Designing isometrical gel precursors to identify the gelation pathway for nickel-selective metallohydrogels.

Two novel multi-responsive metallohydrogels, namely, 2-PF-Ni and 3-PF-Ni, were successfully constructed from phenylalanine derivatives. The 2-PF gelator shows specific responses to Ni; particularly, 2-PF-Ni is lavender colored, which has been rarely reported among hydrogels triggered by Ni. 3-PF-Ni is light green and exhibits perfect thixotropy. This paper provides insights into the gelation mechanisms of these two metallogels.