Mononuclear closo-ruthenacarborane complexes containing a rare eight-membered metal-diphosphine ring

► New 17e and 18e closo-ruthenacarboranes with 1,5-bis(diphosphino)pentane ligand. ► Three of these complexes are featuring ortho-cycloboronation of P-phenyl groups. ► Structures of three odd-electron species were determined by X-ray crystallography.