Magnesium (Mg) alloys are promising materials for the development of biodegradable implants. However, the current in vitro test procedures for cytotoxicity, cell viability and proliferation are not always suitable for this class of materials. In this paper we show that tetrazolium-salt-based assays, which are widely used in practice, are influenced by the corrosion products of Mg-based alloys. Corroded Mg converts tetrazolium salts to formazan, leading to a higher background and falsifying the results of cell viability. Tetrazolium-based assays are therefore not a useful tool for testing the cytotoxicity of Mg in static in vitro assays.

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A staggered conformation with D5d symmetry is adopted by the lithocene anion, the simplest metal‐locene of the main group metals with a sandwich structure (see picture). [Cp2Li]− forms on treatment of [CpLi] with Ph4PCl in a 2:1 molar ratio in THF and is isolated as the Ph4P+ salt.

The initial step of the sol-gel process, that is, the condensation of two molecules of silicic acid has been studied by means of density functional theory. The chosen system represents the reagents under basic reaction conditions. Calculations were performed in the gas phase as well as by employing a solvent model for aqueous solution. For both systems, a reaction intermediate with one pentacoordinated silicon center was found as the most stable structure. The influence of intramolecular hydrogen bonds on the stability of the intermediate structure is discussed, and different pathways for the subsequent condensation step are investigated. Furthermore, the effect of fluoride substitution on the reaction path is investigated.

While, the lithocene anion (Cp2Li-) can simply be generated by reacting 2 equiv of CpLi with PPh4Cl in THF, the attempted synthesis of the sodocene anion under similar reaction conditions results in the crystallization of [Cp-][PPh4 +]. The structure consists of “naked” Cp anions pinched between metaphenyl hydrogens of the phosphonium cations. An ansa-sodocene anion in which the two Cp rings are bridged by a −C(Me)2−C(Me)2− chain is obtained by reaction of Me4C2(C5H4Na)2 with 1 equiv of PPh4Cl in THF. Its crystal structure shows a disordered ansa-sodocene anion containing a sandwiched sodium cation solvated by a THF molecule. Unbridged Cp2Na- was obtained by pushing the (CpNa + Cp-) ⇄ Cp2Na- equilibrium to the sodocene anion side. Cell dimensions, space group symmetry, and the molecular structure of [Cp2Na-][PPh4 +] are remarkably similar to that of [Cp2Li-][PPh4 +]. The anion can be described as a centrosymmetric (η5,η5)Cp2Na- sandwich (average C−Na = 2.630(3) Å) with approximate D 5 d symmetry.

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The syntheses of the arylphosphonic esters 3-Br-5-tBu-1-{P(O)(OiPr) 2 }C 6 H 3 (1), 5-tBu-1,3-{P(O)(OiPr) 2 } 2 C 6 H 3 (2), of the heteroleptic intramolecularly coordinated organostannylenes [4-tBu-2,6-{P(O)(OiPr) 2 } 2 C 6 H 2 ]SnX (3, X = Cl; 4, X = Br; 5, X = I; 6, X = SPh), the organoplumbylene [4-tBu-2,6-{P(O)(OiPr) 2 } 2 C 6 H 2 ]PbCl (7), and the transition metal complex [4-tBu-2,6-{P(O)(OiPr) 2 } 2 C 6 H 2 ]Sn(Cl)-Cr(CO) 5 (8) are reported. The compounds were characterized by 1 H, 13 C, 31 P, 31 P MAS (3), 119 Sn, and 119 Sn MAS (3) NMR spectroscopy, electrospray ionization mass spectrometry (3), Mössbauer spectroscopy (3-5, 8) and single-crystal X-ray diffraction analyses (2, 3-5, 6-8). In contrast to its ethoxy-substituted analogue [4-tBu-2,6-{P(O)-(OEt) 2 } 2 C 6 H 2 ]SnCl, compound 3, like the thiophenolate derivative 6, is monomeric in solution as well as in the solid state. This difference is also manifested by the Mössbauer as well as solid state NMR spectroscopic data. On the other hand, the corresponding organoplumbylene 7 shows a similar chlorido-bridged polymeric structure as its ethoxy-

Making use of the inherent surface anisotropy of different high index surface planes vicinal to the low index Au(111) orientation, one-dimensional polymers have been synthesized following established procedures from two different precursor molecules. The successful polymerization of both 4,4″-dibromo-p-terphenyl and 5,5′-dibromo-salophenato-Co(II) precursors into poly(p-phenylene) and poly-[salophenato-Co(II)], respectively, has been confirmed by scanning tunneling microscopy and low energy electron diffraction. Angle-resolved photoemission spectroscopy data reveal a highly dispersive band in the case of poly(p-phenylene) while no significant dispersion is resolved for poly[salophenato-Co(II)]. On the basis of density functional theory calculations, we explain this observation as a result of a high conjugation along the aromatic phenyl groups in poly(p-phenylene) that is absent in the case of poly[salophenato-Co(II)], where intramolecular conjugation is interrupted in the salophenato-Co(II) unit. Furthermore, we make use of multicenter and delocalization indexes to characterize the electron mobility (corresponding to a high band dispersion) along different paths associated with individual molecular orbitals.