Cyclodiphosphazane appended with pyridyl functionalities: Reactivity, transition metal chemistry and structural studies

•Hemilabile, 8e− donor P,N ligand derived from cyclodiphosphazane.•Controlled reactivity towards chalcogenides.•Exhibits versatile coordination behavior.•Both mono- and bischelating complexes have been isolated.

A pyridyl functionalized cyclodiphosphazane, cis-{(μ-NtBu)P(OCH2C5H4N-o)}2 (1) was synthesized by reacting pyridine-2-methanol with cis-{(μ-NtBu)PCl}2. The reactions of cis-{(μ-NtBu)P(OCH2C5H4N-o)}2 with chalcogenides in appropriate stoichiometry afforded both mono and bis-chalcogenides. The treatment of 1 with ML2Cl2 (M = Pd or Pt; L2 = COD, (SMe2)2) in 1:1 molar ratios resulted in the formation of mononuclear complexes, [MCl2{(μ-NtBu)P(OCH2C5H4N-o)}2] (8 M = Pd; 9 M = Pt), whereas the 1:2 reactions produced binuclear complexes [(MCl2)2{(μ-NtBu)P(OCH2C5H4N-o)}2] (10 M = Pd; 11 M = Pt). The reaction of 1 with [Ru(η6-p-cymene)(μ-Cl)Cl]2 afforded [((η6-p-cymene)RuCl2)2{(μ-NtBu)P(OCH2C5H4N-o)}2] (13). Reaction of [Rh(μ-Cl)(COD)]2 with 1 in a 1:2 molar ratio yielded the mononuclear complex, [{(CO)RhCl}2{(μ-NtBu)P(OCH2C5H4N-o)}2] (14), while the 1:1 reaction of [Rh(μ-Cl)(CO)2]2 with 1 produced a binuclear complex [((CO)RhCl{(μ-NtBu)P(OCH2C5H4N-o)}2] (15). The treatment of 1 with AuCl(SMe2) resulted in the formation of a binuclear complex [(AuCl)2{(μ-NtBu)P(OCH2C5H4N-o)}2] (16). The reaction of 1 with 2 equiv of CuBr gave coordination polymer [{Cu(μ-Br)}2{(μ-NtBu)P(OCH2C5H4N-o)}2]n (17). The crystal structures of 5, 8–10, 13 and 17 were established by single-crystal X-ray diffraction studies.

Graphical abstractSynthesis and transition metal chemistry of a pyridyl functionalized cyclodiphosphazane, cis-{(μ-NtBu)P(OCH2C5H4N-o)}2 (1) are described.Figure optionsDownload full-size imageDownload as PowerPoint slide