Novel N^C^N-cyclometallated platinum complexes with acetylide co-ligands as efficient phosphors for OLEDs

Two new cyclometallated platinum(ii) complexes have been prepared that incorporate a terdentate N^C^N-coordinating ligand and a monodentate acetylide co-ligand. The complexes, namely [PtL 3-CC-C 6H 3F 2] and [PtL 6-CC-C 6H 3F 2] (where HL 3 = 5-methyl-1,3-di(2-pyridyl) benzene; HL 6 = 5-mesityl-1,3-di(2-pyridyl)benzene; H-CC-C 6H 3F 2 = 3,5-difluorophenylacetylene), were prepared by ligand metathesis from the corresponding chloro complex PtL nCl. Both of the new complexes are intensely luminescent in solution, displaying quantum yields superior to PtL nCl. OLEDs have been prepared using the new compounds as phosphorescent emitters. Although both lead to efficient devices, the best electroluminescence quantum efficiencies are obtained with the derivative of HL 6, having the mesityl group on the cyclometallated phenyl ring. The superior performance with this complex can be rationalised in terms of the greater steric hindrance that serves to reduce aggregate-induced quenching

CONSIDERAZIONI A PROPOSITO DI UN CASO DI SCHWANNOMA SOLITARIO BENIGNO DELL'ESOFAGO

MONDUZZI ED

Tuning the colour and efficiency in OLEDs by using amorphous or polycrystalline emitting layers

We investigated the nature of the emissive states in newly synthesized cyclometallated Pt complexes containing a chelating 2-pyridyl tetrazolate (2-PTZ) ligand, namely Pt(ppy)(2-PTZ), and Pt(F2ppy)(2-PTZ) as a solid-state phosphor, by examining their structural properties versus their phosphorescence (PH) and electroluminescence (EL) characteristics. It is found that the observed tuning of both PH and EL spectra, their red shift and shortening decay with increasing concentration in the complex blends are due to the competition between three emissive states: monomer, excimer and dimer. The pure dimer emission appeared in neat films, reaching a high PH quantum yield of about 75% and external EL efficiency approaching 10% for the OLED based on the neat Pt(F2ppy)(2-PTZ) complex film as an emitting layer (EML). X-ray diffraction proved the high structural order of the latter thin film. These findings have a direct impact on the design of a new OLED generation based on single phosphor multi-emission controlled by the structural order degree of the EML. © The Royal Society of Chemistry

From red to near infra-red OLEDs : the remarkable effect of changing from X = \u2013Cl to \u2013NCS in a cyclometallated [Pt(N?C?N)X] complex {N?C?N = 5-mesityl-1,3-di-(2-pyridyl)benzene}

[PtL 6X] {X = Cl or NCS and L 6 = 5-mesityl-1,3-di(2- pyridyl)-benzene} display similar luminescence in solution but, in the solid state, the packing of the molecules is different, with short Pt efPt interactions for X = NCS, leading to a red-shifted emission band. The effect has been used to generate OLEDs that emit squarely in the NIR region (855 nm)

Tuning the colour and efficiency in OLEDs by using amorphous or polycrystalline emitting layers

We investigated the nature of the emissive states in newly synthesized cyclometallated Pt complexes containing a chelating 2-pyridyl tetrazolate (2-PTZ) ligand, namely Pt(ppy)(2-PTZ), and Pt(F2ppy)(2-PTZ) as a solid-state phosphor, by examining their structural properties versus their phosphorescence (PH) and electroluminescence (EL) characteristics. It is found that the observed tuning of both PH and EL spectra, their red shift and shortening decay with increasing concentration in the complex blends are due to the competition between three emissive states: monomer, excimer and dimer. The pure dimer emission appeared in neat films, reaching a high PH quantum yield of about 75% and external EL efficiency approaching 10% for the OLED based on the neat Pt(F2ppy)(2-PTZ) complex film as an emitting layer (EML). X-ray diffraction proved the high structural order of the latter thin film. These findings have a direct impact on the design of a new OLED generation based on single phosphor multiemission controlled by the structural order degree of the EML

T([20]) repeat in the 3'-untranslated region of the MT1X gene: a marker with high sensitivity and specificity to detect microsatellite instability in colorectal cancer

