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Ring-Closure Mechanisms Mediated by Laccase to Synthesize Phenothiazines, Phenoxazines, and Phenazines
2020, Hahn, Veronika, Mikolasch, Annett, Weitemeyer, Josephine, Petters, Sebastian, Davids, Timo, Lalk, Michael, Lackmann, Jan-Wilm, Schauer, Frieder
The green and environmentally friendly synthesis of highly valuable organic substances is one possibility for the utilization of laccases (EC 1.10.3.2). As reactants for the herein described syntheses, different o-substituted arylamines or arylthiols and 2,5-dihydroxybenzoic acid and its derivatives were used. In this way, the formation of phenothiazines, phenoxazines, and phenazines was achieved in aqueous solution mediated by the laccase of Pycnoporus cinnabarinus in the presence of oxygen. Two types of phenothiazines (3-hydroxy- and 3-oxo-phenothiazines) formed in one reaction assay were described for the first time. The cyclization reactions yielded C–N, C–S, or C–O bonds. The syntheses were investigated with regard to the substitution pattern of the reaction partners. Differences in C–S and C–N bond formations without cyclization are discussed.
Iodidobis(≠5-penta-methyl-cyclo-penta-dien-yl)titanium(III)
2010, Kessler, M., Spannenberg, A., Rosenthal, U.
In the title complex mol-ecule, [Ti(C10H15) 2I], the paramagnetic Ti(III) atom is coordinated by two penta-methyl-cyclo-penta-dienyl (Cp*) ligands and one iodide ligand. The two Cp*ligands are in a staggered orientation. The coordination geometry at the titanium atom can be described as distorted trigonal-planar.
Dicyclohexylbis(naphthalen-1-ylmethyl)phosphonium chloride chloroform disolvate
2012, Gowrisankar, S., Neumann, H., Spannenberg, A., Beller, M.
In the title solvated phosphonium salt, C34H40P+·Cl -·2CHCl3, the two cyclohexyl and two 1-naphthylmethyl groups at the P atom are in a distorted tetrahedral arrangement [105.26 (6)-113.35 (6)°]. Both cyclohexyl rings adopt a chair conformation. The dihedral angle between the naphthyl ring systems is 74.08 (3)°.
2,4-Bis(diphenyl-phosphan-yl)-1,1,2,3,3,4-hexa-phenyl-1,3-diphospha-2, 4-dibora-cyclo-butane tetra-hydro-furan sesqui-solvate
2012, Peulecke, N., Müller, B.H., Spannenberg, A., Rosenthal, U.
In the title compound, C60H50B2P 4·1.5C4H8O, the diphospha-diborane mol-ecule lies on an inversion centre, whereas the disordered tetra-hydro-furan solvent mol-ecule is in a general position with a partial occupancy of 0.75. The diphosphadiborane mol-ecule consists of an ideal planar four-membered B 2P2 ring with an additional phenyl and a-PPH2 group attached to each B atom.
Synthesis and Characterization of Oxide Chloride Sr2VO3Cl, a Layered S = 1 Compound
2023, Sannes, Johnny A., Kizhake Malayil, Ranjith K., Corredor, Laura T., Wolter, Anja U. B., Grafe, Hans-Joachim, Valldor, Martin
The mixed-anion compound with composition Sr2VO3Cl has been synthesized for the first time, using the conventional high-temperature solid-state synthesis technique in a closed silica ampule under inert conditions. This compound belongs to the known Sr2TmO3Cl (Tm = Sc, Mn, Fe, Co, Ni) family, but with Tm = V. All homologues within this family can be described with the tetragonal space group P4/nmm (No. 129); from a Rietveld refinement of powder X-ray diffraction data on the Tm = V homologue, the unit cell parameters were determined to a = 3.95974(8) and c = 14.0660(4) Å, and the atomic parameters in the crystal structure could be estimated. The synthesized powder is black, implying that the compound is a semiconductor. The magnetic investigations suggest that Sr2VO3Cl is a paramagnet at high temperatures, exhibiting a μeff = 2.0 μB V-1 and antiferromagnetic (AFM) interactions between the magnetic vanadium spins (θCW = −50 K), in line with the V-O-V advantageous super-exchange paths in the V-O layers. Specific heat capacity studies indicate two small anomalies around 5 and 35 K, which however are not associated with long-range magnetic ordering. 35Cl ss-NMR investigations suggest a slow spin freezing below 4.2 K resulting in a glassy-like spin ground state.
Tris(η5-cyclopentadienyl)hafnium(III)
2011, Burlakov, V.V., Arndt, P., Spannenberg, A., Rosenthal, U.
In the crystal structure of the title compound, [Hf(C5H 5)3], three cyclopentadienyl ligands surround the Hf III atom in a trigonal-planar geometry. The molecule lies on a sixfold inversion axis.
Intermolecular hydrogen bonding in isostructural pincer complexes [OH-(t-BuPOCOPt-Bu)MCl] (M = Pd and Pt)
2019, Joksch, M., Spannenberg, A., Beweries, T.
In the crystal structure of the isostructural title compounds, namely {2,6-bis[(di-tert-butylphosphanyl)oxy]-4-hydroxyphenyl}chloridopalladium(II), [Pd(C22H39O3P2)Cl], 1, and {2,6-bis[(di-tert-butylphosphanyl)oxy]-4-hydroxyphenyl}chloridoplatinum(II), [Pt(C22H39O3P2)Cl], 2, the metal centres are coordinated in a distorted square-planar fashion by the POCOP pincer fragment and the chloride ligand. Both complexes form strong hydrogen-bonded chain structures through an interaction of the OH group in the 4-position of the aromatic POCOP backbone with the halide ligand.
2-hydroxyethylammonium iodide
2014, Kohrt, C., Spannenberg, A., Werner, T.
In the crystal structure of the title salt, C2H 8NO+·I-, N-H⋯O, N-H⋯I and O-H⋯I hydrogen bonds lead to the formation of layers staggered along the c axis.
{N,N-Bis[bis(2,2,2-trifluoroethoxy)phosphanyl]methylamine- κ2 P,P′}bis(η5-cyclopentadienyl) titanium(II)
2013, Haehnel, M., Hansen, S., Spannenberg, A., Beweries, T.
The title compound, [Ti(C5H5)2(C 9H11F12NO4P2)], is a four-membered titanacycle obtained from the reaction of Cp2Ti(η 2-Me3SiC2SiMe3) and CH 3N[P(OCH2CF3)2]2 {N,N-bis[bis(trifluoroethoxy)phosphanyl]methylamine, tfepma}. The Ti II atom is coordinated by two cyclopentadienyl (Cp) ligands and the chelating tfepma ligand in a strongly distorted tetrahedral geometry. The molecule is located on a mirror plane.
Dicarbonyl-{3,3′-di-tert-butyl-5,5′-di-methoxy-2, 2′-bis[(4,4,5,5-tetraphenyl-1,3,2-dioxaphospho-lan-2-yl)-oxy-κP] biphen-yl}hydridorhodium(I) diethyl ether monosolvate
2012, Selent, D., Spannenberg, A., Börner, A.
In the title compound, [Rh(C 74H 68O 8P2)H(CO) 2]·C 4H 10O, the C 2HP 2 coordination set at the Rh I ion is arranged in a distorted trigonal-planar geometry with one P atom of the diphosphite mol-ecule and the H atom adopting the axial coordination sites.