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Four novel CeIII mononuclear complexes of formulas [Ce(ntfa)3(MeOH)2] (1), [Ce(ntfa)3(5,5′-Me2bipy)] (2), [Ce(ntfa)3(terpy)] (3), and [Ce(ntfa)3(bipy)2] (4), where ntfa = 4,4,4-trifluoro-1-(naphthalen-2-yl)butane-1,3-dionato, 5,5′-Me2bipy = 5,5′-dimethyl-2,2′-dipyridyl, terpy = 2,2′:6′,2″-terpyridine, and bipy = 2,2′-bipyridine, have been synthesized and structurally characterized with CeIII displaying coordination numbers of 8, 8, 9, and 10, respectively. Magnetic measurements indicate that all the complexes show a field-induced single-ion magnet behavior under a small applied dc field. The magnetic analysis shows the relevance of the different spin relaxation mechanisms in the magnetic relaxation of the CeIII compounds, with special emphasis on the local-mode process. Multiconfigurational calculations were also performed to get more information on the axiality of the compounds.

Abstract Six mixed metal complexes with 3-aminopyridine (3-ampy) as a co-ligand have been synthesized: catena-{[M(μ2-3-ampy)(H2O)4]SO4·H2O} (M=Ni (1) and Co (2)), [Co(3-ampy)4(NCS)2] (3), [Co(3-ampy)2(NCS)2] (4), [Co(3-ampy)4(N3)2] (5) and mer-[Co(3-ampy)3(N3)3] (6), (NCS−=isothiocyanate ion, N3− azide ion), and characterized by physio-chemical and spectroscopic methods as well as single crystal X-ray and powder diffraction. In the isostructural complexes 1 and 2 single μ2-3-ampy links the Ni(II) and Co(II) centers into polymeric chains. The mononuclear Co(II) and Co(III) pseudohalide complexes 3–6 reveal only terminal 3-ampy ligands. The 3-ampy ligands form supramolecular hydrogen bonded systems via their NH2-groups and non-covalent π-π ring-ring interactions via their pyridine moieties. Thermoanalytical properties were investigated for 1–3. Graphic abstract

Six pseudohalide zinc(II) containing a variety of N-donor auxiliary amines were structurally characterized. These include two mononuclear trigonal bipyramidal [Zn(NTB)(N3)]ClO4·½H2O (3) and [Zn(TPA)(NCS)]ClO4 (4), two distorted octahedral [Zn(1,8-damnph)2(dca)2] (5) and [Zn(8-amq)2(dca)2] (6a) as well as two 1D polymeric chains catena-[Zn(isq)2(μ1,5-dca)2] (7) and catena-[Zn(N,N-Me2en)2(μ1,5-dca)]dca (8), where NTB = tris(2-benzimidazolylmethyl)amine, TPA = tris(2-pyridylmethyl)amine, 1,8-damnph = 1,8-diaminonaphthalene, 8-amq = 8-amino-quinoline, isq = isoquinoline (isq) and N,N-Me2en = N,N-dimethylethylenediamine. In general, with the exception of 6 and 8, the complexes exhibited luminescence emission in MeOH associated with red shift of the emission maxima, and the strongest visible fluorescence peak was detected at 421 nm (λex = 330 nm) in the case of Complex 5.

The synthesis and structural characterization of six dicyanamido-cadmium(II) complexes are reported: catena-[Cd(μ1,3-dca)(μ1,5-dca)(3-ampy)] (1), catena-[Cd3(μ1,3,5-dca)2(μ1,5-dca)4(pyNO)2(H2O)2] (2), catena-{Cd(H2O)2(μ1,5-dca)2](2,6-lut-NO)} (3), catena-[Cd(Me2en)(μ1,5-dca)2] (4), catena-[Cd(Me4en)(μ1,5-dca)2] (5), and [Cd(1,8-damnp)2(dca)2] (6), where dca = dicyanamide anion, 3-ampy = 3-aminopyridine, pyNO = pyridine-N-oxide, 2,6-lut-NO = 2,6-lutidine-N-oxide, Me2en = N,N-dimethyl-ethylenediamine, Me4en = N,N,N′,N′-tetramethyl-ethylenediamine, and 1,8-damnp = 1,8-diaminonaphthaline. The coordination polymers have different dimensionalities: 1 and 5 form 3D networks structures, 3 and 4 form polymeric 1D chains and 1DD double chains, respectively. Ribbons of three fused polymeric chains are observed in 2. In 6, the mononuclear complex units form a hydrogen-bonded supramolecular 3D network. In the coordination polymer compounds, the dca linkers display three bonding modes: the most common μ1,5-dca and the least popular μ1,3- and μ1,3,5-dca bonding. The luminescence emission and thermal properties of the complexes were investigated.

