Keto-enol tautomerization in metal-acyl complexes: the enolization properties of bimetallic .mu.-malonyl compounds

Manganese Alkyls and Hydrides

“…The binuclear species Mn(CO) 5 (u-CO-CO)Mn(CO) 5 was isolated as a deep-purple solid in greater than 50% yield. Unfortunately, under all conditions investigated, only decomposition to CO and Mn 2 (CO) 10 was seen. 15 …”

“…Historically, the most common method for preparation o f both Mn-acyl and Mn-alkyl groups has revolved around the nucleophilicity of the manganese centers in anionic complexes, and this has remained true since the 1980s. The most widely used anion has been the pentacarbonylmanganate anion, [Mn(CO) 5 ]~, which is readily available from manganese carbonyl, Mn 2 (CO) 10 , by reduction, typically with sodium amalgam in THE This anion is sufficiently nucleophilic to attack acyl halides to afford manganese acyls in variable but generally high yields. The preparation o f Mn(COMe)(CO) 5 …”

“…Exchange of D 2 O with the enolizable hydrogens in the manganese heterocycle of (9) occurred with 1 1 : 1 diastereoselectivity. (5) Ph 3 P Mn(CO) 4 (9) Another example o f formation o f an acyl by net nucleophilic attack on a Mn-CO group is afforded by the reaction wherein diazomethane adds to the manganese dimer (10) to give the novel cyclic acyl complex (11) (Equation (6)). 11 Structure (11) is consistent with attack by the 8" CH 2 end o f the CH 2 N 2 molecule on a coordinated CO, either before or after coordination of the nitrogen end to manganese.…”

“…68 For example, this anion was allowed to react with 4-bromo-2-pentene over a period of several hours between -30 °C and 5 °C. Ultimately, 2-pentene, 1,3-pentadiene, 4,5-dimethyl-2,6-octadiene and its regioisomers, MnBr(CO) 5 and Mn 2 (CO) 10 , were formed. IR and NMR data were used to infer the presence of intermediate Mn(r| l -CHMeCH=CHMe)(CO) 5 .…”

Spacer-verbrückte Bis-, Tris- und Tetrakis(ferrocenyl)-1,3-Diketone

“…als potentielle Antitumormittel untersucht. Ein metallsubstituiertes 1,3-Diketon ist der Komplex (Cp*)(Ph 3 P)(NO)(OC)Re±C(O)CH 2 C(O)Re( CO) 4 PMe 3 [10]. Im Zuge unserer Arbeiten u È ber kohlenwasserstoffverbru È ckte Metallkomplexe [11] stellen wir im folgenden eine Reihe von ferrocenylsubstituierten 1,3-Diketonen vor, die u È ber verschiedene Spacer verbru È ckt sind.…”