Dispersionswechselwirkungen in schweren Gruppe 15 Elementverbindungen

This thesis summarizes the synthesis of a variety of new organometallic compounds of heavy group 15 elements. The experiments were further supported by additional quantum chemical calculations using both, density functional theory (DFT) and high level computations at the DLPNO-CCSD(T) level of theory. The main focus of this thesis is on the synthesis, structure and reactivity of dipnictenes with a rigid 1,8-naphthalenediyl (Naph) ligand system, which are further studied by quantum chemical calculations. The arsenic derivative Naph2As2 12 was synthesized and characterized by multinuclear NMR and IR spectroscopy as well as single-crystal X- ray diffraction. Local energy decomposition (LED) analyses at the DLPNO-CCSD(T) level of theory supported the trend of increasing dispersion interaction in the given system upon increasing the atomic number of the group 15 element. It was shown that 12 only forms CH···π and π···π contacts in the solid state, whereas Naph2Sb2 6 also shows intermolecular Sb···π interactions, most likely related to dispersive interactions of the antimony centers. Furthermore, systematic screening reactions behaviour of Naph2As2 and Naph2Sb2 were performed to study their ability to act as Lewis donors. Complexation reactions of Naph2As2 with chromium pentacarbonyl complexes occured with the complexation of both arsenic centers to form Naph2As2[Cr(CO)5]2 17, whereas Naph2Sb2 was found to form the monosubstituted complex Naph2Sb2[Cr(CO)5] 16. Attempts to synthesize the monosubstituted complex Naph2As2[Cr(CO)5] 18 with a substoichiometric amount of chromium pentacarbonyl resulted in a co-crystal with 17. The complexes were further studied by electron localization function plots (ELF) as well as natural population analyses (NPA). Furthermore, the electronic structures and E-Cr bond dissociation energies for all mono- and disubstituted complexes (Naph2E2[Cr(CO)5]n n = 1,2; E = P-Bi) were calculated and showed an decreasing trend from phosphorous to bismuth. Reaction of Naph2As2 12 with Me2SAuCl 19 occured with oxidation of both arsenic centers and the formation of Naph(AsCl)2 20 rather than the expected arsine-gold complex adduct. The oxidation product was isolated and characterized spectroscopically as well as by single- crystal X-ray diffraction. In contrast to 12, 20 shows intermolecular As···π interactions. In order to investigate the electronic structure of 20, additional quantum chemical studies at the DLPNO-CCSD(T) level of theory were performed. LED analyses demonstrated the importance of London dispersion in the intermolecular interactions in the solid-state, which were most likely enhanced by the chlorine substituents in 20. Reaction of Me2SAuCl2 19 with Naph5Sb4Cl2 10, which was obtained from the reaction of 1,8- dilithonaphthalene 3 with SbCl3, resulted in oxidation of 10 and the formation of (NaphSbCl2) 21. 21 was characterized spectroscopically as well as by single-crystal X-ray diffraction. Additional quantum chemical calculations were performed to investigate the intramolecular Sb···π interactions, present in the solid state.


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