Article
Chemistry, Multidisciplinary
Luong Phong Ho, Matthias Tamm
Summary: This article provides a brief overview of the design and preparation of N-heterocyclic carbenes carrying weakly coordinating anions, and summarizes numerous transition metal and main group element complexes isolated in the past decade.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Skyler D. D. Ware, Wendy Zhang, David J. J. Charboneau, Channing K. K. Klein, Sarah E. E. Reisman, Kimberly A. A. See
Summary: This study investigates factors influencing the electrochemical reduction of Sm(III) to Sm(II), including the effects of supporting electrolyte, electrode material, and Sm precursor. The coordination strength of the counteranion of the Sm salt is found to affect the reversibility and redox potential of the Sm(II)/(III) couple, and the counteranion primarily determines the reducibility of Sm(III). Electrochemically generated SmI2 performs similarly to commercial SmI2 solutions in a proof-of-concept reaction.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Organic
Stephen H. Dempsey, Steven R. Kass
Summary: In this study, the dissociation enthalpies of weakly coordinating cations were computed, and their performances were compared. The results showed that substituted tetraphenylphosphonium ion derivatives are effective weakly coordinating cations that perform as well as or even better than P2 and P5 phosphazenium ions.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Jakub Brzeski
Summary: Quantum-chemical calculations were used to investigate the acidity and stability of aluminabenzene-based Lewis acids and anions. Aluminabenzene was found to be a stronger Lewis superacid than antimony pentafluoride, and electron-withdrawing substitutions on the heterocyclic ring led to the formation of extremely strong Lewis superacids. Two of these molecules, AlC5Cl5 and AlC5(CN)(5), were identified as the strongest Lewis acids reported in the literature. Addition of fluoride anion to substituted aluminabenzene-based Lewis acids resulted in the formation of anions with lower electronic stability but higher thermodynamic stability, making them suitable as counterions for reactive cations. The proposed Lewis acids may undergo isomerization and dimerization, while the studied anions are expected to remain stable against such processes.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2023)
Article
Crystallography
Emmanuel Adeniyi, Matthias Zeller, Sergiy V. V. Rosokha
Summary: An X-ray structural analysis revealed that salts of TMPD, MPTZ, and OMB with dodecamethyl- or hexabromo-substituted carbadodecaborate anions have layered structures. The cationic layers contain either well-separated TMPD+ or MPTZ(+) cation radicals or pi-stacks of partially oxidized OMB moieties. Quantum mechanical calculations showed that the formation of isolated cation radicals or pi-bonded associations in these salts is correlated with the strength of multicenter pi-bonding.
Article
Chemistry, Inorganic & Nuclear
Ludwig Zapf, Udo Radius, Maik Finze
Summary: The anionic 1-methyl-3-(tris(pentafluoroethyl)difluorophosphorane)imidazoline-2-ylidenate 3 and the 1,3-bis(tris(pentafluoroethyl)difluorophosphorane)imidazoline-2-ylidenate dianion 4 were obtained from the deprotonation of {(C2F5)(3)PF2}-methylimidazole 1 and the {(C2F5)(3)PF2}(2)-imidazolate anion 2. Reactions of these new ligands with elemental selenium and chloro(phosphine)gold(i) complexes resulted in the formation of an anionic selenium adduct (5) and WCA-NHC gold complexes (6 and 7). The structural and spectroscopic properties of these NHC derivatives, along with quantum chemical calculations, reveal the unique and promising characteristics of the WCA-NHCs 3 and 4.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Lingyao Wang, Tao Jiang, Simon Duttwyler, Yuanbin Zhang
Summary: A new family of weakly coordinating dodecaborate anion hybrid supramolecular Cu(II)-dipyridyl frameworks, denoted as BSF-n (n = 61, 71, 72, 73, 74, 75), were synthesized and characterized, with BSF-61 showing a 3D porous structure and the other structures exhibiting variations in Cu(II)-dipyridyl coordination due to different solvent molecules or hydroxyl groups.