Ten mononuclear rare earth complexes of formula [La(btfa)3(H2O)2] (1), [La(btfa)3(4,4′-Mt2bipy)] (2), [La(btfa)3(4,4′-Me2bipy)2] (3), [La(btfa)3(5,5′-Me2bipy)2] (4), [La(btfa)3(terpy)] (5), [La(btfa)3(phen)(EtOH)] (6), [La(btfa)3(4,4′-Me2bipy)(EtOH)] (7), [La(btfa)3(2-benzpy)(MeOH)] (8), [Tb(btfa)3(4,4′-Me2bipy)] (9) and (Hpy)[Eu(btfa)4] (10), where btfa = 4,4,4-trifuoro-1-phenylbutane-1,3-dionato anion, 4,4′-Mt2bipy = 4,4′-dimethoxy-2,2′-bipyridine, 4,4′-Me2bipy = 4,4′-dimethyl-2,2′-bipyridine, 5,5′-Me2bipy = 5,5′-dimethyl-2,2′-bipyridine, terpy = 2,2′:6′,2′-terpyridine, phen = 1,10-phenathroline, 2-benzpy = 2-(2-pyridyl)benzimidazole, Hpy = pyridiniumH+ cation) have been synthesized and structurally characterized. The complexes display coordination numbers (CN) eight for 1, 2, 9, 10, nine for 5, 6, 7, 8 and ten for 3 and 4. The solid-state luminescence spectra of Tb-9 and Eu-10 complexes showed the same characteristic bands predicted from the Tb(III) and Eu(III) ions. The Overall Quantum Yield measured (ϕTOT) at the excitation wavelength of 371 nm for both compounds yielded 1.04% for 9 and up to 34.56% for 10.

Five-coordinate Cu(II) complexes, [Cu(Ln)X]ClO4/PF6, where Ln = piperazine ligands bearing two pyridyl arms and X = ClO4− for Ln = L1 (1-ClO4), L2 (2-ClO4), L3 (3-ClO4), and L6 (6-ClO4) as well as [Cu(Ln)Cl]PF6 for Ln = L1 (1-Cl), L4 (4-Cl), and L5 (5-Cl) have been synthesized and characterized by spectroscopic techniques. The molecular structures of the last two complexes were determined by X-ray crystallography. In aqueous acetonitrile solutions, molar conductivity measurements and UV-VIS spectrophotometric titrations of the complexes revealed the hydrolysis of the complexes to [Cu(Ln)(H2O)]2+ species. The biological activity of the Cu(II) complexes with respect to DNA cleavage and cytotoxicity was investigated. At micromolar concentration within 2 h and pH 7.4, DNA cleavage rate decreased in the order: 1-Cl ≈ 1-ClO4 &gt, 3-ClO4 ≥ 2-ClO4 with cleavage enhancements of up to 23 million. Complexes 4-Cl, 5-Cl, and 6-ClO4 were inactive. In order to elucidate the cleavage mechanism, the cleavage of bis(4-nitrophenyl)phosphate (BNPP) and reactive oxygen species (ROS) quenching studies were conducted. The mechanistic pathway of DNA cleavage depends on the ligand’s skeleton: while an oxidative pathway was preferable for 1-Cl/1-ClO4, DNA cleavage by 2-ClO4 and 3-ClO4 predominantly proceeds via a hydrolytic mechanism. Complexes 1-ClO4, 3-ClO4, and 5-Cl were found to be cytotoxic against A2780 cells (IC50 30–40 µM). In fibroblasts, the IC50 value was much higher for 3-ClO4 with no toxic effect.

A series of dinuclear metal(ii)-acetato complexes: [Ni2(μ-L(Cl)O)(μ2-OAc)2](PF6)·3H2O (1), [Ni2(μ-L(Cl)O)(μ2-OAc)2](ClO4)·CH3COCH3 (2), [Cu2(μ-L(Cl)O)(μ2-OAc)(ClO4)](ClO4) (3), [Cu2(μ-L(Cl)O)(OAc)2](PF6)·H2O (4), [Zn2(μ-L(Cl)O)(μ2-OAc)2](PF6) (5) and [Mn2(L(Cl)-O)(μ2-OAc)2](ClO4)·H2O (6), where L(Cl)O(-) = 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-chlorophenolate, were synthesized. The complexes were structurally characterized by spectroscopic techniques and single crystal X-ray crystallography. Six-coordinate geometries with doubly bridged acetato ligands were found in Ni(ii), Zn(ii) and Mn(ii) complexes 1, 2, 5 and 6, whereas with Cu(ii) complexes a five-coordinate species was obtained with 4, and mixed five- and six-coordinate geometries with a doubly bridged dimetal core were observed in 3. The magnetic properties of complexes 1-4 and 6 were studied at variable temperatures and revealed weak to very weak antiferromagnetic interactions in 1, 2, 4 and 6 (J = -0.55 to -9.4 cm(-1)) and ferromagnetic coupling in 3 (J = 15.4 cm(-1)). These results are consistent with DFT calculations performed at the B3LYP/def2-TZVP(-f) level of theory. Under physiological conditions, the interaction of the dinculear complexes 1-5 with supercoiled plasmid ds-DNA did not show any pronounced nuclease activity, but Ni(ii) complexes 1 and 2 revealed a strong ability to unwind the supercoiled conformation of ds-DNA. The mechanistic studies performed on the interaction of the Ni(ii) complexes with DNA demonstrated the important impact of the nickel(ii) ion in the unwinding process. In combination with the DNA study, the phosphatase activity of complexes 1, 3, and 5 was examined by the phosphodiester hydrolysis of bis(2,4-dinitrophenol)phosphate (BDNPP) in the pH range of 5.5-10.5 at 25 °C. The Michaelis-Menten kinetics performed at pH 7 and 10.7 showed that catalytic efficiencies kcat/KM (kcat = catalytic rate constant, KM = substrate binding constant) decrease in the order: Ni(ii), 1 > Zn(ii), 5 > Cu(ii), 3. A similar trend was also observed with the turnover numbers at pH = 7. The results are discussed in relation to the coordination geometry and nature of the metal center as well as the steric environment imposed by the compartmental phenoxido ligand.

