Solid‐State NMR Investigations on the Amorphous Network of Precursor‐Derived Si2B2N5C4 Ceramics

Employing a multitude of modern solid state NMR techniques including 13C{15N}REDOR NMR, 1H–13C CP NMR, 11B MQMAS NMR spectroscopic experiments, the structural organization of Si2B2N5C4 ceramic has been studied. The experiments were executed on double isotope enriched (13C, 15N) and natural isotope abundance Si2B2N5C4 ceramics. The materials were synthesized by aminolysis and subsequent pyrolysis of intermediate pre‐ceramic polymers that were obtained from the single source precursor TSDE, 1‐(trichlorosilyl)‐1‐(dichloroboryl)ethane (Cl3Si–CH(CH3)–BCl2). The result of the 13C{15N} REDOR NMR spectroscopic experiment shows that carbon atoms are incorporated into the network by bridging to nitrogen, which already occurs during the polymerization step. Furthermore, the combined results of 11B NMR and 11B MQMAS NMR indicate that boron atoms may also be connected to carbon in addition to nitrogen.