Synthesis of 2,6-bis(bis(2-(methylthio)phenyl)phosphino)-4-methylphenol, a novel polydentate ligand containing two tripodal [S,S,P,O] coordination pockets; crystal structure of the dimeric thallium(I) complex

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The reactions of bis(2-(methylthio)phenyl)chlorophosphine (5a) (2 equivalents) with the O-protected 2,6-dilithio-4-methylphenol followed by acidic workup led to the isolation of 2,6-bis(bis(2-(methylthio)phenyl)phosphino)-4- methylphenol (2). Analogous reactions do not proceed if the sterically bulkier bis(2-(tert-butylthio)phenyl)chlorophosphine (5b) is used instead of 5a. Compound 2 is a topological analog of binucleading ligands built on a 2,6-diaminophenol core, where two tripodal N- or O-ligating compartments are flanking the phenolate functionality. A distinguishing feature of 2 is the "soft" donor environment of the potentially [S,S,P]-ligating pockets flanking the phenolic OH group. Reaction of 2 with TlOEt lead to the formation of the dimeric thallium(I) phenoxide (3), which was characterized by a single crystal X-ray diffraction study. In addition to μ-phenoxide ligation, in the solid state each thallium atom also interacts with two phosphorus atoms from the opposing ligands. The interactions are not equivalent, with the two Tl 1-P distances differing by ca. 0.3 Å. No significant Tl⋯S interactions are present in the solid state. Room temperature 31P NMR measurements indicate the dynamic behavior of 3 in solution. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.

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Zeitschrift fur Anorganische und Allgemeine Chemie