Synthesis, molecular and crystal structure, and stereochemical non-rigidity of (O→Ge)-Bischelate bis[1-(2-oxoperhydroazepinyl)methyl]bromogermanium iodide and triflate

Reactions of (O→Ge)-bischelate dibromogermane (L7CH2)2GeBr2 (4c) with trimethyliodosilane and trimethylsilyl triflate proceed with the substitution of only one bromine atom and yield (O→Ge)-bischelate monobromogermanes (L7CH2)2Ge(Br)X (8c, X = I; 9c, X = OTf; LnCH2 = lactamomethyl C,O-chelate ligand; n = lactam ring size). According to X-ray crystal analysis data, triflate 9c is characterized by nearly ionic structure with the monodentate ligand and anion in trans-positions. The configuration of the germanium atom in the complex is intermediate between trigonal bipyramidal and square pyramidal. Quantum chemical calculations show the absence of additional coordinate bonding between the germanium atom and anion. Dynamic 1H NMR spectroscopy (1H DNMR) was used to study the stereochemical non-rigidity of monobromides 8c and 9c. Activation parameters for the inversion of the germanium atom configuration were calculated in various solvents. Based on the 1H DNMR data and quantum chemistry calculations, possible mechanisms of permutational isomerization are discussed

Black hybrid iodobismuthate containing linear anionic chains

Three hybrid 1,1′-(1,n-alkanediyl)bis(4-methylpyridinium) iodobismuthates 1-3 were prepared by a facile solution route and showed thermal stability in air up to 230 °C. The structures of solids 1 and 3 contain zero-dimensional anions, and the structure of 2 contains one-dimensional linear anionic chains [BiI5]n 2n-. Photoluminescence (PL) in the spectral range between 600 and 750 nm was observed for 1 and 2. DFT calculations and optical studies confirmed that compounds 1-3 are semiconductors with band gaps of 1.73-2.10 eV, which correspond with their intense black (for 2) or red (for 1 and 3) colors. The optical absorption of 2 in the red spectral range is primarily due to charge transfer from the I5p orbitals at the top of the valence band to the Bi6p orbitals at the bottom of the conduction band. © 2018 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique

Black hybrid iodobismuthate containing linear anionic chains

Three hybrid 1,1′-(1,n-alkanediyl)bis(4-methylpyridinium) iodobismuthates 1-3 were prepared by a facile solution route and showed thermal stability in air up to 230 °C. The structures of solids 1 and 3 contain zero-dimensional anions, and the structure of 2 contains one-dimensional linear anionic chains [BiI5]n 2n-. Photoluminescence (PL) in the spectral range between 600 and 750 nm was observed for 1 and 2. DFT calculations and optical studies confirmed that compounds 1-3 are semiconductors with band gaps of 1.73-2.10 eV, which correspond with their intense black (for 2) or red (for 1 and 3) colors. The optical absorption of 2 in the red spectral range is primarily due to charge transfer from the I5p orbitals at the top of the valence band to the Bi6p orbitals at the bottom of the conduction band. © 2018 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique

Silicon and Germanium-Based Sesquioxanes as Versatile Building Blocks for Cage Metallacomplexes. A Review

In the present paper, a rapidly developing field of polynuclear cage metallasilsesquioxanes and metallagermsesquioxanes chemistry is surveyed. Deliberate synthesis techniques aimed at the cages of specific nuclearity are described with the emphasis placed onto analysis of similarities and differences between silicon- and germanium-based substances. General approaches towards design of polymeric supramolecular assemblies based on cage metallasilsesquioxanes and metallagermsesquioxanes are outlined and illustrated with appropriate examples. Striking catalytic properties of the title compounds in homogeneous oxidation reactions are noted as one of their prospective application field. © 2019, Springer Science+Business Media, LLC, part of Springer Nature

Novel carbonate/pyridine tetranuclear nickel complex, exhibiting slow relaxation of the magnetization

Tetranuclear [Ni4(CO3)4(pyridine)8·Na]Cl·pyridine·H2O compound with unusual square-planar geometry was obtained via spontaneous fixation of atmospheric CO2 and its conversion into carbonate bridging ligands. This compound exhibits a slow relaxation of the magnetization caused by a spin-glass behaviour. © 2021 Elsevier B.V

Heptanuclear Cage CuII-Silsesquioxanes: Synthesis, Structure and Catalytic Activity

Two prismatic phenyl- (PhSiO1.5)14(CuO)7 (1, 29 % yield) and methyl- (MeSiO1.5)14(CuO)7 (2, 19 % yield) heptacoppersilsesquioxanes were obtained by the interaction of Cu,Na-based cage silsesquioxanes [(RSiO1.5)12(CuO)4(NaO0.5)4] (R = Ph, Me) with 4,4′-bipyridine and pyrazine, respectively, acting as “silent witness” ligands. Unusual molecular topologies of both compounds 1 and 2, which are the first representatives of cage silsesquioxanes with seven metal ions in their cores, were established by X-ray diffraction studies. Complex 1 was found to be an active precatalyst in the oxidation of alkanes and 1-phenylethanol to alkyl hydroperoxides and acetophenone, respectively. Alkanes were oxidized by hydrogen peroxide, and the alcohol was oxidized by tert-butyl hydroperoxide. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

New Ni4Na2-phenylgermsesquioxane architecture: Synthesis, structure and slow dynamic behaviour

The first Ni(ii)-based metallagermaniumsesquioxane cage compound [(PhGeO1.5)10(NiO)4(NaO0.5)2] presents a sandwich-like structure where two germsesquioxane cages are linked through an {NiO}4 core and exhibits slow dynamics of the magnetization. © 2018 The Royal Society of Chemistry

Unexpected hydrolytic transformation of new type hybrid bromobismuthates with methylpyrazinium dications

A series of new type hybrid bromobismuthates formed by various pyrazinium cations were isolated and studied. In the systems initially containing iodide anions and monocations of substituted pyrazines, the complexes based on doubly charged cations of substituted pyrazines instead of ones based on the corresponding monocations were surprisingly formed. The variation of substituted pyrazinium cations affects not only the crystal structures of hybrid bromobismuthates via tuning the nuclearity of the anions but also the hydrolytic stability of the compounds. A thorough structural study of hydrolytic transformations was performed for halobismuthates for the first time. The results revealed a stepwise course of the process affording several products. Spectral studies of the complexes evidence that the values of optical band gaps (Eg) are low in comparison with those for similar systems which is most likely due to the cooperative effect involving the nature of the corresponding cations together with the features of the supramolecular structures of the complexes. © The Royal Society of Chemistry 2019