Exploring cosmic origins with CORE: Cosmological parameters

We forecast the main cosmological parameter constraints achievable with the CORE space mission which is dedicated to mapping the polarisation of the Cosmic Microwave Background (CMB). CORE was recently submitted in response to ESA’s fifth call for mediumsized mission proposals (M5). Here we report the results from our pre-submission study of the impact of various instrumental options, in particular the telescope size and sensitivity level, and review the great, transformative potential of the mission as proposed. Specifically, we assess the impact on a broad range of fundamental parameters of our Universe as a function of the expected CMB characteristics, with other papers in the series focusing on controlling astrophysical and instrumental residual systematics. In this paper, we assume that only a few central CORE frequency channels are usable for our purpose, all others being devoted to the cleaning of astrophysical contaminants. On the theoretical side, we assume ΛCDM as our general framework and quantify the improvement provided by CORE over the current constraints from the Planck 2015 release. We also study the joint sensitivity of CORE and of future Baryon Acoustic Oscillation and Large Scale Structure experiments like DESI and Euclid. Specific constraints on the physics of inflation are presented in another paper of the series. In addition to the six parameters of the base ΛCDM, which describe the matter content of a spatially flat universe with adiabatic and scalar primordial fluctuations from inflation, we derive the precision achievable on parameters like those describing curvature, neutrino physics, extra light relics, primordial helium abundance, dark matter annihilation, recombination physics, variation of fundamental constants, dark energy, modified gravity, reionization and cosmic birefringence. In addition to assessing the improvement on the precision of individual parameters, we also forecast the post-CORE overall reduction of the allowed parameter space with figures of merit for various models increasing by as much as ∼ 107 as compared to Planck 2015, and 105 with respect to Planck 2015 + future BAO measurements

Microwave-Assisted Solvothermal Synthesis and Optical Properties of Tagged MIL-140A Metal–Organic Frameworks

A series of tagged MIL-140A-R frameworks have been synthesized using a microwave-assisted solvothermal method. Compared with their UiO-66-R polymorphs, the absorption energies in the MIL-140A-R series (R = NH₂, NO₂, Br, Cl, and F) are extended toward the visible region because of the spatial arrangement of the linkers

In Situ Spectroelectrochemical Investigations of the Redox-Active Tris[4-(pyridin-4-yl)phenyl]amine Ligand and a Zn²⁺ Coordination Framework

An investigation of the redox-active tris­[4-(pyridin-4-yl)­phenyl]­amine (NPy₃) ligand in the solution state and upon its incorporation into the solid-state metal–organic framework (MOF) [Zn­(NPy₃)­(NO₂)₂·<i>x</i>MeOH·<i>x</i>DMF]_<i>n</i> (MeOH = methanol and DMF = <i>N</i>,<i>N</i>-dimethylformamide) was conducted using in situ UV/vis/near-IR, electron paramagentic resonance (EPR), and fluorescence spectroelectrochemical experiments. Through this multifaceted approach, the properties of the ligand and framework were elucidated and quantified as a function of the redox state of the triarylamine core, which can undergo a one-electron oxidation to its radical cation. The use of pulsed EPR experiments revealed that the radical generated was highly delocalized throughout the entire ligand backbone. This combination of techniques provides comprehensive insight into electronic delocalization in a framework system and demonstrates the utility of in situ spectroelectrochemical methods in assessing electroactive MOFs

In Situ Spectroelectrochemical Investigations of the Redox-Active Tris[4-(pyridin-4-yl)phenyl]amine Ligand and a Zn²⁺ Coordination Framework

An investigation of the redox-active tris­[4-(pyridin-4-yl)­phenyl]­amine (NPy₃) ligand in the solution state and upon its incorporation into the solid-state metal–organic framework (MOF) [Zn­(NPy₃)­(NO₂)₂·<i>x</i>MeOH·<i>x</i>DMF]_<i>n</i> (MeOH = methanol and DMF = <i>N</i>,<i>N</i>-dimethylformamide) was conducted using in situ UV/vis/near-IR, electron paramagentic resonance (EPR), and fluorescence spectroelectrochemical experiments. Through this multifaceted approach, the properties of the ligand and framework were elucidated and quantified as a function of the redox state of the triarylamine core, which can undergo a one-electron oxidation to its radical cation. The use of pulsed EPR experiments revealed that the radical generated was highly delocalized throughout the entire ligand backbone. This combination of techniques provides comprehensive insight into electronic delocalization in a framework system and demonstrates the utility of in situ spectroelectrochemical methods in assessing electroactive MOFs

In Situ Spectroelectrochemical Investigations of the Redox-Active Tris[4-(pyridin-4-yl)phenyl]amine Ligand and a Zn²⁺ Coordination Framework

An investigation of the redox-active tris­[4-(pyridin-4-yl)­phenyl]­amine (NPy₃) ligand in the solution state and upon its incorporation into the solid-state metal–organic framework (MOF) [Zn­(NPy₃)­(NO₂)₂·<i>x</i>MeOH·<i>x</i>DMF]_<i>n</i> (MeOH = methanol and DMF = <i>N</i>,<i>N</i>-dimethylformamide) was conducted using in situ UV/vis/near-IR, electron paramagentic resonance (EPR), and fluorescence spectroelectrochemical experiments. Through this multifaceted approach, the properties of the ligand and framework were elucidated and quantified as a function of the redox state of the triarylamine core, which can undergo a one-electron oxidation to its radical cation. The use of pulsed EPR experiments revealed that the radical generated was highly delocalized throughout the entire ligand backbone. This combination of techniques provides comprehensive insight into electronic delocalization in a framework system and demonstrates the utility of in situ spectroelectrochemical methods in assessing electroactive MOFs

