10.1021/ja00372a009
The research investigates the reductive elimination reactions of metal-metal multiple bonds, specifically focusing on molybdenum compounds. The study explores how the addition of CO2 or 1,3-diaryltriazenes to 1,2-Mo2R2(NMe2)4 compounds, where R represents various alkyl groups, promotes reductive elimination through alkyl group disproportionation, resulting in a change in metal-metal bond order from three to four. Key chemicals involved in the research include Mo2R2(NMe2)4 compounds with different R groups such as methyl (Me), ethyl (Et), and isopropyl (i-Pr), CO2, and 1,3-diaryltriazenes. The reactions lead to the formation of various products like Mo2(02CNMe2)4, Mo2(ArN3Ar)4, and the corresponding alkanes and alkenes. The study also delves into the mechanisms of these reactions, examining intermediates and the influence of factors such as the presence of β-hydrogen atoms on the alkyl groups and the geometric arrangement of the molecules. The findings provide insights into the reactivity patterns of alkyl groups bonded to dimetal centers and the potential for further studies on reductive eliminations in dinuclear metal complexes.
10.1021/om00139a032
The study investigates a series of molybdenum and tungsten alkyne complexes, M(CO)(RC2R')L2X2, where M represents molybdenum or tungsten, L is a ligand such as PPh3, PES, or py, L2 is dppe (Ph2PCH2CH2PPh2), and X is a halide like Cl or Br. These complexes were synthesized by reacting M(CO)nL2X2 reagents (with n being 2 or 3) with free alkynes. The researchers used nuclear magnetic resonance (NMR), infrared (IR), and electronic absorption spectroscopies to analyze the metal-alkyne bonding interactions. The study found that the alkyne ligands in these complexes behave as "four-electron" donors, as indicated by the NMR chemical shift values. The structure of Mo(CO)(PhC2H)(PES)Br2 was determined through X-ray diffraction, revealing a distorted octahedral geometry with the alkyne ligand cis and parallel to the carbon monoxide ligand. The study also explored the dynamic properties of these complexes, such as rotational barriers and electronic absorption characteristics, providing insights into the stability and reactivity of these metal-alkyne complexes.
10.1016/j.jorganchem.2004.04.030
The study explores the use of a modified conventional microwave oven for the synthesis of over 20 group 6 organometallic compounds, primarily focusing on molybdenum (Mo), tungsten (W), and chromium (Cr) carbonyls. The chemicals involved include hexacarbonyls such as Mo(CO)6, W(CO)6, and Cr(CO)6, which act as starting materials. These compounds react with various ligands, including mono-, bi-, and tridentate ligands like piperidine, 2,2'-bipyridine, 1,10-phenanthroline, pyridine, and phosphines (PPh3, dppm, dppe), to form tetracarbonyl and other complexes. The microwave-assisted reactions generally proceed without the need for an inert atmosphere, resulting in high yields and significantly reduced reaction times compared to conventional methods. For example, cis-[Mo(CO)4(dppe)] is prepared in >95% yield in just 20 minutes. The study also highlights the successful synthesis of dimeric molybdenum(I) cyclopentadienyl complexes, [CpMo(CO)3]2, in 94% yield, and dimolybdenum tetraacetate in 48% yield under an inert atmosphere. The microwave approach allows for the rapid formation of unsaturated, air-sensitive molybdenum-molybdenum triply bonded complexes, enabling complex organometallic reactions to be carried out more efficiently and safely, making them more accessible for both research and teaching purposes.
10.1021/om500925m
The study focuses on the Negishi Cross-Coupling Reaction as an efficient method for synthesizing functionalized amino and alkoxy carbene complexes of chromium, molybdenum, and tungsten. The researchers utilized a variety of chemicals, including metalated aminocarbenes, palladium catalysts, organozinc reagents, and halide compounds. These chemicals served the purpose of facilitating the cross-coupling reactions, which allowed the creation of new amino and alkoxy carbene complexes with functional groups such as aldehyde, ketone, nitrile, and ester. The study provides a route to access these complexes, which are valuable in the synthesis of complex organic molecules and are not easily accessible through other methods.
10.1021/ja00245a068
The research focuses on two main chemical investigations. The first part of the research delves into the synthesis of new tmtaa-metal derivatives using the reactive species Li2tmtaa, an approach that contrasts with the traditional use of tmtaaH2 and yields promising results. The study emphasizes the structural characterization of metalloporphyrin dimers and their electronic properties, with molybdenum atoms and porphyrin moieties playing a central role in the described compounds. The second part of the research introduces a novel route to Allenyl Fluorides, specifically the synthesis of 4-Amino-7-fluorohepta-5,6-dienoic Acid, which is the first fluoroallenyl amino acid. This synthesis is significant as it provides a practical route to fluoroallenes, a functional group with potential applications in enzyme-activated irreversible inhibitors and other biologically active species. The chemicals used in the process include n-BuLi, Mo2(OAc)3, Na-Hg, ferricinium salts, and various solvents and reagents for the synthesis, extraction, and characterization of the target compounds. The conclusions drawn from the research highlight the successful synthesis of the desired fluoroallenes and the potential for further exploration in fluoroallenes chemistry and enzymology.
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