Single molecular switch based on thiol tethered iron(II)clathrochelate on gold

Synthesis, structure, properties and immobilization on a gold surface of the monoribbed-functionalized tris-dioximate cobalt(ii) clathrochelates and an electrocatalytic hydrogen production from H+ ions

“…However, the observed directions of the paramagnetic shifts and their values are characteristic of the low-spin cage cobalt(II) compounds. 1c Additionally, the lowspin character of these macrobicycles was confirmed by SQUID magnetometry data: the values of the magnetic moment, μ eff , in the temperature range studied (5-400 K) were close to the spinonly value for the low-spin complexes with the electronic configuration d 7 (s = 1/2).…”

“…13 The rigidity of the chelate NvC-CvN fragments causes the bite angles, α (half of the chelate N-M-N angles), to persist, whereas the heights, h, of the MN 6coordination polyhedra are affected by the distortion of the macrobicyclic frameworks around their C 3 -pseudoaxes. The trigonal antiprismatic (TAP) geometry that is close to the octahedral one is energetically preferable for the electronic configurations d 6 and d 7 , whereas the rigidity of the boron-containing capping groups and the sterical hindrances between the substituents in ribbed chelate fragments of the clathrochelate frameworks cause a trigonal prismatic (TP) distortion of this geometry (the distortion angle ϕ of a MN 6 -coordination polyhedron is equal to 0°for a TP and to 60°for a TAP). Indeed, the average bite angles, α, vary in a very narrow range from 38.5 to 38.9°, whereas the ϕ angles are from 9.4 to 23.5°, and an increase in their values is accompanied by a decrease in h from 2.44 to 2.37 Å (Table 1).…”

“…For example, in the case of the iron(II) clathrochelates, the immobilized complexes of this type have been used as mediators of the electron transfer for amperometric determination of hydrogen peroxide, 6 whereas their mixed self-assembled monolayers with 1-dodecanethiol have been studied as potent molecular switches. 7 Moreover, the monoribbed-functionalized cobalt(II) clathrochelates are prospective paramagnetic tags for studying the structure of various biological systems. Here, we report the synthetic pathways to the monoribbed-functionalized cobalt(II) clathrochelates as well as the preparation of their mono-and dichloroclathrochelate precursors and the nucleophilic substitutions leading to the target cage compounds (including those with the terminal reactive groups).…”

Electrophilic Addition of Polyaromatic o-Quinones to an Iron(II) Diaminoclathrochelate Leading to the Macrobicyclic Iron(II) tris-Dioximates with Extended Annulated Ribbed Substituents

“…[1][2][3][4] Recently we described an iron(II) clathrochelate with annulated ribbed quinoxaline fragment that exhibited the reversible ligand-centered redox transformations coupled with electrochromism. [5] Its annulated azaheterocyclic moiety has been constructed using nucleophilic substitution of the reactive chlorine atoms in a dichloroclathrochelate precursor FeBd 2 (Cl 2 Gm)(BF) 2 (where Bd 2-and Cl 2 Gm 2-are α-benzildioxime and dichloroglyoxime dianions) (Scheme 1).…”

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

“…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. [14][15][16] The rigidity of their polyazomethine macrobicyclic ligands imposes a strong limitation on the size of the encapsulated metal ion.…”