Significant effect of spin flip on the oxygen atom transfer reaction from (oxo)manganese(v) corroles to thioanisole: insights from density functional calculationsSubmitted by Jun Zhu on Fri, 11/01/2013 - 01:15
The electronic and structural features of (oxo)manganese(V) corroles and their catalyzed oxygen atom transfers to thioanisole in different spin states have been investigated by the B3LYP functional calculations. Calculations show that these corrole-based oxidants and their complexes with thioanisole generally have the singlet ground state, and their triplet forms are also accessible in consideration of the spin–orbit coupling interaction.
Silicon-Containing Formal 4 pi-Electron Four-Membered Ring Systems: Antiaromatic, Aromatic, or Nonaromatic?Submitted by Jun Zhu on Fri, 11/01/2013 - 01:11
Density functional theory calculations (B3LYP) have been carried out to investigate the 4π-electron systems of 2,4-disila-1,3-diphosphacyclobutadiene (compound 1) and the tetrasilacyclobutadiene dication (compound 2). The calculated nucleus-independent chemical shift (NICS) values for these two compounds are negative, which indicates that the core rings of compounds 1 and 2 have a certain amount of aromaticity.
An Isotope (O-18, N-15, and H-2) Technique to Investigate the Metal Ion Interactions Between the Phosphoryl Group and Amino Acid Side Chains by Electrospray Ionization Mass SpectrometrySubmitted by Jun Zhu on Fri, 11/01/2013 - 01:04
Cationic metal ion-coordinated N-diisopropyloxyphosphoryl dipeptides (DIPP-dipeptides) were analyzed by electrospray ionization multistage tandem mass spectrometry (ESI-MS n ). Two novel rearrangement reactions with hydroxyl oxygen or carbonyl oxygen migrations were observed in ESI-MS/MS of the metallic adducts of DIPP-dipeptides, but not for the corresponding protonated DIPP-dipeptides.
Fragmentation of pentacoordinate spirobicyclic aminoacylphosphoranes (P-AAs) by electrospray ionization tandem mass spectrometry concerning P-O and P-N bond cleavageSubmitted by Jun Zhu on Fri, 11/01/2013 - 00:58
The fragmentation pathways of both protonated and sodiated pentacoordinate spirobicyclic aminoacylphosphoranes (P-AAs) have been studied by electrospray ionization multi-stage mass spectrometry (ESI-MSn) in positive mode. The possible pathways and their mechanisms are elucidated through the combination of ESI-MS/MS, isotope (15 N and 2H) labeling and high-resolution Fourier transform ion cyclotron resonance (FTICR)-MS/MS. The relative Gibbs free energies (ΔG) of the product ions and possible fragmentation pathways are estimated at the B3LYP/6-31 G(d) level of theory.
Interpolation of Atomically Thin Hexagonal Boron Nitride and Graphene: Electronic Structure and Thermodynamic Stability in Terms of All-Carbon Conjugated Paths and Aromatic HexagonsSubmitted by Jun Zhu on Fri, 11/01/2013 - 00:53
Two-dimensional hexagonal composite materials (BN)n(C2)m (n, m = 1, 2, ...), which all are isoelectronic with graphene and hexagonal boron nitride (h-BN), have been studied by density functional theory (DFT) with a focus on the relative energies of different material isomers and their band gaps. The well-established chemical concepts of conjugation and aromaticity were exploited to deduce a rationale for identifying the thermodynamically most stable isomer of the specific composites studied.
Ni(II)/Zn Catalyzed Reductive Coupling of Aryl Halides with Diphenylphosphine Oxide in WaterSubmitted by Jun Zhu on Fri, 11/01/2013 - 00:49
P-Arylation in water has been developed via cross-coupling of aryl halides with diphenylphosphine oxide (Ph2P(O)H) and (RP)-(−)-menthyl benzylphosphinate catalyzed by NiCl2·6H2O/Zn under relatively mild conditions.
Stable Iso-osmabenzenes from a Formal [3+3] Cycloaddition Reaction of Metal Vinylidene with AlkynolsSubmitted by Jun Zhu on Fri, 11/01/2013 - 00:22
The magic of Os: An unprecedented formal [3+3] cycloaddition reaction of 1 with alkynols affords stable iso-osmabenzenes at room temperature (see scheme). The phosphonium substituent at the Cβ position and the 18e− nature of the compound play key roles in the origin of the high thermal stability of the products. Isomerization of iso-osmabenzenes into η5-cyclopentadienyl complexes through metalated cyclopentadiene intermediates is also described.
On the Importance of Clar Structures of Polybenzenoid Hydrocarbons as Revealed by the π-Contribution to the Electron Localization FunctionSubmitted by Jun Zhu on Fri, 11/01/2013 - 00:17
The degree of p-electron (de)localization and aromaticity of a series of polybenzenoid hydrocarbons (PBHs) has been analyzed through the π-contribution to the electron localization function (ELFπ), calculated at the B3LYP/6-311G(d,p) hybrid density functional theory level. The extent of p-electron delocalization in the various hexagons of a PBH was determined through analysis of the bifurcation values of the ELFp basins (BV(ELFp)), the spans in the bifurcation values in each hexagon (ΔBV(ELFπ)), and the ring-closure bifurcation values of the ELFπ (RCBV(ELFπ)).
Insertion reactions of allenes with palladium aryl complexes [PdI(Ph)(PPh3)](2) and PdI(Ph)(dppe)Submitted by Jun Zhu on Fri, 11/01/2013 - 00:06
Treatment of [PdI(Ph)(PPh3)]2 with allenes CH2═C═CHR (R = CMe3, CO2Et, P(O)(OEt)2, and SO2Ph) in dichloromethane at room temperature produces a mixture of cis and trans isomers of the π-allyl palladium complexes PdI(η3-CH2C(Ph)CHR)(PPh3) in which the R group is anti to the Ph group. The disubstituted allenes MeCH═C═CHR (R = P(O)(OEt)2 and SO2Ph) similarly react with [PdI(Ph)(PPh3)]2 to give the π-allyl palladium complexes PdI(η3-MeCHC(Ph)CHR)(PPh3) in which the R group is anti and the Me group is syn to the Ph group.
A metallanaphthalyne complex from zinc reduction of a vinylcarbyne complexSubmitted by Jun Zhu on Fri, 11/01/2013 - 00:02
Cl prevents insertion: The first metallanaphthalyne 2 has been obtained by Zn reduction of Os carbyne complex 1. The key to its isolation was the use of o-chlorophenyl instead of phenyl substituents to avoid formation of a putative hydrido metallanaphthalyne intermediate (supported by DFT calculations), which undergoes migratory insertion of the carbyne into the OsH bond and rearrangement to give an indenyl complex as the final product.