Unusual Synthesis of Triosmium Carbene Clusters by Tandem Activation of Chlorohydrocarbons and Heterocyclic Amines

Reactions of the [Os 3 H 2 (CO) 10 ] cluster complex ( 1 ) with six‐membered heterocyclic amines (morpholine, thiomorpholine, piperidine) and halohydrocarbons (CH 2 Cl 2 , ClHC=CHCl, CH 2 =CCl 2 ) at ∼25 °C have been studied. Two main types of products are formed in all studied reactions. One product is carbene cluster [Os 3 (μ−H)(μ−Cl){η 1 −C(CH 3 )N(CH 2 CH 2 ) 2 X}(CO) 9 ] (X=O, S, CH 2 ) ( 3, 3 a and 3 b ). Second product is cluster containing enamine ligand [Os 3 (μ−H){μ‐CH=CHN(C 2 CH 2 ) 2 Х)} 2 (CO) 10 ] (X=O, S, CH 2 ) ( 2, 2 a and 2 b ). The carbene ligand is assembled on a cluster, from three organic molecules, thus representing the first example of carbene ligands formed in this way. Clusters with carbene ligand exist as two stable isomers (rotamers hindered towards the Os−C bond), as confirmed by NMR studies and conformational analysis. We have found that in reactions of cluster 1 with acyclic amines containing an oxygen atom in γ‐position (likely morpholine in CH 2 Cl 2 ), only complexes with bridging enamine ligands are formed. Compounds 2 a, 2 b, 3 and 3 b are characterized by single‐crystal X‐ray diffraction.