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The tetradentate ligand, merging a carbazole unit with high triplet energy and dimethoxy bipyridine, renowned for its exceptional quantum efficiency in coordination with metals like Pt, is expected to demonstrate remarkable luminescent properties. However, instances of tetradentate ligands such as bipyridine-based pyridylcarbazole derivatives remain exceptionally scarce in the current literature. In this study, we developed a tetradentate ligand based on carbazole and 2,3′-bipyridine and successfully complexed it with Pt(II) ions. This novel compound (1) serves as a sky-blue phosphorescent material for use in light-emitting diodes. Based on single-crystal X-ray analysis, compound 1 has a distorted square-planar geometry with a 5/6/6 backbone around the Pt(II) core. Bright sky-blue emissions were observed at 488 and 516 nm with photoluminescent quantum yields of 34% and a luminescent lifetime of 2.6 μs. TD-DFT calculations for 1 revealed that the electronic transition was mostly attributed to the ligand-centered (LC) charge transfer transition with a small contribution from the metal-to-ligand charge transfer transition (MLCT, ~14%). A phosphorescent organic light-emitting device was successfully fabricated using this material as a dopant, along with 3′-di(9H-carbazol-9-yl)-1,1′-biphenyl (mCBP) and 9-(3′-carbazol-9-yl-5-cyano-biphenyl-3-yl)-9H-carbazole-3-carbonitrile (CNmCBPCN) as mixed hosts. A maximum quantum efficiency of 5.2% and a current efficiency of 15.5 cd/A were obtained at a doping level of 5%.

In the title compound, [Ag(CF3SO3)(C10H6F2N2)2], the AgI centre adopts a highly distorted trigonal–planar coordination environment resulting from its coordination by one O atom of the trifluoromethanesulfonate anion and the pyridine N atoms of two crystallographically independent 2′,6′-difluoro-2,3′-bipyridine ligands, which display very similar conformations to one another. Pairwise Ag...O–SO2CF3− [Ag...O = 2.8314 (14) Å] interactions and intermolecular C—H...O interactions between inversion-related units lead to the formation of an eight-membered cyclic dimer in which the silver atoms are separated by 6.2152 (3) Å. In the crystal, the dimers are linked through C—H...O hydrogen bonds, halogen...π and weak π–π stacking interactions, resulting in the formation of a three-dimensional supramolecular network. The title compound exhibits a strong and broad emission band from 400 nm to 550 nm in solution and its photoluminescence quantum efficiency is estimated to be ca 0.2, indicating that the title compound could have applications as an emitting material in organic light-emitting diodes (OLEDs).

The title compound, [Pt(C21H12F2N3O)Cl], crystallizes with two crystallographically independent molecules (A and B) in the asymmetric unit, which adopt similar conformations. The PtII atoms in both molecules adopt distorted square-planar geometries, coordinated by one C and two N atoms from the tridentate 2′,6′-difluoro-6-[3-(pyridin-2-yloxy)phenyl]-2,3′-bipyridine ligand and a chloride anion: the C and Cl atoms are trans. In the crystal, C—H...Cl/F hydrogen bonds, F...π and weak π–π stacking interactions between adjacent A and B molecules and between pairs of inversion-related B molecules lead to the formation of a two-dimensional supramolecular network lying parallel to the ab plane. The sheets are stacked along the c-axis direction and linked by F...π and weak π–π stacking interactions between pairs of inversion-related A molecules, forming a three-dimensional supramolecular network. The photoluminescence quantum efficiency of the title compound in the blue–green region of the visible region (λmax = 517 and 544 nm) is estimated to be ∼0.2–0.3, indicating that the title compound could be a suitable candidate as the emitting material in organic light-emitting diode (OLED) applications.

