The first example of the alkoxy-containing iron(ii) tris-dioximate clathrochelate: synthesis, structure, and properties

Abstract

The reaction of the dichloride iron(II) tris dioximate clathrochelate with triethyl orthoformate in the presence of metallic sodium afforded the diethoxy substituted macrobicyclic complex. The first alkoxy containing clathrochelate was characterized using elemental analysis, MALDI TOF mass spectrometry, IR, UV-Vis, 1 H and 13 C{ 1 H} NMR spectroscopy, and X ray diffraction analysis.Chlorine containing iron(II) and ruthenium(II) tris dioximate clathrochelates easily undergo nucleophilic substitution with the agents of different nature to form mono , di , tri , tetra , and hexafunctionalized clathro chelates. 1-13 In particular, a series of mono , 5 di , and triribbed substituted 3,6 aryloxide clathrochelate deri vatives have been synthesized in the case of the O nuc leophiles (Scheme 1). At the same time, the attempts to obtain the alkoxy substituted clathrochelates by interac tion with alkaline metal alkoxides in the corresponding alcohol medium have failed because of the destruction of the clathrochelate framework with high basic and low nucleophilic in protonogenic media alkoxide anions.The increase in the nucleophilicity and the decrease in the basicity of an alkoxide ion may be achieved by * Dedicated to the 90th anniversary of the L. Ya. Karpov Institute of Physical Chemistry.

Metal-Involving Synthesis and Reactions of Oximes

“…Voloshin and colleagues reported numerous examples of nucleophilic substitutions for chloroglyoximate iron­(II) clathrochelates ( 115 ; Scheme , section and Table ). − These species can also be involved in radical substitution reactions (section ). It is clear that the iron­(II) center serves as an electrophilic activator of the C atom of the Cl–CN–O moiety, whereas upon the radical substitution, this metal center apparently serves as a 1 e̅ -donor to stabilize the radical ligand formed as an intermediate.…”

The first ribbed functionalized tris-dioximate clathrochelates with inherent hydroxyl substituents: Synthesis, spectra and X-ray structure

“…The synthesis of the ribbedfunctionalized clathrochelates with less nucleophilic and harder (according to the Pearson HSAB principle [6]) alkoxy-groups is complicated because of complete destruction of the clathrochelate framework in strongly basic media. Recently, the indirect ethoxylation of the dichlorine-containing clathrochelate precursor gave the first alkoxy-functionalized iron(II) clathrochelate [7]. Previously the clathrochelates with apical hydroxyl and alkoxyl groups were obtained by the direct template cross-linking with boric acid on the Fe 2+ ion matrix [8][9][10][11][12][13][14][15][16].…”