Meh, what can one say. Iran has always wanted to improve relations with Europe, import European technology, trade with Europe. It's very culturally enamoured with Europe; Iranians consider themselves honorary Europeans.
By contrast, they look down on Chinese technology, consider Chinese investment predatory, and always seem to have their hackles up when they deal with China. So let the love of their life, Europe, ride to their rescue. China will buy whatever it require from whomever it pleases. Business is business.