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Organic radicals are widely used as linkers or ligands to synthesize molecular magnetic materials. However, studies regarding the molecular anisotropies of radical-based magnetic materials and their multifunctionalities are rare. Herein, a photoisomerizable diarylethene ligand was used to form {[CoIII(3,5-DTSQ·–)(3,5-DTCat2–)]2(6F-DAE-py2)}·3CH3CN·H2O (o-1·3CH3CN·H2O, 6F-DAE-py2 = 1,2-bis(2-methyl-5-(4-pyridyl)-3-thienyl)perfluorocyclopentene), a valence tautomeric (VT) coordination polymer. We directly observed dual radicals for a single crystal using high-field/-frequency (∼13.3 T and ∼360 GHz) electron paramagnetic resonance (EPR) spectroscopy along the c axis, which was further confirmed by angle-dependent Q-band EPR spectroscopy. Moreover, a conductive anomaly close to the VT transition temperature was observed only when probes were attached at the ab plane of the single crystal, indicative of synergy between valence tautomerism and conductivity. Structural anisotropy studies and density functional theory (DFT) calculations revealed that this synergy is due to electron transfer associated with valence tautomerism. This study presents the first example of dual-radical-based molecular anisotropy and charge-transfer-induced conductive anisotropy in a photoswitchable coordination polymer.

Two homoleptic copper(II) complexes [Cu(L1)2] and [Cu(L2)2] with anionic redox‐active ligands were synthesised, one with urea azine (L1) and the other with thio‐urea azine (L2) ligands. One‐electron oxidation of the complexes initiates an unprecedented redox‐induced electron transfer process, leading to monocationic copper(I) complexes [Cu(L1)2]+ and [Cu(L2)2]+ with two oxidised ligands. While [Cu(L1)2]+ is best described as a CuI complex with two neutral radical ligands that couple antiferromagnetically, [Cu(L2)2]+ is a CuI complex with two clearly different ligand units in the solid state and with a magnetic susceptibility close to a diamagnetic compound. Further one‐electron oxidation of the complex with L1 ligands results in a dication [Cu(L1)2]2+, best described as a CuI complex with a twofold oxidised, monocationic ligand and a neutral radical ligand. The stability in at least three redox states, the accumulation of spin density at the ligands and the facile ligand‐metal electron transfer make these complexes highly attractive for a variety of applications; here the catalytic aerobic oxidation of alcohols to aldehydes is tested., Oxidation‐induced reduction: The oxidation of mononuclear CuII complexes with novel unsymmetric redox‐active urea azine or thio‐urea azine ligands leads to metal reduction and formation of complexes with intriguing electronic structures. The stability in several redox states is the basis for their first application in catalytic aerobic alcohol oxidation.

The donor strength of bifunctional pyridine‐cyclopentadienyl ligands was altered systematically by the introduction of donating groups in the para‐position of the pyridine. In the resulting chromium complexes an almost linear correlation between donor strength and the nitrogen‐chromium distance as well as the electronic absorption maximum is experimentally observed. The connection of electron‐donating groups in the ligand backbone leads to an efficient transfer of the electronic influences to the catalytically active metal centre without restricting it through steric effects. Therefore, catalytic olefin polymerization activity, which is already very high for the previously studied catalysts, increase considerably by attaching para‐amino groups to the chelating pyridine or quinoline, respectively. Combining electron‐rich indenyl ligands with para‐amino substituted pyridines lead to the highest catalytic activities observed so far for this class of organo chromium olefin polymerisation catalysts. The resulting polymers are of ultra‐high molecular weight and the ability of the catalysts to incorporate co‐monomers is also very high., Catalytic activity in ethylene polymerization with single‐site organochromium complexes increases with number and donor strength of substituents. The new systems allow the formation of ultra‐high molecular weight polyethylene with highest productivity and high co‐monomer incorporation. An almost linear correlation between ligand donor strength and polymerization activity is observed.

The present work describes the reaction of triplet dioxygen with the porphyrinogenic calix[4]pyrrolato aluminates to alkylperoxido aluminates in high selectivity. Multiconfigurational quantum chemical computations disclose the mechanism for this spin‐forbidden process. Despite a negligible spin–orbit coupling constant, the intersystem crossing (ISC) is facilitated by singlet and triplet state degeneracy and spin–vibronic coupling. The formed peroxides are stable toward external substrates but undergo an unprecedented oxidative pyrrole α‐cleavage by ligand aromatization/dearomatization‐initiated O−O σ‐bond scission. A detailed comparison of the calix[4]pyrrolato aluminates with dioxygen‐related enzymology provides insights into the ISC of metal‐ or cofactor‐free enzymes. It substantiates the importance of structural constraint and element–ligand cooperativity for the functions of aerobic life., The reaction of triplet dioxygen with closed shell molecules is formally spin‐forbidden. Nature overcomes this prohibition by a variety of enzymes. The surprising reactivity of calix[4]pyrrolato aluminate with O2 is described and the spin‐inversion process is analyzed. The square‐planar aluminates transpire as enzyme models that substantiate the critical role of metal–ligand cooperativity and structural constraint for the functions of aerobic life.