Article
Chemistry, Inorganic & Nuclear
Luong Phong Ho, Matthias Tamm
Summary: In this study, chalcogen-pnictogen dihalide complexes with anionic N-heterocyclic carbene ligands containing a weakly coordinating borate moiety were isolated and characterized.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2022)
Article
Electrochemistry
Alexander W. Black, Wenjian Zhang, Gillian Reid, Philip N. Bartlett
Summary: This study investigated diffusion in weakly coordinating solvents using electrochemical measurements. The diffusion coefficients were measured and compared with theoretical upper and lower bounds. The results showed that the charged metallocene species had larger particle size than expected, highlighting the importance of considering modifications to the Stokes-Einstein equation.
ELECTROCHIMICA ACTA
(2022)
Article
Chemistry, Physical
Peng-Fei Yang, Jian-Xing Liang, Han -Tong Zhao, Wei Shu
Summary: In this study, a straightforward method to access enantioenriched 1,n-diamines containing a chiral alpha-branched aliphatic amine is achieved through Ni-catalyzed asymmetric hydroamination. This method delivers good yields and excellent enantioselectivities with diverse substitution patterns, and exhibits excellent functional group tolerance.
Article
Chemistry, Multidisciplinary
Robin F. Weitkamp, Beate Neumann, Hans-Georg Stammler, Berthold Hoge
Summary: The study revealed that weakly coordinating cations of different sizes have varying effects on the formation of silanol-silanolate motifs, with large cations favoring cyclic structures and the less bulky tetramethyl ammonium cation encouraging the formation of polyanionic silanol-silanolate chains in the solid state.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Inorganic & Nuclear
Firoz Shah Tuglak Khan, Amy L. Waldbusser, Maria C. Carrasco, Hadi Pourhadi, Shabnam Hematian
Summary: This study presents a facile strategy for preparing a series of ferricenium complexes with weakly coordinating anions, and thoroughly investigates their ground state electronic structures, revealing the significant impact of substituents on metal-ligand separations in oxidized species.
DALTON TRANSACTIONS
(2021)
Review
Chemistry, Inorganic & Nuclear
Magnus R. Buchner, Lewis R. Thomas-Hargreaves
Summary: The article provides an overview of two main approaches to enhance reactivity in alkaline earth metal catalysis, either through the use of highly dipolar haloaryls as solvents or by increasing the solubility of ligand systems. The resulting coordination modes, reactivities, synthetic strategies, and the latest results of group 1 complex chemistry in aliphatic solvents are presented, with future challenges highlighted.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Inorganic & Nuclear
A. P. Prakasham, Arkadi Vigalok, Andrei N. Vedernikov
Summary: A series of Pd(II) aryl complexes with a PNO-type pincer ligand bearing a weakly coordinated benzofuran side arm has been studied. The Pd-O distances were found to depend on the aromatic group at the Pd center. Changing the electron density at the metal can affect these interactions and be utilized in chemical reactions.
