Efficient Red Organic Light Emitting Diodes of Nona Coordinate Europium Tris(ß-Diketonato) Complexes Bearing 4'-Phenyl-2,2':6',2''-Terpyridine.

Two novel nona-coordinated Eu(III) complexes [Eu(btfa)3 (Ph-TerPyr)] (Eu-1) and [Eu(NTA)3 (Ph-TerPyr)] (Eu-2) have been synthesized and characterized. The structure of the complexes was elucidated by density functional theory (DFT) methods. The experimental photophysical properties of the complexes were investigated and complemented with theoretical calculations. Effective energy transfer (ET) pathways for the sensitized red luminescence is discussed. The complexes were tested as emitting layers (EML) in organic light emitting diodes (OLEDs). At the optimum doping concentration of 4 wt.%, the double-EML OLEDs of Eu-1 exhibited red electroluminescence (EL) with an EQE of 4.0 % and maximum brightness (B)=1179 cd/m2 , maximum current efficiency (ηc )=5.64 cd/A, and maximum power efficiency (ηp )=4.78 lm/W at the current density (J) of 10 mA/cm2 . Interestingly, the double-EML OLEDs of Eu-2 at the optimum concentration of 3 wt.%, displayed an outstanding EL performance with EQE of 7.32 % and B=838 cd/m2 , ηc =10.19 cd/A and ηp =10.33 lm/W at J=10 mA/cm2 . The EL performance of this device is among the best reported for devices incorporating a europium complex as a red emitter.

Are the Absorption Spectra of Doxorubicin Properly Described by Considering Different Tautomers?

The elucidation of the action of doxorubicin (DOX) has been considered a challenge for cancer therapy. Using theoretical approaches, we investigated the structure and electronic properties of DOX as a function of pH, which we thought likely to be related to the influence of its tautomers. Regarding the relative stabilities among the tautomers, the results obtained from PM6 were the most similar to those obtained from DFT. The theoretical absorption spectrum for each tautomeric species simply showed a single absorption peak located around 400 nm, in contrast to the experimental absorption spectra in the literature that showed four absorption bands. The experimental evidence was properly explained by considering four tautomeric conformers of DOX. The spectroscopic study of the deprotonated tautomers also suggested the presence of four deprotonated tautomers at more basic pH values. The spectrum at pH 10.08 can be explained by the presence of protonated and deprotonated doxorubicin species.

Lanthanide Contraction in Lanthanide Organic Frameworks: A Theoretical and Experimental Study.

In this work, the lanthanide (Ln) contraction phenomenon has been analyzed for three-dimensional structures in the solid state. We chose to study an isostructural series of lanthanide organic frameworks (LOFs) of formula [Ln2(C4H4O4)3(H2O)2]n·H2O and 14 crystallographic structures (except promethium complex). The analysis of Ln contraction was made by analyzing the sum of all Ln-O bond lengths and the sum of all O-O distances, for the oxygen atoms of the coordination polyhedra, calculated with different semiempirical quantum mechanical models. The ∑Ln-O and ∑O-O for this LOF can be fit to a second-order polynomial. Based on the crystallographic structures, it is concluded that the phenomenon of Ln contraction is observed. Our results also suggest that the semiempirical Sparkle/PM3 and Sparkle/RM1 models reproduce the Ln contraction phenomenon well, and similar fits were obtained for ∑Ln-O and ∑O-O bond lengths.

Estimating the Individual Spectroscopic Properties of Three Unique EuIII Sites in a Coordination Polymer.

We isolated a coordination polymer with the formula [Eu3(3,5-dcba)9(H2O)(dmf)3]·2dmf, with three unique EuIII coordination sites in the asymmetric unit, with the EuIII ions bridged by 3,5-dichlorobenzoato (3,5-dcba) ligands. The coordination polymer crystallized in the triclinic space group P1̅ with unit cell dimensions a = 12.4899(15), b = 16.326(2), and c = 25.059(3) Å, α = 84.271(3)°, ß = 84.832(3)°, and γ = 68.585(3)° and V = 4725.2(10) Å3. The characteristic 5D0 → 7F J ( J = 0-4) EuIII transitions were observed upon ligand-centered excitation. Emission lifetimes of 0.825 ± 0.085 and 1.586 ± 0.057 ms were observed and were attributed to the sites with coordination of water or dimethylformamide (dmf) molecules to each ion, respectively. Through a combination of spectroscopy and calculations, we determined the photophysical properties of each unique EuIII site. Energy-transfer rates ligand → EuIII were determined for each unique site using the overlapped polyhedra method. The rates depend on the coordinated water molecules and the different donor-acceptor distances. The two sites without coordinated water molecules and shortest donor-acceptor distance display the fastest energy-transfer rate ligand → EuIII, whereas the site with coordinated water molecules and longest donor-acceptor distance displays the slowest energy-transfer rate. Donor-acceptor distances were estimated computationally and were confirmed by calculating the frontier orbitals in the asymmetric units of the polymer using density functional theory.

