A novel type of cyclic P,N-ligands, pyridyl containing phospholanes, has been synthesized in a moderate yield by the reaction of primary phosphines with 1,4-dichlorobutane in a superbasic medium. A series of homo tetranuclear octahedral Cu4I4L2, dinuclear tetrahedral Cu2I2L3, and dinuclear "head-to-tail" Cu2I2L2 luminescent complexes with these ligands were obtained. All the compounds were characterized using a range of spectroscopic and computational techniques, and in the case of some Cu4I4L2 and Cu2I2L3 complexes, by single crystal X-ray diffraction. The structural diversity of the obtained complexes was reflected in their photophysical properties: phosphorescence spectra of the compounds display emission in broad spectral range of 471-615 nm. TD-DFT computations allow the assignment of a single emission band around 550 nm for Cu2I2L3 complexes and 471 nm for Cu2I2L2 complex to a vertical triplet-singlet transition from a metal-to-ligand and halide-to-ligand charge-transfer (3)(M + X)LCT excited state, whereas a second band at around 600 nm in the spectra of octahedral Cu4I4L2 complexes was assigned predominantly to Cu4I4 cluster-centered ((3)CC) excited state.

No abstract

Eight-membered cyclic functional bisphosphines, namely 1,5-di-aryl-3,7-di(2-pyridyl)-1,5-diaza-3,7-diphosphacyclooctanes (aryl=2-pyridyl, m-tolyl, p-tolyl, diphenylmethyl, benzyl, (R)-(+)-(α-methyl)benzyl), with 2-pyridyl substituents on the phosphorus atoms have been synthesized by condensation of 2-pyridylphosphine, formaldehyde, and the corresponding primary amine. The structures of some of these bisphosphines have been investigated by X-ray crystallography. The bisphosphines readily form neutral P,P-chelate complexes [(κ(2)-P,P-L)MCl2], cationic bis-P,P-chelate complexes [(κ(2)-P,P-L)2 M](2+), or a five-coordinate complex [(κ(2)-P,P-L)2 NiBr]Br. The electrochemical behavior of two of the nickel complexes, and their catalytic activities in electrochemical hydrogen evolution and hydrogen oxidation, including the fuel-cell test, have been studied.

Herein we report the synthesis of a stimuli-responsive binuclear AuIJI) complex based on the 1,5-bisIJptolyl)-3,7-bisIJpyridine-2-yl)-1,5-diaza-3,7-diphosphacyclooctane ligand, which is a novel template for the design of luminescent metal complexes. In the solid state, the complex obtained gives three different crystalline phases, which were characterized by XRD analysis. It was also found that the crystalline phases can be reversibly interconverted by recrystallization or solvent vapour treatment. The emission of these phases varies in the 500-535 nm range. Quite unexpectedly, the emission energy of these phases is mostly determined by the non-covalent interactions of the solvent molecules with the ligand environment, which have nearly no effect on the Au-Au interactions in the chromophoric centre. The complex obtained demonstrates thermo/solvatochromism to display greenish emission in a DCM matrix and blue emission in an acetone matrix at 77 K, in contrast to the blue emission of the phase containing a DCM molecule and greenish-yellow emission of the acetone solvate in a crystal cell at room temperature. The potentially important role of co-crystallized solvent molecules in the ligand-based emission of the complex obtained is supported by DFT calculations.

No abstract