A multinuclear¹H,¹³C and¹¹B solid-state MAS NMR study of 16- and 18-electron organometallic ruthenium and osmium carborane complexes

Abstract

The first (1)H, (13)C, (31)P and (11)B solid state MAS NMR studies of electron-deficient carborane-containing ruthenium and osmium complexes [Ru/Os(p-cym)(1,2-dicarba-closo-dodecaborane-1,2-dithiolate)] are reported. The MAS NMR data from these 16-electron complexes are compared to those of free carborane-ligand and an 18-electron triphenylphosphine ruthenium adduct, and reveal clear spectral differences between 16- and 18-electron organometallic carborane systems in the solid state.

Pseudo electron-deficient organometallics: limited reactivity towards electron-donating ligands

“…[36][37][38][39] The intriguing chemistry in solution of these electron-deficient complexes was also studied in order to understand their biological properties. [40][41][42] Owing to the steric hindrance of the bulky carborane ligand, which prevents the dimerization of the compounds and the formation of more electronic favored 18-e species, these metal-carboranes exhibit remarkable stability as 16-e monomeric species as first demonstrated by Jin and co-workers. [43][44][45][46][47][48] However, when reacted with aromatic amines, the 16-e blue (Ru) and red (Os) complexes are in equilibrium with their yellow 18electron adducts, and the thermal displacement of the equilibrium results in marked thermochromic properties.…”

Carboranes as unique pharmacophores in antitumor medicinal chemistry

“…Ruthenium and osmium are a class of transition metals widely used in cancer therapy. 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 Complexes containing electron-deficient ruthenium and osmium carborane were reported by the Sadler and Hanna groups. 50 , 51 The redox-active response of these carborane-containing complexes to biomolecules have resulted in their potential application in cancer therapy.…”

Arene ruthenium dithiolato–carborane complexes for boron neutron capture therapy (BNCT)

“…The purity of complex 1 was assessed by 1 H NMR spectroscopy in CDCl 3 and was in accordance with previous reports [9,11,14]. The preparation of the RuMs micelles was carried out as previously described [11].…”

“…1). It is a 16-electron complex and therefore electron-deficient at the metal [14]. Complex 1 is highly hydrophobic and insoluble in water [15].…”