A Molecular Keypad Lock That Uses Cu(II) Cations and H2PO4 - Anions as Inputs

Molecular keypad lock devices have considerable advantages over simple molecular logic gates because the output signals not only depend on the proper combination of inputs but also on the sequence of the input signals. Especially, keeping in view the role played by transition metal ions, anions and electronic devices in day to day life, the development of applications in electronic devices upon chemical inputs of these cations or anions in a sequential manner is very important. Previously, we designed a 2, 2'-dihydroxyazobenzene (DHAB)-based model of a keypad lock system depending on the inputs sequence of Zn(II) cations and H2PO4- anions. In the present work, we studied the properties of 2-((E)-(2-((E)-3-bromoallyloxy)phenyl)diazenyl)phenol, compound 1, toward anions in the absence and presence of Cu(II) cations, in order to further explore the potential applications of DHAB-based sensing systems. We demonstrated that the application of compound 1 with the inputs of Cu(II) cations and H2PO4- anions could be realized as a molecular keypad lock which could be of future interest in molecular computing.