Darstellung und Eigenschaften von Chromtricarbonyl‐Komplexen strukturisomerer Borazin‐Derivate

The new hexaalkylborazine chromium tricarbonyls ( n ‐Pr) 3 B 3 N 3 Me 3 Cr(CO) 3 (V), Me 3 B 3 N 3 ( n ‐Pr) 3 Cr(CO) 3 (VI), ( i ‐Pr) 3 B 3 N 3 Me 3 Cr(CO) 3 (VII) and Me 3 B 3 N 3 ( i ‐Pr) 3 Cr(CO) 3 (VIII) have been prepared from fac ‐Cr(CO) 3 (MeCN) 3 and the corresponding borazine in dioxane or without solvent. They are much more labile than the isomeric complex Et 3 B 3 N 3 Et 3 Cr(CO) 3 (IV) which can be readily obtained from Et 3 B 3 N 3 Me 3 Cr(CO) 3 and Et 3 B 3 N 3 Et 3 by ring ligand exchange. The NMR., IR., UV. and Mass spectroscopic data of the complexes IV–VIII will be briefly discussed. The preparation of the borazine derivatives ( n ‐Pr) 3 B 3 N 3 Me 3 (IX) and Me 3 B 3 N 3 ( n ‐Pr) 3 (X) is also reported.