Mu‐Hyun Baik

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanistic Studies on the Hydroxylation of Methane by Methane MonooxygenaseMu-Hyun Baik, Martin Newcomb, Richard A. Friesner, and Stephen J. LippardView Author Information Departments of Chemistry, Columbia University, New York, New York 10027, University of Illinois at Chicago, Chicago, Illinois 60607, and Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 Cite this: Chem. Rev. 2003, 103, 6, 2385–2420Publication Date (Web):May 17,

High-level density functional theory in combination with a continuum solvation model was employed to compute standard redox potentials in solution phase for three different classes of electrochemically active molecules: small organic molecules, metallocenes, and M(bpy)3x (M = Fe, Ru, Os; x = +3, +2, +1, 0, −1). Excellent agreement with experimentally determined redox potentials is found with an average deviation of approximately 150 mV when four different solvents commonly in use for electrochem

The thermodynamics and kinetics for the monofunctional binding of the antitumor drug cisplatin, cis-diamminedichloroplatinum(II), to a purine base site of DNA were studied computationally using guanine and adenine as model reactants. A dominating preference for initial attack at the N7-position of guanine is established experimentally, which is a crucial first step for the formation of a 1,2-intrastrand cross-link of adjacent guanine bases that leads to bending and unwinding of DNA. These struct

Until recently, computational tools were mainly used to explain chemical reactions after experimental results were obtained. With the rapid development of software and hardware technologies to make computational modeling tools more reliable, they can now provide valuable insights and even become predictive. In this review, we highlighted several studies involving computational predictions of unexpected reactivities or providing mechanistic insights for organic and organometallic reactions that l

Quantum chemical molecular modeling has become a standard tool in organometallic chemistry. In particular, density functional theory calculations are now indispensable for investigating the mechanism of even complex reactions and deliver precise energies of intermediates and transition states. Because software packages have become user-friendly and are widely available, even nonexperts can now produce high-quality computer models. In this tutorial, we highlight nontrivial mistakes, misconception

A novel method for the catalytic asymmetric dearomatization by visible-light-activated [2+2] photocycloaddition with benzofurans and one example of a benzothiophene is reported, thereby providing chiral tricyclic structures with up to four stereocenters including quaternary stereocenters. The benzofurans and the benzothiophene are functionalized at the 2-position with a chelating N-acylpyrazole moiety which permits the coordination of a visible-light-activatable chiral-at-rhodium Lewis acid cata

We report the enantioselective [2+2] cycloaddition of simple cinnamate esters, the products of which are useful synthons for the controlled assembly of cyclobutane natural products. This method utilizes a cocatalytic system in which a chiral Lewis acid accelerates the transfer of triplet energy from an excited-state Ir(III) photocatalyst to the cinnamate ester. Computational evidence indicates that the principal role of the Lewis acid cocatalyst is to lower the absolute energies of the substrate

Despite steady progress in catalytic methods for the borylation of hydrocarbons, methane has not yet been subject to this transformation. Here we report the iridium-catalyzed borylation of methane using bis(pinacolborane) in cyclohexane solvent. Initially, trace amounts of borylated products were detected with phenanthroline-coordinated Ir complexes. A combination of experimental high-pressure and high-throughput screening, and computational mechanism discovery techniques helped to rationalize t

Electrocatalysis is a promising tool for utilizing carbon dioxide as a feedstock in the chemical industry. However, controlling the selectivity for different CO₂ reduction products remains a major challenge. We report a series of manganese carbonyl complexes with elaborated bipyridine or phenanthroline ligands that can reduce CO₂ to either formic acid, if the ligand structure contains strategically positioned tertiary amines, or CO, if the amine groups are absent in the lig

Chiral variants of group IX Cp and Cp* catalysts are well established and catalyze a broad range of reactions with high levels of enantioselectivity. Enantiocontrol in these systems results from ligand design that focuses on appropriate steric blocking. Herein we report the development of a new planar chiral indenyl rhodium complex for enantioselective C-H functionalization catalysis. The ligand design is based on establishing electronic asymmetry in the catalyst, to control enantioselectivity d

Enantioselective catalysis of excited-state photoreactions remains a substantial challenge in synthetic chemistry, and intermolecular photoreactions have proven especially difficult to conduct in a stereocontrolled fashion. Herein, we report a highly enantioselective intermolecular [2 + 2] cycloaddition of 3-alkoxyquinolones catalyzed by a chiral hydrogen-bonding iridium photosensitizer. Enantioselectivities as high as 99% ee were measured in reactions with a range of maleimides and other electr

Enantioenriched molecules bearing indole-substituted stereocenters form a class of privileged compounds in biological, medicinal, and organic chemistry. Thus, the development of methods for asymmetric indole alkylation is highly valuable in organic synthesis. Traditionally, achieving N-selectivity in indole alkylation reactions is a significant challenge, since there is an intrinsic preference for alkylation at C3, the most nucleophilic position. Furthermore, selective and predictable access to

We recently reported a bis(imino)pyridine (or pyridine diimine, PDI) manganese precatalyst, (^Ph2PPrPDI)Mn (1), that is active for the hydrosilylation of ketones and dihydrosilylation of esters. In this contribution, we reveal an expanded scope for 1-mediated hydrosilylation and propose two different mechanisms through which catalysis is achieved. Aldehyde hydrosilylation turnover frequencies (TOFs) of up to 4900 min^-1 have been realized, the highest reported for first row m

The depurination reaction of guanosine, protonated or modified with cisplatin at the N7 position, has been studied by density functional theory (DFT), coupled with a continuum treatment of solvation. Protonation accelerates the depurination reaction whereas N7-platination, the initial product of cisplatin binding to DNA, does not. The computed reaction energy profiles demonstrate that N7-platination has only a minor effect on the energetics of the transition state, whereas protonation lowers it

Abstract Much effort has been dedicated to increase the operational lifetime of blue phosphorescent materials in organic light‐emitting diodes (OLEDs), but the reported device lifetimes are still too short for the industrial applications. An attractive method for increasing the lifetime of a given emitter without making any chemical change is exploiting the kinetic isotope effect, where key CH bonds are deuterated. A computer model identifies that the most vulnerable molecular site in an Ir‐phe