Franz A. Mautner

Bio: Franz A. Mautner is an academic researcher from Graz University of Technology. The author has contributed to research in topics: Azide & Crystal structure. The author has an hindex of 39, co-authored 197 publications receiving 5692 citations. Previous affiliations of Franz A. Mautner include University of Graz & University of the Basque Country.

Synthesis, Structural Characterization, Magnetic Behavior, and Single Crystal EPR Spectra of Three New One-Dimensional Manganese Azido Systems with FM, Alternating FM-AF, and AF Coupling

Abstract: Reaction of sodium azide with manganese(II) and pyridine derivatives such as 2-bzpy, 3-bzpy, and 3,5lut (2-benzoylpyridine, 3-benzoylpyridine, and 3,5-dimethylpyridine, respectively) led to the one-dimensional systems cis-[Mn(2-bzpy)(N3)2]n (1), trans-[Mn(3-Bzpy)2(N3)2]n (2), and cis-[Mn(3,5lut)2(N3)2]n (3). Compound 1 crystallizes in the P21/n group: a = 14.413(4) A, b = 16.157(4) A, c = 18.478(5) A, and Z = 12. Compound 2 crystallizes in the C2/c group: a = 14.179(5) A, b = 9.698(4) A, c = 34.351(12) A, and Z = 8. Compound 3 crystallizes in the P21/n group: a = 13.552(6) A, b = 7.730(3) A, c = 16.554(6) A, and Z = 4. Structural determination shows a chain with double μ1,1 azido bridges for 1, an alternating system with double μ1,1 and μ1,3 azido bridges for 2, and finally a chain with double μ1,3 azido bridges for 3. Susceptibility data show ferromagnetic coupling for 1, antiferromagnetic coupling for 3, and alternating ferro−antiferromagnetic interactions for 2. EPR data measured on powdered samples...

[N(CH3)4][Mn(N3)3]: A Compound with a Distorted Perovskite Structure through Azido Ligands

Abstract: C1O;. Satisfactory C, H. N analysis was obtained for the salt with the formula C,,,H,,N,,O,,CI,RuOs,.H,O. 2-(CIO,),: A solution of l-(ClO& (0.16 g. 0.045 mmol) in methanol (25 mL) was added to a solution of sodium methoxide formed by the addition of sodium metal (0.006 g. 0.26 mmol) to methanol (3 mL). The mixture was stirred for 10 min with heating and then cooled. The black solution was concentrated to half of its volume and kept in a refrigerator. Analytically pure black microcrystalline solid was ob- tained. Yield: 0.09 g (69%). UV:Vis (CH,CN):

Piezoelectric properties and phase transition temperatures of the solid solution of (1−x)(Bi0.5Na0.5)TiO3–xSrTiO3

Abstract: The phase diagram of (1 − x)(Bi0.5Na0.5)TiO3–xSrTiO3 was completed and investigations on polarization and strain in this system were carried out. (1 − x)(Bi0.5Na0.5)TiO3–xSrTiO3-ceramics were prepared by conventional mixed oxide processing. The depolarization temperature (Td), the temperature of the rhombohedral–tetragonal phase transition (Tr–t) and the Curie temperature (Tm) were determined by measuring the temperature dependence of the relative permittivity. All solid solutions of (1 − x)(Bi0.5Na0.5)TiO3–xSrTiO3 show relaxor behavior (A-site relaxor). From XRD-measurements a broad maximum of the lattice parameter can be observed around x = 0.5 but no structural evidence for a morphotropic phase boundary was found. SEM-analysis revealed a decrease of the grain size for increasing SrTiO3-content. At room temperature a maximum of strain of about 0.29% was found at x = 0.25 which coincides with a transition from a ferroelectric to an antiferroelectric phase. The temperature dependence of the displacement indicates an additional contribution from a structural transition (rhombohedral–tetragonal), which would be of certain relevance for the existence of a morphotropic phase boundary.

