In continuation of our study of the chemistry of cationic (cycloheptatrienyl)(cyclopentadienyl)manganese(I) sandwich complexes, so-called “tromancenium” salts, we report here on their boron-substituted derivatives focusing on useful boron-mediated synthetic applications. Transmetalation of lithiated tricarbonyl(cyclopentadienyl)manganese (“cymantrene”) with boric or diboronic esters affords monoborylated cymantrenes that are converted by advanced high-power LED photosynthesis followed by oxidation with tritylium to their 8-boron-substituted tromancenium complexes. These new functionalized tromancenium salts are fully characterized by 1 H/ 11 B/ 13 C/ 19 F/ 55 Mn NMR, IR, UV–vis, HRMS spectroscopy, single-crystal structure analysis (XRD) and cyclic voltammetry (CV). IR spectra were thoroughly analyzed by density functional theory (DFT) on the harmonic approximation in qualitative agreement of calculated vibrations with experimental values. Uncommon chemical reactivity of these borylated tromancenium salts is observed, due to the strongly electron-withdrawing cationic tromancenium moiety. No Suzuki-type cross-coupling reactions proved so far achievable, but unusual copper-promoted amination with sodium azide under microwave irradiation is possible. Diazoniation of aminotromancenium affords an extremely reactive dicationic tromanceniumdiazonium salt, which is too labile for standard Sandmeyer reactions, in contrast to analogous chemistry of cobaltocenium salts. Overall, borylated tromancenium salts display unexpected and intriguing chemical properties with the potential for novel synthetic applications in future work.
New clathrochelate complexes of manganese, iron and cobalt containing peripheral organometallic manganese moieties cymantrene or tromancenium were synthesized via self‐assembly from di/tri‐topic dioximes, metal templates and cymantrene/tromancenium boronic acid pinacol esters. These air‐stable, highly colored, oligometallic complexes are composed of various combinations of MnIFeIIMnI, MnICoIIMnI, MnIMnIIMnIIMnI and MnICoIICoIIMnI metal assemblies with corresponding complicated magnetic and electrochemical properties. Full spectroscopic and structural characterization by 1H/11B/13C NMR, HRMS, IR, UV‐vis, single crystal XRD and CV (cyclic voltammetry) is provided. Tetrametallic complexes containing tromanceniumyl substituents with two CoII or MnII central metals exhibit promising anticancer properties against different tumor cell lines.
The title compound, [Mn(C7H7)(C6H5O2)]PF6 or [(Cht)Mn(Cp'CO2H)]PF6, with Cht = cycloheptatrienyl and Cp' = C5H4, is an air-stable, purple, heteroleptic, cationic sandwich complex with manganese in oxidation state +I and π-coordinating cycloheptatrienyl and cyclopentadienyl ligands. The latter ligand carries the carboxylic acid functionality. This `tromancenium-8-carboxylic acid' with hexafluoridophosphate as counter-ion represents a rare case of a cationic carboxylic acid. Structurally, this organometallic carboxylic acid displays the common motif of planar Osp 2...H—Osp 3/Osp 3—H...Osp 2 hydrogen-bonded carboxylic acid dimers with anti-oriented metallocenyl moieties, the cationic charge of which is balanced by octahedrally shaped hexafluoridophosphate anions. Positional disorder is observed in the cycloheptatrienyl ring and the PF6 − anion.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.