Magnetic Switching in Vapochromic Oxalato-Bridged 2D Copper(II)-Pyrazole Compounds for Biogenic Amine Sensing

A new two-dimensional (2D) coordination polymer of the formula {Cu(ox)(4-Hmpz)·1/3H2O}n (1) (ox = oxalate and 4-Hmpz 4-methyl-1H-pyrazole) has been prepared, its structure determined by single-crystal X-ray diffraction. It consists corrugated oxalato-bridged copper(II) neutral layers featuring two alternating bridging modes group within each layer, symmetric bis-bidentate (?-?2O1,O2:?2O2?,O1?) asymmetric bis(bidentate/monodentate) (?4-?O1:?2O1,O2:?O2?:?2O2?,O1?) modes. The three crystallographically independent six-coordinate ions that occur in 1 have tetragonally elongated surroundings with oxygen atoms from ligands, a methylpyrazole-nitrogen defining equatorial plane, other oxalate-oxygen occupying axial positions. monodentate ligands alternatively extrude above below oxalate-bridged water molecules crystallization are located between layers. Compound exhibits fast selective adsorption methylamine vapors to afford adsorbate {Cu(ox)(4-Hmpz)·3MeNH2·1/3H2O}n (2), which is accompanied concomitant color change cyan deep blue. 2 transforms into {Cu(ox)(4-Hmpz)·MeNH2·1/3H2O}n (3) under vacuum for hours. cryomagnetic study 1–3 revealed unique switching strong weak (2 3) antiferromagnetic interactions. external control optical magnetic properties along this series compounds might make them suitable candidates devices chemical sensing.