Abstract To provide a unique opportunity for on‐chip scaled bioelectronics, a symmetrically gated metal‐oxide electric double layer transistor (EDLT) with ion‐gel (IG) gate dielectric and simple in‐plane Corbino electrode architecture is proposed. Using amorphous indium‐gallium‐zinc oxide (a‐IGZO) semiconductor and IG dielectric layers, low‐voltage driven EDLTs with high ionotronic effects can be realized. More importantly, in contrast to the conventional asymmetric rectangular EDLTs which can cause non‐uniform potential variation in the active channel layer and eventually degrade the sensing performance, the new symmetrical in‐plane type EDLTs achieve high and spatially uniform ion responsive behaviors. The symmetrically gated a‐IGZO EDLTs exhibited a responsivity of 129.4% to 5 ppm mercury (Hg2+) ions which are approximately three times higher than that with conventional electrode structure (responsivity of 38.5%). To confirm the viability of the new device architectures and the findings, the detailed mechanism of the symmetric gating effects in the in‐plane EDLTs with a variety of electrical characterization and 3D fine element analysis simulations is also discussed.

In the title compound, C29H22N4O3, the carbazole system forms a dihedral angle of 68.45 (3)° with the mean plane of the bipyridine ring system. The bipyridine ring system, with two methoxy substituents, is approximately planar (r.m.s. deviation = 0.0670 Å), with a dihedral angle of 7.91 (13)° between the planes of the two pyridine rings. Intramolecular C—H...O/N hydrogen bonds may promote the planarity of the bipyridyl ring system. In the pyridyl-substituted carbazole fragment, the pyridine ring is tilted by 56.65 (4)° with respect to the mean plane of the carbazole system (r.m.s. deviation = 0.0191 Å). In the crystal, adjacent molecules are connected via C—H...O/N hydrogen bonds and C—H...π interactions, resulting in the formation of a three-dimensional (3D) supramolecular network. In addition, the 3D structure contains intermolecular π–π stacking interactions, with centroid–centroid distances of 3.5634 (12) Å between pyridine rings. The title compound exhibits a high energy gap (3.48 eV) and triplet energy (2.64 eV), indicating that it could be a suitable host material in organic light-emitting diode (OLED) applications.

In the title compound, C24H22N4O4, the four pyridine rings are tilted slightly with respect to each other. The dihedral angles between the inner and outer pyridine rings are 12.51 (8) and 9.67 (9)°, while that between inner pyridine rings is 20.10 (7)°. Within the molecule, intramolecular C—H...O and C—H...N contacts are observed. In the crystal, adjacent molecules are linked by π–π stacking interactions between pyridine rings and weak C—H...π interactions between a methyl H atom and the centroid of a pyridine ring, forming a two-dimensional layer structure extending parallel to the ac plane. Hirshfeld surface analysis and two-dimensional fingerprint plots indicate that the most important contributions to the crystal packing are from H...H (52.9%) and H...C/C...H (17.3%) contacts.

The title molecule, C38H42N4O4, displays a helical structure induced by the combination of the C—C—C—C torsion angle [−10.8 (2)°] between two 2,3′-bipyridyl units attached to the 1,2-positions of the central benzene ring and consecutive connections between five aromatic rings through the meta- and ortho-positions. Intramolecular C—H...π interactions between an H atom of a pyridine ring and the centroid of a another pyridine ring contributes to the stabilization of the helical structure. In the crystal, weak C—H...π interactions link the title molecules into a two-dimensional supramolecular network extending parallel to the ac plane, in which the molecules with right- and left-handed helical structures are alternately arranged. Hirshfeld surface analysis and two-dimensional fingerprint plots indicate that the molecular packing is dominated by van der Waals interactions between neighbouring H atoms, as well as by C—H...π interactions. One isopropoxyl group is disordered over two sets of sites [occupancy ratio 0.715 (5):0.285 (5)].

In the solvated title compound, [Ir(C12H11N2)2(C11H19O2)]·CH3CO2C2H5, the IrIII ion adopts a distorted octahedral coordination environment resulting from its coordination by two C,N-chelating 2,6-dimethyl-3-(pyridin-2-yl)pyridin-4-yl ligands and one O,O′-chelating 2,2,6,6-tetramethylheptane-3,5-dionate ligand. The C,N-chelating ligands are perpendicular to each other [dihedral angle between the least-squares planes = 87.86 (5)°] and are arranged in a cis-C,C′ and trans-N,N′ fashion. In the crystal, pairwise C—H...π interactions between inversion-related IrIII complexes are present, forming a dimeric structure. The title complex shows bright bluish–green emission with good quantum efficiency in solution at room temperature.