LUMPAC lanthanide luminescence software: Efficient and user friendly.

In this study, we will be presenting LUMPAC (LUMinescence PACkage), which was developed with the objective of making possible the theoretical study of lanthanide-based luminescent systems. This is the first software that allows the study of luminescent properties of lanthanide-based systems. Besides being a computationally efficient software, LUMPAC is user friendly and can be used by researchers who have no previous experience in theoretical chemistry. With this new tool, we hope to enable research groups to use theoretical tools on projects involving systems that contain lanthanide ions.

Unusual photoluminescence properties of the 3D mixed-lanthanide-organic frameworks induced by dimeric structures: a theoretical and experimental approach.

The present work describes a complementary experimental and theoretical investigation of the spectroscopic properties of the four isostructural 3D Ln-MOFs (wherein PDC = pyrazole-3,5-dicarboxylate, [La2(PDC)3(H2O)4]·2H2O (1), [(La0.9Eu0.1)2(PDC)3(H2O)4]·2H2O (2), [(La0.9Tb0.1)2(PDC)3(H2O)4]·2H2O (3) and [(La0.9Eu0.5Tb0.5)2(PDC)3(H2O)4]·2H2O (4)). The experimental data and theoretical calculations show that the singular photophysical properties presented by these Ln-MOFs are induced by strong interaction between the Ln(3+) ions.

Water-soluble Tb3+ and Eu3+ complexes with ionophilic (ionically tagged) ligands as fluorescence imaging probes.

This article describes a straightforward and simple synthesis of ionically tagged water-soluble Eu(3+) and Tb(3+) complexes (with ionophilic ligands) applied for bioimaging of invasive mammal cancer cells (MDA-MB-231). Use of the task-specific ionic liquid 1-methyl-3-carboxymethyl-imidazolium chloride (MAI·Cl) as the ionophilic ligand (ionically tagged) proved to be a simple, elegant, and efficient strategy to obtain highly fluorescent water-soluble Eu(3+) (EuMAI) and Tb(3+) (TbMAI) complexes. TbMAI showed an intense bright green fluorescence emission selectively staining endoplasmic reticulum of MDA-MB-231 cells.

Theoretical methodologies for calculation of Judd-Ofelt intensity parameters of polyeuropium systems.

When Judd-Ofelt intensity parameters of polynuclear compounds with asymmetric centers are calculated using the current procedure, the results are inconsistent. The problem arises from the fact that the experimental intensity parameters cannot be determined for each asymmetric polyhedron, and this precludes the individual theoretical adjustment. In this study, we then propose three different methods for calculation of these parameters of polyeuropium systems. The first, named the centroid method, proposes the calculation considering the center of the dimeric system as the half distances between the two europium centers. The second method, called the overlapped polyhedra method, proposes the calculation considering the overlapping of both europium polyhedra, and the last one, the individual polyhedron method, proposes the use of theoretical mean values of charge factors and polarizabilities associated with each europium-ligand atom bond to calculate the intensity parameters. One symmetric polyeuropium system and one asymmetric system were assessed by using the three methods. Among the methods assessed, the one based on the overlapped polyhedra produced more consistent results for the study of both kinds of systems.

Synthesis and characterization of the europium(III) pentakis(picrate) complexes with imidazolium countercations: structural and photoluminescence study.

Six new lanthanide complexes of stoichiometric formula (C)(2)[Ln(Pic)(5)]--where (C) is a imidazolium cation coming from the ionic liquids 1-butyl-3-methylimidazolium picrate (BMIm-Pic), 1-butyl-3-ethylimidazolium picrate (BEIm-Pic), and 1,3-dibutylimidazolium picrate (BBIm-Pic), and Ln is Eu(III) or Gd(III) ions--have been prepared and characterized. To the best of our knowledge, these are the first cases of Ln(III) pentakis(picrate) complexes. The crystal structures of (BEIm)(2)[Eu(Pic)(5)] and (BBIm)(2)[Eu(Pic)(5)] compounds were determined by single-crystal X-ray diffraction. The [Eu(Pic)(5)](2-) polyhedra have nine oxygen atoms coordinated to the Eu(III) ion, four oxygen atoms from bidentate picrate, and one oxygen atom from monodentate picrate. The structures of the Eu complexes were also calculated using the sparkle model for lanthanide complexes, allowing an analysis of intramolecular energy transfer processes in the coordination compounds. The photoluminescence properties of the Eu(III) complexes were then studied experimentally and theoretically, leading to a rationalization of their emission quantum yields.

