Chiral-at-Metal Osmium(VI) Phosphine Complexes

Pool, Douglas H.; Shapley, Patricia A.

doi:10.1021/om034329f

Cited by 5 publications

(1 citation statement)

References 25 publications

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“…The most noticeable resonance in the 13 C{ 1 H} NMR spectrum in benzene- d 6 at room temperature is a triplet at 185.6 ppm having a C−P coupling constant of 7.3 Hz, which corresponds to the metalated carbon atom C(8) of the tricycle. This chemical shift compares well with those reported for related polycyclic compounds containing metalated aromatic six-membered rings, ,,,,,, while it is shifted toward lower field with regard to the chemical shifts reported for aryl derivatives (δ 125−160). ,, …”

Section: Resultssupporting

confidence: 85%

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

et al. 2010

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The reactions of the hexahydride complex OsH 6 (P i Pr 3 ) 2 (1) with 4,5-dimethyl-2,6-bis(4-methylphenyl)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 L2 leads to a mixture of OsH 2 (H 2 L2)(P i Pr 3 ) 2 (4) and (P i Pr 3 ) 2 H 2 Os-(L2)OsH 2 (P i Pr 3 ) 2 (5), containing five and eight fused rings, respectively. Complex 4 results from the coordination of the N1-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 N1 and N3 of triazine to two different metal centers along with a double ortho-CH bond activation in each proximal phenyl group. Complex 1 reacts with H 4 L3 to afford OsH 2 (H 2 L3)(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 planarity of their cores and suggest electron 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.

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