2-Pyridyl complexes derived directly from pyridine and dodecacarbonyl-triangulo-triosmium

Abstract

Pyridine reacts with Os₃(CO)₁₂ to give a series of bridging 2-pyridyl complexes: [HOs₃(NC₅H₄)(CO)₁₀]; [HOs₃(NC₅H₄)(CO)₉(py)], isomers (A) and (B); [H₂Os₃(NC₅H₄)₂(CO)₈]; and [Os₂(NC₅H₄)₂(CO)₆], isomers (A) and (B). Several of the corresponding derivatives of 4-methyl- and 4-benzyl-pyridine are also described. Evidence is given for successive and reversible reactions in which loss of CO from the cluster is accompanied either by co-ordination of an extra py or by hydrogen transfer from co-ordinated py to the metal. Quinoline and isoquinoline with Os₃(CO)₁₂ give the isomers [HOs₃(NC₉H₆)(CO)₁₀] in which quin has been metallated exclusively at the 2-position whereas iquin gives isomers metallated at the 1- and 3-positions respectively.