Ryan, ZH; Jonathan, JS; Davis, HF
The reactions of Y (a2D), Zr (a3F), Nb (a6D), Mo (a7S), and electronically excited-state Mo (a5S) with propyne (methylacetylene) and 2-butyne (1,2-dimethylacetylene) were investigated using crossed molecular beams. For all of the metals studied, reactions with propyne led to H2elimination, forming MC3H2. For Y propyne, C−C bond cleavage forming YCCH CH3also was observed, with an energetic threshold in good agreement with an earlier determination of D0(Y−CCH). For Y 2-butyne, three reactive channels were observed:  YC4H4H2, YC3H3CH3, and YC3H2CH4. The C−C bond cleavage products accounted for 21 and 27% of the total products at Ecoll69 and 116 kJ/mol, respectively. For Zr and Nb reactions with 2-butyne, competition between H2and CH4elimination was observed, with C−C bond cleavage accounting for 12 and 4% of the total product signal at Ecoll71 kJ/mol, respectively. For reactions of Mo and Mo with 2-butyne, only H2elimination was observed. The similarity between reactions involving two isomeric species, propyne and allene, suggests that H atom migration is facile in these systems. [ABSTRACT FROM AUTHOR] Copyright of Journal of Physical Chemistry A is the property of American Chemical Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts)