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Luff MS, Walther L, Finze M, Radius U. NHC-ligated nickel(II) cyanoborate complexes and salts. Dalton Trans 2024; 53:5391-5400. [PMID: 38415451 DOI: 10.1039/d4dt00231h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
A comprehensive study on the synthesis and characterization of NHC-ligated nickel(II) cyanoborates (CBs) is presented (NHC = N-heterocyclic carbene). Nickel(II) cyanoborates Ni[BH2(CN)2]2·H2O (Ib·H2O), Ni[BH(CN)3]2·0.5H2O (Ic·0.5H2O), Ni[B(CN)4]2·H2O (Id·H2O) were reacted with selected NHCs of different steric size. The reaction of the nickel cyanoborates with small to medium-sized NHCs Me2ImMe and iPr2Im (R2Im = 1,3-di-organyl-imidazolin-2-ylidene; R2ImMe = 1,3-di-organyl-4,5-dimethyl-imidazolin-2-ylidene) afforded cyanoborate salts containing the rare homoleptic fourfold NHC-ligated nickel(II) cations [Ni(NHC)4]2+ (NHC = Me2ImMe (1c-d), iPr2Im (2c-d)) and cyanoborate counter-anions. Bulkier NHCs such as Mes2Im and Dipp2Im afforded complexes trans-[Ni(NHC)2(CB)2] (trans-4b, trans-5c). For the combination of the cyanoborate anion [BH2(CN)2]- and iPr2ImMe the salt of the tris-NHC complex [Ni(iPr2ImMe)3(NC-BH2CN)][BH2(CN)2] (3b) was isolated. Salt metathesis of NHC-ligated nickel(II) halides (Ni(NHC)2X2) (X = Cl, Br) with silver(I) and alkali metal cyanoborates were used to synthesize mono- and disubstituted coordination compounds of the type cis- or trans-[Ni(NHC)2(CB)X] (cis-10c, cis-11c, trans-12b) and cis- or trans-[Ni(NHC)2(CB)2] (cis-13b, cis-14a-c, trans-14a-b, trans-15b, trans-5b). Further investigations reveal that NHC-ligated cyanoborate complexes can act as building blocks for coordination polymers, as observed for structurally characterized 1∞{trans-[Ni(Mes2Im)2(μ2-[NC-BH2-CN])2]·2Ag(μ2-[BH2(CN)2])} (trans-5b·Ag). This study demonstrates the diverse character of cyanoborates in coordination chemistry as both, non-coordinating counter-anions, and weakly to medium coordinating anions forming novel transition metal complexes and salts. It provides evidence that a proper choice of cyanoborate and a proper choice of co-ligand can lead to a rich coordination chemistry of cyanoborate anions.
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Affiliation(s)
- Martin S Luff
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Luis Walther
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Maik Finze
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Udo Radius
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
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Luff MS, Kerpen C, Sprenger JAP, Finze M, Radius U. Nickel(II) Cyanoborates and Cyanoborate-Ligated Nickel(II) Complexes. Inorg Chem 2024; 63:2204-2216. [PMID: 38206799 DOI: 10.1021/acs.inorgchem.3c04164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Nickel(II) cyanoborates Ni[BH2(CN)2]2·H2O (1b·H2O), Ni[BH(CN)3]2·0.5H2O (1c·0.5H2O), and Ni[B(CN)4]2·0.5H2O (1d·0.5H2O) were synthesized, and their reactivity with respect to dppeO2 (=1,2-bis-(diphenylphosphinoethane dioxide)), pyNO (=pyridine-N-oxide), dppe (=1,2-bis-(diphenylphosphinoethane), and DMSO (=dimethyl sulfoxide) was examined. Using these ligands, either cyanoborate (CB) complex salts of [Ni(dppe)2]2+ (2b-d) and [Ni(pyNO)6]2+ (3c-d) were isolated or complexes [Ni(DMSO)4{NC-B(CN)3}2] (1dDMSO) and [Ni(dppeO2)2{NC-B(CN)3}2] (1ddppeO2) were formed. Salt metathesis of [Ni(dppe)Cl2] with alkali metal cyanoborates resulted in mono- and disubstituted coordination compounds [Ni(dppe){NC-BH(CN)2}Cl] (5c) and [Ni(dppe){NC-BH2CN)2}] (4b), which decomposed to salts 2b-d. The synthetical pathways explored offer convenient routes to nickel(II) cyanoborates, nickel(II) complexes ligated with cyanoborates, and nickel(II) complex salts of cyanoborates. Further, our studies demonstrate the diverse character of cyanoborates in coordination chemistry as noncoordinating counteranions and also as medium coordinating anions forming novel transition-metal complexes and salts.
