Clathrochelates meet phosphorus: thiophosphorylation of Fe(ii) dichloroclathrochelate precursor, synthesis of N,S-donor macrobicyclic ligands and their Pd(ii) complexes as potent catalysts of Suzuki cross-coupling reaction

Abstract

Nucleophilic substitution of an iron(ii) dichloroclathrochelate with diphenylphosphine sulfide under PTC afforded a monophosphorylated cage complex. This precursor undergoes further nucleophilic substitution with mono- and diamines giving P,N-substituted mono- and bis-clathrochelates; those with thiophosphoryl and pyridyl groups were used as N,S-donor macrobicyclic ligands toward the palladium(ii) ion. In the resulting Pd,Fe-binuclear 1 : 1 complexes, the clathrochelate moieties retain the geometry, characteristic of low-spin iron(ii) complexes, with a minor distortion caused by intramolecular interactions. The Pd(2+) ion has a twisted square-planar N2SCl-environment. The complexes thus obtained proved to be efficient catalysts of the Suzuki cross-coupling reaction.

Synthesis, X-Ray Structure and (Spectro)electrochemical Study of an Electrochromic Iron(II) Chlathrochelate with Tuned Redox Properties

“…[23] This approach is based on nucleophilic substitution of the reactive chlorine atoms of the dichloroclathrochelate precursor FeBd 2 (Cl 2 Gm)(BF) 2 with 4,5-dimethyl-1,2-phenylenediamine in the presence of triethylamine as organic base followed by in situ oxidation of the amine macrobicyclic intermediate FeBd 2 H} NMR spectra. The molecular structure of this complex was studied both in solid state and in solution using single-crystal X-ray diffraction and various NMR techniques, respectively.…”

“…The intensities of reflections for the crystal FeBd 2 (Me 2 QnGm) (BF) 2 . 0.8 CH 3 CN were measured at 298(2) K with a Bruker Nonius X8Apex CCD diffractometer using graphite monochromated Mo-K a (l=0.71073 Å) radiation.…”

“…X-Band EPR spectra (modulation frequency 100 kHz) of in situ electrochemically generated anion-radical of the FeBd 2 (Me 2 QnGm)(BF) 2 clathrochelate were recorded from its degassed acetonitrile solution (tetraethylammonium perchlorate [TEAP] as background electrolyte) at room temperature with a Varian E-109 spectrometer (Bruker). A home-made molybdenumglass EPR cavity with sealed-in-platinum wire electrodes was used for these combined EPR -electrochemical experiments.…”

“…Cyclic voltammogram (CV) of the complex FeBd 2 (Me 2 QnGm) (BF) 2 was recorded from its 1mM acetonitrile solution using Elins potentiostat P-8 in a conventional one-compartment three-electrode cell with 0.1 M TEAP as a supporting electrolyte. A platinum counter electrode and the Ag/0.1 M AgNO 3 reference electrode in acetonitrile, contacting with the solution under study through a Luggin capillary filled by the supporting electrolyte, were used.…”

“…These fragments of a quasiaromatic macrobicyclic polyazomethine framework have been functionalized using well-known "classical" organic reactions, such as N,O,S,C,P-nucleophilic substitution, [1][2][3] free-radical substitution [4,5] and electrophilic addition to the diamine iron(II) clathrochelate. [6,7] These reactions allowed obtaining the different types of mono-, di-and triribbedfunctionalized cage complexes with pendant and annulated substitutents, thus paving the way to new types of molecular switches, [8] wires, [9,10] light-and redox-driven molecular machines [11][12][13] and clathrochelate-based electrocatalysts for hydrogen evolution reaction.…”