The conversion of [Nb6Cl12]-cluster complex compounds with neutral ligands syntheses, structures, intermolecular interactions and subsequent reactions.
1st reviewer: Prof. Dr. Martin Köckerling, University of Rostock
2nd reviewer: Prof. Dr. Hans-Jürgen Meyer, University of Tübingen
3rd reviewer: Prof. Dr. Mathias Wickleder, University of Cologne
4th reviewer: Prof. Dr. Stefanie Dehnen, University of Marburg
Date of defense: 03.11.2020 - Grade: summa cum laude
In this thesis, the synthesis and characterization of novel niobium cluster complex compounds with neutral ligands L is described. A total of 153 new compounds were synthesized and analyzed by single-crystal X-ray diffraction. They are devided into 91 compounds with a neutral cluster unit (chap. 3.1), 4 neutral network compounds (chap. 3.2), 28 compounds with a cluster cation (chap. 3.3), 5 compounds with oxidized nitrile-containing cluster units and one secondary product (chap. 3.4) and 24 compounds with niobium cluster anions (chap. 3.5). One focus of this work was the analysis of the intermolecular interactions between the cluster units. In addition to a large number of hydrogen bonds and parallel-displaced π-π stacking, T-shaped CH-π, anion-π and lone-pair-π interactions, halogen, chalcogen and pnicogen bonds, as well as chalcogen-chalcogen interactions are reported for the first time, as they are observed in these cluster compounds. By analyzing the neutral cluster compounds, various influences on the lability of the Nb-L bond were investigated and, considering intermolecular interactions, the requirements for a particularly suitable niobium cluster precursor is discussed. With the compound [Nb6Cl14(Pyz)4] ∙ 2 CH2Cl2 (7), it was possible to introduce a starting compound, which enabled the syntheses of more than 70 new cluster compounds. Based on the limits of this starting material 7, a better precursor is presented with [Nb6Cl14(Pyr-4-CN)4] ∙ 3.6 Pyr-4-CN (8). With this compound, it was possible to synthesize the first neutral sulfur- and selenium-coordinated niobium cluster compounds.
Chapter 1: Neutral Nb₆-cluster connections (connections 1-91).
Chapter 2: H-bridged neutral Nb₆ cluster networks (compounds 92-95).
Chapter 3: H-bridged Nb₆ cluster cations (compounds 96-123).
Chapter 4: Oxidized Nb₆-cluster compounds (compounds 124-129).
Chapter 5: Compounds with Nb₆-cluster anion (compounds 130-153).