Abu Dhabi National Oil Co. has reached a deal to buy chemical producer Covestro AG for about €11.7 billion ($13 billion), in what’s set to be the biggest Middle Eastern acquisition of a European firm.

Adnoc and Covestro agreed on a tie-up valuing the chemicals maker at $13.05 billion in a deal that will help the Abu Dhabi energy giant diversify its portfolio beyond its core oil business.

Abu Dhabi’s national oil company has agreed a €14.7bn deal to buy German chemicals group Covestro in one of the largest European takeovers this year. Adnoc, which has been pursuing Covestro since last year, has offered €62 per share for the German company. It will also inject €1.17bn of new money into the chemicals group.