12130-88-0Relevant articles and documents
Reactions of cationic complex [(η5-C5Me5)Re(CO)3I]+ with primary amines leading to cyclic carbamoyl complexes
Aballay, Alvaro,Buono-Core, Gonzalo E.,Godoy, Fernando,Klahn, A. Hugo,Iba?ez, Andrés,Garland, María Teresa
, p. 3749 - 3752 (2010/02/28)
The reaction of cationic complex [(5-C5Me5)Re(CO)3I]+ with aliphatic and aromatic primary amines unexpectedly produced the chelated carbamoyl species trans-(5:1-C5Me4CH2NRC({double bond, long}O))Re(CO)2(I) (1, R = Me; 2, R = Pr; 3, R = Ph; 4, R = p-tolyl). The 1-coordination of carbamoyl moiety linkages to a methylene group of tetramethylcyclopentadienyl ligand was confirmed by X-ray crystallography of complex 3. All the complexes were isolated as pure samples and fully characterized by IR, 1H and 13C NMR spectroscopies, mass spectrometry and elemental analysis.
Role of the transition metal in metallaborane chemistry. Reactivity of (Cp*ReH2)2B4H4 with BH3·thf, CO, and Co2(CO)8
Ghosh,Lei,Shang,Fehlner
, p. 5373 - 5382 (2008/10/08)
The reaction of Cp*ReCl4, [Cp*ReCl3]2, or [Cp*ReCl2]2 (Cp* = η5-C5Me5) with LiBH4 leads to the formation of 7-skeletal-electron-pair (7-sep) (Cp*ReH2)2(B2H3)2 (1) together with Cp*ReH6. Compound 1 is metastable and eliminates H2 at room temperature to generate 6-sep (Cp*ReH2)2B4H4 (2). The reaction of 2 with BH3·thf produces 7-sep (Cp*Re)2B7H7, a hypoelectronic cluster characterized previously. Heating of 2 with 1 atm of CO leads to 6-sep (Cp*ReCO)(Cp*ReH2)B4H4 (3). Both 2 and 3 have the same bicapped Re2B2 tetrahedral cluster core structure. Monitoring the reaction of 2 with CO at room temperature by NMR reveals the formation of a 7-sep, metastable intermediate, (Cp*ReCO)(Cp*ReH2)(B2H3)2 (4), which converts to 3 on heating. An X-ray structure determination reveals two isomeric forms (4-cis and 4-trans) in the crystallographic asymmetric unit which differ in geometry relative to the disposition of the metal ancillary ligands with respect to the Re-Re bond. The presence of these isomers in solution is corroborated by the solution NMR data and the infrared spectrum. In both isomers, the metallaborane core consists of fused B2Re2 tetrahedra sharing the Re2 fragment. On the basis of similarities in electron count and spectroscopic data, 1 also possesses the same bitetrahedral structure. The reaction of 2 with Co2(CO)8 results in the formal replacement of the four rhenium hydrides with a 4-electron Co2(CO)5 fragment, thereby closing the open face in 2 to produce the 6-sep hypoelectronic cluster (Cp*Re)2Co2(CO)5B4H4 (5). These reaction outcomes are compared and contrasted with those previously observed for 5-sep (Cp*Cr2)2B4H8.
Synthesis and X-ray structure of the rhenium methyl complex trans-Cp*Re(CO)2(Me)I and a study of the products of photolysis of the rhenium alkyl methyl and dimethyl complexes Cp*Re(CO)2(Me)R (R = Ph, p-Tolyl, Me) under CO
Leiva, Carmen,Klahn, A. Hugo,Godoy, Fernando,Toro, Adriana,Manriquez, Victor,Wittke, Oscar,Sutton, Derek
, p. 339 - 347 (2008/10/08)
Reaction of Cp*Re(CO)2I2 with methylcopper affords cis-Cp*Re(CO)2(Me)I, which converts to the trans isomer on prolonged reaction or in the presence of neutral alumina. The X-ray structure of the trans isomer has been determined. The related chloro complexes Cp*Re-(CO)2(Me)Cl and Cp*Re(CO)2(p-tolyl)Cl are formed in the photolyses of compounds 3 and 1 (below) in CCl4. Photolysis of Cp*Re(CO)2(Me)R (R = p-tolyl (1), Ph (2), Me (3)) in the presence of CO has been carried out in hydrocarbons, CCl4, and benzene-d6. In hydrocarbons, 1 and 2 produce Cp*Re(CO)3, CH4, and either toluene or benzene, respectively; 3 produces Cp*Re-(CO)3 and CH4. In benzene-d6 1 gave CH3D and toluene-4-d, and 3 gave mainly CH3D. These results are consistent with a general scheme involving successive homolysis of the metal-methyl and metal-aryl bonds to give methyl and aryl radicals that abstract H or D from the solvent and carbonylation of the rhenium dicarbonyl fragment. Products known or expected to arise from further photolysis of Cp*Re(CO)3 in benzene-d6, such as Cp*2Re2(CO)3, Cp*2Re2(CO)5, and Cp*Re(CO)2(η2-C6D6), were also found. Photolysis of 1 in CCl4 in the presence or absence of CO gave CH3Cl and Cp*Re(CO)2(p-tolyl)Cl, but no p-chlorotoluene, indicating the preferential homolysis of the Re-Me bond and the rapid scavenging of the subsequent radicals by the chlorinated solvent. Photolysis of the dimethyl complex 3 gave CH3Cl and some evidence of a small amount of Cp*Re(CO)2(Me)Cl, but the major rhenium product was Cp*Re(CO)2Cl2, consistent with the more facile homolysis of both Re-Me bonds in 3. Production of small amounts of CH2D2 (in benzene-d6) and CH4 and CH2Cl2 (in CCl4) are discussed in terms of a competing pathway. Notably, in none of these photolyses were there observed other than trace amounts of products such as p-xylene, which would be expected to be major products if reductive elimination were to occur.
