Maik Finze

The synthesis and characterization of a new family of N ‐ b oron‐functionalized a nionic NHCs (NBA‐NHCs), I i PrB(CN) ₃ ⁻ ( 5 ), I i Pr(C ₂ F ₅ )BF ₂ ⁻ ( 6 ), IMesB(CN) ₃ ⁻ ( 7 ), and IMes(C ₂ F ₅ )BF ₂ ⁻ ( 8 ), accessible on gram‐scale from air‐ and moisture‐stable precursors, is reported. Multinuclear NMR, IR spectroscopy, and single‐crystal X‐ray diffraction confirm highly electron‐rich carbenic carbon centers and strengthened B–N interactions in these molecules. Selenium adducts 9 – 12 of these NBA‐NHCs indicate an enhanced π ‐acceptor character relative to neutral NHCs, while Tolman electronic parameters of nickel tricarbonyl complexes [(NBA‐NHC)Ni(CO) ₃ ] ⁻ K ⁺ 13 – 16 demonstrate their strong donor ability, similar to dianionic carbenes. Steric maps and buried volume (% V _bur ) analyses of linear gold(I) complexes [(NBA‐NHC)Au(PPh ₃ )] 17 – 20 reveal tunable steric profiles, ranging from anisotropic to strongly shielding environments by varying the N ‐substituents. These results establish NBA‐NHCs as a modular ligand platform enabling control of electronic properties and steric demand at the metal center for future applications in coordination chemistry and catalysis.

Electrochemical fluorination in anhydrous hydrogen fluoride (ECF in aHF) according to the Simons process was used for the fluorination of the anesthetic sevoflurane (CF ₃ ) ₂ CHOCH ₂ F to yield (CF ₃ ) ₂ CHOCHF ₂ , (CF ₃ ) ₂ CHOCF ₃ , and (CF ₃ ) ₂ CFOCF ₃ . The related ethers R ^F OCH ₃ (R ^F = n C ₃ F ₇ , a mixture of n C ₄ F ₉ / i C ₄ F ₉ , i C ₄ F ₉ , t C ₄ F ₉ ) were fluorinated to result in the respective mono‐, di‐, and trifluoromethyl ethers. The vapor pressure curves of selected fluorinated ethers, including (CF ₃ ) ₂ CHOCHF ₂ , (CF ₃ ) ₂ CHOCF ₃ , and (CF ₃ ) ₂ CFOCF ₃ , were determined, and the Antoine fit parameters were used for the extrapolation of the normal boiling points and the enthalpies of vaporization. In addition, the crystal structures of sevoflurane, (CF ₃ ) ₂ CHOCH ₃ , (CF ₃ ) ₂ CHOCHF ₂ , (CF ₃ ) ₂ CHOCF ₃ , and (CF ₃ ) ₂ CFOCF ₃ were determined by x‐ray diffraction, providing a detailed insight into trends of the bond parameters and the intermolecular interactions in the solid state. The interpretation of the bond parameters is supported by calculated values (density functional theory, DFT).

Nickel(0)‐catalyzed [2 + 2 + 2] cycloadditions of linked bisdiynes with diarylacetylenes were performed using the Ni(II) precursor complex [(TMEDA)Ni( o ‐tolyl)Cl] in the presence of PPh ₃ ligands to generate the active Ni(0) species. Optimal reactivity was observed when electron‐rich bisdiynes reacted with electron‐deficient diarylacetylenes, affording air‐stable, approximately C _2v ‐symmetric D‐π‐A‐π‐D bis(arylethynyl)indane‐based dyes containing o ‐terphenyl cores. Spectroscopic analyses revealed strong solvatochromic emission with high quantum yields in solution, except for the nonemissive bis‐ N ‐methylpyridinium derivative 4,4 ^′ ‐(4,7‐bis((4‐(bis(4‐methoxyphenyl)amino)phenyl)ethynyl)−2,3‐dihydro‐1H‐indene‐5,6‐diyl)bis(1‐methylpyridin‐1‐ium) ditriflate, 10 , pointing toward the decisive impact of pyridine methylation on the nonradiative relaxation of the fluorophore. Vibrational studies of the triarylamine dyes displayed a prominent alkyne stretching band in both Raman and IR spectra, applicable for use as a probe. Biorelevant studies revealed that the synthesized dyes bind strongly to double‐stranded DNA and RNA, most likely through groove insertion, leading to significant fluorescence quenching. Only the dicationic derivative 10 showed a characteristic CD response, attributed to additional electrostatic interactions that orient the dye within the DNA minor or RNA major groove. The dyes had minimal effects on polynucleotide thermal stability, suggesting that hydrophobic and van der Waals forces dominate the binding, except for derivative 10 , which also involves electrostatic interactions. All compounds were found to be nontoxic toward human cell lines, indicating their promise as multimodal fluorescence, CD, and Raman probes for intracellular and extracellular bioimaging applications.

