Publications by authors named "Marijana Dakovic"

The ability of coordination polymers (CPs) to form multicomponent heteromeric materials, where the key structural features of the parent CP are retained, has been explored via molecular electrostatic potential-driven co-crystallization technologies. Thirteen co-formers presenting hydrogen-bond donors activated through a variety of electron-withdrawing functionalities were employed, and the extent of activation was evaluated using molecular electrostatic potential values. Attempted co-crystallizations of the seven most promising co-formers with a family of nine CPs ([CdX'(X-pz)]; X' = I, Br, and Cl; X = I, Br, and Cl) resulted in six successful outcomes; all four of the structurally characterized compounds displayed the intended hydrogen bond.

View Article and Find Full Text PDF

The approach for enhancing the elasticity of crystals with suboptimal elastic performances through a rational design was presented. A hydrogen-bonding link was identified as a critical feature in the structure of the parent material, the Cd(II) coordination polymer [CdI(I-pz)] (I-pz = iodopyrazine), to determine the mechanical output and was modified via cocrystallization. Small organic coformers resembling the initial organic ligand but with readily available hydrogens were selected to improve the identified link, and the extent of strengthening the critical link was in an excellent correlation with the delivered enhancement of elastic flexibility materials.

View Article and Find Full Text PDF

Five zinc(II) coordination compounds, [ZnCl(isn)] (), [ZnBr(isn)] (), [Zn(NO)(HO)(isn)] (), [Zn(CHCOO)(isn)] () and [Zn(isn)(HO)](ClO) () (isn = isonicotinamide), were prepared by the reactions of the isonicotinamide (pyridine-4-carboxamide, isn) and corresponding zinc(II) salts. Their crystal structures were determined by the single-crystal X-ray diffraction method. The coordination environment of zinc(II) is tetrahedral in the compounds containing small halide anions (chloride, bromide), and .

View Article and Find Full Text PDF

Crystals of a family of six one-dimensional (1D) coordination polymers of cadmium(II) with cyanopyridines [[CdXL] , where X = Cl, Br, or I and L = 3-cyanopyridine (3-CNpy) or 4-cyanopyridine (4-CNpy)] presented a variety of morphologies and mechanical responses with dominant two-dimensional (2D) anisotropic flexibility, which has not been previously reported. All mechanically adaptable crystals were 2D flexible and displayed a variety of direction-dependent responses; in addition to 2D isotropic flexibility observed for solely elastic materials, 2D anisotropic flexibility was noticed for both elastic and elastic → plastic crystals. The consequences of fine and controlled structural variations on mechanical behavior were additionally explored via microfocus single-crystal X-ray diffraction and complementary theoretical studies, revealing that the relative strength and direction of the hydrogen bonding interactions were the key parameters in delivering a specific mechanical response.

View Article and Find Full Text PDF

A 6-chloro-nicotinate (6-Clnic) salt of a one-dimensional cationic nickel(II) coordination polymer with 4,4'-bi-pyridine (4,4'-bpy), namely, -poly[[[tetra-aqua-nickel(II)]-μ-4,4'-bi-pyridine-κ :'] bis-(6-chloro-nicotinate) tetra-hydrate], {[Ni(CHN)(HO)](CHClNO)·4HO} or {[Ni(4,4'-bpy)(HO)](6-Clnic)·4HO} , (), was prepared by the reaction of nickel(II) sulfate hepta-hydrate, 6-chloro-nicotinic acid and 4,4'-bi-pyridine in a mixture of water and ethanol. The mol-ecular structure of comprises a one-dimensional polymeric {[Ni(4,4'-bpy)(HO)]} cation, two 6-chloro-nicotinate anions and four water mol-ecules of crystallization per repeating polymeric unit. The nickel(II) ion in the polymeric cation is octa-hedrally coordinated by four water mol-ecule O atoms and by two 4,4'-bi-pyridine N atoms in the position.

