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M 4 (CH 2 ) 4 Cubane‐Type Rare‐Earth Methylidene Complexes: Unique Reactivity toward Unsaturated CO, CN, and CS Bonds
Author(s) -
Li Tingting,
Nishiura Masayoshi,
Cheng Jianhua,
Li Yang,
Hou Zhaomin
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201202796
Subject(s) - lutetium , reactivity (psychology) , chemistry , cubane , molecule , yield (engineering) , medicinal chemistry , steric effects , ethylene , electrophile , stereochemistry , crystallography , organic chemistry , materials science , medicine , alternative medicine , pathology , yttrium , catalysis , metallurgy , oxide
The reactivity of the cubane‐type rare‐earth methylidene complex [Cp′Lu(μ 3 ‐CH 2 )] 4 ( 1 , Cp′=C 5 Me 4 SiMe 3 ) with various unsaturated electrophiles was investigated. The reaction of 1 with CO (1 atm) at room temperature gave the bis(ketene dianion)/dimethylidene complex [Cp′ 4 Lu 4 (μ 3 ‐CH 2 ) 2 (μ 3 ,η 2 ‐O‐CCH 2 ) 2 ] ( 2 ) in 86 % yield through the insertion of two molecules of CO into two of the four lutetium–methylidene units. In the reaction with the sterically demanding N , N ‐diisopropylcarbodiimide at 60 °C, only one of the four methylidene units in 1 reacted with one molecule of the carbodiimide substrate to give the mono(ethylene diamido)/trimethylidene complex [Cp′ 4 Lu 4 (μ 3 ‐CH 2 ) 3 { i PrNC(=CH 2 )N i Pr}] ( 3 ) in 83 % yield. Similarly, the reaction of 1 with phenyl isothiocyanate gave the ethylene amido thiolate/trimethylidene complex [Cp′ 4 Lu 4 (μ 3 ‐CH 2 ) 3 {PhNC(S)=CH 2 }] ( 4 ). In the case of phenyl isocyanate, two of the four methylidene units in 1 reacted with four molecules of the substrate at ambient temperature to give the malonodiimidate/dimethylidene complex [Cp′ 4 Lu 4 (μ 3 ‐CH 2 ) 2 {PhN=C(O)CH 2 (O)CNPh} 2 ] ( 5 ) in 87 % yield. In this reaction, each of the two lutetium–methylidene bonds per methylidene unit inserted one molecule of phenyl isocyanate. All the products have been fully characterized by NMR spectroscopy, X‐ray diffraction, and microelemental analyses.