Tris‐Dioximate Cobalt(I,II,III) Clathrochelates: Stabilization of Different Oxidation and Spin States of an Encapsulated Metal Ion by Ribbed Functionalization

Abstract

Boron-capped hexachlorine-containing cobalt(II) clathrochelates were prepared by means of template condensation of dichloroglyoxime (Cl 2 GmH 2 ) with boron-containing Lewis acids on a cobalt(II) ion matrix. The nucleophilic substitution of the reactive chlorine atoms of these macrobicyclic tris-dioximates with thiolate anions gave the hexasulfide cobalt(II) and dodecasulfide Co III Co II Co III mono-and bis-clathrochelates. The treatment of the hexachlorine-containing cobalt(II) precursors with primary aliphatic amines afforded hexaamine cobalt(III) clathrochelates. The reduction of these precursors led to the clathrochelate [Co(Cl 2 Gm) 3 (BR) 2 ] -anions, which were isolated as the salts with bulky organic cations. The relative stability of these cobalt(I) complexes accounted for a strong electronic effect of six electron-withdrawing ribbed chlorine substituents. Superconducting quantum interference device (SQUID) magnetometry, EPR, and multi-

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

“…cobalt(I)/cobalt(II) or cobalt(II)/cobalt(III) pairs}. [17][18][19][20][21][22] Another pathway of transformations of these cage metal complexes is based on the ligand-centered processes, such as chemical or electrochemical redox reactions of heterocyclic ribbed fragments, annulated to the quasiaromatic macrobicyclic framework. Recently [23] we reported the synthesis and reactivity of an iron(II) clathrochelate FeBd 2 (QnGm) (BF) 2 (where Bd 2-and Gm are a-benzildioxime dianion and glyoxime residue, respectively) carrying an annulated ribbed quinoxaline (Qn) fragment.…”

New types of the germanium-capped clathrochelate iron(II) and cobalt(III) tris-dioximates: The synthesis, structure and electrochemical properties

“…The field strength of the clathrochelate bis-germanium-capped ligand is similar to that of its boron-, tinand antimony-cross-linked analogs with aliphatic and aromatic α-dioximate chelate fragments, but is substantially higher than that of the macrobicyclic ligands with amine ribbed substituents [14]. The redox properties of the iron(II) and cobalt(III) complexes synthesized and their analogs were studied by cyclic voltammetry (CVA).…”

“…A number of the macrobicyclic iron and cobalt tris-dioximates (clathrochelates) formed by capping with Lewis-acidic derivatives of the p-elements of III, IV and V Periods have been isolated and structurally characterized up to date [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Most of them have been synthesized using the direct template reactions on the corresponding metal ion as a matrix, and their molecules with the equivalent chelate and capping fragments have one C 3 axis (passing through the two capping atoms) and three C 2 axes (passing through the middles of the C-C bonds in α-dioximate chelate fragments).…”

Temperature dependence of the thermodynamic parameters of cobalt(II) clathrochelate: X-ray diffraction and calorimetric characteristics of the low temperature structural phase transition

“…electronic configuration) [1]. This is explained by significant electronic effects of six strong electron-acceptor substituents in the edge chelating moieties of the highly conjugated polyazomethine cell ligand, which lead to a decrease in the donor capacity of coordinating oxime nitrogen atoms [2].…”

“…This is explained by significant electronic effects of six strong electron-acceptor substituents in the edge chelating moieties of the highly conjugated polyazomethine cell ligand, which lead to a decrease in the donor capacity of coordinating oxime nitrogen atoms [2]. A previous [1] multitemperature X-ray diffraction study of a single crystal of Co(Cl 2 Gm) 3 (Bn-C 4 H 9 ) 2 clathrochelate (Scheme 1) made it possible both to characterize the structure of the 1/2 l 3/2 spin transition in the crystal of this complex and reveal the structural manifestation of the Jahn-Teller effect, and to establish a structural phase transition in a low temperature region. This work was intended to scrutinize this structural phase transition by X-ray diffraction analysis and calorimetry and to determine its thermodynamic parameters.…”