With an aim to study the electronic effect of the group lying in the para-position of phenol-based compartmental Mannich-base ligands, five dinuclear nickel(II) complexes [Ni2L1−5(μ-NO3)(NO3)2] have been synthesized [R = Me (1), CHMe2 (2), CMe3 (3), Cl (4), and OMe (5)] having octahedral structures (fac-manner) in each case as confirmed by single-crystal X-ray diffraction (1–4). The Ni⋯Ni distance (3.42–3.49 A) and Ni–O–Ni bridging bond angle (118.62–121.45°) of 1–4 is proportional to the electronic partial charge (I-effect) of the para-substituents as 3 2 > 5 > 1 > 4 in terms of kcat values (6–81 s−1), as per the Michaelis–Menten profile. DFT calculations establish that the electron-donating group decreases the reaction energy barrier via reducing the energy gap between the orbital of electron-sufficient para-substituted phenolate group and the electron-demanding leaving group. The exceptionally high activity of complex 3 also establishes the rationality of our catalyst design in our previous work (Inorg. Chem. 2015, 54, 2315–2324).

A series of Cu(II)-thiocyanato complexes derived from sterically hindered N-donors diamines were synthesized and characterized: catena-[Cu(Me3en)(μ-NCS)(NCS)] (1), catena-[Cu(NEt2Meen)(μ-NCS)(NCS)] (2), catena-[Cu(N,N,2,2-Me4pn)(μ-NCS)(NCS)] (3), the dimeric: [Cu2(N,N′-isp2en)2(μ-NCS)2(NCS)2] (4) and the monomeric complex [Cu(N,N′-t-Bu2en)(NCS)2] (5), where Me3en = N,N,N′-Trimethylethylenediamine, NEt2Meen = N,N-diethyl-N′-methylethylenediamine, N,N,2,2-Me4pn = N,N,2,2-tetramethylpropylenediamine, N,N′-isp2en = N,N′-diisopropylethylenediamine and N,N′-t-Bu2en = N,N′-di(tert-butyl)ethylenediamine. The complexes were characterized by elemental microanalyse, IR and UV-Vis spectroscopy and single crystal X-ray crystallography. Density Functional Theory was used to evaluate the role of steric effects in compounds 4 and 5 and how this may affect the adaption of a specific geometry, NCS-bonding mode and the dimensionality of the resulting complex.

Four bridged-azido Cu(II) complexes were synthesized and structurally characterized: [Cu-2(Et(3)en)(2)(mu(1,1)-N-3)(2)(N-3)(2)] (1), [Cu-2(ip(2)en)(2)(mu(1,1)-N-3)(2)(N-3)(2)] (2), catena-[Cu-2(Et(2)Meen)(2)(mu(1,3)-N-3)(3)]ClO4 (3) and catena-[Cu(ambza)(mu(1,1,3)-N-3)(2)] (4), where Et(3)en = N, N, N'-triethyl-1,2-diaminoethane; ip(2)en = N, N'-diisopropyl-1,2-diaminoethane; Et(2)Meen = N, N-diethyl-N'-methyl-1,2-diaminoethane; and ambza = 2-aminobenzylamine. Single crystal X-ray crystallography revealed that complexes 1 and 2 are dinuclear with doubly bridged mu(1,1)-N-3, whereas complexes 3 and 4 constitute polymeric species with an alternative sequence of single and double mu(1,3)-N-3 bridges for 3 with a 1D chain, and triple mu(1,1,3)-bridging azide in 4 with a 2D extended structure. Variable temperature magnetic susceptibilities over the temperature range of 2-298 K revealed a weak antiferromagnetic coupling (J = -1.8 cm(-1)) for 1, and a ferromagnetic coupling with J values of 7.0 and 7.7 cm(-1), respectively, for complexes 2 and 4, respectively. Compound 3 shows a new topology for Cu(II) alternating chains [Cu(1)(mu(1,3)-N-3)(2)Cu(1')]-(mu(1,3)-N-3)-[Cu(2')(mu(1,3)-N-3)(2)Cu(2 '')]-(mu(1,3)-N-3)-[Cu(1)(mu(1,3)-N-3)(2)Cu(1')]-... Three different coupling constants were obtained through a fitting procedure and by DFT calculations.

