atoms from DMF are bonded to uranium. Pyromellitate ensures the connection of the UO10 units through the carboxylate arms in a chelating mode. This results in the formation of a network with diamond‐shaped channels, developed along the c axis and encapsulating the DMF molecules. In contrast to 1, no stable phase is observed upon removing the DMF species by heating.

Thorium(IV) organic frameworks with aromatic polycarboxylate ligands

Contrary to the fairly well established structural chemistry of uranium(VI) with aromatic polycarboxylate ligands, the knowledge on thorium(Th) structural chemistry with this family of ligands is very limited. In this paper, we report the synthesis, spectroscopic and thermal studies, and crystal structures of three Th organic frameworks with 1,2,4,5-benzenetetracarboxylate (btca) or 1,4-benzenedicarboxylate (bdc). Both [Th(btca)(DMF)2(H2O)] (1) and [Th(bdc)2(DMF)2] (2) (DMF = dimethylformamide) have two dimensional (2D) layered structures constructed with 9- (1) or 10- (2) fold coordinated Th polyhedrons and µ 4-btca (1) or µ 2-bdc (2) ligands, respectively, with two coordinated DMF molecules in cis- (1) or trans- (2) positions on each Th atom. The third phase, [Th(bdc)2] (3), has a 3D pillared framework built with eightfold coordinated Th polyhedrons and µ 4-bdc ligands. Their vibrational modes have been investigated and correlated to the structures. VT-PXRD confirmed that 3 is thermally robust to 500 °C and the weight loss at ~300 °C is due to the loss of water molecules in the solvent accessible voids in the crystal lattice. Thorium(IV) organic frameworks (TOC): Three new thorium organic frameworks with aromatic polycarboxylate ligands have been synthesized and characterized. 2D layered structures are favored at room temperature and a thermal robust, 3D thorium organic framework has been made under hydrothermal conditions. Their vibrational modes and thermal stabilities have been further investigated.

Single crystal to single crystal (SC-to-SC) transformation from a nonporous to porous metal-organic framework and its application potential in gas adsorption and Suzuki coupling reaction through postmodification.

A new amino-functionalized strontium-carboxylate-based metal-organic framework (MOF) has been synthesized that undergoes single crystal to single crystal (SC-to-SC) transformation upon desolvation. Both structures have been characterized by single-crystal X-ray analysis. The desolvated structure shows an interesting 3D porous structure with pendent -NH2 groups inside the pore wall, whereas the solvated compound possesses a nonporous structure with DMF molecules on the metal centers. The amino group was postmodified through Schiff base condensation by pyridine-2-carboxaldehyde and palladium was anchored on that site. The modified framework has been utilized for the Suzuki cross-coupling reaction. The compound shows high activity towards the C-C cross-coupling reaction with good yields and turnover frequencies. Gas adsorption studies showed that the desolvated compound had permanent porosity and was microporous in nature with a BET surface area of 2052 m(2) g(-1). The material also possesses good CO2 (8 wt %) and H2 (1.87 wt %) adsorption capabilities.

A New Chiral Coordination Polymer with Large Cavities of [Cu3(NA)6(DMF)3]n: Synthesis, Structural and Magnetic Property

A new metal–organic architectures, [Cu3(NA)6(DMF)3]n (1), where NA stands for nicotinic acid, has been successfully synthesized and characterized by elemental analysis, IR, TG analysis and single crystal X-ray diffraction. Single-crystal X-ray diffraction reveals that the CuII centers adopt a distorted square pyramidal geometry, and nicotinic acid acts as a bidentate ligand connected with the adjacent two Cu atoms by the pyridyl and carboxylate groups to form a 3D framework structure. The framework exhibits open chiral channels with coordinated DMF molecules inside it. In addition, the magnetic properties have also been studied.

Synthesis, characterization and oscillator-vibrated near-infrared (NIR) luminescence of two pseudo-polymorphic [Yb4((OH)2-Salophen)4] complexes

Through the self-assembly of the (OH)2-Salophen H4L (H4L=N,N′-bis(3-hydroxylsalicylidene)benzene-1,2-diamine) with LnCl3·6H2O or Ln(NO3)3·6H2O (Ln=La, Yb or Gd) in different solvent systems MeCN–EtOH and MeCN–DMF, the mixed (L)4− and (H2L)2− coordination modes induce the formation of anion-independent while pseudo-polymorphic homoleptic linear tetranuclear complexes [Ln4(H2L)2(L)2(EtOH)2] (Ln=La, 1; Ln=Yb, 2 or Ln=Gd, 3) and [Ln4(H2L)2(L)2(DMF)2] (Ln=La, 4; Ln=Yb, 5 or Ln=Gd, 6), respectively. The result of their photophysical properties shows the characteristic NIR luminescence for both Yb3+-based complexes 2 and 5 with emissive lifetimes in microsecond ranges, while the difference of nearby and/or distant oscillator-based (OH and/or CH) vibrations from two coordinated EtOH or DMF molecules within the inner coordination spheres of Yb3+ ions in the two complexes has a decisive effect on their NIR luminescent properties.

