Table 2.
Comparative theoretical and experimental asym C≡C frequencies [cm−1].[a]
| M | Theory (R=tBu) | Exptl (R=SiPh3) | Exptl (R= | 4-tBuC6H4) | Exptl (R=tBu) | |||
|---|---|---|---|---|---|---|---|---|
| 1a, 2a, 3a | 1b, 2b, 3b | 1c, 2c, 3c | ||||||
| asym | Diff | asym | Diff | asym | Diff | asym | Diff | |
| Ca | 2099 | 0 | 1980 | 0 | 2032 | 0 | 2035 | 0 |
| Sr | 2085 | 14 | 1969 | 11 | 2004 | 28 | 2002 | 33 |
| Ba | 2075 | 24 | 1955 | 25 | 1997 | 35 | 1998 | 37 |
Diff=CaasymC≡C−Sr or BaasymC≡C.