research director vs director of research

research director and director of research both are nouns.

Word	Noun	Adjective	Verb	Adverb
research director	Yes	No	No	No
director of research	Yes	No	No	No

As nouns, research director and director of research are synonyms defined as:

research director and director of research: a supervisor in a research center

research director (noun)	director of research (noun)
a supervisor in a research center	a supervisor in a research center