Copper 2 perchlorate hexahydrate

All of the reagents used, namely 3-hydroxybenzaldehyde (3-HBA; ≥99%), 2-pyridinecarboxaldehyde (2-PCA; 99%), 2′,4′-dihydroxy-2-methoxychalcone (DH-2-MC; 97%), 2′,4′-dihydroxy-3-methoxychalcone (DH-3-MC; 97%), and copper(II) perchlorate hexahydrate (98%), were obtained from Sigma Aldrich (St. Louis, MO, USA). All of the solvents were of purity grade p.a. and were used without any purification. Methanol (MeOH) and hydrochloric acid (HCl) were purchased from Stanlab (Lublin, Poland), dichloromethane (DCM) from Eurochem BGD (Tarnów, Poland), and ethyl alcohol absolute (EtOH) from POCH (Gliwice, Poland).

Chemicals were purchased from commercial sources and used without further purification, unless otherwise noted. Tetraethyl orthosilicate, cetyltrimethylammonium bromide, sodium aluminate, sodium hydroxide, aqueous solutions of hydrogen peroxide (30 wt%) and perchloric acid (60%) were purchased from Wako Pure Chemical Industries. Tris(2-pyridylmethyl)amine and oxo[5,10,15,20-tetra(4-pyridyl)porphyrinato]titanium(iv) (Ti–TPyP) were supplied from Tokyo Chemical Industry. Copper(ii) perchlorate hexahydrate was supplied by Sigma-Aldrich. Acetone and acetonitrile were purchased from Nacalai tesque as a spectral grade and used as received. Ultra-pure water was provided by a water purification system, Millipore Direct-Q3 UV, wherein the electronic conductance was 18.2 MΩ cm. Benzene was purchased from Wako Pure Chemical Industries and purified by washing with sulphuric acid and water following distillation. [Cu(tmpa)(CH₃CN)](ClO₄)₂, [Cu(tepa)(ClO₄)]ClO₄, [Cu^II₂(N5)(H₂O)₂](NO₃)₄ and Al-MCM-41 were synthesised by literature methods.53a ,61 (link)–64

All reagents used for device fabrication and sensing were utilized without further pre-treatment. ARS, a commercially available river sample with trace elements in river water (Elevated Level, NMIJ CRM 7202-c, Supplementary Table S1), and iron(III) nitrate enneahydrate (Fe³⁺) were obtained from FUJIFILM Wako Pure Chemical Co., Ltd. The target metal ions including cobalt(II) perchlorate hexahydrate (Co²⁺), calcium perchlorate tetrahydrate (Ca²⁺), lead(II) perchlorate trihydrate (Pb²⁺), cadmium perchlorate hydrate (Cd²⁺), nickel(II) perchlorate hexahydrate (Ni²⁺), copper(II) perchlorate hexahydrate (Cu²⁺), magnesium perchlorate hexahydrate (Mg²⁺), aluminum perchlorate non-ahydrate (Al³⁺), mercury(II) perchlorate hydrate (Hg²⁺), and zinc perchlorate hexahydrate (Zn²⁺) were purchased from Sigma-Aldrich. The building blocks of the chemosensors purchased from Tokyo Chemical Industry Co., Ltd. were 3-NPBA, BPR, PR, and PV. A buffer material purchased from DOJINDO was 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES). All aqueous solutions were prepared using Milli-Q water (18.2 Ω cm).