Low-dimensional compounds containing cyanido groups. XXIV. Crystal structure, spectroscopic and thermal properties of two Cu(II) tetracyanidoplatinate complexes with tetradentate N-donor ligands

• Two complexes of different structural types have been isolated.
• Separate triples of parallel square-planar [Pt(CN)4]2− units are formed.
• Using of one tetradentate instead of two bidentate ligands causes structural changes.

Violet crystals of [Cu2(teta)2Pt(CN)4]2[Pt(CN)4]2 (1, teta = N,N’-bis(2-aminoethyl)-1,2-diaminoethane; triethylenetetramine) and {[Cu3(bapen)3Pt(CN)4][Pt(CN)4]2·13H2O}n (2, bapen = N,N′-bis(3-aminopropyl)-1,2-diaminoethane) were crystallized from the water–methanol or aqueous solutions containing Cu(II) salt, teta or bapen ligand and K2[Pt(CN)4]. Both compounds were characterized using elemental analysis, IR and UV–Vis spectroscopy, thermal and X-ray crystal structure analysis. Two ν(CN) absorption bands in the IR spectra of the complexes imply non-equivalency of cyanido groups meaning the presence of both, terminal and bridging ones and together with the results of elemental analysis indicate simple chain-like structure. Thermal decompositions of the prepared complexes are few-step processes which comprise liberation of crystal water (only for 2), decay of N-donor ligands L and release of cyanido groups. Finally, an X-ray crystal structure analysis has shown their complicated crystal structures. On one hand, complex 1 is of ionic character and is formed from a couple of trinuclear [Cu(teta)-Pt(CN)4-Cu(teta)]2+ complex cations and a couple of discrete [Pt(CN)4]2− anions. On the other hand, complex 2 is of polymeric character and is formed by 1D chains of {[Cu3(bapen)3Pt(CN)4]4+}n composition, 2n single [Pt(CN)4]2− anions and 13n molecules of crystal water.

Two complexes of different structural types from the systems Cu(II)-tetradentate-N-donor ligand-[Pt(CN)4]2− have been isolated. These were characterized by IR and UV–Vis spectroscopy, thermal analysis and X-ray crystal structure analysis. On one hand, complex [Cu2(teta)2Pt(CN)4]2[Pt(CN)4]2 is of ionic character formed from couples of trinuclear complex cations and discrete [Pt(CN)4]2− anions. On the other hand, complex {[Cu3(bapen)3Pt(CN)4][Pt(CN)4]2·13H2O}n is of polymeric character and is formed by 1D chains of {[Cu3(bapen)3Pt(CN)4]4+}n composition, 2n single [Pt(CN)4]2− anions and 13n molecules of crystal water.Figure optionsDownload as PowerPoint slide