Multiple C-H Bond Activation of Phenyl-Substituted Pyrimidines and Triazines Promoted by an Osmium Polyhydride: Formation of Osmapolycycles with Three, Five, and Eight Fused Rings

作者：Esteruelas Miguel A^*; Fernandez Israel; Herrera Antonio; Martin Ortiz Mamen; Martinez Alvarez Roberto; Olivan Montserrat; Onate Enrique; Sierra Miguel A; Valencia Marta

来源：Organometallics, 2010, 29(4): 976-986.

DOI：10.1021/om901030q

The reactions of the hexahydride complex OsH(6)(P(i)Pr(3))(2) (1) with 4,5-dimethyl-2,6-bis(4-methlylphenyl)-pyrimidine (H(2)L1), 2,4,6-tris-(4-methylphenyl)-1,3,5-triazine (H(4)L2), and 2,4,6-triphenylpyrimidine (H(4)L3) have been studied. Complex 1 reacts with H(2)L1 to give a mixture of the metallapolycyclic derivatives OsH(3)(HL1)(P(i)Pr(3))(2) (2) and OsH(2)(L1)(P(i)Pr(3))(2) (3). Compound 2 arises from the coordination of the N3-pyrimidine nitrogen atom to osmium and the ortho-CH bond activation of the C2-bonded phenyl group. The formation of 3 involves the coordination of the N1-pyrimidine nitrogen atom to osmium and the ortho-CH bond activation of both phenyl groups. The reaction of 1 with H(4)L(2) leads to a mixture of OsH(2)(H(2)L(2))(P(i)Pr(3))(2) (4) and (P(i)Pr(3))(2)H(2)Os-(L(2))OsH(2)(P(i)Pr(3))(2) (5), containing five and eight fused rings, respectively. Complex 4 results from the coordination of the NI -triazine nitrogen atom to osmium and the ortho-CH bond activation of the phenyl groups at positions 2 and 6 of the triazine ring. Complex 5 results from the coordination of the NI and N3 of triazine to two different metal centersalong with a double ortho-CH bond activation in each proximal phenyl group. Complex 1 reacts with H(4)L(3) to afford OsH(2)(H(2)L(3))(P(i)Pr(3))(2) (6) and (P(i)Pr(3))(2)H(2)Os(L3)OsH(2)(P(i)Pr(3))(2) (7), which are related to 4 and 5, respectively. Complexes 2, 3,4, and 5 have been characterized by X-ray diffraction analysis. The structures prove the plananty of their cores and suggest clectron delocalization through the polycyclic system. Quantum chemical calculations (DFT level) on model Compounds clearly indicate that the Os-C and Os-N bonds of the newly formed metallapolycycles exhibit a remarkable double-bond character that is higher for the Os-C bond, in very good agreement with the experimental findings.

• 出版日期2010-2-22