Study On The Synthesis And Structures Of Alkyl Substituted Cyclopentadienyl Metal Carbonyl Complexes

Increasing attention has been paid to dinuclear metal complexes, due to the significantcooperative effect of both metal centers on their reactivity and catalytic applications. Intensivestudy of these complexes will help to provide new catalyts with potential applicationprospects and expand organometallic chemical theory. In this dissertation, reactions of thefour monosubstituted cyclopentadienyl ligands with Fe（CO）₅, Mo（CO）₆and Ru₃（CO）₁₂werestudied, obtained7new complexes. In the same time, reactions of substitutedtetramethylcyclopentadienyl ligands with Fe（CO）₅, Mo（CO）₆and Ru₃（CO）₁₂were alsostudied, obtained8new complexes. It showed that the steric effects of the substituents hadinfluence on the molecular structures, especially on the M-M bond distances. The main resultsare listed as following:（1） Monosubstituted cyclopentadienyl ligands C5H5R[R=CH₂CH₂CH₃（1）; n-Bu （2）;CH₂CH=CH₂（3）; CH₂Ph （4）] were synthesized. Reactions of these substitutedcyclopentadienyl ligands with Fe（CO）₅, Mo（CO）₆and Ru₃（CO）₁₂in refluxing xylene gave thecorresponding7new dinuclear metal carbonyl complexes.trans-（η⁵-C₅H₄CH₂CH₂CH₃）₂Mo₂（CO）₆（5）, trans-（η⁵-C₅H₄nBu）₂Mo₂（CO）₆（6）,trans-（η⁵-C₅H₄CH₂CH=CH₂）₂Mo₂（CO）₆（7）, trans-（η⁵-C₅H₄CH₂Ph）₂Mo₂（CO）₆（8）,trans-{（η⁵-C₅H₄nBu）Fe（CO）（μ-CO）}₂（9）, trans-{（η⁵-C₅H₄CH₂Ph）Fe（CO）（μ-CO）}₂（10）,trans-{（η⁵-C₅H₄CH₂Ph）Ru（CO）（μ-CO）}₂（11）. By comparing the M-M distance of the similarmetal carbonyl complexes, it showed that the steric effect of substituent had important effecton the M-M bond distances of the complexes.（2） Tetramethyl cyclopentadienyl ligand C5Me4H（CH₂）2CH₃（12）, C5Me4HCH（CH₃）₂（13）, C5Me4HCH（CH₂）₄（14） were synthesized. Tetramethyl cyclopentadienyl ligand reactedwith Fe（CO）₅, Mo（CO）₆and Ru₃（CO）₁₂in refluxing xylene gave the corresponding8newdinuclear metal carbonyl complexes. trans-{[η⁵-C₅Me₄（CH₂）₂CH₃]Fe（CO）（μ-CO）}₂（15）,trans-{[η⁵-C₅Me₄CH（CH₃）₂]Fe（CO）（μ-CO）}₂（16）,trans-{[η⁵-C₅Me₄CH（CH₂）₄]Fe（CO）（μ-CO）}₂（17）,trans-{[η⁵-C₅Me₄（CH₂）₂CH₃]Ru（CO）（μ-CO）}₂（18）,trans-{[η⁵-C₅Me₄CH（CH₂）₄]Ru（CO）（μ-CO）}₂（19）, trans-[η⁵-C₅Me₄（CH₂）₂CH₃]₂Mo₂（CO）₆（20）, trans-[η⁵-C₅Me₄CH（CH₃）₂]₂Mo₂（CO）₆（21）, trans-[η⁵-C₅Me₄CH（CH₂）₄]₂Mo₂（CO）₆（22）.With increasing the quantities of substituent groups, the steric hindrance from cyclopentadienylring will be increased, and the electronic effect of cyclopentadienyl ring shows some different.That will result in the M-M bond distances of the complexes changing. （3） Total15unknown complexes were characterized by IR spectra,1H NMR, andelemental analysis. The molecular structures of7typical complexes were determined byX-ray diffraction analysis.