Infrared Photodissociation Spectroscopy of Ti＋（CO2）2Ar and Ti＋（CO2）n （n=3-7） Complexes

Ti＋（CO2）2Ar and Ti＋（CO2）n （n=3-7） complexes are produced by laser vaporization in a pulsed supersonic expansion. The ion complexes of interest are each mass-selected in a time- of-flight spectrometer, and studied with infrared photodissociation spectroscopy. For each complex, a sharp band in the CO stretching frequency region is observed, which confirms the formation of the OTi＋CO（CO2）~_l oxide-carbonyl species. Small OTi＋CO（CO2）~_1 complexes （n_〈5） exhibit CO stretching and antisymmetric CO2 stretching vibrational bands that are blue-shifted from those of free CO and CO2. The experimental observations indicate that the coordination number of CO and CO2 molecules around TiO＋ is five. Evidence is also observed for the presence of another electrostatic bonding Ti＋（CO2）2 structural isomer for the Ti＋（CO2）2Ar complex, which is characterized to have a bent OCO-Ti＋-OCO structure stabilized by argon coordination.

Photodissociation Dynamics of AlO at 193 nm using Time-Sliced Ion Velocity Imaging

The photodissociation dynamics of Al O at 193 nm is studied using time-sliced ion velocity mapping.Two dissociation channels are found through the speed and angular distributions of aluminum ions:one is one-photon dissociation of the neutral AlO to generate Al(2 Pu)+O(3 Pg),and the other is two-photon ionization and then dissociation of AlO^+to generate Al^+(1 Sg)+O(3 Pg).Each dissociation channel includes the contribution of AlO in the vibrational states v=0-2.The anisotropy parameter of the neutral dissociation channel is more dependent on the vibration state of AlO than the ion dissociation channel.

Imaging Reaction Dynamics of Y+SO2

The reaction dynamics of yttrium atoms with sulfur dioxide molecules at a high collision energy of 36 kcal/mol was studied using time-sliced velocity map ion imaging,crossed molecular beam and laser-ablation method.The product YO was detected via multiphoton ionization at various wavelengths in the region of 482-615 nm.The slice images of YO show a broad velocity distribution and forward-backward peaking angular distribution.The forward scattering signal is stronger than its backward distribution.This indicates that the reaction proceeds via an intermediate complex and the lifetime of the intermediate state is less than one rotational period.The formation of complex suggests that electron transfer occurs in the oxidation reaction.

Infrared Photodissociation Spectroscopic and Theoretical Study of the HC2nO+（n=3-6） Cations

The carbon chain cations, HC2nO+(n=3-6) are produced via a pulsed laser vaporization supersonic expansion ion source in the gas phase. Their infrared spectra are measured via mass-selected infrared photodissociation spectroscopy of the CO “tagged”[HC2nO·CO]+ cation complexes in 1600-3500 cm-1 frequency range. The geometric and electronic structures of the [HC2nO·CO]+ complexes and the core HC2nO+(n=3-6) cations are determined with the aid of density functional theory calculations. These HC2nO+(n=3-6) ions are identified to be linear carbon chain derivatives terminally capped by hydrogen and oxygen. The triplet ground states are 10-15 kcal/mol lower in energy than the singlet states, indicating cumulene-like carbon chain structures.

Mononuclear Carbonyl Anion Complexes of GroupsⅣandⅤMetals

The anionic carbonyl complexes of groupsⅣandⅤmetals TM(CO)6,7(TM=Ti,Zr,Hf,V,Nb,Ta)are prepared in the gas phase using a laser vaporation-supersonic expansion ion source.The infrared spectra of TM(CO)_(6,7)-anion complexes in the carbonyl stretching frequency region are measured by mass-selected infrared photodissociation spectroscopy.The six-coordinated TM(CO)_(6)-anions are determined to be the coordination saturate complexes for both the groupⅣand groupⅤmetals.The TM(CO)_(6)-complexes of groupⅣmetals(TM=Ti,Zr,Hf)are 17-electron complexes having a~2A1gground state with D3dsymmetry,while the TM(CO)_(6)-complexes of groupⅤmetals(TM=Ⅴ,Nb,Ta)are 18-electron species with a closed-shell singlet ground state possessing Ohsymmetry.The energy decomposition analyses indicate that the metal-CO covalent bonding is dominated by TM-(d)→(CO)6π-backdonation and TM-(d)←(CO)6σ-donation interactions.

A general strategy for MOFs coupled to optical fiber for highly sensitive humidity sensing

To achieve real-time and high-sensitive humidity sensing,a universal method was developed to allow arbitrary nanocrystals to be attached to the end of an optical fiber,further producing an effective interference spectrum.To validate this approach,four classical metal-organic framework(MOF) materials(ZIF-8,UiO-66,HKUST-1,MIL-101) are connected to the end of a single-mode optical fiber by this connection method to form humidity sensors.

Highly Site-and Enantioselective N-H Functionalization of N-Monosubstituted Aniline Derivatives Affording Pyrazolones Bearing a Quaternary Stereocenter

Chiral phosphoric acid catalyzed the regio-and enantioselective N-H functionalization of N-alkylaniline with pyrazolones derived ketimines as electrophiles,providing a variety of chiral pyrazolones containing a tetrasubstituted stereocenter bearing a new N,N'-acetal motif in excellent yields and high enantioselectivities.This strategy was featured by low catalyst loading,mild conditions,and high efficiency and selectivity.