A substituted pyridazine was used to construct a family of mononuclear heteroleptic complexes [Ln(tta)₃(dppn)], Ln = Pr–Lu; Htta = thenoyltrifluoroacetone; dppn = 3,6-di(2-pyridyl)pyridazine. All the complexes obtained were characterized by CHN elemental analysis, NMR spectroscopy, ESI mass spectrometry, FTIR spectroscopy and single crystal X-ray analysis. The photophysical properties of lanthanide complexes were carefully investigated, and the dppn ligand was found to act as a chromophore centre to sensitize metal-centred emission of the Nd, Sm, Eu, and Yb complexes under UV excitation. It has been shown that a powder sample of the Eu complex can contain two isomers with somewhat different symmetries of the environment of the metallocentre. The mechanism for the emission of luminescent Nd, Sm, Eu, and Yb complexes was investigated by TDDFT calculations and the results confirmed the conclusion made on the basis of experimental data regarding the likely pathway of energy transfer from the chromophore centre to the emissive level of Ln(III).

Phosphine ligands, containing chromophore substituents –π-spacer–NPh₂ (π-spacer = biphenyl, L1; naphthalene-ethynylphenyl, L2; and ethynyl-(phenylethynyl)anthracene, L3), were used to generate the corresponding gold(I) alkynyl complexes Au1–Au3 (alkynyl = ethynylphenyl-2,2′-bipyridine, epbpy). These compounds demonstrate intense fluorescence, which originates from the bipolar donor–π-acceptor systems of coordinated phosphines with negligible contribution from the epbpy fragment. Due to the charge transfer characteristic of the excited state, Au1–Au3 reveal significant emission solvatochromism (particularly discernible for Au2, 428 nm in cyclohexane → 580 nm in acetonitrile). The bipyridine moiety of Au1–Au3 was utilized for binding these metalloligands to the {Eu(tta)₃} red emitter (tta = 3-thenoyltrifluoroacetonate) to give a family of novel dyads Au1Eu–Au3Eu. Incomplete energy transfer from L1–L3 to lanthanide ions, which are primarily sensitized by diketonate ligands, leads to dual luminescence. Analogous to the parent complexes Au1–Au3, the fluorescence component of the dyads is highly sensitive to the solvent polarity that provides great opportunities for color tuning, including white light generation.

Abiotic synthesis of nucleobases and amino acids is of critical importance as it sheds light on potential prebiotic chemical reactions. During thermal decomposition of formamide in vacuum conditions, purine, cytosine, adenine, hypoxanthine, uracil, pterin, urea, urocanic acid, glycine, alanine and norvaline were detected. The compounds were obtained without catalyst by heating at 100–180 °C or microwave heating of formamide. Reaction network of self-catalyzed chemical reactions is suggested, showing how from only one parent molecule, nucleobases, urea and the amino acid glycine can be produced. The reaction pathways are theoretically determined using SCS-MP2 calculations. Communicated by Ramaswamy H. Sarma