Three coordination polymers of metal(II)-dicyanamido (dca) complexes with 4-methoxypyridine-N-oxide (4-MOP-NO), namely, catena-[Co(&micro, 1,5-dca)2(4-MOP-NO)2] (1), catena-[Mn(&micro, 1,5-dca)2(4-MOP-NO)2] (2), catena-[Cd(&micro, 1,5-dca)2(4-MOP-NO)2] (3), and the mononuclear [Cu(&kappa, 1dca)2(4-MOP-NO)2] (4), were synthesized in this research. The complexes were analyzed by single crystal X-ray diffraction as well as spectroscopic methods (UV/vis, IR). The polymeric 1-D chains in complexes 1&ndash, 3 were achieved by the doubly &micro, 1,5-bridging dca ligands and the O-donor atoms of two axial 4-MOP-NO molecules in trans configuration around the distorted M(II) octahedral. On the other hand, the two &ldquo, trans-axial&rdquo, pyridine-N-oxide molecules in complexes 2 and 3 display opposite orientation (s-trans). The DFT (density functional theory) computational studies on the complexes 1&ndash, 3 were consistent with the experimentally observed crystal structures. Compounds 1 and 2 display weak antiferromagnetic coupling between metal ions (J = &minus, 10.8 for 1 and &minus, 0.35 for 2).

A series of Cu(II)-isothiocyanato coordination compounds derived from sterically hindered N-donor diamines were synthesized and characterized: catena-[Cu(Me3en)(&mu, NCS)(NCS)] (1), catena-[Cu(NEt2Meen)(&mu, NCS)(NCS)] (2), catena-[Cu(N,N,2,2-Me4pn)(&mu, NCS)(NCS)] (3), the dimeric: [Cu2(N,N&prime, isp2en)2(&micro, NCS)2(NCS)2] (4) and the monomeric compound [Cu(N,N&prime, t-Bu2en)(NCS)2] (5), where Me3en = N,N,N&prime, trimethylethylenediamine, NEt2Meen = N,N-diethyl-N&prime, methylethylenediamine, N,N,2,2-Me4pn = N,N,2,2-tetramethylpropylenediamine, N,N&prime, isp2en = N,N&prime, diisopropylethylenediamine and N,N&prime, t-Bu2en = N,N&prime, di(tert-butyl)ethylenediamine. The coordination compounds were characterized by elemental microanalyses, IR, and UV&ndash, Vis spectroscopy as well as single crystal X-ray crystallography. Density Functional Theory (DFT) was used to evaluate the role of steric effects in compounds 4 and 5 and how this may affect the adaption of a specific geometry, NCS-bonding mode, and the dimensionality of the resulting coordination compound.

Synthetic methods have been developed to prepare novel 1,3-benzotellurazoles carrying acylamino and arylamino moieties in position 2, in order to investigate their propensity to self-assemble to supramolecular structures. The targeted compounds were obtained in yields ranging from 44% to 67%, by reacting bis(2-aminophenyl) ditelluride with acyl- and aryl isothiocyanates, respectively, and subsequent reductive cyclization of the resulting thiourea derivatives. Seven novel 1,3-benzotellurazole derivatives were prepared: 2-benzoylamino-1,3-benzotellurazole, 2-(4-chlorobenzoylamino)-1,3-benzotellurazole, 2-(2-bromobenzoylamino)-1,3-benzotellurazole, 2-(4-bromobenzoylamino)-1,3-benzotellurazole, 2-(4-methoxybenzoylamino)-1,3-benzotellurazole, 2-phenylamino-1,3-benzotellurazole, and 2-(4-chlorophenylamino-1,3-benzotellurazole. A simplified protocol was employed to synthesize all acyl isothiocyanates needed for their preparation from benzoyl halide derivatives and potassium thiocyanate. The reductive cyclization of the intermediate thioureas was challenging, only the use of hydroxymethanesulfinate in the presence of elemental mercury provided synthetically useful product yields. A mechanism was proposed, consisting of the insertion of mercury into the Te-Te bond, followed by intramolecular nucleophilic attack of the thiocarbonyl moiety by the resulting insertion product. All 2-acylamino-1,3-benzotellurazoles are crystalline solids, which are stable to ambient light, air and moderate heat. A characterization of selected samples by X-ray crystallography indicated that they form dimers in solid state, resulting from hydrogen bonding between the exocyclic and endocyclic nitrogen atoms of two adjacent molecules. This sets them apart from 2-alkyl- and 2-aryl-1,3-benzotellurazoles, which are known to self-assemble into supramolecular wires.

Five mono-nuclear Cu(II) and Ni(II) complexes and one dinuclear Zn(II) complex were synthesized from the Schiff bases N,N'-bis(3-ethoxy-2-hydroxybenzylidene)-1,2-phenylenediamine (H2LOEt-phda) and 2-ethoxy-6-({2-[(3-ethoxy-2-hydroxybenzylidene)amino]-benzyl}iminomethyl)phenol (H2LOEt-ambza): [Cu(LOEt-phda)(H2O)].H2O (1), [Ni(LOEt-phda)].H2O (2), [Cu(LOEt-ambza)].H2O·EtOH (3), [Cu(LOEt-ambza)].H2O (4), [Ni(LOEt-ambza)] (5) and [Zn2(LOEt-ambza)(μ-OAc)(OAc)] (6). The complexes were structurally characterized with elemental microanalyses, IR, UV-Vis and ESI-MS spectroscopic techniques as well as single crystal X-ray crystallography. The metal centers display distorted square planar geometries in 2–4 and 5 and distorted square pyramidal (SP) in 1, whereas in 6 an intermediate geometry between SP and TBP was observed around the first Zn2+ ion and a tetrahedral around the second ion, with one acetate is acting as a bridging ligand. In all cases, metal ions were incorporated into the N2-O2 binding site with no involvement of the alkoxy groups in the coordination. The LOEt-ambza-complexes 3–6 revealed significant dihedral angles between the phenol rings and the plane containing the central benzene ring, and large O2-O2 bond distances (5.1-5.9 Ǻ). Results are discussed in relation to other related Schiff base complexes.

