1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Schlagintweit JF, Jakob CHG, Meighen-Berger K, Gronauer TF, Weigert Muñoz A, Weiß V, Feige MJ, Sieber SA, Correia JDG, Kühn FE. Fluorescent palladium(II) and platinum(II) NHC/1,2,3-triazole complexes: antiproliferative activity and selectivity against cancer cells. Dalton Trans 2021; 50:2158-2166. [PMID: 33496310 DOI: 10.1039/d0dt04114a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fluorescent Pd(ii) and Pt(ii) complexes bearing 4-methylene-7-methoxycoumarin (MMC) and 2,6-diispropylphenyl (Dipp) substituted NHC/1,2,3-triazole hybrid ligands are described. Depending on the reaction conditions two different ligand coordination modes are observed, i.e., bidentate solely coordinating via NHCs or tetradentate coordinating via NHCs and 1,2,3-triazoles. All Dipp substituted complexes show antiproliferative activity against cervix (HeLa) and breast (MCF-7) human carcinoma cells. The activity significantly depends on the coordination mode, with the tetradentate motif being notably more effective (HeLa: IC50 = 3.9 μM to 4.7 μM; MCF-7: IC50 = 2.07 μM to 2.35 μM). Amongst the MMC series, only the Pd(ii) complex featuring the bidentate coordination mode is active against HeLa (IC50 = 6.1 μM). In contrast to its structurally related Dipp derivative (SI = 0.6), it shows a high selectivity for HeLa (SI > 16) compared to healthy skin cells (HaCaT). According to fluorescence microscopy, this compound is presumably located in late endosomes or lysosomes.
Collapse
Affiliation(s)
- Jonas F Schlagintweit
- Molecular Catalysis, Catalysis Research Center and Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, D-85748 Garching bei München, Germany.
| | - Christian H G Jakob
- Molecular Catalysis, Catalysis Research Center and Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, D-85748 Garching bei München, Germany.
| | - Kevin Meighen-Berger
- Cellular Protein Biochemistry, Department of Chemistry and Institute for Advanced Study, Technische Universität München, Lichtenbergstraße 4, D-85748 Garching bei München, Germany
| | - Thomas F Gronauer
- Chair of Organic Chemistry II, Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, D-85748 Garching bei München, Germany
| | - Angela Weigert Muñoz
- Chair of Organic Chemistry II, Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, D-85748 Garching bei München, Germany
| | - Vanessa Weiß
- Molecular Catalysis, Catalysis Research Center and Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, D-85748 Garching bei München, Germany. and Ausbildungszentrum der Technischen Universität München, Lichtenbergstraße 4, D-85748 Garching bei München, Germany
| | - Matthias J Feige
- Cellular Protein Biochemistry, Department of Chemistry and Institute for Advanced Study, Technische Universität München, Lichtenbergstraße 4, D-85748 Garching bei München, Germany
| | - Stephan A Sieber
- Chair of Organic Chemistry II, Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, D-85748 Garching bei München, Germany
| | - João D G Correia
- Centro de Ciências e Tecnologias Nucleares and Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Campus Tecnológico e Nuclear, Estrada Nacional N°10 (km 139, 7), 2695-066 Bobadela LRS, Portugal
| | - Fritz E Kühn
- Molecular Catalysis, Catalysis Research Center and Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, D-85748 Garching bei München, Germany.
| |
Collapse
|
3
|
Bernd MA, Bauer EB, Oberkofler J, Bauer A, Reich RM, Kühn FE. Macrocyclic NHC complexes of group 10 elements with enlarged aromaticity for biological studies. Dalton Trans 2020; 49:14106-14114. [PMID: 33016296 DOI: 10.1039/d0dt02598d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Two sets of macrocyclic, bio-inspired, non-heme ligands are utilized for the synthesis of NiII, PdII and PtII complexes. The ligands consist of a 16-atom macrocycle, formed by four methylene bridged NHC moieties, with imidazole or benzimidazole as building blocks. The complexes exhibit a square planar coordination geometry and are characterized by NMR, ESI-MS, elemental analysis, SC-XRD and UV/Vis. For complexes incorporating benzimidazole, an evaluation of luminescence properties is performed, and is found that phosphorescence is present for the PdII derivative and there is fluorescence for the PtII derivative. Stability studies in cell culture medium are performed for subsequent MTT assays. Here, the NiII complexes show low to no activity, and PdII and PtII complexes exhibit remarkable low IC50 values in cisplatin resistant A2780cisR cells.
Collapse
Affiliation(s)
- Marco A Bernd
- Department of Chemistry and Catalysis Research Center, Molecular Catalysis, Technische Universität München, Lichtenbergstr. 4, 85747 Garching b. München, Germany.
| | - Elisabeth B Bauer
- Department of Chemistry and Catalysis Research Center, Molecular Catalysis, Technische Universität München, Lichtenbergstr. 4, 85747 Garching b. München, Germany.
| | - Jens Oberkofler
- Department of Chemistry and Catalysis Research Center, Molecular Catalysis, Technische Universität München, Lichtenbergstr. 4, 85747 Garching b. München, Germany.
| | - Andreas Bauer
- Department of Chemistry and Catalysis Research Center, Chair of Organic Chemistry I, Technische Universität München, Lichtenbergstr. 4, 85747 Garching b. München, Germany.
| | - Robert M Reich
- Department of Chemistry and Catalysis Research Center, Molecular Catalysis, Technische Universität München, Lichtenbergstr. 4, 85747 Garching b. München, Germany.
| | - Fritz E Kühn
- Department of Chemistry and Catalysis Research Center, Molecular Catalysis, Technische Universität München, Lichtenbergstr. 4, 85747 Garching b. München, Germany.
| |
Collapse
|
5
|
Schlagintweit JF, Dyckhoff F, Nguyen L, Jakob CH, Reich RM, Kühn FE. Mixed tetradentate NHC/1,2,3-triazole iron complexes bearing cis labile coordination sites as highly active catalysts in Lewis and Brønsted acid mediated olefin epoxidation. J Catal 2020. [DOI: 10.1016/j.jcat.2020.01.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|