A series of new anionic lanthanide(III) complexes with the general formula NEt 4 [LnL 4 ] (1-Ln; HL = dimethyl[(4-methylphenyl)sulfonyl]amidophosphate; Ln = La, Nd, Eu), were synthesized and characterized by IR, UV− vis, and NMR spectroscopies, the differential scanning calorimetry method, thermogravimetric and X-ray analysis, and photoluminescence measurements. Single-crystal structures of NEt 4 [EuL 4 ] (1-Eu) were determined at 293 and 100 K and evidenced the single-crystal-to-single-crystal phase transition. Both phases are in the monoclinic crystal system in centrosymmetric groups of the same Laue class. The room temperature structure is in C2/c (No. 15), while lowtemperature structure is in the P2 1 /c (No. 14) space groups. The coordination environment geometry around the central europium(III) ion is a distorted square antiprism in both polymorphs, while the peripheral methoxy and tolyl groups show different orientations. This phenomenon indicates the occurrence of a thermally driven second-order phase transition during the cooling−heating process. The europium(III) complex exhibits an unusual emission spectrum, clearly dominated by the 5 D 0 − 7 F 4 bands, and an emission decay time equaling 3.5 ms, being among the highest values known for europium coordination compounds.

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A new bis-chelating scorpionate type CAPh ligand and its lanthanide complexes in solid state and solution.

As a continuation of studies of carbacylamidophosphate based coordination compounds a series of the lanthanide and yttrium complexes of general formula PPh4[LnL4], where Ln=La, Nd, Tb and Y; L– = [CCl3(CO)N(PO)(OCH3)2]– has been synthesized. The resulting compounds were characterized by means of thermal gravimetric analysis, IR, 1H NMR, UV-Vis absorption and luminescent spectroscopy. It was found, that each lanthanide ion of the [Ln(L)4]– complex anion is bonded to two oxygen atoms belonging to the phosphoryl and carboxyl groups of four bidentate chelated ligands, completing coordination number of lanthanide ion to eight. Analysis of signals integral intensity in the investigated NMR spectra of coordination compounds PPh4[LnL4] (Ln = La, Y) indicates the molar ratio of dimethyl-N-trichloroacetylamidophosphate ligand and tetraphenylphosphonium cation as 4:1, which corresponds to the proposed structure of the complexes. According to the absorption spectroscopy investigations data there is one type of lanthanide sites in the complexes. Low symmetry of lanthanide ion coordination environment was concluded from bands ratio in the europium complex luminescence spectrum. From the TGA analysis the stability of the coordination compounds till 160°C can be concluded. It was shown that tetraphenylphosphonium cation sensitizes europium ion emission and photo-excitation of PPh4[EuL4] complex by UV light results in red Eu3+ centered luminescence with dominating band of 5D0–7F2 transition in the spectrum and decay time equal one and a half millisecond.