C-H bond activation of coordinated pyridine: ortho-pyridyl-ditechnetiumhydridocarbonyl metal cyclus. Crystal structure and dynamic behavior in solution.

摘要: The reaction of pyridine with ditechnetium decacarbonyl [Tc2(CO)10] (1) leads to a novel ortho-pyridyl-ditechnetium hydrido complex, [Tc2(mu-H)(mu-NC5H4)(NC5H5)2(CO)6] (2) and its precursor [Tc2(mu-CO)2(NC5H5)2(CO)6] (3). At ambient temperature 1 was found react slowly afford the substitution product 3 after 120 h. However, heating mixture reflux exclusively pyridine-ortho-metalated complex 2 in only 30 min. Similarly, can be converted completely into upon for Both compounds were characterized by NMR spectroscopy X-ray analysis. show dynamic behavior solution that investigated one-dimensional two-dimensional spectroscopy. isomerization according relative position non-bridging ligands. For existence three isomers shown at equilibrium conditions, 2a (56%) trans-diaxial, 2b (38%) cis-diaxial, 2c (6%) axial-equatorial arrangement pyridines. an detected between two isomers, 3a (67%) cis-diaxial 3b (33%) trans-diaxial