Crystal structure, spectroscopic and thermal properties of [Zn(Lap)2(DMF)(H2O)] and isomorphous [M(Lap)2]n (M: Cd, Mn) complexes

The solid state structure of the lapacholate (Lap−) complexes with Zn(II), Cd(II) and Mn(II) were determined by X-ray diffraction methods. [Zn(Lap)2(DMF)(H2O)] crystallizes in the triclinic space group P1¯ with a=10.5051(4), b=12.8020(4), c=13.0394(4)Å, α=60.418(2), β=83.904(2), γ=86.206(2)°, and Z=2 molecules per unit cell. The isomorphous complexes [M(Lap)2]n (M: Cd, Mn) crystallize in the tetragonal space group P43212 with a=b=13.5770(6)Å, c=14.5730(6)Å (Cd), and a=b=13.3539(4), c=14.7148(4)Å (Mn), and Z=4. In [Zn(Lap)2(DMF)(H2O)] the Zn(II) ion is in a distorted octahedral environment coordinated to two different and nearly perpendicular Lap− molecules acting as bidentate ligands through their adjacent carbonyl and phenol oxygen atoms. The remaining two cis-coordination sites are occupied by water and DMF molecules. [M(Lap)2]n (M: Cd, Mn) isomorphous complexes are also octahedral and present a supra-molecular arrangement in the lattice. There is only one independent Lap− molecule that coordinates the metal through all three ligand binding sites, giving rise to a 3-D structure of [M(Lap)2]n complexes that extends throughout the crystal lattice.The lapachol binding to metal is also revealed by the IR spectra. In fact, the carbonyl CO stretching frequency is appreciable red-shifted in the complexes as compared to uncoordinated lapachol ligand. As expected, the IR and UV–Vis spectra of the isomorphous pair of complexes closely resemble to each other.Up to above 300°C there are significant differences in the TGA of the Zn complex when compared with the isomorphous pair: while the former shows the loss of the secondary ligands (water and DMF), the latter exhibits a plateau signaling the lesser labile character of the lapacholate ligand.

Phase Formation Study of Ca-Terephthalate MOF-Type Materials

Ca(BDC)(DMF)(H2O) with square lattice topology (sql) and rhombic-shaped channels crystallizes under solvothermal conditions (H2O/DMF mixture) in orthorhombic (Ca-BDC-orth) and triclinic (Ca-BDC-tric) conformations. The latter structure is solved and described here for the first time. The main difference between the two phases lies in the orientation of the coordinated DMF molecule located within the channels of the structure, influencing their porosity properties. In spite of the small deviances in crystal structure, the formation of individual phases can be controlled by the amount of base agent (TEA) and the temperature of crystallization. Triclinic phase is formed at lower synthesis temperature, and it is transformed into orthorhombic phase at increased temperatures. Systematic phase formation study varying TEA/Ca2+ molar ratios and the synthesis temperature showed that higher temperature of the synthesis is required for the Ca-BDC-orth phase to occur from Ca-BDC-tric using the TEA/Ca2+ ratio between 0.63–1.30 compared to the syntheses with TEA/Ca2+ values out of this range. Within the range of 0.63–1.30 the dissociation of the base is in the buffer region indicating that stability of triclinic phase is related to the thermodynamics at equilibrium conditions.

A tetranuclear copper cluster-based MOF with sulfonate-carboxylate ligands exhibiting high proton conduction properties.

A tetranuclear copper cluster-based MOF with sulfonate-carboxylate ligands has been synthesized. It possesses one-dimensional irregular channels lined with sulfonate, carboxylate, and DMF molecules, which show a high proton conductivity of 7.4 × 10(-4) S cm(-1) at 95 °C and 95% relative humidity.

Computer simulation study of the intermolecular structure of phosphoric acid-N,N-dimethylformamide mixtures.

The structures and energies of the complexes (H3PO4)2, H3PO4-DMF, and (H3PO4)2-DMF were analyzed at the B3LYP level of approximation. It was found that H-bonds form between H3PO4 and DMF molecules, but the strength of the H-bond depends strongly on its molecular environment. Effects of the solvent were taken into account via the CPCM approach. According to the B3LYP-СPCM calculations, the O···O distance in (H3PO4)2-DMF is shorter and its H-bonds are stronger than in the other complexes studied. In order to study the effects of concentration on the intermolecular structure, molecular dynamics simulations of H3PO4-DMF mixtures with mole fractions of acid of <0.1 were performed. The calculations indicated that the largest fraction of the acid protons are involved in hydrogen bonding with oxygen atoms of the DMF molecules. An increased probability of acid-acid hydrogen-bond formation at phosphoric acid mole fractions >0.06 was also noted.

Stepwise assembly of a semiconducting coordination polymer [Cd8S(SPh)14(DMF)(bpy)]n and its photodegradation of organic dyes.