The syntheses and structural characterization of three new monodimensional azido-bridged manganese(II) complexes with empirical formulae [Mn(N3)2(aminopyz)2]n (1), [Mn(N3)2(4-azpy)2]n (2) and [Mn(N3)2(4-Bzpy)2]n (3) (pyz = pyrazine (1,4-diazine)), 4-azpy = 4-azidopyridine and 4-Bzpy = 4-benzoylpyridine) are reported. 1 is a monodimensional compound with double EO azido bridges, 2 is an alternating monodimensional compound with double end-on and double end-to-end azido bridges in the sequence di-EO-di-EE and 3 is a monodimensional compound with double end-on and double end-to-end azido bridges in the sequence di-EO-di-EO-diEO-di-EO-di-EE. The magnetic properties of 1–3 are reported. Periodic DFT calculations were performed to estimate the J values and quantum Monte Carlo simulations were carried out using the calculated J values to check their accuracy in comparison with the experimental magnetic measurements. From this theoretical analysis, two appealing features of the di-EO Mn(II) compounds can be extracted: first, the exchange coupling becomes more ferromagnetic when the Mn–N–Mn bridging angle becomes larger and the spin density of the bridging nitrogen atoms has an opposite sign to that of the Mn(II) centers.

The reaction of a methanolic solution containing the bi-compartmental phenolic ligand 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-chlorophenol (LCl-OH) with MCl2·nH2O in the presence of NH4PF6 or NaClO4 afforded the dinuclear bridged-phenoxido dichlorido-metal(II) complexes [Co2(μ-LClO)(H2O)2Cl2][Co2(μ-LClO)(MeOH)2Cl2](PF6)2 (1), [Ni2(μ-LClO)(MeOH)2Cl2]PF6 (2), [Ni2(μ-LClO)(MeOH)(H2O)Cl2]ClO4·1.25H2O (3), [Cu2(μ-LClO)Cl2]PF6·1/2MeOH (4) and [Zn2(μ-LClO)Cl2]PF6·MeOH (5). The complexes were characterized by elemental microanalyses, conductivity measurements, IR and UV-Vis spectroscopy, mass spectrometry and single crystal X-ray crystallography. Each M(II) center within the dinuclear complex cations is octahedrally coordinated in complexes 1–3, and five-coordinated distorted square pyramidal in 4 and 5. Magnetic susceptibility measurements at variable temperature of the complexes 1–4 revealed weak to moderate antiferromagnetic coupling with |J| values = 8.38, 39.0, 30.2 and 0.79 cm−1, respectively. The results of DFT calculations correlate well with the experimentally determined antiferromagnetic coupling and show that the magnetic exchange coupling occurs mainly through the phenoxido bridge M–O–M. Implications of geometry around the central metal ion, M⋯M distance, M–O–M bond angle and overlapping of magnetic orbitals on the magnetic exchange coupling are discussed.

Since the commercialization of rechargeable lithium-ion energy storage systems in the early 1990s, graphite intercalation compounds (GICs) have served as the number one negative electrode material in most of today's batteries. During charging the performance of a battery is closely tied with facile Li insertion into the graphite host structure. So far, only occasionally time-domain nuclear magnetic resonance (NMR) measurements have been reported to study Li self-diffusion parameters in GICs. Here, we used several NMR techniques to enlighten Li hopping motions from an atomic-scale point of view. Li self-diffusion in the stage-1 GIC LiC${}_{6}$ has been studied comparatively by temperature-variable spin-spin relaxation NMR as well as (rotating frame) spin-lattice relaxation NMR. The data collected yield information on both the relevant activation energies and jump rates, which can directly be transformed into Li self-diffusion coefficients. At room temperature the Li self-diffusion coefficient turns out to be ${10}^{\ensuremath{-}15}\phantom{\rule{0.28em}{0ex}}{\mathrm{m}}^{2}\phantom{\rule{0.28em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$, thus, slightly lower than that for layer-structured cathode materials such as Li${}_{x\ensuremath{\approx}0.7}$TiS${}_{2}$.