Theoretical spectroscopic study of europium tris(bipyridine) cryptates.

A series of europium cryptates are studied, using semiempirical methods to predict electronic and spectroscopic properties. The results are compared with theoretical (DFT) and experimental results published by Guillaumont and co-workers (ChemPhysChem2007, 8, 480). Triplet energies calculated by semiempirical methods have errors similar to those obtained by TD-DFT methodology but hundreds of times faster. Moreover, the semiempirical results not only reproduce well the experimental values but also help explain the low values of quantum efficiency observed for these complexes.

Single component white-OLEDs derived from tris(ß-diketonato) europium(III) complexes bearing the large bite angle N

Two new organo-europium complexes (OEuCs) [Eu(tfac)3(TB-Im)] (Eu1) [Eu(hfac)3(TB-Im)] (Eu2) incorporating fluorinated (hexafluoroacetylacetone; Hhfaa) or hemi-fluorinated (trifluoroacetylacetone; Htfac) ß-diketones together with the large bite angle N^N ligand (2-(4-thiazolyl)benzimidazole; TB-Im) have been synthesized and characterized. The structure of the complexes has been established by single crystal X-ray diffraction (SC-XRD) analysis and shows that the coordination sphere is composed of a EuO6N2 core (octacoordinated). Continuous shape measures (CShMs) revealed that the geometry around Eu(III) is trigonal dodecahedral with approximate D2d-symmetry. Efficient red emission is observed for both the complexes in solution with a fairly large photoluminescence quantum yield (PLQY (QLEu) = 39.00-47.00%). Furthermore, by utilizing the experimental photoluminescence (PL) data and theoretical modelling employing density functional theory (DFT) in conjunction with LUMPAC, energy transfer (ET) and back energy transfer rates were calculated, and an ET mechanism for the sensitized PL is proposed and discussed in detail. Finally, the complexes were used as an emitting layer (EML) to fabricate 20 organic light emitting diodes (OLEDs) by varying the doping concentration. Interestingly, both the complex-based OLEDs at 4 wt% doping concentration display white electroluminescence (EL) with the brightness (B) = 100.5-364.1 cd m-2 at very low turn-on voltage (Vturn-on) = 3.9-4.6 V. The overall electroluminescence performance of Eu1 and Eu2 is higher than that of the reported europium based single component white-OLEDs.

Theoretical and experimental spectroscopic investigation of new Eu(III)-FOD complex containing 2-pyrrolidone ligand.

The preparation and photoluminescent properties of the new [Eu(FOD)3(2-Pyr)2] complex (FOD = 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octadionate; 2-Pyr = 2-pyrrolidone) are reported. The obtained complex was characterized by elemental analysis, complexometric titration using EDTA, infrared spectroscopy, and single-crystal X-ray diffraction studies. The coordination polyhedron of the complex is described as a distorted square antiprismatic with both 2-Pyr monodentate ligands coordinated to Eu(III) via the oxygen atoms, in neutral form, while the three FOD molecules are coordinated in the anionic form. Structural modeling at the PBE1PBE/SVP/MWB52 level of theory provided a geometry in excellent agreement with the one obtained experimentally. Spectroscopy properties such as intensity parameters (Ω2 and Ω4), radiative emission rate (Arad), and chemical partition of Arad for [Eu(FOD)3(2-Pyr)2] and [Eu(FOD)3(H2O)2] were calculated by using the QDC model with help of the semiempirical wavefunctions. The modeling of the ligand-to-metal energy transfer for both complexes was performed, allowing to obtain the theoretical emission quantum yield and to characterize the most relevant molecular orbitals involved.

Utilization of a Pt(ii) di-yne chromophore incorporating a 2,2'-bipyridine-5,5'-diyl spacer as a chelate to synthesize a green and red emitting d-f-d heterotrinuclear complex.

