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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Limon on January 05, 2022, 07:42:45 AM

Title: Hydroesterification styrene
Post by: Limon on January 05, 2022, 07:42:45 AM

Hello guys, I need your help on an exercise. I have to write the mechanism of hydroesterification of styrene. In the exercise they gave me the complex  : [(dippe)Ni(PhCHCH2)], CO, MeOH and a styrene. So, for me, the complex got 16 electrons because dippe and styrene are L ligands, and Ni° = 10 electrons. In the first step of the mechanism they said that the oxidation state of my complex is changed by 2 units. So that means that 2 ligands X are added on my Nickel. But I don't know which ligands are linked to my nickel. Is that styrene ?

Thank you for your help (sorry for my English, not my first language).

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Title: Re: Hydroesterification styrene
Post by: Orcio_87 on January 05, 2022, 10:44:17 AM

Quote

In the first step of the mechanism they said that the oxidation state of my complex is changed by 2 units. So that means that 2 ligands X are added on my Nickel.

If oxidation state increased by 2 it means (for example) reaction with Cl₂, Br₂, 2 units of HCN.
If oxidation state decreased by 2 it means (for example) reaction with 2 units of NO.

Decrease of oxidation state is also possible as dippe (as phosphine ligand) can stabilize negative oxidation state as does CO.