CHICAGO • The Scottish-born winner of the Nobel Prize for Chemistry on Wednesday took a jab at United States presidential candidate Donald Trump, who has bragged that he was "smart" to avoid paying taxes.

"I am not very smart. The IRS (Internal Revenue Service) will run off with a third of it," said Northwestern University professor Fraser Stoddart, referring to his portion of the 8 million Swedish kronor (S$1.3 million) award, which he shares with Dr Jean-Pierre Sauvage of France and Dr Bernard Feringa of the Netherlands.

"Did you all get that? I'm not very smart," Prof Stoddart added, to laughter and applause during a champagne-fuelled press conference to celebrate the Nobel win.

Mr Trump, the Republican nominee for US president, has refused to release his tax returns.

In the first presidential debate on Sept 26, Democratic nominee Hillary Clinton suggested that Mr Trump is hiding "something terrible", and that he had not paid any federal income tax.

Mr Trump's answer: "That makes me smart." Days later, the New York Times published a bombshell based on a leaked copy of his 1995 tax documents, showing he declared a loss of nearly US$1 billion (S$1.4 billion), and could likely have avoided paying taxes for almost two decades.

Prof Stoddart, who said he has lived in the US for 20 years, did not press any deeper into politics, but said he wants to use whatever is left of his prize money to help others.

"One of the things that drive academia in this country is philanthropy," he said. "What I want to do, of course, is give back."

The trio won for developing the world's smallest molecular machines, which may some day have uses in cancer treatment, robotics and prosthetics.

Prof Stoddart described their work as "a fundamental advance in chemistry" that will take some time before it translates into real-life applications.

He also urged young people to press on with their goals, even if they face detractors and doubts.

AGENCE FRANCE-PRESSE