Reply to Comment on “Cyclopentadienylideneketene: theoretical confirmation of a key infrared band”

✍ Scribed by Anthony P. Scott; Leo Radom

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 177 KB
• Volume: 212
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/s0009-2614(08)80018-8

✦ Synopsis

In their Comment, Liu and Zhou [ 1 ] question the assignment by us [2] and others [3][4][5][6][7][8][9] of a band in the vicinity of 2085-2090 cm -~ (henceforth referred to for simplicity as the 2089 cm -1 band) to the ketenic stretch of cyclopentadienylideneketene (CPDK, 1) (see fig. 1 ). In this Reply, we gather together the evidence for and against such an assignment and conclude that the balance is very strongly in the affirmative.

The only evidence provided by Liu and Zhou (LZ) against the assignment of the 2089 cm-' band to CPDK is that the effect of tetradeutero substitution is not well reproduced by theory. Indeed, the calculated shift for such substitution is less than 1 cm-[ 1,8-10 ] compared with experimental values [ 9-11 ] of 6-9 cm-h On this basis, LZ concluded that, although it is possible that anharmonicity is responsible for the difference, it is "likely that the observed band is due to a molecule other than CPDK".