Chalcogenolate clusters can be interlinked with organic linkers into semiconducting coordination polymers with photocatalytic properties. Here, discrete clusters of Cd8S(SPh)14(DMF)3 were interlinked with 4,4'-bipyridine into a one dimensional coordination polymer of [Cd8S(SPh)14(DMF)(bpy)]n with helical chains. A stepwise mechanism for the assembly of the coordination polymer in DMF was revealed by an ex situ dynamic light scattering study. The cluster was electrostatically neutral and showed a penta-supertetrahedral structure. During the assembly each cluster was interlinked with two 4,4'-bipyridine molecules, which replaced the two terminal DMF molecules of the clusters. In their solid-state forms, the cluster and the coordination polymer were semiconductors with wide band gaps of 3.08 and 2.80 ev. They photocatalytically degraded rhodamine B and methylene blue in aqueous solutions. The moderate conditions used for the synthesis could allow for further in situ studies of the reaction-assembly of related clusters and coordination polymers.

Crystal Structure Analysis of Betti Base 1-((2-hydroxynaphthalen-1-yl)(2-hydroxyphenyl)methyl)urea•2DMF Solvate

A novel Betti base compound, 1-((2-hydroxynaphthalen-1-yl)(2-hydroxyphenyl)methyl)urea, UBB, was synthesized and characterized by spectral, structural and thermal studies. Single crystal X-ray diffraction studies reveal that the racemic mixture of the compound, when crystallized from DMF, yields R-isomer preferentially (prismatic crystals), whereas, when crystallized from 5:1 (v/v) mixture of DMF-THF, it yields S-isomer (rectangular shaped crystals) with two molecules of DMF, included in both the cases. The crystal structure is discussed in terms of supramolecular interactions and molecular modeling. Both R and S enantiomeric DMF solvate crystals are in their chiral triclinic P1 space group.

Syntheses, crystal structures, and properties of four coordination polymers with a new bifunctional ligand

Four new coordination polymers, {[Cd2(L)2·H2O]·4DMF·14H2O}n (1), {[Cd (L)]·2DMF·6H2O}n (2), {[Zn2(L)2]·4DMF·5H2O}n (3) and {[Cu (L)]·2DMF}n (4) (H2L=2,5-bis((4H-1,2,4-triazol-4-yl)carbamoyl)terephthalic acid), have been synthesized under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction. All of them exhibit three-dimensional structures possessing one-dimensional channels filled with solvent molecules. 1 is a 3D framework with large 1D channels (6.60×8.56Å2) filled with free DMF molecules and the 3D structure of 1 is a new (4, 8) network with Schläfli symbol {416.612}{44.62}2. 2 and 3 with different metal centers have similar structure except for the numbers of free water molecules. They both feature a (4, 4)-connected 3D network of {65.10} {65.8} topology with left- and right-handed helical chains along b-axis. While 4 is a 3D framework with typical CdSO4 topology. In addition, 1–3 show strong fluorescent emissions at room temperature, which can be assigned to the ligand-to-ligand charge transfer (LLCT) emissions.

Coordinating and hydrogen bonding ability of a bifunctional 2D paddle-wheel copper(II) coordination polymer

A new copper(II) complex of formula {[Cu2(H2btc)2(dmf)2]·4dmf}n (1) [H4btc=1,2,4,5-benzenetetracarboxylic acid, dmf=dimethylformamide] has been synthesised and its structure determined by X-ray diffraction. The structure displays a new square grid of “paddle-wheel” tetracarboxylate-bridged dicopper(II) units with an intradimer copper–copper separation of 2.619(2)Å. The dmf molecules are retained through weak axial coordinative bonds and hydrogen bonding interactions with the carboxylic groups of the porous neutral network of 44 net topology. The magnetic behaviour of 1 corresponds to a strong antiferromagnetic coupling within each dicopper(II) unit (J=−343cm−1 with the Hamiltonian being defined by H=−JS1·S2). Complex 1 does not adsorb N2 but it exhibits certain absorption of CO2 with a hysteretic desorption behaviour typical of flexible MOFs.

Formation of Lanthanide(III)-Containing Metallosupramolecular Arrays Induced by Tris(spiroborate) Twin Bowl

Lanthanide(III)-containing metallosupramolecular arrays were prepared in the crystalline state simply by mixing trifluoromethanesulfonate salts of yttrium(III), lanthanum(III), europium(III), terbium(III), erbium(III), and ytterbium(III) with a rac-tris(spiroborate) twin bowl in N,N-dimethylformamide (DMF). In the crystal, the lanthanide(III) ion coordinated to eight or nine DMF molecules to form spherical tricationic complexes, and the spiroborate twin bowl iteratively glued the complexes to each other to form one-dimensional arrays that were unidirectionally packed in the crystal. In each case, the array structure was stabilized by many aromatic C–H···π interactions and C–H···O hydrogen bonds between the twin bowls and the lanthanide(III) complexes. Among the lanthanide(III) ions, yttrium(III), terbium(III), erbium(III), and ytterbium(III) gave almost the same crystal lattice and packing, whereas a different array structure and crystal packing was observed when lanthanum(III) and europium(III) were used...