Die Umsetzung von tBuC≡P mit [(CH3CN)3Mo(CO)3] führt zum Zweikernkomplex [Mo(CO)4〈Mo(CO)2(η4‐P3CtBu){η4‐P2(CtBu)2}〉] 1 sowie den Carbinkomplexen [Mo(CO)4〈{P3(CtBu)2}{Mo(CO)2(CtBu)}{η3‐P2(CtBu)2}〉] 2 und [Mo(CtBu){η4‐P2(CtBu)2(CO)}{η5‐P3(CtBu)2}] 3 als isolierte Produkte. Alle Verbindungen wurden durch die Kristallstrukturanalyse, mittels NMR‐ und IR‐Spektroskopie sowie massenspektrometrisch strukturell charakterisiert. Der Zweikernkomplex 1 hat einen 1,3‐Diphosphacyclobutadienylring und einen 1,2,4‐Triphosphacyclobutadienylligand. In 2 sind ein 1,3‐Diphosphacyclobutadienylring und ein σ‐gebundener 1,2,4‐Triphospholylligand an zwei Mo‐Komplexzentren gebunden. Das Charakteristikum von 3 ist neben einem π‐gebundenen 1,2,4‐Triphospholyl‐ ein 3,4‐Diphosphacyclopentadienon‐Ligand, der sich durch CO‐Einschub während der Cyclodimerisierung zweier Phosphaalkine gebildet haben sollte.
The 62-electron cluster [Ru 4 (CO) 13 (µ 3 -PPh)] (1) reacts with phosphalkynes RCtP [(R ) tBu, Ar′ (2,4,6-tBu 3 C 6 H 2 )] to yield a series of unsymmetrically capped bisphosphinidene clusters characterized by a ketene substituted µ 4 -PR ligand. The reaction pathway was followed by 31 P-NMR spectroscopy and reveals that, in the first step of the reaction, a CO substitution of 1 occurs in order to form an intermediate with a σ-or π-bonded phosphaalkyne. After scavenging of CO the chain compound [Ru 4 (CO) 12 (µ 3 -PPh)(µ 3 -PC(CO)R)] [R ) tBu (2), Ar′ ( 7)] is created. Further CO elimination leads to the closo-complexes [Ru 4 (CO) 10 (µ-CO)-(µ 4 -PPh)(µ 4 -PC(CO)R)] [R ) tBu (3), Ar′ (4)]. Due to steric reasons the nido-cluster [Ru 3 (CO) 9 (µ 3 -PPh){µ 3 -PC(CO)tBu}] (5) is the final product in the reaction starting from Ar′CtP. The molecular structures of the complexes 2-5 are discussed.1 provides an opportunity to explore the chemistry of RCtP on cluster frames, and our findings are presented herein.
Results and DiscussionThe reactions of [Ru 4 (CO) 13 (µ 3 -PPh)] (1) with different phosphaalkynes lead to various ketene ligand-containing clusters. The ligand tBuCtP reacts with 1 at ambient temperatures to yield the complex [Ru 4 (CO) 12 -(µ 3 -PPh)(µ 3 -PC(CO)tBu)] (2) (Scheme 1), whereas at 60 °C the closo-complex [Ru 4 (CO) 10 (µ-CO)(µ 4 -PPh)(µ 4 - † Dedicated to Professor W. Siebert on the occasion of his 60th birthday.
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