N-H-Aktivierung an Os3 -Clustern. Darstellung und Charakterisierung von Os3(CO)11(NH3), Os3(CO)11(NHC6H10) und OS3(CO)10(μ - H)(μ - NC6H10) / N-H Activation on 0s3 Clusters. Preparation and Characterization of Os3(CO)11(NH3), Os3(CO)11(NHC6H10) and Os3(CO)10(μ-H)(μ-NC6H10)