PURPOSE: Stratifying patients defective in mismatch repair (dMMR) with high microsatellite instability (MSI-H) in colorectal cancer (CRC) is of increasing relevance and may provide a more tailored approach to CRC adjuvant therapy. Here, we describe the discovery of a new MSI marker for colorectal cancer located in the 3'-untranslated region (3'UTR, T20 mononucleotide repeat) of the metallothionein 1X gene (MT1XT20). METHODS: We studied 340 consecutive CRCs using three multiplexed polymerase chain reactions amplifying BAT25, BAT26, TGFBR2, MybT22, BAT40, MT1XT20, NR21, NR24, CAT25, D2S123, D5S346, D17S250, D18S58, CSF1PO, D7S820, and D18S51. Fragments length was evaluated by automated capillary electrophoresis. RESULTS: Based on the NCI/ICG-HNPCC criteria for MSI classification, 40 CRCs were found to be MSI-high (11.8%), 46 (13.5%) CRCs were MSI-low, and 254 CRCs (74.7%) were stable (MSS). MT1XT20 showed very high sensitivity (97.3%) comparable to BAT26 (97.5%) and CAT25 (97.1%) and the best specificity (100%) as well as MybT22 and CAT25. Indeed, MT1XT20 instability was detected in 36 out of 37 cases (97.3%) of MSI-high colorectal cancers, whereas no MT1XT20 alterations were observed in 254 MSS or in 46 MSI-low cases. On the contrary, BAT40 was found to be unstable in 8/46 MSI-low cases, BAT25 in 6/46, BAT26 4/46, NR21 1/46, and NR24 in 1/45. CONCLUSIONS: Our results suggest that MT1XT20 represents a sensitive and specific marker for MSI testing and could be included in a complete set of MSI markers for the confident identification of familial or sporadic dMMR patients in CRCs

Microsatellite instabilityDNA testing in routinely processed colorectal carcinomas: correlation with clinicopathologic and survival data in 340 consecutive cases

Background. Colorectal cancer (CRC) is characterized by a multistep progression of genetic errors. Two different pathways are identified, that of chromosomal instability (CIN) and the microsatellite instability (MSI) pathway. Widespread microsatellite instability (MSI high, MSI-H phenotype) is present in 10-20% of sporadic colorectal cancers and characterizes patients with the inherited Lynch syndrome (Hereditary non polyposis colorectal cancer, HNPCC). MSI-H tumors have distinctive pathologic features, and are believed to behave less aggressively when compared with tumors that lack microsatellite instability (microsatellite stable, MSS) or that show instability at a few loci (microsatellite low, MSI-L phenotype). Methods. We studied 340 consecutive CRCs for MSI using multiplexed polymerase chain reaction (PCR) for 12 microsatellite markers followed by capillary electrophoresis with a DNA sequencer. DNA was extracted from routinely processed formalin-fixed tissue. All surgical specimens underwent routine histopathological analysis for grading and staging. Tumors were considered MSI-H when 4 or more of the 12 loci were mutated , MSI-L when 1-3 loci were mutated and MSS when no mutations were identified. Results. 40 CRCs were MSI-H (11,5%), 45 CRCs were MSI-L (13,5%) and 255 CRCs were MSS (75%). Correlation with clinicopathologic features confirms previous findings that show how MSI-H CRCs are more common in the right colon, display poorly differentiated histologic features and show prominent lymphocytic infiltration when compared with MSI-L and MSS tumors. Survival analysis after a median follow-up of 45 months shows that MSI-H tumors have a better prognosis in patients with stage 1 and 2 disease, but the prognosis is considerably worse for stage 3 and 4 disease (p<0.01) that received standard chemotherapy treatment. Conclusions. MSI-H CRCs show distinctive clinical and pathological features. In our series patients survival depended on tumor stage at presentation. The results of the study argue for MSI testing on routinely processed CRCs

A nationwide audit of the use of radiotherapy for rectal cancer in Italy.

BACKGROUND: There is good evidence that radiotherapy is beneficial in advanced rectal cancer, but its application in Italy has not been investigated. METHODS: We conducted a nationwide survey among members of the Italian Society of Colo-Rectal Surgery (SICCR) on the use of radiation therapy for rectal cancer in the year 2005. Demographic, clinical and pathologic data were retrospectively collected with an online database. Italy was geographically divided into 3 regions: north, center and south which included the islands. Hospitals performing 30 or more surgeries per year were considered high volume. Factors related to radiotherapy delivery were identified with multivariate analysis. RESULTS: Of 108 centers, 44 (41%) responded to the audit. We collected data on 682 rectal cancer patients corresponding to 58% of rectal cancers operated by SICCR members in 2005. Radiotherapy was used in 307/682 (45.0%) patients. Preoperative radiotherapy was used in 236/682 (34.6%), postoperative radiotherapy in 71/682 (10.4%) cases and no radiotherapy in 375 (55.0%) cases. Of the 236 patients who underwent preoperative radiotherapy, only 24 (10.2%) received short-course radiotherapy, while 212 (89.8%) received long-course radiotherapy. Of the 339 stage II-III patients, 159 (47%) did not receive any radiotherapy. Radiotherapy was more frequently used in younger patients (P < 0.0001), in patients undergoing abdominoperineal resection (APR) (P < 0.01) and in the north and center of Italy (P < 0.001). Preoperative radiotherapy was more frequently used in younger patients (P < 0.001), in large volume centers (P < 0.05), in patients undergoing APR (P < 0.005) and in the north-center of Italy (P < 0.05). CONCLUSION: Our study first identified a treatment disparity among different geographic Italian regions. A more systematic audit is needed to confirm these results and plan adequate interventions