View Article and Find Full Text PDF

A one-dimensional nickel(II) coordination polymer with the mixed ligands 6-fluoro-nicotinate (6-Fnic) and 4,4'-bi-pyridine (4,4'-bpy), namely, -poly[[di-aqua-bis-(6-fluoro-pyridine-3-carboxyl-ato-κ)nickel(II)]-μ-4,4'-bi-pyri-dine-κ :'] trihydrate], {[Ni(6-Fnic)(4,4'-bpy)(HO)]·3HO} , (), was prepared by the reaction of nickel(II) sulfate hepta-hydrate, 6-fluoro-nicotinic acid (CHFNO) and 4,4'-bi-pyridine (CHN) in a mixture of water and ethanol. The nickel(II) ion in is octa-hedrally coordinated by the O atoms of two water mol-ecules, two O atoms from -monodentate 6-fluoro-nicotinate ligands and two N atoms from bridging 4,4'-bi-pyridine ligands, forming a isomer. The bridging 4,4'-bi-pyridine ligands connect symmetry-related nickel(II) ions into infinite one-dimensional polymeric chains running in the [10] direction.

View Article and Find Full Text PDF

A copper(II) dimer with the deprotonated anion of 2-bromo-nicotinic acid (2-BrnicH), namely, tetrakis(μ-2-bromonicotinato-κ :')bis[aquacopper(-II)](-), [Cu(HO)(CHBrNO)] or [Cu(HO)(2-Brnic)], (), was prepared by the reaction of copper(II) chloride dihydrate and 2-bromo-nicotinic acid in water. The copper(II) ion in has a distorted square-pyramidal coordination environment, achieved by four carboxyl-ate O atoms in the basal plane and the water mol-ecule in the apical position. The pair of symmetry-related copper(II) ions are connected into a centrosymmetric paddle-wheel dinuclear cluster [Cu⋯Cu = 2.

View Article and Find Full Text PDF

A simple model focusing on electrostatic contributions to interaction energies was found to be very effective for rationalizing the appearance of specific supramolecular interactions in a series of Cu(ii) coordination compounds. The experimental space was provided by a combination of Cu(ii) cations with acac-based anions (hexafluoracetylacetonato and trifluoracetylacetonato) and a series of pyridine-oxime ligands (3-pyridinealdoxime, methyl 3-pyridyl ketoxime, 4-pyridinealdoxime, methyl 4-pyridyl ketoxime, phenyl 4-pyridyl ketoxime). The calculated molecular electrostatic potential (MEP) values at competing hydrogen-bond acceptor sites, for ten structurally characterized complexes, provided guidelines for predicting supramolecular connectivity in cases when the MEP difference exceeded certain cut-off values, while two different and well-defined outcomes are possible within the so called 'grey zone', delineated by a range of MEP differences.

View Article and Find Full Text PDF

Crystalline coordination polymers tend to be brittle and inelastic, however, we now describe a family of such compounds that are capable of displaying mechanical elasticity in response to external pressure. The design approach successfully targets structural features that are critical for producing the desired mechanical output. The elastic crystals all comprise 1D cadmium(II) halide polymeric chains with adjacent metal centres bridged by two halide ions resulting in the required stacking interactions and short "4 Å" crystallographic axes.

View Article and Find Full Text PDF

In order to develop transferable and practical avenues for the assembly of coordination complexes into architectures with specific dimensionality, a strategy utilizing ligands capable of simultaneous metal coordination and self-complementary hydrogen bonding is presented. The three ligands used, 2(1)-pyrazinone, 4(3)-pyrimidinone and 4(3)-quinazolinone, consistently deliver the required synthetic vectors in a series of Cd coordination polymers, allowing for reproducible supramolecular synthesis that is insensitive to the different steric and geometric demands from potentially disruptive counterions. In all nine crystallographically characterized compounds presented here, directional intermolecular N-H⋯O hydrogen bonds between ligands on adjacent complex building blocks drive the assembly and orientation of discrete building blocks into largely predictable topologies.

View Article and Find Full Text PDF

A new tecton, 1,8-diiodoethynylanthracene, with two halogen-bond donor sites was synthesized and characterized. This tecton is capable of forming two parallel halogen bonds at once, which makes it a useful building block for the construction of a variety of supramolecular squares and rectangles.

