Microwave-assisted one-pot synthesis of new ionic iridium complexes of [Ir(bzq)2(N^N)]+A- type and their selected electroluminescent properties

Iridium C,N-cyclometalated complexes with an ionic structure are considered to be promising candidates for application in host/guest solid-state phosphorescent single-layer devices because the employment of such dopants offers the possibility of reducing their concentration in organic matrices as well as allows obtaining organic light emitting devices (OLEDs) with interesting emission parameters. We report herein a methodology enabling the synthesis of cyclometalated ionic iridium(iii) complexes of the type [Ir(C^N)₂(N^N)]⁺A^- according to a three-component one-pot strategy involving the acceleration of the reaction via microwave irradiation. The developed protocol allowed efficient synthesis of a series of new cationic iridium(iii) coordination derivatives, which were isolated and spectroscopically characterized, while the structures of two of them were determined by the X-ray method. Moreover, the iridium(iii) derivatives were subjected to the cyclic voltammetry studies in order to determine the energies of the HOMO and LUMO levels as well as to estimate their electrochemical properties and to predict some electronic properties. Additionally, the ONIOM calculation scheme that was used to predict HOMO-LUMO gaps for the studied Ir(iii) complexes showed a good correlation between the experimental and calculated values. In order to determine the influence of the structure and nature of the ancillary ligand on the location of the maximum emission band, the photophysical properties of the synthesized iridium complexes were characterized. Finally, the selected compounds were used as emitters for the construction of polymer light emitting diodes (PLEDs) based on a poly(N-vinylcarbazole)/2-(4-tert-butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole (PVK/PBD) matrix. The highest luminance, above 10 000 cd m^-2, was recorded for the device containing only 1.0 wt% of [Ir(bzq)₂(1,10-phenanthroline)]⁺PF₆^- in the PVK/PBD. The fabricated PLEDs exhibit current efficiency in the range of 1.0 to 2.2 cd A^-1.

Radioactivity in breast milk following 111In-octreotide

The concentration of 111In in breast milk in a 10 weeks postpartum woman was measured at daily intervals up to 72 h post-injection of 5.3 mCi (196 MBq) of 111In-octreotide (OctreoScan). Radiation surveys were also performed at the breast surface. The disappearance of 111In from the breast milk exhibited a bi-exponential pattern with a maximum concentration of 14.2 nCi (0.54 kBq) per 125 ml feeding at 4 h, with lower values thereafter. External surveys at the breast surface also showed a bi-exponential decrease with time. The maximum reading was 8.3 mrem x h(-1) (0.83 mSv x h(-1)) immediately after administration. This rapidly decreased due to 85% urinary excretion by 24 h. Breast milk tracer content and external surveys at the breast surface were determined at 3 h intervals for up to 10 days. If a newborn is nursed for the first 10 days, the internal and external dose equivalents would be 22.97 mrem (0.23 mSv) and 27.86 mrem (0.28 mSv), respectively, for a total of 50.83 mrem (0.5 mSv). The patient was instructed to resume breast-feeding on day 10, when the newborn received a total dose equivalent of 1.55 mrem (0.016 mSv). This dosimetry is based on a very conservative assumption, whereby 100% of the ingested 111In becomes systemic and follows adult bio-behaviour. Oral indium has been shown to be poorly absorbed from the gastrointestinal tract (approximately 0.15%), which suggests the infant's dose could be considerably less. Based on this case report, mathematical relationships are presented for determining the nursing infant's dose equivalent from internal and external exposures relative to time after the maternal administration of 111In-octreotide (OctreoScan).