Reported are single crystal SQUID and single crystal high‐frequency/high‐field EPR data of a trinuclear complex with a rare six‐coordinate coordination sphere of a DyIII center coupled to two terminal six‐coordinate NiII ions. The analysis of the single crystal spectroscopic parameters allows for an accurate description of the ground state wavefunction. The experimental analysis is supplemented by the analysis of the paramagnetic NMR spectra, allowing for a thorough description of the DyIII center. The experimental data are interpreted on the basis of an ab initio ligand field analysis, and the computed parameters are in good agreement with the experimental observations. This supports the quality of the theoretical approach based on a pseudo‐spin Hamiltonian for the electronic ground state. Further support emerges from the ab initio ligand field theory based analysis of a structurally very similar system that, in contrast to the complex reported here, shows single molecule magnetic properties, and this is in agreement with the quantum‐chemical prediction and analysis., Discussed is a linear trinuclear DyIIINiII 2 complex with a rare hexacoordinate DyIII center. The magnetic properties were studied experimentally by single crystal SQUID magnetometry, single crystal high‐frequency/high‐field EPR and paramagnetic NMR spectroscopy. Parameters describing the ground state multiplet splitting have also been computed by ab‐initio quantum‐chemical calculations, and the large variety of experimental techniques allows for a thorough validation of the computational analysis.

A series of three organochromium(III) complexes, based on a quinoline-substituted cyclopentadienyl ring coordinated to a CrCl2 moiety—C5Me4(C9NH6)CrCl2 (1), C5Ph4(C9NH6)CrCl2 (2), and C5Me4(C11NH10...

The high cost of commercial components and parts for post-mortem computed tomography angiography (PMCTA) has resulted in the development of a very low cost PMCTA-kit. It contains ubiquitous parts from hardware stores, and rapid prototyping derived models for 3D-printing. Design specifications have been tested and improved after finite-element modelling. A case study performed in using the final PMCTA kit parts for a PMCTA shows perfect vascular contrast without relevant leaks.

The control of the redox reactivity, magnetic and optical properties of the different redox states of complexes with redox‐active ligands permits their rational use in catalysis and materials science. The redox‐chemistry of octahedrally coordinated high‐spin CoII complexes (three unpaired electrons) with one redox‐active bisguanidine ligand and two acetylacetonato (acac) co‐ligands is completely changed by replacing the acac by hexafluoro‐acetylacetonato (hfacac) co‐ligands. The first one‐electron oxidation is metal‐centered in the case of the complexes with acac co‐ligands, giving diamagnetic CoIII complexes. By contrast, in the case of the less Lewis‐basic hfacac co‐ligands, the first one‐electron oxidation becomes ligand‐centered, leading to high‐spin CoII complexes with a radical monocationic guanidine ligand unit (four unpaired electrons). Ferromagnetic coupling between the spins on the metal and the organic radical in solution is evidenced by temperature‐dependent paramagnetic NMR studies, allowing to estimate the isotropic exchange coupling constant in solution. Second one‐electron oxidation leads to high‐spin CoII complexes with dicationic guanidine ligand units (three unpaired electrons) in the presence of hfacac co‐ligands, but to low‐spin CoIII complexes with radical monocationic, peralkylated guanidine ligand (one unpaired electron) in the presence of acac co‐ligands. The analysis of the electronic structures is complemented by quantum‐chemical calculations on the spin density distributions and relative energies of the possible redox isomers., The substitution of the methyl groups of acetylacetonato (acac) co‐ligands in a cobalt(II) complex with a redox‐active bisguanidine ligand by trifluoromethyl groups (hfacac co‐ligands) changes the redox properties. One‐electron oxidation of the complexes with acac co‐ligands is metal centered (Co(II)→Co(III)). By contrast, a radical monocationic bisguanidine ligand is formed upon one‐electron oxidation of the complexes with hfacac co‐ligands. The changes are accompanied by distinct changes in the magnetic and optical properties.

