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Facile alkyne coupling reactions in dirhenium carbonyl complexes

Journal Article · · Organometallics; (United States)
DOI:https://doi.org/10.1021/om00029a021· OSTI ID:5989623
; ;  [1]
  1. Univ. of South Carolina, Columbia (United States)

The complex (OC)[sub 4]Re[trans-[mu]-HC=C(CO[sub 2]Me)]Re(CO)[sub 5] (1) was converted to the reactive acetonitrile complex (OC)[sub 4]Re[trans-[mu]-HC=C(CO[sub 2]Me)]Re(CO)[sub 4](NCMe) (2) by reaction with Me[sub 3]NO in acetonitrile. Under an atmosphere of CO, complex 2 reacts with HC[triple bond]CO[sub 2]Me in refluxing CH[sub 2]Cl[sub 2] to yield the new complexes (OC)[sub 4]Re[[mu]-C(H)=C(CO[sub 2]Me)C(H)=C(CO[sub 2]Me)]-Re(CO)[sub 5] (3; 11%) and (OC)[sub 4]Re[C(H)=C(CO[sub 2]Me)C(H)=C(CO[sub 2]Me)C(H)= C(CO[sub 2]Me)]Re(CO)[sub 4] (4a,b; 49%, existing in solution as a mixture of isomers) by the head-to-tail coupling of two and three HC[equivalent to]CCO[sub 2]Me molecules, respectively. In the absence of CO only compound 4 and a small amount of the new compound [ovr Re(CO)[sub 4][C[sup 6]H[sub 2](CO][sub 2]Me)(CO[sub 2]Me)[sub 2]] (5;6%) were obtained. Complex 3 was converted into 4 by reaction with additional HC[equivalent to]CCO[sub 2]Me in the presence of Me[sub 3]NO. When heated to 98[degrees]C, 4 was transformed into 5 in 22% yield. Three of the products, 3, 4a, and 5 were characterized crystallographically. In complex 3 the two linked HC[equivalent to]CCO[sub 2]Me groups form a four-carbon chain between the metal-containing groups. One of the carboxylate substituents is also coordinated to form a five-membered metallacyclic ring. In complex 4a the metal-containing groups are joined by a six-carbon chain formed from the three alkynes, and two of the carboxylate groups are coordinated to form five- and six-membered metallacyclic rings. The six-carbon chain in 4 was transformed into a 2,4,6-tris(methoxycarbonyl)phenyl group that is [sigma]-coordinated to the metal atom and also has one of its carboxylate groups coordinated. 10 refs., 3 figs., 6 tabs.

OSTI ID:
5989623
Journal Information:
Organometallics; (United States), Journal Name: Organometallics; (United States) Vol. 12:5; ISSN ORGND7; ISSN 0276-7333
Country of Publication:
United States
Language:
English