A new heterotrinuclear (d-f-d) complex [Eu(btfa)31c] (btfa = 4,4,4-trifluoro-1-phenyl-1,3-butanedione and 1c = [(Ph)(Et3P)2Pt-C[triple bond, length as m-dash]C-R-C[triple bond, length as m-dash]C-Pt(Et3P)2(Ph)] (R = 2,2'-bipyridine-5,5'-diyl) has been synthesized by utilizing the N,N-donor sites of the organometallic chromophore. The complex was characterized by analytical and spectroscopic methods. Photophysical properties of the complex were analysed in detail using both steady-state and time-resolved emission and excitation spectroscopy. The optical absorption spectrum of the complex is dominated by the spin allowed π-π* transitions of the btfa and 1c units in the UV-visible region (200-418 nm) and thus is excitable over a wide range of wavelengths across the UV into the visible region of the electromagnetic spectrum. The complex displays typical red Eu(iii) emission when excited at 345 nm. However, it also shows green emission when excited at 464 nm and, thus could be an interesting candidate for full colour display applications. The change in the colour could be a result of the high value of the energy back-transfer rate (6.73 × 105 s-1) from the triplet state of the organometallic chromophore to the 5D1 state of Eu(iii). Judd-Ofelt (J-O) intensity parameters (Ω2 and Ω4), radiative (AR), non-radiative (AR) decay rates and intrinsic quantum yield (Q) have been calculated.

Correction: Utilization of a Pt(II) di-yne chromophore incorporating a 2,2'-bipyridine-5,5'-diyl spacer as a chelate to synthesize a green and red emitting d-f-d heterotrinuclear complex.

Correction for 'Utilization of a Pt(ii) di-yne chromophore incorporating a 2,2'-bipyridine-5,5'-diyl spacer as a chelate to synthesize a green and red emitting d-f-d heterotrinuclear complex' by Idris Juma Al-Busaidi et al., Dalton Trans., 2021, DOI: 10.1039/d0dt04198j.

Ultrasound-guided fine needle aspiration biopsy of thyroid nodules performed in the office.

INTRODUCTION: The majority of thyroid fine needle aspiration biopsies (FNAB) today are performed in the office freehand by palpation. Not infrequently, patients are sent to radiology for an ultrasound-guided FNAB (USG-FNB). Real-time ultrasound (US) allows for continuous visualization of the needle during insertion and sampling. Historically, USG-FNAB has been a procedure performed by a radiologist in a designated radiology suite. In more recent years, with the development of smaller more portable US machines, there has been a push for clinicians other than radiologists to perform the procedure. OBJECTIVE: To evaluate the accuracy and specimen adequacy of thyroid FNAB performed in the office under US guidance by one senior otolaryngologist. METHODS: Retrospective chart review of 203 patients who underwent ultrasound-guided USG-FNA of the thyroid gland between September, 2005, to February, 2007, in the office setting by one senior otolaryngologist. Specimens were reviewed onsite at the time of biopsy for cellular adequacy by a cytotechnologist. RESULTS: A total of 203 patients, 176 females and 27 males, underwent USG-FNA of the thyroid gland. The average age of the females was 52 years, and 59.4 years for the males. A total of 271 FNA biopsies were performed. Two hundred and twenty FNAB were satisfactory specimens (81.2%), 26 were unsatisfactory (9.6%), and 25 (9.2%) were limited due to blood clotting or hypocellularity. Of the FNA specimens that had enough cells to evaluate, 159 were benign, 48 were indeterminate for malignacy, and 13 were positive for malignancy. Of the nodules biopsied, 143 were greater than 1.5 cm (average 2.59 cm, unsatisfactory rate 12.6%), and 128 were less than 1.5 cm (average 1.21 cm, unsatisfactory rate 6.3%). In 44 patients, one or more nodule was biopsied at the same office visit. DISCUSSION: Thyroid US is an indispensable tool in the workup and diagnosis of thyroid disease. It may be used to help identify pathology and physical features suspicious for malignancy and guide FNAB of suspicious nodules. The availability of an office US machine allows the referring physician to perform a service that is normally done in a different department. This ultimately frees up time for both the patient and physician and reduces health care costs by eliminating extra office visits. More importantly, it allows the primary physician to be more knowledgeable and hands on with the patient's overall care. CONCLUSION: This study shows that a trained physician may perform a USG-FNA of the thyroid gland in the office with results comparable to that in the radiology literature.

Hypothyroidism following hemithyroidectomy for benign nontoxic thyroid disease.