The reactivity of carboxybenzoic acids substituted in ortho, meta and para positions (phthalic, isophthalic and terephthalic acids) has been explored. These acids have been used for the synthesis of dinuclear Mn III and polynuclear Mn II compounds, obtaining unexpected results. From all the reactions, one dinuclear Mn III compound, [{Mn(H 2O)(phen)} 2(μ-2-COOHC 6H 4COO) 2(μ-O)](ClO 4) 2 (1), one mixed valence compound, [{Mn(phen) 2} 2(μ-O) 2](NO 3) 3 (2), and four Mn II compounds, [{Mn(H 2O)(phen) 2} 2(μ-4-COOC 6H 4COO)](NO 3) 2 (3), [Mn 3(μ-4- COOC 6H 4COO) 3(bpy) 2] n (4), [{Mn(phen) 2} 2(μ-2-COOHC 6H 4COO) 2](ClO 4) 2 (5) and [Mn(μ-2-COOC 6H 4COO)(H 2O) 2(phen)] n (6), (phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine) have been obtained and characterised by X-ray diffraction, showing different coordination modes for the carboxylate ligand: a bidentate bridge in a syn-syn, syn-anti or anti-anti mode, a bis-monodentate bridge and a bis-bidentate bridge. The six compounds show antiferromagnetic coupling, with magnetic interaction constants of -3.7 and -332.5 cm -1 for the dinuclear Mn III (1) and Mn IIIMn IV (2) compounds and -0.04, -4.5, -1.5 and -0.55 cm -1 for Mn II compounds 4-6. Each Mn II compound shows a different EPR spectrum at 4 K, which has been simulated including the ZFS parameters. The catalase activity of the compounds with phthalate and terephthalate ligands has been studied, the former being less active than the latter. © 2012 Elsevier Ltd. All rights reserved., This work was supported by the Ministerio de Ciencia e Innovación of Spain through the project CTQ2009-07264/BQU, the Comissió Interdepartamental de Recerca i Innovació Tecnològica of la Generalitat de Catalunya (CIRIT) (2009-SGR1454). V.G. thanks the Ministerio de Ciencia e Innovación for the PhD grant BES-2007-15668. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

The structures of [Cu(pic)(NCS)(H2O)2] · 2H2O, complex 1, and [Na2Co(pic)2(N3)2(H2O)6][Co(pic)2(N3)2] · 2H2O, complex 2, were determined by X-ray crystallography. Crystal data: 1, C7H12CuSN2O6, orthorhombic, space group Pbca, a = 8.749(4), b = 10.786(5), c = 26.882(9) Å, Z = 8, Rw =0.046 for 826 observed diffractometer data; 2, C24H32Co2Na2N16O16, triclinic, space group P1̄, a = 7.297(3), b = 8.806(4), c = 15.820(7) Å, a = 105.31(3), β = 95.09(3), γ = 99.86(3)°, Z = 1, and Rw = 0.064 for 1680 observed MoKa data. Complex 1 features six-coordinated copper atoms, N,O-bidentate chelate picolinato anions, and μ(N,S) bridging thiocyanato groups with N at the basal site and S at the apical site of tetragonal bipyramid. The remaining two sites are occupied by aqua molecules, whereas two other water molecules serve as lattice water. The bridging thiocyanato groups link the copper polyhedra to form chains along the b axis of the unit cell. Complex 2 contains two Co(III) atoms located at different inversion centers. Co 1 in the [Na2Co(pic)2(N3)2(H2O)6]+ cation is six-coordinated by two trans picolinato anions (A) via their N 1 and O 1 atoms and by two terminal azido ligands. Two oxygen atoms (O 2 and O 2a) of two picolinate anions (A) act as μ(Ο,Ο) bridging atoms at basal sites to form a four-membered Na2O2 ring. Each sodium atom is further linked to three aqua ligands giving rise to trigonal-bipyramidal coordination environments. Two additional lattice water molecules are located between the dimeric sodium polyhedra. Co 2, in the [Co(pic)2(N3)2]- anion, is also six-coordinated by pairs of trans N,O-picolinate anions (B) and terminal azido groups.

The structures of two polymeric complexes of chromium(III) azide with pyridine, KCr(py)4(N3)4 (1), and RbCr(py)3(N3)4 (2), were determined by X-ray crystallography. Crystal data: 1, C20H20N16CrK, monoclinic, space group C2/c, a = 1611.2(5), b = 1050.6(3), c = 1609.0(5) pm, β = 91.69(3)°, Ζ = 4 and Rw = 0.037 for 923 diffractometer data; 2, C15H15N15CrRb, monoclinic, space group P21/n, a = 1311.9(3), b = 1139.0(4), c = 1523.3(4) pm, β = 109.39(2)°, Ζ = 4 and Rw = 0.046 for 2336 data. The crystal structure of 1 contains six-coordinated chromium and potassium cations with two pyridine ligands and four µ(1,3) bridging azido groups forming a three-dimensional network structure. The chromium atoms are trans-coordinated by the pyridine ligands, whereas the potassium cations are cis-coordinated. The polymeric complex 2 features di-µ(l,1,3) azido bridged CrRbN2 rings, distorted octahedral chromium(III) coordination geometry, sevencoordinated rubidium, and di-μ(1,3) azido bridges which link the binuclear RbCr(pyridine)3(N3)2 moieties into infinite chains parallel to the b axis.