The title compound, C12H6N4, crystallizes with four independent molecules (A, B, C and D) in the asymmetric unit. The dihedral angles between the two pyridine rings in each molecule are 25.25 (8)° in A, 5.51 (9)° in B, 11.11 (9)° in C and 16.24 (8)° in D. In the crystal, molecules A and B are linked by C—H...N hydrogen bonds to form layers extending parallel to the ab plane, while molecules C and D are linked by C—H...N hydrogen bonds forming –C–D–C–D– chains propagating along the b-axis direction. The layers and the chains are stacked alternately along the c axis through offset π–π and C[triple-bond]N...π [N-to-pyridine-centroid distance = 3.882 (2) Å] interactions, resulting in the formation of a supramolecular framework.

The asymmetric unit of the title compound, [Ir(C17H11F2N2)3]·0.5CH3(CH2)4CH3·0.5CH2Cl2, comprises one IrIII atom, three 2,6-difluoro-3-[5-(2-fluorophenyl)pyridin-2-yl]pyridin-4-yl ligands and half each of an n-hexane and a dichloromethane solvent molecule located about crystallographic inversion centres. The IrIII atom displays a distorted octahedral coordination geometry, having three C,N-chelating 2,6-difluoro-3-[5-(2-fluorophenyl)pyridin-2-yl]pyridin-4-yl ligands arranged in a meridional manner. The IrIII ion lies almost in the equatorial plane [deviation = 0.0069 (15) Å]. The average distance [2.041 (3) Å] of Ir—C bonds is slightly shorter than that [2.076 (3) Å] of Ir—N bonds. A variety of intra- and intermolecular C—H...F and C—H...π hydrogen bonds, as well as intermolecular C—F...π interactions, contribute to the stabilization of the molecular and crystal structures, and result in the formation of a two-dimensional network parallel to the ab plane. No interactions between n-hexane solvent molecules and the other components in the title compound are observed.

The reaction of mercury(II) chloride with bis(pyridin-3-ylmethyl)sulfane (L, C12H12N2S) in methanol afforded the title crystalline coordination polymer catena-poly[[dichloridomercury(II)]-μ-bis(pyridin-3-ylmethyl)sulfane-κ2N:N′], [HgCl2L]n. The asymmetric unit consists of one HgII cation, one L ligand and two chloride anions. Each HgII ion is coordinated by two pyridine N atoms from separate L ligands and two chloride anions. The metal adopts a highly distorted tetrahedral geometry, with bond angles about the central atom in the range 97.69 (12)–153.86 (7)°. Each L ligand bridges two HgII ions, forming an infinite –(Hg–L)n– zigzag chain along the b axis, with an Hg...Hg separation of 10.3997 (8) Å. In the crystal, adjacent chains are connected by intermolecular C—H...Cl hydrogen bonds, together with Hg—Cl...π interactions [chloride-to-centroid distance = 3.902 (3) Å], that form between a chloride anion and the one of the pyridine rings of L, generating a two-dimensional layer extending parallel to (101). These layers are further linked by intermolecular C—H...π hydrogen bonds, forming a three-dimensional supramolecular network.

The asymmetric unit of the title compound, [Co(NO3)2L]n, L = N-(pyridine-2-ylmethyl)pyridine-3-amine (C11H11N3), contains one CoII centre, two nitrate anions and one L ligand in which the Cpy—C—N—Cpy moiety adopts a trans conformation with a torsion angle of −173.1 (3) Å. The coordination geometry of the CoII atom is a distorted pentagonal bipyramid. One amine N atom from the L ligand and four O atoms from two η2-nitrato ligands form the basal plane and two pyridyl N atoms from two symmetry-related L ligands occupy the apical positions [N—Co—N = 171.86 (11)°]. The displacement of the central CoII atom from the basal plane (r.m.s. deviation = 0.085 Å) is 0.1491 (12) Å. Each bidentate nitrate group is bonded asymmetrically to the cobalt atom in an chelating fashion. The CoII ions are linked by the L ligands to form a zigzag chain propagating along the c-axis direction. Within the zigzag chain, C—H...O hydrogen bonds between the ligands and the nitrate anions are observed. Adjacent zigzag chains are connected via intermolecular π–π stacking interactions [centroid-to-centroid distance = 3.844 (2) Å] between the pyridine rings together with N/C—H...O hydrogen bonds.