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Affiliation(s)
- Martin S Luff
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Christoph Kerpen
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Jan A P Sprenger
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Maik Finze
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Udo Radius
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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Goloviznina K, Bakis E, Philippi F, Scaglione N, Rekis T, Laimina L, Costa Gomes M, Padua A. Attraction between Like Charged Ions in Ionic Liquids: Unveiling the Enigma of Tetracyanoborate Anions. J Phys Chem Lett 2024; 15:248-253. [PMID: 38165169 DOI: 10.1021/acs.jpclett.3c02983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Intermolecular interactions in ionic liquids are mainly governed by Coulombic forces. Attraction between cations has been previously observed and was attributed to dispersion interactions between nonpolar moieties, hydrogen bonding, or π stacking. In this study, we present the intriguing behavior of tetracyanoborate anions in ionic liquids that, unlike their dicyanamide and tricyanomethanide counterparts, form dimers in both solid and liquid phases. A joint simulation and experimental study uncovers the origin of such anion-anion attraction: stabilization by induction and dispersion forces between several cyano groups, which is strong enough to overcome electrostatic repulsion. These findings open up new opportunities in the rational design of ionic liquids, where interactions between ions of the same charge can be controlled and fine-tuned by the presence of cyano groups.
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Affiliation(s)
- Kateryna Goloviznina
- Physicochimie des Électrolytes et Nanosystèmes Interfaciaux (PHENIX), Sorbonne Université and CNRS, F-75005 Paris, France
| | - Eduards Bakis
- Faculty of Chemistry, University of Latvia, Jelgavas 1, Riga LV-1001, Latvia
| | - Frederik Philippi
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, London W12 0BZ, United Kingdom
| | - Nicolas Scaglione
- Laboratoire de Chimie, Ecole Normale Superieure de Lyon and CNRS, F-69364 Lyon, France
| | - Toms Rekis
- Faculty of Chemistry, University of Latvia, Jelgavas 1, Riga LV-1001, Latvia
| | - Laura Laimina
- Faculty of Chemistry, University of Latvia, Jelgavas 1, Riga LV-1001, Latvia
| | - Margarida Costa Gomes
- Laboratoire de Chimie, Ecole Normale Superieure de Lyon and CNRS, F-69364 Lyon, France
| | - Agilio Padua
- Laboratoire de Chimie, Ecole Normale Superieure de Lyon and CNRS, F-69364 Lyon, France
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Schopper N, Landmann J, Sprenger JAP, Zapf L, Bertermann R, Ignat'ev NV, Finze M. Alkylcyanoborate Anions: Building Blocks for Fluorine-Free Low-Viscosity, Electrochemically and Thermally Stable Ionic Liquids. Chemistry 2023; 29:e202301497. [PMID: 37395305 DOI: 10.1002/chem.202301497] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/01/2023] [Accepted: 07/03/2023] [Indexed: 07/04/2023]
Abstract
A set of mixed-substituted potassium alkylcyano- and alkylcyanofluoroborates has been synthesized using easily accessible starting compounds and characterized by elemental analysis, NMR and vibrational spectroscopy, and mass spectrometry. In addition, single-crystal structures of salts of the cyanoborate anions have been derived from X-ray diffraction experiments. The 1-ethyl-3-methylimidazolium room temperature ionic liquids ([EMIm]+ -RTILs) with the new borate anions have been synthesized and their physicochemical properties, that is, high thermal and electrochemical stability, low viscosity, and high conductivity, have been compared to the properties of related [EMIm]+ -RTILs. The influence of the different alkyl substituents at boron has been assessed. The exemplary study on the properties with the [EMIm]+ -ILs with the mixed water stable alkylcyanoborate anions points towards the potential of these fluorine-free borate anions, in general.
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Affiliation(s)
- Nils Schopper
- Julius-Maximilians-Universität Würzburg, Institut für Anorganische Chemie, Institut für nachhaltige Chemie & Katalyse mit Bor (ICB), Am Hubland, 97074, Würzburg, Germany
| | - Johannes Landmann
- Julius-Maximilians-Universität Würzburg, Institut für Anorganische Chemie, Institut für nachhaltige Chemie & Katalyse mit Bor (ICB), Am Hubland, 97074, Würzburg, Germany
| | - Jan A P Sprenger
- Julius-Maximilians-Universität Würzburg, Institut für Anorganische Chemie, Institut für nachhaltige Chemie & Katalyse mit Bor (ICB), Am Hubland, 97074, Würzburg, Germany
| | - Ludwig Zapf
- Julius-Maximilians-Universität Würzburg, Institut für Anorganische Chemie, Institut für nachhaltige Chemie & Katalyse mit Bor (ICB), Am Hubland, 97074, Würzburg, Germany
| | - Rüdiger Bertermann
- Julius-Maximilians-Universität Würzburg, Institut für Anorganische Chemie, Institut für nachhaltige Chemie & Katalyse mit Bor (ICB), Am Hubland, 97074, Würzburg, Germany
| | - Nikolai V Ignat'ev
- Julius-Maximilians-Universität Würzburg, Institut für Anorganische Chemie, Institut für nachhaltige Chemie & Katalyse mit Bor (ICB), Am Hubland, 97074, Würzburg, Germany
- Consultant, Merck Life Science KGaA, 64293, Darmstadt, Germany
| | - Maik Finze
- Julius-Maximilians-Universität Würzburg, Institut für Anorganische Chemie, Institut für nachhaltige Chemie & Katalyse mit Bor (ICB), Am Hubland, 97074, Würzburg, Germany
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