Abstract
On highly hydroxylated silica, Os
3(CO)
12, H
2Os
3(CO)
10 or Os
6(CO)
18 are simply physisorbed at room temperature. At 150°C there is an oxidative addition of the surface SiOH group to the OsOs bond of Os
3(CO)
12 with formation of the surface species: HOs
3(CO)
10(OSi).
Such a structure was confirmed by the synthesis of the model compound HOs
3(CO)
10(OSi Ph
3). When the physisorbed clusters Os
3(CO)
12, H
2Os
3(CO)
10, Os
6(CO)
18 or the chemisorbed clusters HOs
3(CO)
10(OSi
▪), are heated at 200°C, a breakdown of the cluster frame occurs, with formation of osmium(II) carbonyl species of the type [Os(CO)
2 (OSi
▪)
2]
n
or [Os(CO)
3(OSi
▪)
2]
2. Similar reactions are observed on alumina.