The asymmetric unit in the title compound, [Ag(C11H11N3)]PF6·2CH3CN or {[AgL]·PF6·2CH3CN}n, L = N-(pyridin-3-ylmethyl)pyridin-3-amine, comprises one AgI atom, one L ligand, two acetonitrile solvent molecules and one PF6− anion disordered over two orientations in a 0.567 (11):0.433 (11) ratio. Each AgI atom is coordinated by two pyridine N atoms from two L ligands in a slightly distorted linear coordination geometry [N—Ag—N = 170.55 (8)°]. Each L ligand bridges two AgI ions, resulting in the formation of a zigzag chain propagating along the [101] direction. In the crystal, Ag...Ag contacts [3.3023 (5) Å] and intermolecular π–π stacking interactions [centroid-to-centroid distance = 3.5922 (15) Å] between the pyridine rings link these chains into a corrugated layer parallel to the (\overline{1}01) plane. The layers are stacked with a separation of 10.4532 (5) Å, and acetonitrile solvent molecules and PF6− anions as guests are intercalated between the layers. The layers are connected through several N/C—H...F hydrogen bonds and P—F...π interactions [F...ring centroid = 3.241 (8) Å] between the layer and the intercalated guests and between the intercalated guests, forming a three-dimensional supramolecular network.

Background Colorectal cancer (CRC) is one of the most common malignancies worldwide. Approximately 10%–15% of the CRC cases have defective DNA mismatch repair (MMR) genes. Although the high level of microsatellite instability status is a predictor of favorable outcome in primary CRC, little is known about its frequency and importance in secondary CRC. Immunohistochemical staining (IHC) for MMR proteins (e.g., MLH1, MSH2, MSH6, and PMS2) has emerged as a useful technique to complement polymerase chain reaction (PCR) analyses. Methods In this study, comparison between the MMR system of primary CRCs and paired liver and lung metastatic lesions was done using IHC and the correlation with clinical outcomes was also examined. Results Based on IHC, 7/61 primary tumors (11.4%) showed deficient MMR systems, while 13/61 secondary tumors (21.3%) showed deficiencies. In total, 44 cases showed proficient expression in both the primary and metastatic lesions. Three cases showed deficiencies in both the primary and paired metastatic lesions. In 10 cases, proficient expression was found only in the primary lesions, and not in the corresponding metastatic lesions. In four cases, proficient expression was detected in the secondary tumor, but not in the primary tumor. Conclusions Although each IHC result and the likely defective genes were not exactly matched between the primary and the metastatic tumors, identical results for primary and metastatic lesions were obtained in 77% of the cases (47/61). These data are in agreement with the previous microsatellite detection studies that used PCR and IHC.

Background Mycobacterial culture is the gold standard test for diagnosing tuberculosis (TB), but it is time-consuming. Polymerase chain reaction (PCR) is a highly sensitive and specific method that can reduce the time required for diagnosis. The diagnostic efficacy of PCR differs, so this study determined the actual sensitivity of TB-PCR in tissue specimens. Methods We retrospectively reviewed 574 cases. The results of the nested PCR of the IS6110 gene, mycobacterial culture, TB-specific antigen-induced interferon-γ release assay (IGRA), acid-fast bacilli (AFB) staining, and histological findings were evaluated. Results The positivity rates were 17.6% for PCR, 3.3% for the AFB stain, 22.2% for mycobacterial culture, and 55.4% for IGRA. PCR had a low sensitivity (51.1%) and a high specificity (86.3%) based on the culture results of other studies. The sensitivity was higher (65.5%) in cases with necrotizing granuloma but showed the highest sensitivity (66.7%) in those with necrosis only. The concordance rate between the methods indicated that PCR was the best method compared to mycobacterial culture, and the concordance rate increased for the methods using positive result for PCR or histologic features. Conclusions PCR of tissue specimens is a good alternative to detect tuberculosis, but it may not be as sensitive as previously suggested. Its reliability may also be influenced by some histological features. Our data showed a higher sensitivity when specimens contained necrosis, which indicated that only specimens with necrosis should be used for PCR to detect tuberculosis.

