complexing

/K AH0 M P L EH1 K S IH0 NG/
verb
  1. 1

    To form a complex with another substance

  2. 2

    To complicate.

noun
  1. 1

    The formation of a complex; complexation

Source: https://en.wiktionary.org/wiki/complex, https://en.wiktionary.org/wiki/complexing