Synthesis, crystal structure and luminescent properties of novel lanthanide complexes with CAPh type ligand diphenyl-N-benzoylamidophosphate and bidentate nitrogen donors

Herein we report the synthesis and investigations of the new lanthanide coordination compounds [LnL3bipy] (Ln1) and [LnL3phen] (Ln2) with carbacylamidophosphate type ligand diphenyl-N-benzoylamidophosphate (HL = [PhCONHPO(OPh)2]) and additional ligands 2,2′-bipyridine and 1,10-phenantroline. The obtained complexes were characterized by means of X-Ray, thermal gravimetric analysis, IR, 1H NMR, UV absorption spectroscopy and luminescence spectroscopy at 298 and 77 K. The X-ray diffraction analysis of Eu1 and Eu2 shows that the complexes crystalize in monoclinic crystal system, P 21/n space group. Efficient energy transfer from organic ligands after their excitation sensitizes the lanthanide interior emission from 5D0 or 5D4 levels of EuIII or TbIII respectively, leading to a strong metal-centered luminescence with decay time 1.5–2.0 ms. Intrinsic quantum yields (QLnLn) for europium complexes found to be equal 78 (Eu1) and 70% (Eu2). Overall QY equals 46 and 42% respectively.