Reversible temperature-responsible emission in solutions within 293–333 K produced by dissociative behavior of multinuclear Cu(I) complexes with aminomethylphosphines

•Phosphorescence of multinuclear Cu(I) complexes with PNNP ligands is due to 3(X + M)LCT.•Structure impact on dissociation and oxidation of complexes in DMF and DMSO solutions.•Correlation of time-dependent emission with transformations of the complexes in solutions.•The transformations produce two structural motifs with temperature-responsive emission.•TADF is the assumed reason for the reversible changes in emission within 293–333 K.