A chiral two-dimensional coordination polymer based on CuII and (S)-4,4′-bis(4-carboxyphenyl)-2,2′-bis(diphenylphosphinoyl)-1,1′-binaphthyl: Synthesis, structure, and magnetic and optical properties

• Two-dimensional chiral {[Cu2(L)2(dmf)2]·H2O·9 dmf}n (1) was synthesized.
• 1 exhibits a copper(II)-based paddle wheel as secondary building unit.
• Activated 1 was employed in catalysis (cyanosilylation and isomerization).
• 1 shows strong antiferromagnetic coupling in the Cu2(L)2(dmf)2 units.
• 1 exhibits ligand-based luminescence (S1 → S0 transition of the aromatic units).

The functionalized binaphthyl derivative (S)-4,4′-bis(4-carboxyphenyl)-2,2′-bis(diphenylphosphinoyl)-1,1′-binaphthyl (H2L) was employed as linker in the synthesis of the chiral CuII-based two-dimensional network {[Cu2(L)2(dmf)2]·H2O·9 dmf}n (1). Single-crystal X-ray analysis showed a two-dimensional structure with a copper paddle wheel as secondary building unit. One dmf molecule is additionally axially coordinated to each Cu cation. A lamellar structure results consisting of alternating [Cu2(L)2(dmf)2]n and solvent (dmf, H2O) layers. According to DTA/TG measurements the coordinated dmf molecules are released at about 320 °C, followed by decomposition around 460 °C. Magnetic susceptibility measurements on 1 indicate strong antiferromagnetic coupling between the two metal centers in Cu2(L)2(dmf)2. Compound 1 exhibits ligand-based luminescence, assigned to the S1 → S0 transition of the aromatic units. Moreover, the emission spectrum of 1 is blueshifted in comparison to H2L, due to different dihedral angles within the respective structures. Activated 1 (heating to 300 °C under vacuum for 3 h) showed low activity in the catalytic cyanosilylation of benzaldehyde (up to 27.1% conversion) and the isomerization of α-pinene oxide to campholenic aldehyde (up to 15.5% conversion).

The two-dimensional chiral CuII-based coordination polymer {[Cu2(L)2(dmf)2]·H2O·9 dmf}n (1) with a copper-based paddle wheel as secondary building unit was synthesized from the functionalized binaphthyl derivative (S)-4,4′-bis(4-carboxyphenyl)-2,2′-bis-(diphenylphosphinoyl)-1,1′-binaphthyl (H2L) and copper(II) nitrate in dmf/water. Magnetic susceptibility measurements on 1 indicate strong antiferromagnetic coupling between the two metal centers in Cu2(L)2(dmf)2. Moreover, 1 exhibits ligand-based luminescence, assigned to the S1 → S0 transition of the aromatic units.Figure optionsDownload as PowerPoint slide