Search results for "General Materials Science"
showing 10 items of 6837 documents
Insights into the crystal packing of phosphorylporphyrins based on the topology of their intermolecular interaction energies
2014
Four metal complexes of 5,15-bis(diethoxyphosphoryl)-10,20-diphenylporphyrin 1M (M = Cd(II), Ni(II), Pd(II), and Pt(II)) were synthesized and crystallographically characterized. The crystal organization patterns were analyzed using DFT (B97-D3/def2-SVP) calculations of the intermolecular interaction energies between complexes in the crystals. For the systematic analysis of crystal packing, the calculations were extended to previously reported compounds 1M (M = H2, Cu(II), and Zn(II)). Quantitative analysis of the interaction energies shows the essential role of weak intermolecular interactions, such as C-H⋯O, C-H⋯π and M⋯π, in the formation of basic structural motifs and their organization …
From six-coordinate to eight-coordinate iron(ii) complexes with pyridyltriazolo-pyridine frameworks
2016
A new octacoordinated Fe(II) compound, [FeII(LN4)2](BPh4)2·3CH2Cl2, as an example of the scarce FeN8 systems, has been isolated with a tetradentate triazolopyridine-based ligand from a solution containing the related hexacoordinated [FeII(LN3)2]2+ complex, with LN3 = pyridyltriazolo-pyridyl-bromopyrimidine and LN4 = bis(pyridyltriazolo-pyridine).
Design of bimetallic magnetic chains based on oxalate complexes: towards single chain magnets
2009
We describe the synthesis, structure and magnetic characterization of several oxalate-based bimetallic 1D systems. We will exemplify how by suitable choice of the molecular building blocks and strict control of their arrangement in the solid state, the magnetic properties of these low-dimensional materials can be tuned to finally obtain bimetallic oxalate chains behaving as single-chain magnets (SCM). First, we will focus on compounds [K(18-crown-6)][MII(bpy)Cr(ox)3] (1, 2; MII = Mn, Co; bpy = C10N2H8). The MnCr derivative behaves as a 1D ferromagnet down to 2 K, the lowest investigated temperature. The lack of magnetic ordering in this chain prompted us to prepare the more anisotropic MnCo…
Iron( ii ) and cobalt( ii ) complexes based on anionic phenanthroline-imidazolate ligands: reversible single-crystal-to-single-crystal transformations
2018
A series of low-spin FeII and CoII complexes based on phenanthroline-imidazolate (PIMP) ligands are reported. The FeII complex (H9O4)[Fe(PIMP)3]·(C4H10O)2(H2O) (1a) shows reversible crystalline phase transformations to afford two new phases (H9O4)[Fe(PIMP)3]·(H2O) (1b) and (H9O4)[Fe(PIMP)3]·(C8H18O)(C4H10O)(H2O) (1c) by release of diethyl ether and absorption of diethyl/dibutyl ether, respectively. This reversible uptake/release of solvent molecules is a clear example of single-crystal-to-single-crystal transformation involving a discrete metal complex. On the other hand, the corresponding CoII complex (H9O4)[Co(PIMP)3]·(C4H10O)2(H2O)2 (2) does not exhibit similar phase transformations. In …
On the Rationalization of Formation of Solvates: Experimental and Computational Study of Solid Forms of Several Nitrobenzoic Acid Derivatives
2020
Analysis of crystal structures, molecular properties, interaction strength in solution and computationally generated non-solvated form solid form landscapes of five chloronitrobenzoic acid isomers ...
A thermally/chemically robust and easily regenerable anilato-based ultramicroporous 3D MOF for CO 2 uptake and separation
2021
The combination of the properly designed novel organic linker, 3,6-N-ditriazoyil-2,5-dihydroxy-1,4-benzoquinone (trz2An), with CoII ions results in a 3D ultramicroporous MOF with high CO2 uptake capacity and separation efficiency, with particular attention to CO2/N2 and CO2/CH4 gas mixtures. This material consists of 1D chains of octahedrally coordinated CoII ions linked through the anilato ligands in the equatorial positions and to the triazole substituents from two neighbouring chains in the two axial positions. This leads to a 3D microporous structure with voids with an affinity for CO2 molecules and channels that enable the selective entrance of CO2 but not of molecules with larger kine…
Co–Co and Co–Fe cyano-bridged pentanuclear clusters based on a methylpyrazinyl-diamine tetradentate ligand: spin crossover and metal substitution eff…
2017
A pentanuclear [CoII3CoIII2] cluster complex has been developed by a solvothermal synthesis. Its highly stable metal-mixed Fe–Co derivatives display robust spin crossover (T1/2 = 268 K) controlled by the degree of substitution.
Supramolecular Assembly of Organophosphonate Diesters Using Paddle-Wheel Complexes: First Examples in Porphyrin Series
2014
The reactions of dicopper tetrapivalate complex Cu2(μ-OOC-t-Bu)4(NCMe)2 (1) with triphenylphosphine oxide and diethyl phosphite allow paddle-wheel (PW) copper(II) complexes with phosphorus-containing axial ligands (2, 3) to be obtained. When meso-bis(diethoxyphosphoryl)porphyrins 4M were employed in this ligand exchange reaction, a series of one-dimensional (1D) homo- and heterometallic coordination polymers 5M composed of PW subunits and organophosphonate diesters were prepared and characterized by means of single crystal X-ray analysis. Planar porphyrinate 4Pd and nonplanar metalloporphyrinates 4Cu and 4Ni proved to be appropriate molecular structural blocks for assembly of coordination p…
Synthesis and solid state structure for a series of poly(1-pyrrolylmethyl)benzene derivatives. Control of the interplaying π–π and C–H⋯π interactions?
2006
The syntheses of new hexa- and 1,2,4,5-tetra-1-pyrrolylmethyl-benzene (1 and 2, respectively) compounds and their crystal structures, along with those for the related disubstituted o-, m- and p-di-1-pyrrolylmethyl-benzene (3–5) derivatives are reported. The arrangements of molecules in the 1-D structure for 2–5 are controlled by the interplay of two different weak interactions: π–π and C–H⋯π (Ph) interactions. The absence of such interactions in the packing of 1 seems to be related to the arrangement of the pyrrolylmethyl arms with respect to the benzene core, which prevents the π cloud of the aromatic ring to be part of any intermolecular interaction. In addition, C–H⋯π (pyrrolyl) interact…
Extending the halogen-bonded supramolecular synthon concept to 1,3,4-oxadiazole derivatives
2016
A series of five crystal structures of 1:1 halogen-bonded complexes were obtained from 4-[5-(4-alkoxyphenyl)-1,3,4-oxadiazole-2-yl]pyridine and 1,3,5-trifluorotriiodobenzene. Electronic structure calculations show that the N(oxadiazole)⋯I interaction in the new synthon is as strong as the classic N(pyridine)⋯I interaction. Oxygen to sulfur atom subsitution on the oxadiazole ring results in a different supramolecular packing where the N(pyridine)⋯I interaction is favored, which could be rationalized by the changes in the molecular electrostatic potential predicted from the theoretical calculations.