Unsaturation in binuclear heterometallic carbonyls: the cyclopentadienyliron manganese carbonyl CpFeMn(CO)n system as a hybrid of the Cp2Fe2(CO)n and Mn2(CO)n systems
| Autor: | Liqiang Lv, R. Bruce King, Xiuli Feng, Nan Li |
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| Rok vydání: | 2016 |
| Předmět: |
Agostic interaction
chemistry.chemical_classification 010304 chemical physics Double bond chemistry.chemical_element General Chemistry Manganese 010402 general chemistry Photochemistry Triple bond 01 natural sciences Catalysis 0104 chemical sciences Crystallography chemistry Heteronuclear molecule Unpaired electron 0103 physical sciences Materials Chemistry Single bond Density functional theory |
| Zdroj: | New Journal of Chemistry. 40:7482-7492 |
| ISSN: | 1369-9261 1144-0546 |
| DOI: | 10.1039/c5nj03459k |
| Popis: | The experimentally known CpFeMn(CO)7 system as well as the related unsaturated CpFeMn(CO)n systems (n = 6, 5) have been investigated by density functional theory. For CpFeMn(CO)7 unbridged and doubly bridged structures with a heteronuclear Fe–Mn single bond lie within ∼5 kcal mol−1 of each other with the experimentally known unbridged structure being the lower energy structure. The three lowest-energy unsaturated CpFeMn(CO)6 structures, lying within ∼1 kcal mol−1 of each other, have very diverse structural features. The lowest-energy CpFeMn(CO)6 structure contains an unusual three-center two-electron C–H–Mn bond involving an agostic hydrogen of the Cp ring. Another such structure is a triply bridged triplet CpFe(μ-CO)3Mn(CO)3 closely related to the experimentally known Cp2Fe2(μ-CO)3 having a central FeMn double bond containing the two unpaired electrons of the triplet spin state. The third low-energy CpFeMn(CO)6 structure is a CpFe(CO)Mn(CO)4(η2-μ-CO) structure with a four-electron donor bridging η2-μ-CO group similar to that found in the lowest energy Mn2(CO)9 structure. The lowest-energy structure of the even more unsaturated CpFeMn(CO)5 has a short FeMn distance of only ∼2.2 A suggesting a formal triple bond. Higher energy CpFeMn(CO)5 structures have a four-electron donor η2-μ-CO group in addition to a formal FeMn double bond. The CpFeMn(CO)5 structure in which the oxygen atom of the η2-μ-CO group is bonded to manganese lies ∼9 kcal mol−1 in energy below the isomeric structure in which the oxygen of the η2-μ-CO group is bonded to iron. |
| Databáze: | OpenAIRE |
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