Synthesis and structure of monoribbed-functionalized disulfide iron(II) clathrochelates and their coordination as the ligands toward platinum(II) and platinum(IV) ions

Disulfide monoribbed-functionalized clathrochelates (i.e., fuctionalization of one of the three α-dioximate fragments) with ribbed thioalkyl, S3-thioalkyl and hydroxythioalkyl substituents have been synthesized starting from the FeBd2(Cl2Gm)(BF)2 precursor (where Bd2− and Cl2Gm2− are α-benzyldioxime and dichloroglyoxime dianions) using the corresponding thiol/triethylamine system in dichloromethane solution. Clathrochelate S6-dithiol in basic media underwent the intramolecular dealkylation to yield the S3-thiocrown etheric clathrochelate. Clathrochelates obtained have been studied as the ligands toward Pt2+ and Pt4+ ions. The S-demethylation reaction of the methylsulfide complex with [PtCl4]2− dianion produced the polynuclear complexes of the dianionic clathrochelate dithiolate ligand. The reaction of n-butylsulfide clathrochelate with the trans-PtIVCl4(C6H5CH2CN)2 afforded the binuclear compound with the disulfide iron(II) clathrochelate as a monodentate ligand. The obtained macrobicycles, their clathrochelate derivatives, and polynuclear complexes have been characterized using elemental analysis, MALDI-TOF and PD mass, IR, UV–Vis, and NMR spectra, and X-ray crystallography. The encapsulated iron(II) ion coordination polyhedra distortion angle φ values and the main distances in the molecules of polynuclear complexes have been deduced (obtained) using 57Fe Mössbauer parameters and EXAFS data, respectively.

Graphical abstractMonoribbed-functionalized iron(II) clathrochelates with thioalkyl, S3-thioalkyl and hydroxythioalkyl substituents have been synthesized. Clathrochelate S6-dithiol in basic media underwent the intramolecular dealkylation to yield the S3-thiocrown etheric macrobicycle. Clathrochelates obtained have been studied as the ligands toward Pt2+ and Pt4+ ions. The S-demethylation reaction of the methylsulfide complex with [PtCl4]2− produced the polynuclear complexes of the dianionic clathrochelate ligand. The reaction of n-butylsulfide complex with trans-PtIVCl4(C6H5CH2CN)2 afforded the binuclear compound with the clathrochelate as monodentate ligand.Figure optionsDownload full-size imageDownload as PowerPoint slide