The construction of longer chains of sp-hybridized atoms, while relatively facile for carbon, is essentially unknown in the absence of carbon. Our recent results with the 1,3-haloboration of the [WNN] fragment of a Chatt-type complex are herein utilized in the synthesis of homo- and heterobimetallic complexes spanned by long all-inorganic sp chains. Notably, this includes structural confirmation of the longest sp-hybridized inorganic chain ever constructed, in a bimetallic complex with a six-atom all-sp {NNBBNN} bridging ligand.

A new one‐pot synthesis of 1,3‐divinylimidazolidin‐2‐one ( DVI ) starting from cheap and commercially available substances, i.e., di(chloroethyl)amine and phosgene or triphosgene was developed. The two‐step procedure provides a convenient access to DVI in high purity and good yield without the application of any catalytic system. Additionally, an alternative route that relies on the utilization of carbon dioxide for the preparation of DVI was assessed.

A series of bis(trifluoromethyl)amido coinage metal(I) complexes were synthesized in yields of 52-93%. This includes N-heterocyclic carbene (NHC) complexes of copper(I), silver(I), and gold(I). In addition, the complex [(Ph₃P)Au{N(CF₃)₂}] was obtained in 70% yield. The complexes are thermally robust, with decomposition temperatures of 151-259 °C (DSC onset), and they were characterized by spectroscopic methods and elemental analysis. The bis(trifluoromethyl)amido complexes [(IDipp)M{N(CF₃)₂}] (M = Cu, Ag, Au), [(ItBu)M{N(CF₃)₂}] (M = Cu, Ag), and [(Ph₃P)Au{N(CF₃)₂}] were studied by single-crystal X-ray diffraction (SCXRD). A detailed analysis of selected bond parameters, aided by DFT calculations and ETS-NOCV studies, provided insight into the properties of the {N(CF₃)₂}^- ligand. The bis(trifluoromethyl)amido ligand is a weaker σ-donor than related nonfluorinated dialkylamido ligands, for example {N(CH₃)₂}^- and {NiPr₂}^-. In addition, the salts [Ag(IDipp)₂]⁺([Ag{N(CF₃)₂}₂]^-)_0.25(Cl^-)_0.75, [Ag(ItBu)₂]⁺(HF₂)^-, {[tBu₂Im]⁺}₂{N(CF₃)₂}^-(HF₂)^-, and [tBu₂Im]⁺(HF₂)^- were characterized by SCXRD.

Ionic liquids (ILs) composed of the [EMIm] ⁺ , [BMIm] ⁺ , or [Pyr ₁₄ ] ⁺ cation and the pentafluoroethyl(fluoro)phosphate anions [ mer -(C ₂ F ₅ ) ₃ PF ₃ ] ⁻ (FAP3), [ trans -(C ₂ F ₅ ) ₂ PF ₄ ] ⁻ (FAP2), and [(C ₂ F ₅ )PF ₅ ] ⁻ (FAP1) were synthesized from (C ₂ F ₅ ) ₃ PF ₂ .

