Synthesis, crystal and molecular structure of η3-allylundecacarbonylosmium tetrafluoroborate

Abstract The η3-allylundecacarbonylosmium tetrafluoroborate has been synthesized in high yield by treatment of Os3(CO)11MeCN with allyl alcohol and subsequent protonation. It has been studied by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic space group Pna21 (no. 33) with a 17.933(2), b 11.440(2), c 11.797(2)A and Dc 2.76 g cm−3 for Z = 4. A final R value of 0.046 (Rw = 0.083) based on 2067 reflections was obtained. The presence of the positively charged allyl ligand in the triosmium cluster lengthens the Os1Os2 and Os2Os3 bonds (0.057A) and 0.074 A, respectively) relative to the OsOs bonds in Os3(CO)12.