Mesityloxomolybdän‐ und ‐wolfram‐Verbindungen. I. Die Struktur von LiMoO₂Me₂Mes(OEt₂)₂

Abstract

Die Struktur der bekannten, aus MoO2Mes2 1 und LiMe dargestellten Verbindung LiMoO2Me2Mes(OEt2)2 2 [2] sowie ihre NMR‐spektroskopischen Daten werden mitgeteilt. 2 bildet ein in der Raumgruppe P1 kristallisierendes Dimer durch Verknüpfung zweier [MoO2Me2Mes]−‐Anionen über Oxo‐Liganden durch zwei Kationen [Li(OEt2)2]+. Der gebildete [‥OMoOLi‥]2− Achtring ist eben.

Mononuclear Organomolybdenum(VI) Dioxo Complexes: Synthesis, Reactivity, and Catalytic Applications

“…It was reported that 1 reacts with MeLi in ether solution under formation of LiOMe and a thermally instable compound with an analytical composition corresponding to the formula Mo(mes) 2 ·(OEt 2 ) 2 2a. Later, the product of the reaction of MeLi and MoO 2 (mes) 2 was found to be of the composition LiMoO 2 Me 2 (mes) 2 (OEt 2 ) 2 ( 2 ). 3a,b The X-ray crystal structure of this compound was determined 3b…”

“…Insertion reactions of 1 with carbon monoxide, 3c,d isocyanides,3e and isocyanates 3f were also studied. 1 reacts with CO in pyridine to give dimesityl ketone and a dihydropyridine dimer, which represented the first example of N-acylation of a pyridine by CO mediated by a transition metal complex 3d.…”

“…Insertion reactions of 1 with carbon monoxide, 3c,d isocyanides,3e and isocyanates 3f were also studied. 1 reacts with CO in pyridine to give dimesityl ketone and a dihydropyridine dimer, which represented the first example of N-acylation of a pyridine by CO mediated by a transition metal complex 3d. Isocyanides react with 1 , affording dimesityl imine (mes 2 CNR), mesitylamide (mesCONHR), and dinuclear μ-oxo-η 2 -iminoacyl complexes [mesMo(C(mes)NR)O] 2 (μ-O) (R = t Bu, C 6 H 11 , CH 2 C 6 H 5 ) 3e.…”

“…1 reacts with CO in pyridine to give dimesityl ketone and a dihydropyridine dimer, which represented the first example of N-acylation of a pyridine by CO mediated by a transition metal complex 3d. Isocyanides react with 1 , affording dimesityl imine (mes 2 CNR), mesitylamide (mesCONHR), and dinuclear μ-oxo-η 2 -iminoacyl complexes [mesMo(C(mes)NR)O] 2 (μ-O) (R = t Bu, C 6 H 11 , CH 2 C 6 H 5 ) 3e. A terminal isocyanide complex, MoO 2 mes 2 (CN) t Bu ( 3 ), was also isolated and considered to be a possible intermediate in the previous reaction 3e.…”

Unerwartete Bildung von Monomesitylmolybdän(V,VI)-Verbindungen

“…Auch die Umsetzung von 1 mit Dimesitylmagnesium [12] liefert keine besseren Ergebnisse. Heyn [3] weist darauf hin, daû die Bildung von 2 (und auch von MoOMes 3 [13]) von Nebenreaktionen begleitet wird, und daû bei der Umsetzung von 1 mit Phenylgrignardreagens [3 b] [1]. Trigonal-bipyramidale Strukturen werden ha È ufig fu È r d 0 -Spezies gefunden, wa È hrend d 1 -und d 2 -Zentralatome eher quadratisch-pyramidale Geometrien einnehmen sollen [14].…”