A remarkably unsymmetric hexairon core embraced by two high-symmetry tripodal oligo-α-pyridylamido ligands

Oligo-α-pyridylamides offer an appealing route to polyiron complexes with short Fe-Fe separations and large room temperature magnetic moments. A derivative of tris(2‐aminoethyl)amine (H6tren) containing three oligo-α-pyridylamine branches and thirteen nitrogen donors (H6L) reacts with [Fe2(Mes)4] to yield an organic nanocage built up by two tripodal ligands with interdigitated branches (HMes = mesitylene). The nanocage has crystallographic D3 symmetry but hosts a remarkably unsymmetric hexairon-oxo core, with a central Fe5(μ5-O) square pyramid, two oxygen donors bridging basal sites, and an additional Fe center residing in one of the two tren-like pockets. Bond Valence Sum (BVS) analysis, Density Functional Theory (DFT) calculations, and electrochemical data were then used to establish the protonation state of oxygen atoms and the formal oxidation states of the metals. To this purpose, a specialized set of BVS parameters was devised for Fe2+-N3- bonds with nitrogen donors of oligo-α-pyridylamides. This allowed us to formulate the compound as [Fe6O2(OH)(H3L)L], with nominally four FeII and two FeIII ions. Mössbauer spectra indicate that the compound contains two unique FeII sites, identified as a pair of closely spaced hydroxo-bridged metal ions in the central Fe5(μ5-O) pyramid, and a substantially valence-delocalized FeII2FeIII2 unit. Broken-symmetry DFT calculations predict strong ferromagnetic coupling between the two iron(II) ions, leading to a local S = 4 state that persists to room temperature and explaining the large magnetic moment measured at 300 K. The compound behaves as a single-molecule magnet, with magnetization dynamics detectable in zero static field and dominated by an Orbach-like mechanism with Ueff/kB = 49(2) K and τ0 = 4(2)·10−10 s

Guest selectivity of [Ni2] supramolecular helicates

Two new paramagnetic supramolecular helicates with formula (X@[Ni2L3])3+ (X = Cl, or Br; L = a bis-pyrazolylpyridine ligand) have been prepared and are described. Helicates of this metal are very rare with virtually no prior examples of them acting as host of anionic species. The persistence in solution of the new assemblies has been demonstrated unambiguously by mass spectrometry and paramagnetic NMR. This has allowed to establish the preference of the coordination [Ni2] host for Cl− over Br−, in agreement DFT calculations. These results show the promise of the use of metallohelicates as suitable systems for the selective encapsulation of specific anions in solution

How Do Public Service Media Innovate? : an Analysis of Product Development by European PSM

In this study, we use institutional theory to explore to what extent public service media (PSM) rely on institutional links and on tight coupling with the environment to develop new products for digital news. This framework is especially relevant for understanding how PSM innovate, as they differ from commercial media, and the mimicry of industry trends can lead to tensions with their public service mission. Thirty-six interviews were conducted with senior managers, editors, and other professional roles involved in project development at eight PSM organizations in six European countries. The results indicate that to reduce uncertainty, PSM follow two partially complementary approaches: mimetic isomorphism, i.e., relying on what is seen as best practice by other players within their sector, and tight coupling, i.e., closely connecting with the environment (especially with the audience). Other PSM are the most important source of inspiration, as relationships are close and organizational forms are similar. In contrast, digital-born media are considered to be successful in attracting younger audiences but differ greatly from PSM. In summary, PSM do not simply mimic other players perceived to be successful but consider their own specificities in terms of audiences, purposes, strengths, weaknesses, and public service mission

How polarized are online and offline news audiences? A comparative analysis of twelve countries

Polarization is a key area of interest for media and communication scholars. We develop a way of measuring how polarized news audience behaviour is at the national level. Then, we analyze survey data from twelve countries and find (1) that cross-platform (online and offline) news audience polarization is highest in the United States, and within Europe, higher in polarized pluralist/southern countries than in democratic corporatist countries. Furthermore, (2) in most countries, online news audience polarization is higher than offline, but in a small number it’s lower. Taken together, our findings highlight that, despite the well-documented fears associated with algorithmic selection, news audience polarization is not inevitable in environments that are increasingly characterized by digital news consumption, and that the historical, economic, and political factors emphasized by the comparative tradition remain critically important for our understanding of global trends