Ligand Effects on the Emission Characteristics of Molecular Eu(II) Luminescence Thermometers.

Discrete molecular organometallic europium(II) complexes are promising functional materials due to their ability to behave as highly sensitive band-shift luminescence thermometers. Furthering our understanding of the design principles salient to the emission behavior of such systems is important for developing them in this emerging application. To this end, a series of pseudo--symmetric organometallic europium(II) complexes bearing systematically varying ligand sets were synthesized and characterized to probe the influence of subtle structural modification on their optical properties.

Expanding the series of alkali metal plumbolyl complexes to Na and K.

Herein we detail the straightforward and scalable synthesis of sodium and potassium complexes of the 2,5-bis(-butyldimethylsilyl)-3,4-diphenylplumbolyl dianion (Pbl). Their solid-state structures were found to comprise either monomeric solvates or coordination polymers depending on the alkali metal ion and crystallization medium. These complexes were readily prepared with high yields and purity compared to known routes to the dilithium congener of Pbl and are well-positioned to serve as convenient precursors for salt metathesis-type reactions leading to metal complexes of the understudied Pbl ligand.

Toward Opto-Structural Correlation to Investigate Luminescence Thermometry in an Organometallic Eu(II) Complex.

Lanthanide-based luminescent materials have unique properties and are well-studied for many potential applications. In particular, the characteristic 5d → 4f emission of divalent lanthanide ions such as Eu allows for tunability of the emissive properties via modulation of the coordination environment. We report the synthesis and photoluminescence investigation of pentamethylcyclopentadienyleuropium(II) tetrahydroborate bis(tetrahydrofuran) dimer (), the first example of an organometallic, discrete molecular Eu band-shift luminescence thermometer.

Bis[pyrrolyl Ru(ii)] triads: a new class of photosensitizers for metal-organic photodynamic therapy.

A new family of ten dinuclear Ru(ii) complexes based on the bis[pyrrolyl Ru(ii)] triad scaffold, where two Ru(bpy) centers are separated by a variety of organic linkers, was prepared to evaluate the influence of the organic chromophore on the spectroscopic and photodynamic therapy (PDT) properties of the compounds. The bis[pyrrolyl Ru(ii)] triads absorbed strongly throughout the visible region, with several members having molar extinction coefficients () ≥ 10 at 600-620 nm and longer. Phosphorescence quantum yields ( ) were generally less than 0.

Synthesis, properties and reactivity of BCl aza-BODIPY complexes and salts of the aza-dipyrrinato scaffold.

The synthesis and characterisation of the BCl2-chelated complexes of both archetypal aza-dipyrrin sub-types are presented. A stepwise halogen exchange, leading to a mixed-halide Cl-B-F intermediate, is implicated in the conversion of F-aza-BODIPYs to Cl-aza-BODIPYs upon treatment with BCl3. The utility of the Cl-aza-BODIPY scaffold to facilitate substitutions at boron is demonstrated under mild conditions through treatment with aryl Grignard reagents.

Classifying donor strengths of dipyrrinato/aza-dipyrrinato ligands.

A parameter is reported by which to use C NMR chemical shifts to measure and predict the donor capabilities of N^N dipyrrinato and aza-dipyrrinato ligands chelating in L^X fashion. The results enable the rationalisation of the properties of these ligands and their complexes, as well as enable rational design incorporating both steric and electronic considerations when tuning to effect desired applications. Complexes containing these ligands are prevalent due to their desirable photophysical properties such as high chemical stability, resistance to photodegradation, strong absorbance, and ease of chemical modifiability.

Synthesis and reactivity of aza-dipyrrin alkali metal salts.

We report the lithium, sodium and potassium salts of aza-dipyrrins and detail their use as anionic aza-dipyrrinato ligand sources in complexation. Of the three types of alkali salts studied, those of lithium are found to be most useful as synthetic precursors. For example, they selectively afford heteroleptic aza-dipyrrinato zinc complexes which can be further modified via ligand exchange.