The structures of mer-Cr(py)3(N3)3 (1) and polymeric NaCr(py)4(N3)4 (2) were determined by X-ray crystallography. Crystal data; 1, C15H15N12Cr, triclinic, space group P1̄, a = 895.3(2), b = 999.1(3), c = 1269.9(5) pm , α = 106.76(3), β = 96.69(3), γ = 116.30(2)°, V = 943.8(6) · 106 pm3, Z = 2 and Rw = 0.038 for 1736 observed MoKα diffractometer data; 2, C20H20N16CrNa, monoclinic, space group C2/c, a = 1561.2(3), b = 1028.8(2), c = 1573.6(4) pm, β = 90.70(2)°, V = 2 527.3(9) · 106 pm3, Z = 4 and = 0.033 for 1272 MoKα diffractometer data. The coordination around the chromium (III) ion in the discrete molecules of 1 is six-coordinate with mean distances Cr-N(py) of 210.2(4) pm and Cr-N(N3) of 200.8(4) pm. The terminal azido ligands are almost linear and asymmetric, the N-N bonds nearer to the metal (118.8(6) to 120.5(7) pm) being significantly longer than the terminal ones (114.7(7) to 115.5(7) pm). In compound 2, each chromium or sodium cation is six-coordinated by four azido groups and two pyridine molecules. The azido groups act as μ(1,3) bridging ligands between chromium and sodium octahedra to form a three-dimensional network structure. The chromium atoms are trans-coordinated by the pyridine ligands whereas the sodium cations are cis-coordinated.

{The use of di-2-pyridyl ketone {[}(2-py)(2)CO]/dicyanamide ``blend{''} in cobalt(II), manganese(II) and nickel acetate chemistry has yielded neutral cubane clusters. The preparation of {[}Mn-4(O2CMe)(2)\{N(CN)(2)\}(2)\{(2-py)(2)C(OH)O\}(4)]-2(2-py)(2)CO-4H( 2)O (1) and {[}M-4(O2CMe)(2)\{N(CN)(2)\}(2)\{(2-py)(2)C(OH)O\}(4)]center dot 10H(2)O {[}M = Ni (2), Co (3)] was achieved by the reaction of {[}M(O2CMe)(2)]center dot 4H(2)O with (2-py)(2)CO and Na{[}N(CN)(2)] in MeOH/H2O (1:5, v/v) at room temperature. The metal(II)-mediated hydrolysis of (2-py)2CO to give the coordinated monoanion of the hydrate gem-diol form involves a nucleophilic attack of H2O on the carbonyl group. In the case of the cobalt reaction system, there is a second product. Upon employing an excess of (2-py)2CO, long reaction times, reflux conditions and high dilution, slow oxidation of Co-II takes place leading to the isolation of the mononuclear cobalt(111) complex {[}Co\{(2-py)(2)C(OH)O\}(2)]{[}N(CN)(2)]center dot 4H(2)O (4) in yields higher than 70\%. The structures of 1, 2 and 4 have been solved by single-crystal X-ray diffraction studies, while a unit-cell determination indicated that complex 3 is isostructural with 2. The tetranuclear cluster molecules of 1 and 2 have cubane {[}M-4(mu(3)-OR)(4)](4+) cores with divalent metal atoms and deprotonated oxygen atoms {[}originating from the (2-py)2C(OH)O- ligands] occupying alternate vertices. The centrosymmetric {[}Co\{(2-py)(2)C(OH)O\}(2)](+) cation of complex 4 has an octahedral structure with the (2-py)(2)C(OH)O- ligands adopting the tridentate N,O,N'-chelating coordination mode. The magnetic properties of 1-3 have been studied by variable-temperature dc magnetic susceptibility techniques. The studies indicate weak antiferromagnetic coupling for 1 and ferromagnetic behaviour for 2 and 3. A three-J model was found to be adequate for describing the thermal variation of the molar magnetic susceptibilities of 1 and 2. The magnetochemical results have been compared with literature data. ((c) Wiley-VCH Verlag GmbH \& Co. KGaA, 69451 Weinheim, Germany, 2005).}

The structure of a 1:2 complex of manganese(I1) azide with pyridine has been determined by X-ray crystallography. The crystals are tetragonal and belong to the space group I 4Ja, with a = 1551.7(4), c = 1003.1(1) pm and Z = 8. The structure has been refined to R = 0.67 for 1152 observed MoKa diffractometer data. The manganese atom is octahedrally coordinated by six ligand nitrogen atoms at distances of 219.5(5), 221.7(4) and 225.9(3) pm. These octahedra are linked together by the p(1,3)-azido ligands to form a three dimensional network. The azide groups are almost linear and appear to be symmetrical, the N-N distances being 115.1(6) and 117.0(5) pm. The symmetry of the azido ligands is confirmed by disappearance of the v"N3 mode from the infrared spectrum.

The crystal structure of calcium azide dihydrate trans-bicyclo-[4.4.0]-1,4,6.9-tetraazadecane has been determined by single crystal X-ray diffraction at 100 K. [Ca(N3)2(H2O)2 (C6H14N4 crystallizes in the orthorhombic space group Pnma, Z = 4. with a - 1396.6(5), b = 1407.1(5), c = 712.2(2) pm. Calcium is hexacoordinated to four azide groups and two water molecules. The elongated octahedra are linked via μ(1,3)-bridging azide ions to form monolayers parallel to the ac-plane. The C6H14N4 molecules are arranged between these layers.