In the title compound, {[Ag(C29H25N3)2]NO3·CH3OH·H2O}n, the AgI cation is four-coordinated by two pyridine N atoms and two imidazole N atoms from four individual 4-(1-(5′-isopropyl-[1,1′:3′,1′′-terphenyl]-2′-yl)-1H-imidazol-2-yl)pyridine (i-pro-pyim) ligands. This gives rise to a highly distorted tetrahedral geometry with bond angles falling in the range 100.33 (19)–122.76 (19)°. Two crystallographically independent i-pro-pyim ligands (A and B) adopt very similar conformations to one another, such that the dihedral angles between the pyridyl and imidazolyl rings in the two ligands are 40.7 (3) and 42.2 (3)°, respectively. Each i-pro-pyim ligand binds two symmetry-related Ag+ cations, leading to the formation of 14-membered cyclic dimers, in which the AgI atoms are separated by 6.963 (2) Å for the Ag–A2–Ag dimer and 7.020 (2) Å for Ag–B2–Ag. These cyclic dimers are alternately connected to each other by sharing AgI atoms, resulting in the formation of a looped-chain structure extending along the [100] direction. Moreover, adjacent looped chains are connected by intermolecular π–π interactions [centroid-to-centroid distance = 3.689 (4) Å], giving rise to the formation of a two-dimensional supramolecular network propagating parallel to (110). Several intermolecular C—H...O and O—H...O hydrogen bonds further contribute to the stabilization of the crystal structure.

Background: Atypia of undetermined significance (AUS) is a category that encompasses a heterogeneous group of thyroid aspiration cytology. It has been reclassified into two subgroups based on the cytomorphologic features: AUS with cytologic atypia and AUS with architectural atypia. The nuclear characteristics of AUS with cytologic atypia need to be clarified by comparing to those observed in Hashimoto thyroiditis and benign follicular lesions. Methods: We selected 84 cases of AUS with histologic follow-up, 24 cases of Hashimoto thyroiditis, and 26 cases of benign follicular lesions. We also subcategorized the AUS group according to the follow-up biopsy results into a papillary carcinoma group and a nodular hyperplasia group. The differences in morphometric parameters, including the nuclear areas and perimeters, were compared between these groups. Results: The AUS group had significantly smaller nuclear areas than the Hashimoto thyroiditis group, but the nuclear perimeters were not statistically different. The AUS group also had significantly smaller nuclear areas than the benign follicular lesion group; however, the AUS group had significantly longer nuclear perimeters. The nuclear areas in the papillary carcinoma group were significantly smaller than those in the nodular hyperplasia group; however, the nuclear perimeters were not statistically different. Conclusions: We found the AUS group to be a heterogeneous entity, including histologic follow-up diagnoses of papillary carcinoma and nodular hyperplasia. The AUS group showed significantly greater nuclear irregularities than the other two groups. Utilizing these features, nuclear morphometry could lead to improvements in the accuracy of the subjective diagnoses made with thyroid aspiration cytology.