Presented here is a comprehensive study of highly oxidized multiple‐decker complexes composed of TbIII and CdII ions and two to five phthalocyaninato ligands, which are stabilized by electron‐donating n‐butoxy groups. From X‐ray structural analyses, all the complexes become axially compressed upon ligand oxidation, resulting in bowl‐shaped distortions of the ligands. In addition, unusual coexistence of square antiprism and square prism geometries around metal ions was observed in +4e charged species. From paramagnetic 1H NMR studies on the resulting series of triple, quadruple and quintuple‐decker complexes, ligand oxidation leads to a decrease in the magnetic anisotropy, as predicted from theoretical calculations. Unusual paramagnetic shifts were observed in the spectra of the +2e charged quadruple and quintuple‐decker complexes, indicating that those two species are actually unexpected triplet biradicals. Magnetic measurements revealed that the series of complexes show single‐molecule magnet properties, which are controlled by the multi‐step redox induced structural changes., This work was financially supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Numbers JP14J02656 (Y.H.), JP20225003 (M.Y.), JP15K05467 (K.K.), JP24750119 (K.K.), 18K14242 (Y.H.), 19K05401(Y.K), Tohoku University Molecule & Material Synthesis Platform in Nanotechnology Platform Project, CREST, JST JPMJCR12L3 (M.Y.), PhD scholarship from the Beilstein‐Institut zur Förderung der Chemischen Wissenschaften (M.D.), the German‐Japanese University Consortium (HeKKSaGOn), the state of Baden‐Württemberg through bwHPC and the German Research Foundation (DFG) through grant no INST 40/467‐1 FUGG (JUSTUS cluster), European Union (ERC StG 2012–306826 e‐GAMES), Networking Research Center on Bioengineering, Biomaterials, and Nanomedicine (CIBER‐BBN), the Spanish Ministry of Economy and Competitiveness (projects FANCY CTQ2016‐80030‐R, MOTHER MAT2016‐80826‐R and the “Severo Ochoa” Programme for Centers of Excellence in R&D, SEV‐2015‐0496), Generalitat de Catalunya (2017SGR918), 111 Project (B18030) from China (M.Y.), the scientific grants R‐143‐000‐A80‐114, R‐143‐000‐A65‐133 from the National University of Singapore. We thank Dr. Norihisa Hoshino for EPR measurements, Dr. Tetsuko Nakaniwa and Prof. Dr. Genji Kurisu and Dr. Takefumi Yoshida for SCXRD measurements. This paper is Contribution No. 62 from the Research Center for Thermal and Entropic Science.

Guided by DFT based modeling the chemical shift range of a hydride resonance in the proton nuclear magnetic resonance (NMR) spectrum of the intermediate-spin, square planar iron complex tBu(PNP)Fe–H was predicted and detected as a broad resonance at −3560 ppm (295 K) with a temperature dependent shift of approximately 2000 ppm between 223 and 383 K. The first detection of a metal-bonded hydrogen atom by solution NMR in a complex with a paramagnetic ground state illustrates the interplay of theory and experiment for the characterization of key components in paramagnetic base metal catalysis.

Nanophase separation during injection molding of high density polyethylene (HDPE) together with polyethylene reactor blend (RB) additives that have ultrabroad bimodal molar mass distribution and a high content of ultrahigh molar mass polyethylene (UHMWPE), produces thermoplastic all-polyethylene composites reinforced with extended-chain UHMWPE nanostructures formed in situ. Neither alien fibers, inorganic fillers, hazardous nanoparticles nor modified single- and multi-step molding processes are required to convert HDPE into higher performance engineering plastics. The RB40 additive is readily tailored by ethylene polymerization on silica-supported chromium two-site catalysts and contains 40 wt% UHMWPE (Mw = 1.5 × 106 g∙mol−1) dispersed in 50 wt% HDPE wax (Mw = 1.1 × 103 g∙mol−1). The presence of disentangled nanophase-separated UHMWPE together with HDPE wax serving as a processing aid enables injection molding of all-PE composites with high UHMWPE content of up to 24 wt% without changing processing parameters typical for HDPE. As verified by both scanning electron microscopic analyses of samples etched with hot xylene and thermal analysis, the HDPE matrix is efficiently reinforced by in situ formed polyethylene shish-kebab fibers where flow-induced crystallization yields extended-chain UHMWPE nanostructures as shish nucleating the crystallization of HDPE kebab. For the first time, by etching quenched samples, it was possible to completely suppress kebab formation and to image in situ extended-chain UHMWPE shish with an average diameter of 80 nm. Upon increasing the UHMPE content the average total diameter of shish-kebab fiber-like structures drastically decreases from micron to nanometer range, forming non-woven-like architectures. This self-reinforcement simultaneously improves toughness, stiffness and strength parameters unparalleled by conventional melt-blending HDPE with micron-sized UHMWPE and HDPE wax. Compared to HDPE, the addition of 60 wt% RB40 increases the Young's modulus to 4.2 GPa, tensile strength to 160 MPa and impact strength to 20 kJ/m2. This sustainable route to self-reinforced all-PE composite composites preserves the high energy, resource, cost and eco-efficiencies typical for pure hydrocarbon resins. Here, we examine the impact of RB40 addition on in situ nanostructure formation and its correlation with thermal and mechanical properties of all-PE composites.

