Controlling function by structure-intermolecular interactions and crystal engineering with N-donor ligands

In the solid state regime, crystal engineering based on non-covalent synthesis requires an intuition about the intermolecular forces that can dictate the molecular architecture. Hydrogen bonds have become an instrumental tool in the self assembly and supramolecular chemistry. A variety of Schiff’s bases ligands based on azomethine functional units have been synthesized by condensation of the corresponding aldehydes with hydrazine monohydrate and their structures have been revealed by X-ray diffraction. The Br\ub7\ub7\ub7Br intermolecular interaction in Cambridge Structural Database was studied and a relation between OPL measurements and the positions of bromine atoms in two Schiff’s bases has been drawn. A 2D square grid coordination polymer with a dimension of 16 716\uc5 based on Fe(II) metal centers and bis-pyridinyl methylene hydrazine organic spacer had been assembled and the structure was characterized by X-ray single-crystal diffraction. The square grid with an accessible voids volume of ca. 20% is also hosting [Fe(phen)3]2+ complex as well as free ligand and water solvates which represent a unique example of a coordination polymer host capable of intercalating neutral and cationic guests. The guests assembled inside these grids has independently synthesized and characterized by X-ray single crystal diffraction where σ-π and π-π stacking are the only intermolecular interactions controlling their intercalation behaviour. A different stoichiometry resulted in an 1D coordination chain of Fe(II) centers where the sheets of arrays are supported by hydrogen bonding building up an infinite 2D square grid assembly. Different hydrogen bonding motifs varied with different counter ions in the case of the solely ligands have been emphasized. The crystal packing of 4-bromothiophene porphyrin-Zn(II) was shown to depend on S\ub7\ub7\ub7S non-covalent interactions and OPL properties of the free bases and Ag(II) porphyrins are discussed. A homochiral double helical packing caused by S\ub7\ub7\ub7S interactions in [Co(SCN)4]2- with [Ru(phen)3]2+ is manifested

Structural chemistry and optical application

The demand for materials with optical activities against LASER radiation has been extensively increased over the last decade with the development of sophisticated high energetic LASER sources. The goal is to obtain organic or metal-organic molecules capable of increasing their absorptions against LASER irradiance while still maintaining a degree of transmittance. For instance, Zn-meso-tetrakis [bromothiophene] porphyrin is presented here as an efficient optical power limiter against Nd:YAG beam. Moreover, Schiffs bases based on bromothiophenes show a degree of NLO performance against LASER.Single crystal X-ray crystallography has represented an active area of research leading to better understanding of many chemical and structural phenomena, thus the geometrical and electronic analogy for the fourth and the fifth bromine atoms position at the thiophene ring had been addressed. This thesis describes porphyrins, metalloporphyrins and conjugated thiophenes as optical limiters and non-linear optical materials with insight on the chemical and physico-chemical theories describing these actions. The organic molecules prepared in this work are meso-tetrakis 4-and 5-Bromo thiophene porphyrins, Bis thiophenyl 2-methylene hydrazine, Bis 4-bromothiophenyl 2-methylene hydrazine and Bis 5-bromothiophenyl 2-methylene hydrazine. The metal-organic molecules prepared in this work are Ag (II), Zn (II) meso-tetrakis 4- and 5-Bromo thiophene porphyrins as well as Zn (II) trans-bis nicotinato chloride. The syntheses, characterizations and optical properties as well as x-ray crystal structures of 2 metal-organic and 3 organic structures are presented and discussed

The role of intermolecular interactions in the assemblies of FeII and CoII tetrakis-isothiocyanatometalates with tris(1,10-phenanthroline)-RuII: Crystal structures of two dual-metal assemblies featuring octahedral cationic and tetrahedral anionic modules

Two new dual-metal assemblies: 2[Ru(phen)3]2+\ub7[Fe(SCN)4]2−\ub72SCN−\ub74H2O 1 and [Ru(phen)3]2+\ub7[Co(SCN)4]2− 2, (phen:1,10-phenanthroline), have been prepared and their structures were characterized by X-ray diffraction. In 1, the cationic octahedral enantiomers are arranged with a ΛΔΛΔΛ sequence supported by π–π stacking and the anionic inorganic tetrahedral units are oriented between these stacks by interacting with the nearby water molecules through strong O–H...O and O–H...S hydrogen bonds. In 2, homochiral double helices in the b-direction are revealed, with tetrakis-isothiocyanate CoII anions arranged in the crystal to furnish one-dimensional (1D)-helical chains with S...S intermolecular interactions at 3.512(2) and 3.966(2)\uc5 supporting [Ru(phen)3]2+ Λ- and Δ-helices with Ru...Ru shortest distance of 8.676(7)\uc5. In both 1 and 2, the supramolecular assembly is maintained by C–H...S hydrogen bonds extending between the phenanthroline aromatic carbons in the cationic nodes and the sulphur atoms of the isothiocyanates anions. Analysis of S...S interactions in isothiocyanate containing compounds using Cambridge structural database (CSD) showed an angle dependence categorizing these interactions into “type-I” and “type-II”

An interpenetrating primitive cubic net formed by hydrogen bonds and coordination bonds in catena-poly[[bis(methanol-κO)bis(thiocyanato-κN)iron(II)]-μ-1,2-bis(4-pyridylmethylene)hydrazine-κ2N:N\u27]

In the title compound, [Fe(NCS)2(C12H10N4)(CH4O)2]n, at 153(2) K, the Fe atom is located on an inversion centre, as is the centre of the N-N bond in the ligand molecule. The structure contains a one-dimensional coordination polymer with an Fe...Fe distance of 15.866(7) \uc5 and can be described as two interpenetrating six-connected primitive cubic (pcu) three-dimensional networks when additional intermolecular O-H...S hydrogen bonds are taken into account. The compound is not isostructural with the corresponding MnII compound as they differ in the rotation around the M-O bond by 90\ub0, giving rise to completely different hydrogen-bond patterns. This study demonstrates the impact of conformational differences on the final supramolecular arrangement

