Tricarbonyltechnetium(I) and -rhenium(I) complexes with N '-thiocarbamoylpicolylbenzamidines

N,N-Dialkylamino(thiocarbonyl)-N'-picolylbenzamidines react with (NEt4)(2)[M(CO)(3)X-3] (M = Re, X = Br: M = Tc, X = Cl) under formation of neutral [M(CO)(3)L] complexes in high yields. The monoanionic NNS ligands bind in a facial coordination mode and can readily be modified at the (CS)(NRR2)-R-1 moiety. The complexes [Tc-99(CO)(3)(L-PyMor)] and]Re(CO)(3)(L)] (L = L-PyMor, L-PyEt) were characterized by X-ray diffraction. Reactions of [Tc-99m(CO)(3)(H2O)(3)](+) with the N'-thiocarbamoylpicolylbenzamidines give the corresponding Tc-99m complexes. The ester group in HLPyCOOEr allows linkage between biomolecules and the metal core. (C) 2012 Elsevier Ltd. All rights reserved.

Luminous efficiency enhancement of PVK based OLEDs with fac-[ClRe(CO)(3)(bpy)]

The luminous efficiency of organic light-emitting diodes based on poly(N-vinylcarbazole), PVK, was improved by adding fac-[ClRe(CO)(3)(bpy)], bpy = 2,2`-bipyridine, to PVK host. Emissive layers with various Re(I) complex/host ratio were employed and optoelectronic properties were compared with the single PVK device. The single PVK device exhibits a characteristic electroluminescence with blue emission, lambda(max) 420 nm, assigned to the PVK excimer. On the other hand, the intense and broad band at lambda(max) 580 nm of the Re(I) complex/PVK OLEDs is ascribed to the metal-to-ligand charge transfer excited state emission of fac-[ClRe(CO)(3)(bpy)]. At 30 V, the device luminous efficiency increased from 16 mcd/A for the single PVK device to 211 mcd/A for the 11% (w/w) Re(I) complex/PVK OLED, in which fac-[ClRe(CO)(3)(bpy)] acts as an electron-trap in PVK films. The device current is space-charge limited and exhibits typical emissive layer thickness dependence. (C) 2011 Elsevier B.V. All rights reserved.

Optomechanical trans-to-cis and cis-to-trans isomerization and unusual photophysical behavior of fac-[Re(CO)(3)(phen)(CNstpy)](+)

Unusual high photoassisted quantum yields for cis-to-trans (phi(254) (nm) = 0.27 +/- 0.05) isomerization of CNstpy coordinated to fac-[Re(CO)(3)(phen)(CNstpy)](+) were determined along with trans-to-cis ones (phi(313) (nm)= 0.58 +/- 0.02; phi(365) (nm)= 0.61 +/- 0.06; phi(404) (nm) = 0.42 +/- 0.02). Additionally, in contrast to other similar rhenium(I) complexes, the cis photoproduct is quasi non-emissive and comparable to the trans-complex. The cis-to-trans photoisomerization is due to the deactivation from the ILcis-CNstpy excited state in competition to the usual (MLCTRe -> phen)-M-3 luminescence. These efficient cis to trans and trans to cis photoisomerization can be conveniently used in light powered molecular machines. (C) 2012 Elsevier B.V. All rights reserved.