View Article and Find Full Text PDF

Four new Zn(II) and Cd(II) picolinamide (pia) complexes with cyanate and azide, e.g. [Zn(OCN)2(pia)2] (1), [Cd(OCN)2(pia)2]n (2), [Zn(N3)2(pia)2] (3) and [Cd(N3)2(pia)2]n·nH2O (4), have been prepared and characterized by IR and NMR spectroscopy, and thermal (TG/DTA) methods.

View Article and Find Full Text PDF

Based on previously reported antiproliferative activity screening, four most promising disubstituted 2-phenylbenzothiazole hydrochlorides were chosen for detailed study. Water solubility, as well as liphophilicity/hydrophilicity balance of organic core were modified by conversion to mesylate salts. For purpose of structure/activity studies their structures were determined by X-ray structure analysis.

View Article and Find Full Text PDF

The cation of the title compound, C(14)H(15)N(2)O(2) (+)·Cl(-), comprises two almost ideally planar systems, 3-nitro-phenyl (r.m.s.

View Article and Find Full Text PDF
N-(4-Methyl-benz-yl)-3-nitro-aniline.

Acta Crystallogr Sect E Struct Rep Online

June 2012

In the title compound, C(14)H(14)N(2)O(2), the angle between the mean plane of the N-methyl-3-nitro-aniline system (r.m.s.

View Article and Find Full Text PDF
6-Iodo-2-methyl-1,3-benzothia-zole.

Acta Crystallogr Sect E Struct Rep Online

February 2011

The title compound, C(8)H(6)INS, is essentially planar, the largest deviation from the mean plane being for the I atom [0.075 (3) Å]. The crystal structure is mainly stabilized by inter-molecular C-I⋯N halogen bonds, forming zigzag supra-molecular chains in [10].

View Article and Find Full Text PDF

The title compounds, trans-diaquabis(nitrato-kappaO)bis(pyridine-4-carboxamide-kappaN(1))copper(II), [Cu(NO(3))(2)(C(6)H(6)N(2)O)(2)(H(2)O)(2)], (I), and trans-diaquatetrakis(pyridine-4-carboxamide-kappaN(1))copper(II) bis(perchlorate), [Cu(C(6)H(6)N(2)O)(4)(H(2)O)(2)](ClO(4))(2), (II), are composed of mononuclear coordination entities involving Cu(II) ions and isonicotinamide. In (I), the centrosymmetric tetragonally distorted octahedral copper(II) environment contains trans-related isonicotinamide and water molecules in the equatorial plane and two nitrate ions occupying the axial sites. In (II), the equatorial plane of the C(2)-symmetric distorted octahedron is built up of four isonicotinamide ligands, while water molecules occupy the axial positions.

View Article and Find Full Text PDF

The title compound, [Ni(N(3))(2)(C(6)H(6)N(2)O)(2)], was obtained as the first crystalline product from the reaction of Ni(NO(3))(2)·6H(2)O, picolinamide and NaN(3) in aqueous media. After a few days in the mother liquor, crystals of the cis isomer transformed into the trans isomer [Đaković & Popović (2007 ▶). Acta Cryst.

View Article and Find Full Text PDF

In the title compound, [Hg(NO3)(C6H6N2O)2]NO3, the Hg(II) atom is five-coordinate. The distorted square-pyramidal mercury(II) coordination environment is achieved by two N,O-bidentate picolinamide ligands, with one O-monodentate nitrate ion in the apical position. A seven-coordinate extended coordination environment is completed by two additional weak Hg.

View Article and Find Full Text PDF

In the title compound, [Ni(N(3))(2)(C(6)H(6)N(2)O)(2)], the Ni(II) atom lies on an inversion centre. The distorted octahedral nickel(II) coordination environment contains two planar trans-related N,O-chelating picolinamide ligands in one plane and two monodentate azide ligands perpendicular to this plane. Molecules are linked into a three-dimensional framework by N-H.

View Article and Find Full Text PDF