A method for the experimental determination of ligand-field (LF) energy splitting in mononuclear lanthanide complexes, based purely on variable-temperature NMR spectroscopy, was developed. The application of this method in an isostructural series of anionic lanthanide bis(cyclooctatetraenide) double-decker compounds bearing large rigid substituents is demonstrated. Using the three-nuclei plot approach devised by Reilley, the isostructurality of the compound series and the identical orientation of the magnetic main axis of all Ln3+ ions in the series Tb3+ to Tm3+ are demonstrated. Measurement of the 2H NMR spectra of partially deuterated analogues of the complexes permitted determination of the axial magnetic susceptibility anisotropies χax for all five ions in the temperature range from 185 to 335 K. For this purpose, analysis of the hyperfine shifts was combined with structural models derived from density functional theory calculations. In a final step, the temperature dependence of the χax values was used for determination of the three axial LF parameters, adapting a method employed previously for phthalocyanine-based systems. The temperature dependence dictated by the LF parameters determined by this NMR-based approach is compared to the results of recently published ab initio calculations of the system, indicating reasonable agreement of both methods. For all ions except Dy3+, the NMR method determines the same mJ ground state as the calculations and the order and energies of the excited states match well. However, the sign of the magnetic anisotropy of the dysprosium complex in the temperature range evaluated here is not correctly predicted by the published calculations but can be described accurately by the NMR approach. This shows that our experimental method for determination of the LF parameters is an ideal complementation to other theoretical and experimental methods.

We examined the possibility of inflicting serious injuries with sharp objects in an experimental setting by throwing four sharp objects from different distances and with different throwing techniques. Using an overarm-handle (OA/H), overarm-blade (OA/B), underarm-handle (UA/H), underarm-blade (UA/B) and thrust (T/H) throwing technique, 10 adults (sex ratio 1:1) threw a chef's knife, a skinning knife, a paring knife and office scissors from 4 m and 2 m distance at synthetic abdomen models made of 10% gelatin covered with synthetic skin. The amount of hits and penetrations of the target and their penetration depth were noted, as was the rotation of the blade tip towards the target along its flight trajectory. The chef's knife injury/hit ratio was 0.167/4 m and 0.160/2 m; the skinning knife recorded an injury/hit ratio of 0.087/4 m and 0.153/2 m; the paring knife of 0.087/4 m and 0.113/2 m; and the scissors 0.087/4 m and 0.067/2 m. Mean penetration depths were as follows: the chef's knife: 4 m, 4.42 cm, 2 m, 3.41 cm; the skinning knife: 4 m, 4.19 cm, 2 m, 4.11 cm; the paring knife: 4 m, 1.62 cm, 2 m, 1.55 cm; and the scissors: 4 m, 2.08 cm, 2 m, 0.95 cm. Handle-throw penetration-depths were: 4 m: 3.77 cm and 2 m: 2.86 cm; blade-throw depths were: 4 m: 3.14 cm and 2 m: 2.69 cm. Overarm-throw penetration-depths were: 4 m: 3.62 cm and 2 m: 3.25 cm; and underarm-throw penetration-depths were 4 m: 3.30 cm and 2 m: 2.30 cm. No thrust-throws with the paring knife and scissors could pierce the target. The tips pointed toward the target at angles of 60°-120°, earlier in handle-throws than blade-throws, especially with the paring knife and the scissors. When thrown, especially with a handle-held technique, heavier objects pierced more often and more deeply. Thrust-throws at short distances are unlikely to pierce a human.

Tailored polyethylene reactor blend additives (RB) with ultrabroad bimodal molar mass distributions comprise nanophase-separated ultrahigh molar mass polyethylene (UHMWPE) uniformly dispersed in polyethylene wax. During injection molding of high-density polyethylene (HDPE) together with variable amounts of the nanophase-separated HDPE wax/UHMWPE (70/30) additive (RB30) flow-induced oriented crystallization affords shish-kebab fiber-like UHMWPE nanostructures accounting for efficient HDPE self-reinforcement. RB additives are readily prepared by ethylene polymerization on silica-supported two-site chromium catalysts which simultaneously produce HDPE wax together with disentangled nanoplatelet-like UHMWPE. The presence of HDPE wax is essential for lowering melt viscosity at high UHMWPE content. Since HDPE wax crystallizes onto extended-chain UHMWPE shish to form kebab structures, high HDPE wax content is tolerated without encountering emission problems and impairing mechanical properties as observed in the a...