Hypothyroidism following hemithyroidectomy for benign nontoxic thyroid disease is an underappreciated phenomenon. Up until recently, it was common practice for physicians to place post-hemithyroidectomy patients on thyroid suppression therapy during the immediate postoperative period. That practice began to fall out of favor as a result of two developments: (1) the publication of data that put into question the efficacy of levothyroxine therapy for preventing recurrent disease or thyroid growth and (2) a heightened awareness of the morbidity associated with levothyroxine. We conducted a retrospective chart-review study of 58 patients with benign nontoxic thyroid disease who had undergone hemithyroidectomy from 1994 through 2003 at one institution. Of these 58 patients, 14 (24.1%) had become hypothyroid after surgery, including 7 who had been so diagnosed 1 month postoperatively and 6 at 2 months. The remaining 44 patients were euthyroid. The mean preoperative serum thyroid-stimulating hormone (TSH) levels in the hypothyroid and the euthyroid groups were 2.39 and 1.07 microlU/ml, respectively-a statistically significant difference (p < 0.0001). A tissue diagnosis consistent with chronic inflammation (lymphocytic thyroiditis or Hashimoto's thyroiditis) was found in 50.0% of the hypothyroid patients, compared with only 6.8% of the euthyroid patients-again, a significant difference (p < 0.001). No significant difference was seen between the two grqups with respect to age, sex, or the weight of the resected gland. We conclude that hypothyroidism after hemithyroidectomy is not an uncommon occurrence. Apparent risk factors include a high mean preoperative serum TSH level and tissue pathology consistent with chronic inflammation. It may be wise to follow patients with these identifiable risk factors more closely during the postoperative period; monitoring should include scheduled serial serum TSH draws.

Parameters for the RM1 Quantum Chemical Calculation of Complexes of the Trications of Thulium, Ytterbium and Lutetium.

The RM1 quantum chemical model for the calculation of complexes of Tm(III), Yb(III) and Lu(III) is advanced. Subsequently, we tested the models by fully optimizing the geometries of 126 complexes. We then compared the optimized structures with known crystallographic ones from the Cambridge Structural Database. Results indicate that, for thulium complexes, the accuracy in terms of the distances between the lanthanide ion and its directly coordinated atoms is about 2%. Corresponding results for ytterbium and lutetium are both 3%, levels of accuracy useful for the design of lanthanide complexes, targeting their countless applications.

Chemical Partition of the Radiative Decay Rate of Luminescence of Europium Complexes.

The spontaneous emission coefficient, Arad, a global molecular property, is one of the most important quantities related to the luminescence of complexes of lanthanide ions. In this work, by suitable algebraic transformations of the matrices involved, we introduce a partition that allows us to compute, for the first time, the individual effects of each ligand on Arad, a property of the molecule as a whole. Such a chemical partition thus opens possibilities for the comprehension of the role of each of the ligands and their interactions on the luminescence of europium coordination compounds. As an example, we applied the chemical partition to the case of repeating non-ionic ligand ternary complexes of europium(III) with DBM, TTA, and BTFA, showing that it allowed us to correctly order, in an a priori manner, the non-obvious pair combinations of non-ionic ligands that led to mixed-ligand compounds with larger values of Arad.

The impact of resident involvement on otolaryngology surgical outcomes.

OBJECTIVES/HYPOTHESIS: Intraoperative experience is an essential element of surgical training, but has the potential to impact patient outcomes. The purpose of this study was two-fold: 1) to evaluate the effect of resident involvement on morbidity and mortality following otolaryngology procedures and 2) to examine the influence of resident training level on the same outcomes. STUDY DESIGN: Retrospective cohort study. METHODS: This study reviewed 2,320,920 patients captured in the 2005 to 2012 National Surgical Quality Improvement Program databases to identify surgical otolaryngology cases. Outcomes of interest included surgical complications, medical complications, and mortality. Cases with and without resident involvement were propensity matched (caliper = 0.2) to account for nonrandomized assignment, and data were subject to multivariate logistic regression analyses. RESULTS: Residents participated in 38.4% of the 20,307 cases identified. Cases with resident involvement demonstrated longer operative duration (178.8 minutes vs. 80.1 minutes, P < .001), increased surgical complexity (23.5 relative value units [RVU] vs. 12.4 RVU, P < .001) and greater overall morbidity burden. Logistic regression analyses of the matched cohort revealed that resident participation did not independently increase morbidity (odds ratio [OR] = 0.969, P = .751) or mortality (OR = 0.893, P = .758). A separate logistic regression analysis of the unmatched cohort using resident postgraduate year showed that training level did not confer differential risk to patients. CONCLUSIONS: Our data indicate that resident involvement does not increase the risk of morbidity or mortality, and that trainees are being assigned to appropriate cases for their level of experience. These findings suggest that the contemporary paradigm of graduate otolaryngology surgical education does not negatively impact patient outcomes. LEVEL OF EVIDENCE: 2c Laryngoscope, 126:602-607, 2016.