Topological Ferrimagnetic Behavior of Two New [Mn(L)2(N3)2]n Chains with the New AF/AF/F Alternating Sequence (L = 3-Methylpyridine or 3,4-Dimethylpyridine)

Abstract: The reaction of manganese(II) and pyridine derivatives such as 3-methylpyridine (3-Mepy) and 3,4-dimethylpyridine (3,4-Dmepy) led to the new one-dimensional systems trans-[Mn(3-Mepy)2(N3)2]n (1) and trans-[Mn(3,4-Dmepy)2(N3)2]n (2). Compound 1 crystallizes in the monoclinic system, space group P2(1)/n, a = 11.201(3) A, b = 14.499(4) A, c = 14.308(4) A, Z = 6, and compound 2 crystallizes in the triclinic system, space group P1, a = 11.502(4) A, b = 14.246(5) A, c = 16.200(8) A, Z = 6. The two compounds show the same general one-dimensional arrangement of double azido bridges between neighboring manganese atoms with the unprecedented -Mn-(mu(1,3)-N3)2-Mn-(mu(1,3)-N3)2-Mn-(mu(1,1)-N3)2-Mn- sequence. Susceptibility and magnetization measurements reveal a ferrimagnetic-like behavior derived from the topology of the chain. A model of the Heisenberg chain, comprising classical spins coupled through alternating exchange interactions J1J1J2... is proposed to describe the magnetic behavior.

Synthesis and Structural Characterization of [Mn(ethyl isonicotinate)2(N3)2]n, a Two-Dimensional Alternating Ferromagnetic−Antiferromagnetic Compound. Magnetostructural Correlations for the End-to-End Pseudohalide−Manganese System

Abstract: Three compounds with formula [Mn(L)2(N3)2]n, in which L is 4-acpy = 4-acetylpyridine (1), Etinc = ethyl isonicotinate (2), and py = pyridine (3), have been studied from the magnetic point of view. The new compound [Mn(L)2(N3)2]n (2) crystallizes in the monoclinic system, space group P21/a (No. 14), formula [C16H18MnN8O4], with a = 15.176(5) A, b = 9.060(3) A, c = 15.760(6) A, β = 111.62(3)°, and Z = 4. Compounds 1 and 2 are two-dimensional systems, whereas 3 is a 3-D compound. Compound 2 shows ferromagnetic Mn2(N3)2 dimeric entities linked antiferromagnetically to the four neighboring dimeric entities by four end-to-end azido bridges, leading to an alternate ferromagnetic−antiferromagnetic two-dimensional compound. MO calculations have been performed to study the superexchange pathway for the manganese 1,3-azido system.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Structural variation in copper(I) complexes with pyridylmethylamide ligands: structural analysis with a new four-coordinate geometry index, tau4.

Abstract: Four Cu(I) complexes were synthesized with a family of pyridylmethylamide ligands, HLR [HLR = N-(2-pyridylmethyl)acetamide, R = null; 2,2-dimethyl-N-(2-pyridylmethyl)propionamide, R = Me3; 2,2,2-triphenyl-N-(2-pyridylmethyl)acetamide, R = Ph3)]. Complexes 1–3 were synthesized from the respective ligand and [Cu(CH3CN)4]PF6 in a 2 : 1 molar ratio: [Cu(HL)2]PF6 (1), [Cu2(HLMe3)4](PF6)2 (2), [Cu(HLPh3)2]PF6 (3). Complex 4, [Cu(HL)(CH3CN)(PPh3)]PF6, was synthesized from the reaction of HL with [Cu(CH3CN)4]PF6 and PPh3 in a 1 : 1 : 1 molar ratio. X-Ray crystal structures reveal that complexes 1, 3 and 4 are mononuclear Cu(I) species, while complex 2 is a Cu(I) dimer. The copper ions are four-coordinate with geometries ranging from distorted tetrahedral to seesaw in 1, 2, and 4. Complexes 1 and 2 are very air sensitive and they display similar electrochemical properties. The coordination geometry of complex 3 is nearly linear, two-coordinate. Complex 3 is exceptionally stable with respect to oxidation in the air, and its cyclic voltammetry shows no oxidation wave in the range of 0–1.5 V. The unusual inertness of complex 3 towards oxidation is attributed to the protection from bulky triphenyl substituent of the HLPh3 ligand. A new geometric parameter for four-coordinate compounds, τ4, is proposed as an improved, simple metric for quantitatively evaluating the geometry of four-coordinate complexes and compounds.

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Abstract: : The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

MOFs, MILs and more: concepts, properties and applications for porous coordination networks (PCNs)

Abstract: This review (over 380 references) summarizes metal–organic frameworks (MOFs), Materials Institute Lavoisier (MILs), iso-reticular metal–organic frameworks (IR-MOFs), porous coordination networks (PCNs), zeolitic metal–organic frameworks (ZMOFs) and porous coordination polymers (PCPs) with selected examples of their structures, concepts for linkers, syntheses, post-synthesis modifications, metal nanoparticle formations in MOFs, porosity and zeolitic behavior for applications in gas storage for hydrogen, carbon dioxide, methane and applications in conductivity, luminescence and catalysis.