A5021337428- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Organometallic Complex Synthesis and Catalysis
- Metalloenzymes and iron-sulfur proteins
- Electrocatalysts for Energy Conversion
- Ammonia Synthesis and Nitrogen Reduction
- Asymmetric Hydrogenation and Catalysis
- Crystallography and molecular interactions
- Inorganic Chemistry and Materials
- Carbon dioxide utilization in catalysis
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Catalytic Cross-Coupling Reactions
- Process Optimization and Integration
- Medical Research and Treatments
- Petroleum Processing and Analysis
- Magnetism in coordination complexes
California Institute of Technology
2021-2025
Colgate University
2016-2019
University of Houston
1989
Nitrogenases, the enzymes that convert N
Ruthenium complexes supported by two new CNN-pincer ligands were synthesized. Both tested as catalysts for the hydrogenation of esters under mild conditions (105 °C, 6 bar H2). A striking dependence on ligand structure was observed, a dimethylamino-substituted gave nearly inactive catalyst, while diethylamino-substituted variant up to 980 catalytic turnovers benzyl benzoate. This system catalyzes various substrates including ethyl, benzyl, and hexyl esters, but is surprisingly unreactive...
Nitrogenase enzymes catalyze the reduction of N2 to NH3 at a complex Fe-M (M = Mo, Fe, or V) cofactor (FeMco), which displays eight metal centers and sulfide carbide bridges with MFe7S8C composition. The role unusual μ6-carbide ligand its effects on remain unclear. Here, we describe transfer MoFe3S3 cluster supported by bisphenoxide from previously reported terminal Mo yield pentametallic MoS3Fe3CMo composition, also bridging CO that resembles lo-CO form nitrogenase. This has an S 1/2 spin...
A series of six pincer–ruthenium complexes has been synthesized and applied in the catalytic hydrogenation esters. The ruthenium have formula Ru(pincer)HCl(CO), where CNN-pincer ligands feature N-heterocyclic carbene (NHC), pyridine, dialkylamino donor groups. Through systematic variation steric bulk NHC substituent amine substituents, a clear structure–function relationship emerges. most active catalysts this bulkiest employed, 2,6-diisopropylphenyl. For group, substituted with isopropyl or...
Nitrogen-fixing organisms perform dinitrogen reduction to ammonia at an Fe-M (M = Mo, Fe, or V) cofactor (FeMco) of nitrogenase. FeMco displays eight metal centers bridged by sulfides and a carbide having the MFe7S8C cluster composition. The role ligand, unique motif in protein active sites, remains poorly understood. Toward addressing how carbon bridge affects physical chemical properties cluster, we isolated synthetic models subsite MFe3S3C displaying chelating carbyne ligand. We developed...
We report the conversion of a series CNN–pincer–ruthenium complexes Ru(CNN)HCl(CO) to CC-chelated form Ru(CC)(PR3)2H(CO) on reaction with sodium tert-butoxide and monodentate phosphines. When phosphine is triphenylphosphine, cis-phosphine at room temperature, which convert trans isomer elevated temperatures. tricyclohexylphosphine, only trans-phosphine observed. The are active catalysts for hydrogenation esters, without need added base. ligand structure–activity relationship in mirrors that...
Bệnh nguyên bào nuôi thai kỳ (Gestational trophoblastic disease – GTD) phát sinh từ bánh rau bất thường bao gồm các thể bệnh tiền ác tính tới tính. Dịch tễ học của GTD khác nhau ở nhiều vùng trên thế giới. Ngoài mô học, nghiên cứu di truyền giúp ích đáng kể cho chẩn đoán. Siêu âm và xét nghiệm hCG có hiện sớm chửa trứng rất trong điều trị. Theo dõi huyết thanh là cần thiết để đoán u Trophoblastic Neoplasia GTN) thời gian theo tùy thuộc vào loại trứng. GTN nguy cơ thấp (điểm < 7) được trị...
Nitrogen-fixing organisms perform dinitrogen reduction to ammonia at an iron-M (M = Mo, Fe, or V) cofactor (FeMco) of nitrogenase. FeMoco displays eight metal centers bridged by sulfides and a carbide having the MoFe 7 S 8 C cluster composition. The role ligand, unique motif in protein active sites, remains poorly understood. Toward addressing its function, we isolated synthetic models subsite MFe 3 displaying carbyne ligand. We developed protocols for structurally related clusters, [Tp*MFe...
<p>Nitrogen-fixing organisms perform dinitrogen reduction to ammonia at an iron-M (M = Mo, Fe, or V) cofactor (FeMco) of nitrogenase. FeMoco displays eight metal centers bridged by sulfides and a carbide having the MoFe<sub>7</sub>S<sub>8</sub>C cluster composition. The role ligand, unique motif in protein active sites, remains poorly understood. Toward addressing its function, we isolated synthetic models subsite...