Herein we present a comprehensive study of the highly oxidized species of multiple-decker complexes composed of Tb(III) and Cd(II) ions and two to five phthalocyaninato ligands, which are stabilized by electron-donating n-butoxy chains. Paramagnetic 1H NMR measurements for the series of triple, quadruple and quintuple-decker complexes revealed that ligand oxidations lead to a decrease in magnetic anisotropy, as predicted from ab initio calculations. Unusual paramagnetic shifts were observed in +2e charged quadruple and quintuple-decker complexes, indicating that those two species are actually triplet biradicals. The X-ray structural analysis for the series of oxidized multiple-decker complexes revealed that all the species show an axial compression induced by the ligand oxidations, resulting in the bowl-shaped distortion of the ligands, in agreement with predictions from DFT calculations. Magnetic measurements revealed that the series of complexes show single-molecule magnet (SMM) properties, which are controlled by the multi-step redox induced structural changes.

Combination of three radical anionic Ph-BIAN ligands (Ph-BIAN=bis-(phenylimino)-acenaphthenequinone) with lanthanoid ions leads to a series of homoleptic, six-coordinate complexes of the type Ln(Ph-BIAN)3 . Magnetic coupling data were measured by paramagnetic solution NMR spectroscopy. Combining 1 H NMR with 2 H NMR of partially deuterated compounds allowed a detailed study of the magnetic susceptibility anisotropies over a large temperature range. The observed chemical shifts were separated into ligand- and metal-centered contributions by comparison with the Y analogue (diamagnetic at the metal). The metal-centered contributions of the complexes with the paramagnetic ions could then be separated into pseudocontact and Fermi contact shifts. The latter is large within the Ph-BIAN scaffold, which shows that magnetic coupling is significant between the lanthanide ion and the radical ligand. Pseudocontact shifts were further correlated to structural data obtained from X-ray diffraction experiments. Ligand-field parameters were determined by fitting the temperature dependence of the observed magnetic susceptibility anisotropies. The electronic structure determined by this approach shows, that the Er and Tm analogues are candidates for single molecule magnets (SMM). These results demonstrate the possibilities for the application of NMR spectroscopy in investigations of paramagnetic systems in general and single molecule magnets in particular.

A tricoordinated FeI complex with two cyclic-alkyl(amino) carbene (cAAC) and one chlorido ligand, (cAAC)2FeCl (1), is studied by means of 1H NMR spectroscopy and DFT calculations. Due to the cAAC ligands, which can take significant amounts of spin density from the metal center, and due to the magnetic anisotropy of the FeI ion (P. P. Samuel et al., J. Am. Chem. Soc., 2014, 136, 11964–11971), compound 1 is a rare example of a paramagnetic d-block compound which is expected to have significant contributions from both contact and pseudocontact terms to the hyperfine NMR shift. Compound 1 is fluxional, which makes the analysis of its 1H NMR spectrum more difficult but allows a preliminary assignment from EXSY spectra. Then, a software-aided approach enabled a satisfactory signal assignment of all protons which are distanced from the FeI center and carbene cyclic core, and thereby the extraction of the axial and rhombic components of the magnetic susceptibility anisotropy tensor (Δχ). Components of Δχ enable the calculation of zero-field spitting D and E parameters from solution NMR measurements of 1, and these parameters are compared to previously reported experimental and theoretical values.

Reported are the syntheses, structures and magnetic properties, also by NMR spectroscopy in solution, of a series of 13 linear trinuclear 3d–4f compounds with a lanthanide(III) surrounded by two NiII ions, NiII2LnIII, where the central LnIII is hexacoordinate. For three of the crystal structures, an additional H2O molecule is coordinated to the central LnIII ion, leading to a monocapped trigonal prismatic structure. However, NMR spectroscopy indicates that in solution, these complexes also have a hexacoordinate LnIII center. The solution magnetic anisotropies, determined by NMR spectroscopy, indicate that the axial components of the anisotropies are relatively small and that the DyIII derivative might therefore not exhibit single molecule magnetism. The axial anisotropies determined by NMR spectroscopy are in good agreement with the expectations based on the distorted trigonal prismatic ligand field.