Self-assembly of Ru4 and Ru8 assemblies by coordination using organometallic Ru(II)2 precursors: Synthesis, characterization and properties

Coordination-driven self-assembly of binuclear half-sandwich p -cymene ruthenium(II) complexes [Ru 2 (μ-η 4 -C 2 O 4 )(MeOH) 2 (η 6 - p -cymene) 2 ](O 3 SCF 3 ) 2 ( 1a ) or [Ru 2 (μ-η 4 - N , N' -diphenyloxamidato)(MeOH) 2 (η 6 - p -cymene) 2 ](O 3 SCF 3 ) 2 ( 1b ) separately with an imidazole-based tetratopic donor L in methanol affords two tetranuclear metallamacrocycles 2a and 2b , respectively. Conversely, the similar combination of L with 2,5-dihydroxy-1,4-benzoquinonato (dhbq) bridged binuclear complex [Ru 2 (μ-η 4 -C 6 H 2 O 4 )(MeOH) 2 (η 6 - p -cymene) 2 ](O 3 SCF 3 ) 2 ( 1c ) in 1:2 molar ratio resulted in an octanuclear macrocyclic cage 2c . All the self-assembled macrocycles 2a – 2c were isolated as their triflate salts in high yields and were characterized fully by multinuclear ( 1 H, 13 C and 19 F) NMR, infrared (IR) and electrospray ionization mass spectrometry (ESIMS). In addition, the molecular structure of macrocycle 2a was established unequivocally by single-crystal X-ray diffraction analysis and adopts a tetranuclear rectangular geometry with the dimensions of 5.53 Å × 12.39 Å. Furthermore, the photo- and electrochemical properties of these newly synthesized assemblies have been studied by using UV–vis absorption and cyclic voltammetry analysis.