# Triphenylphosphine (PPh3) vs. 1,2-bis(diphenylphosphino)ethane (dppe) ligand?

What about $$\ce{NiCl2(dppe)}$$ makes it a more efficient catalyst for Suzuki cross-coupling as opposed to $$\ce{NiCl2(PPh3)2}$$ or $$\ce{NiCl2(PCy3)2}$$? How does the dppe ligand increase the reactivity of the catalyst?

Literature claims:

The experiment I am following is from J. Chem. Educ. 2017, 94(6), 786-789 (https://doi.org/10.1021/acs.jchemed.6b00273). The supporting information contains class data which says that the turnover number using a dppe ligand is roughly 4 times that of $$\ce{PCy3}$$ or $$\ce{PPh3}$$. The paper suggests that increasing electron ability increases catalytic activity, so what about electron donating ability changes catalytic activity and what makes dppe more electron donating?

• You ask this question: What about $\ce{NiCl2(dppe)}$ makes it a more efficient catalyst for Suzuki cross-coupling as opposed to $\ce{NiCl2(PPh3)2}$ or $\ce{NiCl2(PCy3)2}$? However, you didn't gives any literature support to show this is, in deed, a true claim. Can you provide any site mentioning this so-called fact? – Mathew Mahindaratne Dec 15 '19 at 1:08
• Apologies for not including a reference. The experiment I am following is from J. Chem. Educ., 94 (2017), 786-789. The supporting information contains class data which says that the turnover number using a dppe ligand is roughly 4 times that of PCy3 or PPh3. The paper suggests that increasing electron ability increases catalytic activity, so what about electron donating ability changes catalytic activity and what makes dppe more electron donating? – cjperkie Dec 16 '19 at 19:17
• Would you include these literature finding in your question? – Mathew Mahindaratne Dec 16 '19 at 20:06
• I'm going to include these literature finding in your question. I hope you won't mind. – Mathew Mahindaratne Dec 16 '19 at 20:12
• The simple explanation for why dppe is more electron-rich is because alkyl groups are more electron-donating than aryl groups. – orthocresol Dec 16 '19 at 21:16