Thermal Versus Photochemical Pathways of a Manganese 10-Vertex Metalladecaborane: [nido-6-Mn(CO)3B9H13][NMe4]

Abstract The relationship between the thermal and photochemical reaction pathways of the 10-vertex metalladecaborane complex, [ nido -6-Mn(CO) 3 B 9 H 13 ][NMe 4 ] ( 1 ), has been investigated. The reaction types observed included a nido -6 to nido -5 cage isomerization process and a nido -6 to hypercloso -metallaborane conversion through hydrogen loss and cage closure reactions. The particular reaction pathway observed was found to depend upon the reaction conditions employed. UV photochemical irradiation of 1 resulted in the formation of the hypercloso -[Mn(CO 3 )B 9 H 9 ][NMe 4 ] structure while the thermal reaction effected an isomerization process to form the nido -5-[Mn(CO) 3 B 9 H 13 ][NMe 4 ] complex. Varying the solvent, under certain conditions, also yielded cage degradation reactions. The spectroscopic and structural characterization of the products of these reactions included multi-nuclear NMR, including 11 B and 2D 11 B– 11 B COSY NMR, FTIR, and UV–Visible methods. The X-ray crystallographic structures of the complexes [ nido -6-Mn(CO) 3 B 9 H 13 ][NMe 4 ] ( 1 ) and [ nido -5-Mn(CO) 3 B 9 H 13 ][NMe 4 ] ( 2 ) are also reported in this work.