Localised to intraligand charge-transfer states in cyclometalated platinum complexes: an experimental and theoretical study into the influence of electron-rich pendants and modulation of excited states by ion binding.

The neopentyl ester of 1,3-di(2-pyridyl)benzene-5-boronic acid (dpy-B) is a useful intermediate in the divergent synthesis of N;C;N-coordinating, 1,3-di(2-pyridyl)benzene ligands, HL(n), that carry aryl substituents at the 5-position of the central ring. The platinum(ii) complexes, PtL(n)Cl, of several such ligands have been prepared, incorporating pendant anisoles, arylamines, an oxacrown, and an azacrown, all of which are strongly luminescent in solution at 298 K. The emission of the complexes is partially quenched by oxygen, and all of the compounds are very efficient sensitisers of singlet oxygen.

Intramolecular excimers based on rigidly-linked platinum(II) complexes: intense deep-red triplet luminescence in solution.

By linking together two cyclometallated, N--C--N-coordinated platinum(II) complexes through a xanthene core, intense luminescence in the red region of the spectrum is achieved in solution at room temperature (lamda max = 690 nm, phi(lum) = 0.20, tau = 1.7 micros in CH2Cl2) due to the efficient formation of an intramolecular excimer.

Cyclometalated platinum(II) complexes of pyrazole-based, N=C=N-coordinating, terdentate ligands: the contrasting influence of pyrazolyl and pyridyl rings on luminescence.

1,3-Bis(1-pyrazolyl)-5-methyl-benzene, HL(2), undergoes cyclometalation at the C(2) position upon reaction with K(2)PtCl(4), to generate an N=C=N-coordinated complex, PtL(2)Cl. This compound is luminescent in degassed solution at 298 K, emitting in the blue region of the spectrum on the microsecond time scale (lambda(max) = 453 nm, tau = 4.0 micros, Phi(lum) = 0.

Complexation of the triphosphate anion: tuning the structure of cyclen based macrotricycles with 1,3-dimethylbenzene and 2,6-dimethylpyridine linkers. A potentiometric and NMR study.

The host-guest interaction between orthophosphate, pyrophosphate and triphosphate anions and three cyclen-based macrotricyclic ligands was investigated by potentiometric measurements and NMR spectroscopy. The ligands differ from one another by the nature of their spacers, which are 1,3-dimethylbenzene (TMC), 2,6-dimethylpyridine (TPyC) or a combination of the two (TMPyC). In aqueous solution, each ligand gave protonated species that further formed ternary complexes after binding with anions; these complexes were analyzed as a result of hydrogen bond formation and coulombic attraction between the organic host and the inorganic guest.

Host-guest interaction between cyclen based macrotricyclic ligands and phosphate anions. A potentiometric investigation.

The host-guest interaction between orthophosphate, pyrophosphate and triphosphate anions and three cyclen based macrotricyclic ligands possessing ortho- (TOC), meta- (TMC) and para-xylenyl (TPC) linkers was investigated by potentiometric measurements. The ternary species present in solution and their stability constants have been determined. The different behaviours are explained in terms of hydrogen bond formation and coulombic attraction between the organic host and the inorganic guest.

Cyclen based bis-macrocyclic ligands as phosphates receptors. A potentiometric and NMR study.

The host-guest interaction between orthophosphate, pyrophosphate and triphosphate anions and four cyclen based bis-macrocycles ligands possessing ortho-(BOC), meta-(BMC), para-xylenyl (BPC) or 2,6-pyridinyl (BPyC) linker was investigated by potentiometric measurements and NMR spectroscopy. Each ligand gave protonated species in aqueous solution that further formed ternary complexes after binding with anions; these complexes were analyzed as a result of hydrogen bond formation and Coulombic attraction between the organic host and the inorganic guest. The equilibrium constants for all the detected species are reported and the selectivity, illustrated with species distribution diagrams, is discussed.