Supercapacitors and batteries both have great potential to store energy, albeit based on different storage mechanisms. Batteries can store large amount of energy via faradaic processes but the energy is delivered at a comparatively slower rate. In contrast, supercapacitors are able to rapidly deliver the stored energy, i.e., have high power properties. This ability is mostly achieved through the storage mechanism that is based on the formation of electric double layers by adsorption of the electrolyte ions at porous carbon-based electrodes. ^[1] The electrolyte is the vital component of the supercapacitor as many properties of the supercapacitors can be influenced through the electrolyte. ^[2] Three main characteristics are of utmost importance for an optimal electrolyte: conductivity, viscosity and stability. Thermal stability and material compatibility are also important. Viscosity and conductivity have a direct influence on the ion transport and thus performance of the supercapacitors. The stability or more specifically, the electrochemical window of the electrolyte is of particular interest due to the proportionality of the energy to the voltage ( E =0.5* C * U ² ). ^[3] Thus it is possible to significantly enhance the energy density through modest increases of the voltage. Ionic liquids, which are salts in the liquid phase below 100°C, are interesting as “solvent-free” electrolytes. The properties of ILs can be tailored through the choice of anion and cation and as such they are sometimes considered “designer solvents”. ^{[3,4 ,5 ]} Room temperature ionic liquids (RTILs), salts which are liquid at room temperature, have attracted attention due to the possibility to obtain a device with a voltage above 3 V. The perceived disadvantage of ILs, i.e., low conductivity and high viscosity, can be tweaked by utilizing weakly-coordinating anions. ^[3] Borate-based anions are of particular interest in this regard. Electrolytes based on [B(CN) ₄ ] ⁻ have been tested in supercapacitors and exhibit good conductivity/viscosity and wide stability. ^[6] This improvement can be pushed further with cyano(fluoro)borates without significant loss of stability. ^[7] However, [B(CN) ₄ ] ⁻ ionic liquids are reported to polymerize if they decompose. ^[8,9] Our results shown that the cyano(fluoro)borate-based RTIL electrolytes in combination with microporous activated carbon exhibit behaviour during cyclic voltammetry that suggests a passivation of the surface/ blocking of the porous network. From a variety of candidates, N-butyl-N-methyl-pyrrolidinium tricyanomonofluoroborate, Pyr ₁₄ MFB, and 1-ethyl-3-methyl-immidazolium tricyanomonofluoroborate, EMImMFB, have been selected as subjects for in-depth study. To investigate blocking of the micropores, cyclic voltammetry and voltage floating will be conducted also with a mesoporous carbon material. Furthermore, the impact of conductive additives upon the long-term stability of the microporous activated carbon will be examined. Finally, we will present our approach to identify possible decomposition products mainly responsible for ageing of the microporous electrodes by performing NMR measurements on electrolytes aged under potentiostatic conditions. [1] A. Noori, M. F. El-Kady, M. S. Rahmanifar, R. B. Kaner, M. F. Mousavi, Chem. Soc. Rev. 2019 , 48 , 1272–1341. [2] C. Zhong, Y. Deng, W. Hu, J. Qiao, L. Zhang, J. Zhang, Chem. Soc. Rev. 2015 , 44 , 7484–7539. [3] J. Feng, Y. Wang, Y. Xu, Y. Sun, Y. Tang, X. Yan, Energy Environ. Sci. 2021 , 14 , 2859–2882. [4] A. Balducci, J. Power Sources 2016 , 326 , 534–540. [5] A. Brandt, S. Pohlmann, A. Varzi, A. Balducci, S. Passerini, MRS Bull. 2013 , 38 , 554–559. [6] V. L. Martins, A. J. R. Rennie, N. Sanchez-Ramirez, R. M. Torresi, P. J. Hall, ChemElectroChem 2018 , 5 , 598–604. [7] J. Riefer, L. Zapf, J. A. P. Sprenger, R. Wirthensohn, S. Endres, A.-C. Pöppler, M. Gutmann, L. Meinel, N. V. Ignat'ev, M. Finze, Phys. Chem. Chem. Phys. 2023 , 25 , 5037–5048. [8] J. Kruusma, A. Tõnisoo, R: Pärna, E. Nõmmiste, I. Kussik, M. Vahtrus. I. Tallo, T. Romann, E. Lust, J. Electrochem. Soc. 2017 , 164 , A3393-A3402. [9] T. Romann, E. Anderson, P. Pikma, H. Tamme, P. Möller, E. Lust Electrochem. Commun. 2017 , 74 , 38-41. The authors thank Solvionic for providing the IL cation precursors within the scope of the EMPHASIS project. This project has received funding from the European Union’s Horizon Europe research and innovation programme under grant agreement N° 101091997. This output reflects only the authors’ view and the European Union cannot be held responsible for any use that may be made of the information contained therein.

The chemical character of closo -borate radical anions is investigated and compared to electrophilic and nucleophilic organic radicals.