Article
Chemistry, Multidisciplinary
Sophia Weng, Wei Lun Toh, Yogesh Surendranath
Summary: The rates and selectivity of electrochemical CO2 reduction are influenced by the identity of alkali metal cations. This study shows that Au- and Ag-catalyzed CO2 reduction can occur with weakly coordinating tetraalkylammonium cations. Competition experiments reveal that the organic cation can exclusively control the selectivity and activity of CO2 reduction. These findings suggest the potential use of water-soluble organic cation salts as supporting electrolytes for CO2 electrolysis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Manuel Schmitt, Ingo Krossing
Summary: The metal dinitrogen bonding in a wide series of terminal end-on dinitrogen complexes was investigated using charge displacement analysis. The effect of sigma donation and pi backdonation on the N-N bond was discussed and compared with observations for carbonyl complexes. It was found that sigma donation had no significant effect on the N-N bond strength, whereas pi backdonation caused elongation of the N-N bond.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Philipp Dabringhaus, Silja Zedlitz, Luisa Giarrana, David Scheschkewitz, Ingo Krossing
Summary: Schnockel's [(AlCp*)(4)] and Jutzi's [SiCp*][B(C6F5)(4)] are important in modern main-group chemistry with various applications in synthesis and catalysis. However, the reactivity between AlCp* and [SiCp*](+) has not been explored. In this study, their reaction was investigated and complex salts [Cp*Si(AlCp*)(3)][WCA] were obtained. The tetrahedral [SiAl3](+) core not only represents a rare example of a low-valent silicon-doped aluminium-cluster, but also provides a convenient preparative entry towards low-valent Si-Al clusters.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Antoine Barthelemy, Harald Scherer, Hanna Weller, Ingo Krossing
Summary: This study presents the synthesis and characterization of two salts [(L)GaGa(L)][Al(ORF)(4)]2 ([pf]- = [Al(ORF)(4)]-), which include the first dicationic digallene [(L)Ga?Ga(L)]2+ and a digallane [(L)Ga-Ga(L)]2+. The dicationic digallene features a trans-bent [L-GaGa-L]2+ bond analogous to neutral R-GaGa-R molecules and similar to Robinson's famous Digallyne [R-GaGa-R]2-. The dicationic digallane is similar to the widely used Jones magnesium dimer but has a very short Ga-II-Ga-II single bond.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Chloe L. Shaves, Nery Villegas-Escobar, Ewan R. Clark, Ian M. Riddlestone
Summary: The use of a sterically demanding pincer ligand leads to the synthesis of an unusual square planar aluminium complex. Due to the constrained geometry imposed by the ligand scaffold, the four-coordinate aluminium center remains Lewis acidic and exhibits different metal-ligand cooperative pathways for activating ketones and CO2. Furthermore, it demonstrates the rare capability of catalytically reducing CO2 to a methanol equivalent at room temperature as a single-component aluminium system.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Physical
Dustin Kubas, Malte Semmel, Ouda Salem, Ingo Krossing
Summary: CO2 valorization is a key measure to achieve climate neutrality. Heteropoly acids are introduced as capable dehydration catalysts for direct dimethyl ether (DME) synthesis from CO2 and H-2. Thermodynamic calculations confirm that direct DME synthesis is superior to sole methanol synthesis. Experimental results show that direct DME synthesis has higher yields compared to methanol synthesis at 250 degrees Celsius.
Article
Chemistry, Multidisciplinary
Dustin Kubas, Jennifer Maria Beck, Erdogan Kasisari, Timo Schaetzler, Anita Becherer, Anna Fischer, Ingo Krossing
Summary: The direct synthesis of dimethyl ether (DME) from CO2 hydrogenation was investigated using an improved bifunctional catalyst in a fixed bed reactor. Various combinations of a methanol-producing part and a methanol dehydration part were tested, and the results showed that HPA-coated catalysts exhibited higher activity and resilience toward deactivation. Dual-grain preparation method showed superior performance over single-grain.
Review
Chemistry, Multidisciplinary
Malte Sellin, Ingo Krossing
Summary: CO is one of the most important ligands in organometallic chemistry and can form transition metal carbonyl cations (TMCCs), but their synthesis is challenging due to their high reactivity.
ACCOUNTS OF CHEMICAL RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Jan M. Rall, Max Lapersonne, Marcel Schorpp, Ingo Krossing
Summary: This article reports the synthesis and characterization of nickelocenium cations. Diamagnetic [NiCp2]2+ represents the first example of an unsubstituted parent metallocene dication. The salts were generated and characterized using various experimental methods.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Antoine Barthelemy, Harald Scherer, Michael Daub, Alexis Bugnet, Ingo Krossing
Summary: The reaction between bisdicyclohexylphosphinoethane (dcpe) and subvalent M(I) sources [M-I(PhF)(2)][pf] (M=Ga+, In+; [pf]-=[Al(ORF)(4)]-; R-F=C(CF3)(3)) resulted in the formation of salts [{M(dcpe)}(2)][pf](2), which contain the first reported dicationic, trans-bent digallene, and diindene structures. The M-I double bonds, which display a ditetrylene-like structure, are surprisingly short. Quantum chemical calculations and molecular analyses were conducted to compare the bonding situation in these salts with that in the isoelectronic and isostructural, but neutral digermenes and distannenes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Andreas Billion, Andreas Vogel, Jonas Schulte, Harald Scherer, Ingo Krossing
Summary: Oxymethylene dimethyl ethers (OMEn) are promising sustainable synthetic fuels synthesized from CO2 and green H-2. This study presents a novel continuous, anhydrous reaction setup to overcome synthetic problems and successfully synthesizes OMEn. The catalysts immobilized in ionic liquids demonstrate excellent catalytic performance and stable results in continuous operations.
