Abstract: | Two zinc clusters Zn4(H3L)4(NO3)4?5H2O ( Zn4 , H4L=(1,2‐bis(1H‐benzo[d]imidazol‐2‐yl)ethane‐1,2‐diol) and [Zn5(H2L′)6](NO3)4]?8H2O?2CH3OH ( Zn5 , H3L′=(1,2‐bis(benzo[d] imidazol‐2‐yl)‐ethenol) have been obtained by the reaction of Zn(NO3)2?6H2O with H4L at 80 °C or 140 °C under solvothermal condition. Powder X‐ray Diffraction (PXRD) of precipitate and Electrospray Ionization Mass Spectrometry (ESI‐MS) of reaction solution revealed the existence of transformation behavior from Zn4 to Zn5 by increasing the temperature from 80 °C to 140 °C, or directly heating Zn4 at 140 °C via solvothermal reaction. Here we proposed a possible mechanism involves split process of Zn4 and reassembly to form Zn5 . ESI‐MS for single crystals revealed [Zn4(H3L)4?3H]+ splits to [Zn(H3L)]+ via [Zn2(H3L)2?H]+. Time dependent ESI‐MS of reaction solution revealed the [Zn(H2L′)]+→[Zn2(H2L′)2?H]+→[Zn5(H2L′)6?H]3+ stepwise assembly. It also has been captured the in situ reaction mainly occurs in the step of [Zn(H3L)]+ to [Zn(H2L′)]+. |