An inter-penetrating primitive cubic net formed by hydrogen bonds and coordination bonds in catena-poly[[bis-(methanol-κO)bis-(thio-cyanato- κN)iron(II)] -μ 1,2-bis(4-pyridyl-methylene)hydrazine- κ2 N:N′]

In the title compound, [Fe(NCS)2(C12H10N4)(CH4O)2] n , at 153 (2) K, the Fe atom is located on an inversion centre, as is the centre of the N - N bond in the ligand mol-ecule. The structure contains a one-dimensional coordination polymer with an Fe⋯Fe distance of 15.866 (7) \uc5 and can be described as two inter-penetrating six-connected primitive cubic (pcu) three-dimensional networks when additional inter-molecular O - H⋯S hydrogen bonds are taken into account. The compound is not isostructural with the corresponding Mn II compound as they differ in the rotation around the M - O bond by 90\ub0, giving rise to completely different hydrogen-bond patterns. This study demonstrates the impact of conformational differences on the final supramolecular arrangement

catena-Poly[[chloro(pyridinium-3-carboxylato-κO)zinc(II)]-μ-nicotinato-κ2O:N]

The title bis-nicotinate zinc chloride, [Zn(C6H4NO2)Cl(C6H5NO2)]n, has an infinite head-to-tail one-dimensional chain structure. The compound was synthesized under mild hydrothermal conditions. The ZnII atom exhibits a distorted tetrahedral coordination geometry. The structure is statistically disordered, with 0.5 site occupancy for the Zn atom and the H atom located on the pyridine N atom. As a result, Zn positions in the crystal structure alternate between two sites related by a crystallographic twofold axis and rows of molecules are formed, supported by strong N-H...O hydrogen bonds

A three-dimensional net of Δ-tris(1,10-phenanthroline)ruthenium(II) in the dual-metal self-assembly of bis[tris(1,10-phenanthroline)ruthenium(II)] tetraisothiocyanatoiron(II) bis(perchlorate)

The title compound, [Ru(C12H8N2)3]2[Fe(NCS)4](ClO4)2, crystallizes in a tetragonal chiral space group (P41212) and the assigned absolute configuration of the optically active molecules was unequivocally confirmed. The Δ-[RuII(phen)3]2+ complex cations (phen is 1,10-phenanthroline) interact along the 41 screw axis parallel to the c axis, with an Ru...Ru distance of 10.4170(6) \uc5, and in the ab plane, with Ru...Ru distances of 10.0920(6) and 10.0938(6) \uc5, defining a primitive cubic lattice. The Fe atom is situated on the twofold axis diagonal in the ab plane. The supramolecular architecture is supported by C-H...O interactions between the [RuII(phen)3]2+ cation and the disordered perchlorate anion. This study adds to the relatively scarce knowledge about intermolecular interactions between [RuII(phen)3]2+ ions in the solid state, knowledge that eventually may also lead to a better understanding of the solution state interactions of this species; these are of immense interest because of the photochemical properties of these ions and their interactions with DNA

Multi-component self-assembly of molecule based materials by coordination networks and weak intermolecular synthons

The coordination polymer [Fe(SCN)2(1,2-bis(4-pyridylmethylene)hydrazine)2]n [Fe(phenanthroline)3]2n(ClO4)2n\ub7n1,2-bis(4-pyridylmethylene)hydrazine\ub74nH2O 1 was crystallised from a MeOH/MeCN solution and the structure consists of layered (4,4) 2D-nets with supramolecular ([Fe(phen)3]2bphz)4+ units in the pores and disordered water and perchlorate anions. The same supramolecular motif could be independently prepared as [Fe(phen)3]2\ub7bphz(ClO4)4\ub7xMeOH 2, and the [Ru(phenanthroline)3]2+ compound 3, isostructural to 1, was also prepared although a complete structure determination was prevented by low crystal quality. Compounds 1 and 3 are rare examples of how several large and different components can be assembled inside a 2D coordination network and provide a concept for multi-component self-assembly

Network analysis of barium oxalates Ba(C2O4)m(HC2O4)n(H2C2O4)p(H2O)q, including the new, uniform, five-connected loh net

The structures of three compounds from the system Ba(C2O4)m(HC2O4)n(H2C2O4)p(H2O)q have been structurally reinvestigated by low-temperature X-ray diffraction. Ba(C2O4)(H2O)2, 1, Ba(C2O4)(H2C2O4)(H2O)2, 2, and Ba(C2O4)0.5(HC2O4)(H2O), 3. The compounds are composed of three-dimensional coordination network structures with bridging oxalates and water molecules. Compound 1 is binodal, four and five connected with topology (4462)(4466)-tcs; 2 contains the common 66-dia net and 3 displays the new uniform network topology 610-loh. Together with the recently reported 610-ghw and 610-rld-z nets, and the 610-fnu net, the loh net forms a subclass of five-connected 610-nets based on the distorted trigonal bipyramidal coordination

catena-Poly[[bis(N,N\u27-dimethylformamide)cadmium(II)]-μ2-oxalato]

The title compound, [Cd(C2O4)(C3H7NO)2]n, is isostructural with its MnII analogue. The structure comprises zigzag polymeric chains with the oxalate groups situated on inversion centres and the CdII atoms located on twofold rotation axes.The coordination geometry around CdII is distorted octahedral and the intrachain Cd...Cd distance is 5.842(1) \uc5. C—H...O hydrogen bonds exist between the parallel polymeric chains