Manganese Telluride Carbonyl Complexes: Facile Syntheses and Exotic Properties-Reversible Transformations, Hydrogen Generation, Paramagnetic, and Semiconducting Properties.

A novel family of five Mn-Te-CO complexes was prepared via facile syntheses: mono spirocyclic [MnTe(CO)] (), four-membered MnTe ring-type [MnTe(CO)] (), hydride-containing square pyramidal [HMnTe(CO)] (), and dumbbell-shaped [MnTe(CO)] () and [MnTe(CO)] (). Electron-precise complexes and exhibit unusual paramagnetism arising from two types of Mn atoms in different oxidation states, as determined by X-ray photoelectron spectroscopy, electron paramagnetic resonance, and density functional theory (DFT) calculations. The structural transformations from small-sized MnTe and MnTe to the largest MnTe were controllable, the off/on magnetic-switched transformation between HMnTe and was reversible, and the magnetic transformation between MnTe and was observed. Interestingly, the reversible dehydridation and hydridation between the HMnTe-based cluster and [MnTe(CO)] were successfully accomplished, in which the release of a high yield of H was detected by gas chromatography. In addition, upon the addition of CO, cluster first forms a carbonyl-inserted intermediate [HMnTe(CO)] (), detected by the high resolution ESI-MS, which is readily transformed to a dimeric dihydrido cluster [{HMnTe(CO)}] () with the introduction of O. These low- to high-nuclearity complexes exhibit rich redox properties with semiconducting behavior in solids, possessing low but tunable energy gaps (1.06-1.62 eV) due to efficient electron transport via nonclassical C-H···O(carbonyl) interactions. The structural nature, reversible structural transformations, controllable on/off magnetic switches, electron communication networks, and associated chemical properties for hydrogen generation are discussed in detail and supported by DFT calculations, density of states, band structures, and noncovalent interaction analyses.