Related triply-bridging ligands derived from triosmium dodecacarbonyl and formamidines or 2-aminopyridines

Abstract N , N ′-Dibenzyl- or diisopropyl-formamidines react with Os 3 (CO) 12 or Os 3 (CO) 10 (cyclooctene) 2 to give different types of nonacarbonyl, HOs 3 (CO) 9 (i-PrNCHN-i-Pr) and H 2 Os 3 (CO) 9 (PhCH 2 NCHNCH 2 C 6 H 4 ), the difference being in the ability of the benzyl group to be ortho -metallated. N -Benzyl-2-aminopyridine, on the other hand, gives isomers analogous to each of these clusters.