Synthesis and characterisation of two Cu(I) metalloligands based on tetradentate tripodal ligands

Two new tetradentate tripodal ligands (L1 and L2) have been synthesized via Schiff base condensation of tris(2-aminoethyl)amine (tren) with 4-(4-pyridinyl)benzaldehyde or 4-(3-pyridinyl)benzaldehyde in ethanol. Four Cu(I) complexes [CuL1]PF6, [CuL1]I, [CuL2]PF6 and [CuL2]I (1-4) have been prepared and characterised by NMR, HR-MS, SEM-EDS, FT-IR, Raman and UV-Vis measurements. X-ray structures for 1 and 4 are presented. In both structures, the four-coordinate copper(I) centres are bound within the cavity defined by the tren backbone. In such Cu(I) complexes, steric considerations dictate that the three uncoordinated pyridine nitrogen donors will have their coordination vectors oriented in a mutually divergent manner suitable for coordination to three different metal centres and thus are preorganized to act as new tripodal metalloligands.