Thiolate-Bridged Heterodinuclear Manganese–Cobalt Complexes with Bridging Hydride Ligands

Abstract

Synthesis and structural elucidation of a series of thiolate-bridged heterobimetallic MnCo complexes are described. Irradiation of [Mn 2 (CO) 10 ] in the presence of Li[BH 3 SPh] followed by room-temperature reaction with [Cp*CoCl] 2 (Cp* = η 5 -C 5 Me 5 ) afforded dithiolate-and hydride-bridged dinuclear heterobimetallic MnCo complex [{(Mn(CO) 3 }(μ-SPh) 2 (μ-H){CoCp*}] (1). The solid-state structure of 1 established that the two metal fragments, {Mn(CO) 3 } and {Cp*Co}, are linked by a Mn−Co bond. In addition to 1, the reaction also yielded half-sandwiched trithiolate-bridged dinuclear MnCo complex [{Mn(CO) 3 }(μ-SPh) 3 (CoCp*)] (2) and a dinuclear heterometal-coordinated diborane analogue [{Mn(CO) 3 }(μ-η 2 :η 2 -SBH 3 )-(μ-H)(CoCp*)] (3). To isolate the Se analogues of 1−3, a similar reaction was carried out in the presence of Li[BH 3 SePh] that led to the formation of complexes [{(Mn(CO) 3 }(μ-SePh) 2 (μ-H)(CoCp*)] ( 4), [{Mn(CO) 3 }(μ-SePh) 3 (CoCp*)] ( 5), and [{Mn(CO) 3 }(μ-η 2 :η 2 -SeBH 3 )(μ-H)(CoCp*)] (6). All of the complexes were characterized by employing multinuclear nuclear magnetic resonance and infrared spectroscopies as well as mass spectrometric techniques. Single-crystal X-ray diffraction analyses of complexes 1, 2, and 4 helped to establish the molecular formulations and structural integrity of these complexes. The bonding interactions present in these di-or trichalcogenate-bridged dinuclear heterobimetallic complexes were explicated computationally by density functional theory calculations that supported the {Mn−H−Co} and Mn−Co bonding interactions in 1 and 4. The inherent electronic properties of all of the complexes were demonstrated by ultraviolet−visible spectroscopy. Furthermore, the critical involvement of the bridging chalcogenato functionalities was probed via cyclic voltammetry and complementary spectroelectrochemical studies.

A metal–organic framework-supported dinuclear iron catalyst for hydroboration of carbonyl compounds

“…1 Therefore, chemists have shown great interest in the design, synthesis, and catalytic activity studies of dinuclear/multinuclear transition metal complexes. Three major strategies have been applied to prepare these dinuclear/multinuclear complexes: [1][2][3] (i) bridging two or more metal centres with one-atom bridges such as phenolates, alkoxides, or thiolates; [4][5][6][7] (ii) bridging two or more metal centres with two-atom or three-atom bridges such as pyrazolates, pyridazines, or carboxylates; 8,9 (iii) two or more metal centres are bound to isolated donor sets that are connected by long flexible chains or in a supramolecular fashion. [10][11][12] However, as bridging ligands usually provide excess donor atoms, many of the resulting metal complexes consist of coordination "saturated" or "blocked" metal sites that are inactive in catalysis.…”