The asymmetric unit in the title compound, {[Ag(C12H12N2S)]·NO3}n or {[AgL]·NO3}n, L = bis(pyridin-3-ylmethyl)sulfane, consists of an AgI cation bound to a pyridine N atom of an L ligand and an NO3− anion that is disordered over two orientations in an 0.570 (17):0.430 (17) occupancy ratio. Each AgI cation is coordinated by two pyridine N atoms from adjacent L ligands to form an infinite zigzag chain along [110]. In addition, each AgI ion binds to an S donor from a third L ligand in an adjacent parallel chain, resulting in the formation of a twisted-ribbon type of double-stranded chain propagating along the [110] or [1-10] directions. The AgI atom is displaced out of the trigonal N2S coordination plane by 0.371 (3) Å because of interactions between the AgI cation and O atoms of the disordered nitrate anions. Intermolecular π–π stacking interactions [centroid-to-centroid distance = 3.824 (3) Å] occur between one pair of corresponding pyridine rings in the double-stranded chain. In the crystal, the double-stranded chains are alternately stacked along the c axis with alternate stacks linked by intermolecular π–π stacking interactions [centroid-to-centroid distance = 3.849 (3) Å], generating a three-dimensional supramolecular architecture. Weak intermolecular C—H...O hydrogen bonds between the polymer chains and the O atoms of the nitrate anions also occur.

In the title compound, [Ir(C11H8N)2(C18H14N)], the IrIII ion adopts a distorted octahedral coordination environment defined by three C,N-chelating ligands, one stemming from a 2-(4-phenyl-5-methylpyridin-2-yl)phenyl ligand and two from 2-(pyridin-2-yl)phenyl ligands, arranged in a facial manner. The IrIII ion lies almost in the equatorial plane [deviation = 0.0069 (15) Å]. In the crystal, intermolecular π–π stacking interactions, as well as intermolecular C—H...π interactions, are present, leading to a three-dimensional network.

The asymmetric unit of the title compound, {[AgL]·BF4·0.5CH3OH}n, L = N-(pyridin-4-ylmethyl)pyridine-3-amine, C11H11N3, contains one AgI ion, one ligand L, one tetrafluoridoborate anion disordered over two orientations in a 0.669 (13):0.331 (13) ratio and one half of a methanol solvent molecule situated on an inversion center. Each AgI ion is coordinated by two N atoms from two L ligands in a distorted linear geometry [N—Ag—N = 174.70 (19)°]. Each L ligand bridges two AgI ions, thus forming polymeric helical chains propagating in [010]. In the crystal, Ag...Ag [3.3369 (10) Å] and π–π interactions between the aromatic rings [centroid-to-centroid distance = 3.676 (4) Å] link these chains into layers parallel to (10-1). Ag...F and weak N(C)—H...F interactions further consolidate the crystal packing.

The asymmetric unit of the title compound, [Pt(C10H5F2N2)(C5H7O2)], comprises one PtII atom, one 2,6-difluoro-2,3-bipyridine ligand and one acetylacetonate anion. The PtII atom adopts a distorted square-planar coordination geometry, being C,N-chelated by the 2,6-difluoro-3-(pyridin-2-yl)pyridin-4-yl ligand and O,O′-chelated by the pentane-2,4-dionate ligand. The two pyridine rings of the bipyridine ligand are approximately coplanar, making a dihedral angle of 1.2 (2)°. A variety of intra- and intermolecular C—H...O and C—H...F hydrogen bonds, as well as π–π interactions [centroid–centroid distances = 4.337 (3) and 3.774 (3) Å] contribute to the stabilization of the molecular and crystal structures, and result in the formation of a three-dimensional supramolecular framework.

The title molecule, [Ir(C14H14FN2O)2(C5H7O2)], is located on a twofold rotation axis, which passes through the IrIII atom and the central C atom of the pentane-2,4-dionate anion. The IrIII atom adopts a distorted octahedral coordination geometry, being C,N-chelated by two 2-tert-butoxy-6-fluoro-3-(pyridin-2-yl)pyridin-4-yl ligands and O,O′-chelated by the pentane-2,4-dionato ligand. The bipyridinate ligands, which are perpendicular to each other [dihedral angle between the two least-squares planes = 89.95 (5)°], are arranged in a cis-C,C′ and trans-N,N′ fashion relative to the central metal cation. Intramolecular C—H...O and C—H...N hydrogen bonds and intermolecular C—H...F hydrogen bonds as well as π—π interactions between neighbouring pyridine rings [centroid–centroid distance 3.680 (1) Å] contribute to the stabilization of the molecular and crystal structure, respectively.