Heterometallic one-dimensional chain with tetradeca metal repetition constructed by amidate bridged dirhodium and pivalate bridged diplatinum complexes influenced by hydrogen bonding

Abstract

A novel heterometallic one-dimensional (1-D) chain complex, [{Rh₂(acam)₄}₃{Pt₂(OPiv)₂(NH₃)₄}₄](ClO₄)₈ (4, acam = acetamidate, OPiv = pivalate), has been synthesized and characterized by single-crystal X-ray analysis and diffuse reflectance spectroscopy. Complex 4 comprises [Rh₂(acam)₄] (i.e. [Rh₂]) and [Pt₂(OPiv)₂(NH₃)₄](ClO₄)₂ (i.e. [Pt₂]), where Rh and Pt atoms are axially linked by metal–metal bonds with a repetition of –{[Rh₂]–[Pt₂]–[Rh₂]–[Pt₂]–[Rh₂]–[Pt₂]–[Pt₂]}_n–. All metal oxidation states in 4, determined by structural and X-ray photoelectron spectral analyses, are +2. The unbridged Rh–Pt and Pt–Pt bonds in 4 are supported by multiple hydrogen bonds; the distances of Rh–Pt bonds are relatively longer than those in previously reported 1-D chains despite smaller torsion angles between the Rh and Pt coordination planes. Diffuse reflectance spectra revealed that the electronic structure of 4 has a larger gap between filled and vacant σ-type orbitals and a smaller gap between a filled π*(Rh₂) and a vacant σ-type orbital.