Spectroscopic Characterization of Nonconcerted [4 + 2] Cycloaddition of 1,3-Butadiene with Lanthanacyclopropene To Form Lanthanum–Benzene in the Gas Phase

2017 ◽  
Vol 121 (6) ◽  
pp. 1233-1239 ◽  
Author(s):  
Dilrukshi Hewage ◽  
Wenjin Cao ◽  
Jong Hyun Kim ◽  
Ya Wang ◽  
Yang Liu ◽  
...  
1984 ◽  
Vol 38 ◽  
Author(s):  
Joda C. Wormhoudt ◽  
Alan C. Stanton ◽  
Joel A. Silver

AbstractTwo processes of great importance in the semiconductor industry are vapor deposition and plasma etching. This paper presents a review of laser techniques for spectroscopic characterization of the gas phase species involved in these processes. Band strength and other spectroscopic data for selected molecules are used to give estimates of the detection sensitivity in vibrational and electronic bands. Preliminary results are given from work presently in progress in our laboratory on the detection of such species. The discussion includes examples of the application of these techniques to a number of laboratory deposition and etching devices.


Science ◽  
2018 ◽  
Vol 361 (6405) ◽  
pp. 912-916 ◽  
Author(s):  
Xuan Wu ◽  
Lili Zhao ◽  
Jiaye Jin ◽  
Sudip Pan ◽  
Wei Li ◽  
...  

The alkaline earth metals calcium (Ca), strontium (Sr), and barium (Ba) typically engage in chemical bonding as classical main-group elements through their ns and np valence orbitals, where n is the principal quantum number. Here we report the isolation and spectroscopic characterization of eight-coordinate carbonyl complexes M(CO)8 (where M = Ca, Sr, or Ba) in a low-temperature neon matrix. Analysis of the electronic structure of these cubic Oh-symmetric complexes reveals that the metal–carbon monoxide (CO) bonds arise mainly from [M(dπ)] → (CO)8 π backdonation, which explains the strong observed red shift of the C-O stretching frequencies. The corresponding radical cation complexes were also prepared in gas phase and characterized by mass-selected infrared photodissociation spectroscopy, confirming adherence to the 18-electron rule more conventionally associated with transition metal chemistry.


Science ◽  
2015 ◽  
Vol 349 (6243) ◽  
pp. 58-61 ◽  
Author(s):  
Rebecca B. Mackenzie ◽  
Christopher T. Dewberry ◽  
Kenneth R. Leopold

We report the observation of a covalently bound species, formic sulfuric anhydride (FSA), that is produced from formic acid and sulfur trioxide under supersonic jet conditions. FSA has been structurally characterized by means of microwave spectroscopy and further investigated by using density functional theory and ab initio calculations. Theory indicates that a π2 + π2 + σ2 cycloaddition reaction between SO3 and HCOOH is a plausible pathway to FSA formation and that such a mechanism would be effectively barrierless. We speculate on the possible role that FSA may play in the Earth’s atmosphere.


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