Article
Chemistry, Multidisciplinary
Philipp Dabringhaus, Tim Heizmann, Ingo Krossing
Summary: This study reports the reactivity of a monomeric Ga(I) cation activated with a pyridine-diimine pincer ligand towards small molecules, including controlled oxidative additions into C-Cl, H-P, and P-P bonds, as well as [4+1] cycloaddition to butadienes. Intriguingly, the insertion product into the P-P bond allows for the quantitative release of the P-4 molecule upon reaction with AlEt3 and butadienes. The experimental study is supported by high-level computational analysis. Evaluation: 7 points.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Gauthier Studer, Alexei Schmidt, Jan Buettner, Maximilian Schmidt, Anna Fischer, Ingo Krossing, Birgit Esser
Summary: This article introduces a potential rechargeable aluminum-ion battery (AIB) material with a high specific capacity. The redox polymer can act as a positive electrode material, overcoming the limitations of current AIBs. It exhibits a reversible two-electron redox process and achieves a specific capacity of up to 167 mA h g(-1), surpassing graphite as a positive electrode material. The AIB also demonstrates excellent capacity retention at fast rates and can be cycled reversibly at slower rates, making it a promising candidate for sustainable energy storage devices.
ENERGY & ENVIRONMENTAL SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Christoph Riesinger, David Roehner, Ingo Krossing, Manfred Scheer
Summary: A rational synthetic pathway was developed to synthesize a series of cyclo-P-5-bearing multi-decker complexes. By combining [Cp*Fe(mu,eta(5 : 5)-P-5)] (A) with low-valent transition metal cations, triple-decker complexes [Cp*Fe(mu,eta(5 : 5)-P-5)MCp '''][WCA] (M = Cr - Ni; WCA = weakly coordinating anion, Cp ''' = 1,2,4-(Bu3C5H2)-Bu-t) were obtained. Utilizing arene complexes [M(C6R6)(2)][WCA](n) (M = Fe, Co) allowed the synthesis of unprecedented cyclo-P-5-containing quadruple-decker complexes [{Cp*Fe(mu,eta(5 : 5)-P-5)}(2)M][pf](n) (M = Fe, Co).
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Andreas Billion, Marcel Schorpp, Rebecca Feser, Manuel Schmitt, Lea Eisele, Harald Scherer, Takaaki Sonoda, Hajimu Kawa, Burkhard Butschke, Ingo Krossing
Summary: Weakly coordinating anions (WCAs) are used to stabilize and isolate reactive cations. The alkoxyaluminate-based WCA [Al(OC(CF3)(3))(4)](-) ([pf](-)) is widely used but can still be coordinated by small cations. A novel WCA [Al(OC10F15)(4)](-) ([pfAd](-)) is more stable due to its rigid core framework. Various salts containing [pfAd](-) were synthesized and characterized by spectroscopy and crystallography. The water stability of [pfAd](-) was demonstrated by the successful synthesis of Tl[pfAd] in a mixture of solvents.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Andreas Billion, Jonas Schulte, Andreas Vogel, Felix Hilfinger, Ingo Krossing
Summary: A novel continuous route for synthesizing oxymethylene dimethyl ethers (OMEn) by the reaction of molecular formaldehyde and dimethyl ether is presented. Acidic, porous, and thermally stable zeolites proved to be effective catalysts for this reaction. The results contribute to a better understanding of the complex reaction network in the OMEn synthesis and provide important insights for establishing an energy efficient and sustainable OMEn production process.