Thermal spin crossover behaviour of two-dimensional Hofmann-type coordination polymers incorporating photoactive ligands

Two spin crossover (SCO)-active 2D Hofmann-type framework materials, [Fe(3-PAP)2Pd(CN)4] (A) and [Fe(4-PAP)2Pd(CN)4] (B) containing the photoactive azo-benzene-type ligands 3-phenylazo-pyridine (3-PAP) and 4-phenylazo-pyridine (4-PAP) were prepared. These materials form non-porous Hofmann-type structures whereby 2D [FeIIPd(CN)4] grids are separated by 3- or 4-PAP ligands. The iron(ii) sites of both materials (A and B) undergo abrupt and hysteretic spin transitions with characteristic transition temperatures T1/2↓,↑: 178, 190 K (ΔT: 12 K) and T1/2↓,↑: 233, 250 K (ΔT: 17 K), respectively. Photo-magnetic characterisations reveal light-induced excited spin state trapping (LIESST) activity in both A and B with characteristic T(LIESST) values of 45 and 40 K. Although both free ligands show trans- to-cis isomerisation in solution under UV-irradiation, as evidenced via absorption spectroscopy, such photo-activity was not observed in the ligands or complexes A and B in the solid state. Structural analysis of a further non-SCO active isomer to B, [Fe(4-PAP)2Pd(CN)4]·1/2(4-PAP) (B·(4-PAP)), which contains free ligand in the pore space is reported

Untangling Complex Redox Chemistry in Zeolitic Imidazolate Frameworks Using Fourier Transformed Alternating Current Voltammetry

Two zeolitic imidazolate frameworks, ZIF-67 and ZIF-8, were interrogated for their redox properties using Fourier transformed alternating current voltammetry, which revealed that the 2-methylimidazolate ligand is responsible for multiple redox transformations. Further insight was gained by employing discrete tetrahedral complexes, [M­(DMIM)₄]²⁺ (DMIM = 1,2-dimethylimidazole, M = Co^II or Zn^II) which have similar structural motifs to ZIFs. In this work we demonstrate a multidirectional approach that enables the complex electrochemical behavior of ZIFs to be unraveled

Dinuclear Ruthenium Complex Based on a π-Extended Bridging Ligand with Redox-Active Tetrathiafulvalene and 1,10-Phenanthroline Units

The synthesis of a π-extended bridging ligand with both redox-active tetrathiafulvalene (TTF) and 1,10-phenanthroline (phen) units, namely, bis­(1,10-phenanthro­[5,6-<i>b</i>])­tetrathiafulvalene (BPTTF), was realized via a self-coupling reaction. Using this ligand and Ru­(tbbpy)₂Cl₂ (tbbpy = 4,4′-di-<i>tert</i>-butyl-2,2′-bipyridine), the dinuclear ruthenium­(II) compound [{Ru­(tbbpy)₂}₂(BPTTF)]­(PF₆)₄ (<b>1</b>) has been obtained by microwave-assisted synthesis. Structural characterization of <b>1</b> revealed a crossed arrangement of the TTF moieties on adjacent dimers within the crystal structure. The optical and redox properties of <b>1</b> were investigated using electrochemical, spectroelectrochemical, electron paramagnetic resonance (EPR), and absorption spectroscopic studies combined with theoretical calculations. One exhibits a rich electrochemical behavior owing to the multiple redox-active centers. Interestingly, both the ligand BPTTF and the ruthenium compound <b>1</b> are EPR-active in the solid state owing to intramolecular charge-transfer processes. The results demonstrate that the TTF-annulated bis­(phen) ligand is a promising bridging ligand to construct oligomeric or polymeric metal complexes with multiple redox-active centers

[V₁₆O₃₈(CN)]^9–: a soluble mixed-valence redox-active building block with strong antiferromagnetic coupling

A new discrete [V16O38(CN)]9- cluster, which displays the hitherto unknown 8- charge on the duster shell and is the first to encapsulate the cyanide anion, has been synthesized and characterized by IR and UV/vis/near-IR spectroscopy, electrochemistry, and magnetic susceptibility measurements. Bond valence sum calculations conducted on the basis of the crystal structure analysis of K9[V16O38(CN)]·13H2O confirm that this new member of the polyoxovanadate series is a mixed-valence complex. The intervalence charge transfer bands arising from intrametal interactions reveal that a localized (class II) assignment is appropriate for the duster; however, a small degree of electronic delocalization is present. Interesting possibilities exist for the incorporation of this unit into higher dimensionality framework structures, where the redox, optical, and magnetic properties can be exploited and tuned

Electronic, Optical, and Computational Studies of a Redox-Active Napthalenediimide-Based Coordination Polymer

The new one-dimensional coordination framework (Zn­(DMF)­NO₃)₂(NDC)­(DPMNI), where NDC = 2,6-naphthalenedicarboxylate and DPMNI = <i>N</i>,<i>N</i>′-bis­(4-pyridylmethyl)-1,4,5,8-naphthalenetetracarboxydiimide, which has been crystallographically characterized, exhibits two redox-accessible states due to the successive reduction of the naphthalenediimide (NDI) ligand core. Solid-state electrochemical and vis–near-IR spectroelectrochemical measurements coupled with density functional theory (DFT) calculations enabled the origins of the optical transitions in the spectra of the monoradical anion and dianion states of the material to be assigned. Electron paramagnetic resonance (EPR) spectroscopy revealed that the paramagnetic radical anion state of the DPMNI core could be accessed upon broad-spectrum white light irradiation of the material, revealing a long-lived excited state, possibly stabilized by charge delocalization which arises from extensive π<i>–</i>π* stacking interactions between alternating NDC and NDI aromatic cores which are separated by a distance of 3.580(2) Å