A recombinant ketoreductase from Pichia glucozyma (KRED1-Pglu) was used for the enantioselective reduction of various mono-substituted acetophenones. Reaction rates of meta- and para-derivatives were consistent with the electronic effects described by σ-Hammett coefficients; on the other hand, enantioselectivity was determined by an opposite orientation of the substrate in the binding pocket. R...

Structures and stabilities of a new family of multi-decker tricarbonyl-bridged sandwich complexes of transition metals (Cr, Mn, Fe) have been studied using DFT B3LYP/6-311+G(df,p) calculations. Stable structures satisfy the (12n + 6) electron-counting rule, where n is the number of metal atoms. Lengthening of the molecular chains is accompanied by growth of aromaticity of the inner basal cycles...

The Dawson-type polyanion [α-Mo(18)O(54)(SO(3))(2)](4-), with two SO(3)(2-) templates embedded inside a polyoxomolybdate(vi) cage, exhibits thermochromism over an exceptionally wide temperature range (∼500 K). The temperature dependence of the cluster structure, established from X-ray crystallography, IR and Raman spectroscopy and DFT calculations, is related to a decreasing HOMO-LUMO gap in th...

Metal-organic frameworks (MOFs) containing d(0) metals such as NH2-MIL-125(Ti), NH2-UiO-66(Zr) and NH2-UiO-66(Hf) are among the most studied MOFs for photocatalytic applications. Despite structural similarities, we demonstrate that the electronic properties of these MOFs are markedly different. As revealed by quantum chemistry, EPR measurements and transient absorption spectroscopy, the highest...

Submitted for the MAR13 Meeting of The American Physical Society Nematicity driven by hybridization in the iron-based superconductors1 VALENTIN STANEV, Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, PETER LITTLEWOOD, Physical Sciences and Engineering, Argonne National Laboratory, Argonne, Illinois 60439, USA — We introduce an effective three-orbital model to s...

The synthesis of a silyliumylidene cation complex 2 stabilized by Ni0-based donating ligand is reported. Experimental and theoretical studies demonstrate that the highly electrophilic SiII center dative Ni→Si σ-interaction π-donations from amino- Ni-moieties. Due to energetically close frontier orbitals localized on Si Ni atoms, presents competitive reactivity at sites.

The uranyl tetrachloride dianion (UO(2)Cl(4)(2-)) is observed in the gas phase using electrospray ionization and investigated by photoelectron spectroscopy and relativistic quantum chemical calculations. Photoelectron spectra of UO(2)Cl(4)(2-) are obtained at various photon energies and congested spectral features are observed. The free UO(2)Cl(4)(2-) dianion is found to be highly stable with a...

A combination of density functional theory calculations, electronic absorption and resonance Raman spectroscopy has been applied to a series of beta-substituted zinc porphyrins to elucidate how the substituent affects the electronic structure of the metalloporphyrin and assign the nature of electronic transitions in the visible region. The use of conjugated beta substituents invokes a large per...

The improvement of molecular electronic devices such as organic light-emitting diodes requires fundamental knowledge about the structural and electronic properties of the employed molecules as well as their interactions with neighboring molecules or interfaces. We show that highly resolved scanning tunneling microscopy (STM) and spectroscopy (STS) are powerful tools to correlate the electronic ...

The spatial resolution of a scanning tunneling microscope (STM) can be enhanced using light element-terminated probes with spatially localized electron orbitals at the apex atom. Conductive diamond probes can provide carbon atomic orbitals suitable for STM imaging with sub-Ångström lateral resolution and high apex stability crucial for the small tunneling gaps necessary for high-resolution expe...