Reproducible high-yield syntheses of [Ru3(CO)12], [H4Ru4(CO)12], and [Ru6C(CO)16]2− by a convenient two-step methodology involving controlled reduction in ethylene glycol of RuCl3·nH2O

Ru3CO12 [H4Ru4(CO)12], and [Ru6C(CO)16]2- have been synthesized in reproducible high yields and under mild conditions (1 atm) by a two-step methodology involving (i) first carbonylation of RuCl3·nH2O dissolved in ethylene glycol to give a mixture of tri- and di-carbonyl ruthenium(II) species, probably of the kind [Ru(CO)3Cl2(ethylene glycol)] and [Ru(CO)2Cl2(ethylene glycol)x ] (x = 1, 2), and (ii) addition of specific amounts of alkali carbonates and further reductive carbonylation to give the desired ruthenium carbonyl cluster. The selectivity of the second step is controlled by the: (i) nature and quantity of the alkali carbonate (Na2CO3 or K2CO3); (ii) gas-phase composition (CO or CO+H2); (iii) temperature.