piperidine and pyridine reacting with vanadyl acetylacetonate IR spectrumWatch this thread
I've taken IR spectrums of VO(acac)2, and the appropriate adducts which form when you react VO(acac)2 with pyridine and piperidine, and I've noticed that the V=O frequency has shifted.
I understand that the nitrogen atom in both pyridine and piperidine donate electron density to the vanadium central ion, which in turn weakens the V=O bond, causing the appropriate peak to shift.
I don't understand why piperidine causes a larger shift to the V=O peak than pyridine?
Is it linked with the hybridisation that occurs in the two bases - piperidine features sp3 hybridisation making it more basic than pyridine?