Zinc azide · 4-methylpyridine (1) is formed by the reaction of zinc azide with the corresponding pyridine in aqueous solution. The crystal structure was determined by single crystal X-ray diffraction methods. The crystals of 1 are monoclinic, space group C2/c, Z = 4, a = 1085.5(2), b = 1692.7(11), c = 619.7(6) pm, β = 113.47(5)°. Each zinc atom is surrounded by five nitrogen atoms (four from azide groups and one from the pyridine adduct) in a distorted trigonal bipyramidal fashion. The ZnN5-polyhedra share common edges to form chains along the crystallographic c-axis.

Karl Viëtors Studie in PMLA, LIX, 142–183 hat unter anderem überzeugend dargetan, daβ der Zusatz Ist fortzusetzen zu Goethes Gedicht auf Schillers Schädel weder eine Wiederaufnahme des Wilhelm Meister im Sinn hat, noch besagen will, daβ das Gedicht als solches fortgesetzt, gewiβermaβen verlängert hätte werden sollen. Goethe habe vielmehr an ein zweites oder eine Reihe weiterer Gedichte gedacht, die sich mit Problemen der Naturphilosophie befaβt hätten, wie sie im Gedicht angedeutet sind.

Als Gottfried Christoph Lichtenberg 1799 starb, war er der öffentlichen Meinung als angesehener Physiker und als viel bewunderter satirischer Schriftsteller bekannt, der allerdings mit dem Aufstieg der deutschen Literatur nicht habe Schritt halten können. Von dem Zeitpunkte aber an, da sein Bruder, bald nach Lichtenbergs Tode, aus dem Nachlaβ die Notizhefte herausgab, jene unausschöpfliche, Jahrzehnte hindurch fortgeführte Sammlung von Beobachtungen und Gedanken, von Wendungen und Einfällen, begann ihr Glanz, sein bei Lebzeiten veröffentlichtes Werk zu überstrahlen. Ihre Wirkung verstärkte sich langsam, aber stetig, und heute sind sie allein berühmt. Tiefsinnig in ihrer Toleranz, amüsant noch im schrulligen Eigensinn, voll von “Widersprüchen”, sind sie uns wert um ihrer selbst willen und als ein Spiegel ihrer Zeit mit seltsamen Brechungswinkeln. Der oft bemerkte angebliche Widerspruch zwischen angespanntem Rationalismus und der Hingabe an mystische Stimmungen ist nur eines der Probleme, die uns sein Werk aufgibt, und vielleicht nicht das bedeutendste.

“Die Form ist doch in ihrer tiefsten Bedeutung unzertrennlich vom Gehalt, ja in ihrem Ursprung fast eins mit demselben …”Mörike.Mozart auf der Reise nach Prag ist Mörikes letzte Novelle und seine letzte vollgültige Dichtung überhaupt. Die künstlerische Eigenart des reifen Mörike hat sich hier zum Standbild verdichtet, zu seinem in jedem Sinn “vollendetsten” Prosawerk, bezaubernd durch die innere Ausgewogenheit von Heiterkeit und Ernst.

The crystal structure of [Mg(H2O)6](N3)2 was determined by single crystal X-ray diffraction (421 independent observed MoKα-counter reflections. R = 0.037). The crystals are orthorhombic, space group Fmmm, Z = 4, a = 644.3(1), b = 1134.4(1), c = 1333.5(3) pm. The magnesium atoms are octahedrally coordinated to six oxygen atom s of water molecules, the azide groups are not coordinated to metal atoms, N -N = 117.0(2) pm.

The production of hydrogen in a fixed bed reactor at a maximum pressure of 50 bar by oxidising an oxygen carrier (Fe2O3/Al2O3/CeO2) with 0.06 g min−1 of steam at 1023 K is discussed. Reductions were performed with synthesis gas at ambient pressure and 1023 K for 90 minutes. The influences of the elevated system pressure on the carbon contamination, the quantification of the contaminations in the produced hydrogen and the oxygen carrier conversion are analysed. The results show that small amounts of carbon depositions are formed during the reduction, which are re-oxidised with steam leading to the contamination of the hydrogen. The hydrogen purity obtained in the experiments is within the range of 99.958% to 99.999% with CO as the main impurity. The amount of contaminations as a result of the oxidation of the solid carbon is not influenced by the elevated system pressure, which confirms the suitability of the reformer steam-iron process in a fixed bed to produce pressurised hydrogen directly from a hydrocarbon feed. The oxygen carrier conversion displays an initial drop followed by a slightly linear decrease. Air-oxidations revealed a regeneration effect on the oxygen carrier conversion, which reversed a part of the conversion losses.

The crystal structure of Rb2Ca(N3)4 · 4H2O has been determined by single crystal X-ray methods. The compound is isotypic with K2Ca(N3)4 · 4 H2O and crystallizes in the orthorhombic space group Ccca, Z = 4, a = 1949.1(12) pm, b = 1099.5(3) pm, c - 622.2(1) pm.