The P1 protein of wheat yellow mosaic virus exerts RNA silencing suppression activity to facilitate virus infection in wheat plants.

Wheat yellow mosaic virus (WYMV) causes severe wheat viral disease in Asia. However, the viral suppressor of RNA silencing (VSR) encoded by WYMV has not been identified. Here, the P1 protein encoded by WYMV RNA2 was shown to suppress RNA silencing in Nicotiana benthamiana. Mutagenesis assays revealed that the alanine substitution mutant G175A of P1 abolished VSR activity and mutant Y10A VSR activity remained only in younger leaves. P1, but not G175A, interacted with gene silencing-related protein, N. benthamiana calmodulin-like protein (NbCaM), and calmodulin-binding transcription activator 3 (NbCAMTA3), and Y10A interacted with NbCAMTA3 only. Competitive Bimolecular fluorescence complementation and co-immunoprecipitation assays showed that the ability of P1 disturbing the interaction between NbCaM and NbCAMTA3 was stronger than Y10A, Y10A was stronger than G175A. In vitro transcript inoculation of infectious WYMV clones further demonstrated that VSR-defective mutants G175A and Y10A reduced WYMV infection in wheat (Triticum aestivum L.), G175A had a more significant effect on virus accumulation in upper leaves of wheat than Y10A. Moreover, RNA silencing, temperature, and autophagy have significant effects on the accumulation of P1 in N. benthamiana. Taken together, WYMV P1 acts as VSR by interfering with calmodulin-associated antiviral RNAi defense to facilitate virus infection in wheat, which has provided clear insights into the function of P1 in the process of WYMV infection.

An international, multicenter, survey-based analysis of practice and management of acute liver failure.

INTRODUCTION: Acute liver failure (ALF) is an acute liver dysfunction with coagulopathy and hepatic encephalopathy in a patient with no known liver disease. As ALF is rare and large clinical trials are lacking, the level of evidence regarding its management is low-moderate, favoring heterogeneous clinical practice. In this international multicenter survey study, we aimed to investigate the current practice and management of patients with ALF. METHODS: An online survey targeting physicians who care for patients with ALF was developed by the International Liver Transplantation Society ALF Special-Interest Group. The survey focused on management and liver transplantation (LT) practices of ALF. Survey questions were summarized overall and by geographic region. RESULTS: A total of 267 physicians completed the survey with a survey response rate of 21.36%. Centers from all continents were represented. More than 90% of physicians were specialized in either transplant hepatology/surgery or anesthesiology/critical care. Two hundred and fifty-two (94.4%) respondents' institutions offered LT. A total of 76.8% of respondents' centers had a dedicated liver- or transplant- intensive care unit (p<0.001). Median time to LT was within 48 hours in 12.7% of respondents' centers, 72 hours in 35.6%, one week in 37.6%, and more than one week in 9.6% (p<0.001). Deceased-donor liver graft (49.6%) was the most common type of graft offered. For consideration of LT, 84.8% of physicians used King's College Criteria and 41.6% used Clichy Criteria. Significant differences were observed between Asia, Europe, and North America for offering LT, number of LTs performed, volume of ALF patients, admission to a dedicated intensive care unit, median time to LT, type of liver graft, monitoring hepatic encephalopathy and intracranial pressure, management of coagulopathy, and utilization of different criteria for LT. DISCUSSION: In our study, we observed significant geographic differences in the practice and management of ALF. As ALF is rare multicenter studies are valuable to identify global practice.

Updated epithelial barrier dysfunction in chronic rhinosinusitis: Targeting pathophysiology and treatment response of tight junctions.

Tight junction (TJ) proteins establish a physical barrier between epithelial cells, playing a crucial role in maintaining tissue homeostasis by safeguarding host tissues against pathogens, allergens, antigens, irritants, etc. Recently, an increasing number of studies have demonstrated that abnormal expression of TJs plays an essential role in the development and progression of inflammatory airway diseases, including chronic obstructive pulmonary disease, asthma, allergic rhinitis, and chronic rhinosinusitis (CRS) with or without nasal polyps. Among them, CRS with nasal polyps is a prevalent chronic inflammatory disease that affects the nasal cavity and paranasal sinuses, leading to a poor prognosis and significantly impacting patients' quality of life. Its pathogenesis primarily involves dysfunction of the nasal epithelial barrier, impaired mucociliary clearance, disordered immune response, and excessive tissue remodeling. Numerous studies have elucidated the pivotal role of TJs in both the pathogenesis and response to traditional therapies in CRS. We therefore to review and discuss potential factors contributing to impair and repair of TJs in the nasal epithelium based on their structure, function, and formation process.

Construction and Hierarchical Self-Assembly of Multifunctional Coordination Cages with Triangular Metal-Metal-Bonded Units.

Herein, a series of face-capped (Tr2M3)4L4 (Tr = cycloheptatrienyl cationic ring; M = metal; L = organosulfur ligand) tetrahedral cages 1-3 functionalized with 12 appended crown ether moieties were designed and synthesized. The reversible binding of ammonium cations with peripheral crown ether moieties to adjust internal guest-binding was realized. Combination of a bisammonium linker and cage 3 led to the formation of a supramolecular gel SPN1 via host-guest interactions between the crown ether moieties and ammonium salts. The obtained supramolecular gel exhibited multiple-stimuli responsiveness, injectability, and excellent self-healing properties and could be further developed to a SPN1-based drug delivery system. In addition, the storage modulus of SPN1 was 20 times higher than that of the model gel without Pd-Pd bonded blocks, and SPN1 had better self-healing properties compared with the latter, demonstrating the importance of such cages in improving mechanical strength without losing the dynamic properties of the material. The cytotoxicity in vitro of the drug-loaded (doxorubicin or methotrexate) SPN1 was significantly improved compared to that of free drugs.

Solvato-Controlled Assembly and Structural Transformation of Emissive Poly-NHC-Based Organometallic Cages and Their Applications in Amino Acid Sensing and Fluorescence Imaging.

Stimuli-induced structural transformation of supramolecular cages has drawn increasing attention because of their sensitive feature to external variations as model systems to simulate biological processes. However, combining structural transformation and useful functions has remained a difficult task. This study reports the solvato-controlled self-assembly of two unique topologies with different emission characteristics, a water-soluble Ag8 L4 cage (A) and an Ag4 L2 cage (B), produced from the same sulfonate-pendant tetraphenylethene (TPE) bridged tetrakis-(1,2,4-triazolium) ligand. Both cages show interesting solvent-responsive reversible structural transformation, and the change of fluorescence signals can efficiently track the process. Additionally, water-soluble cage A exhibits unique properties in thermochromism, thiol amino acid sensing, and subcellular imaging in aqueous media.

Formation of Metallosupramolecular Helicates and Mesocates from Poly-N-Heterocyclic Carbene Ligands.

In this work, a series of poly-NHC-based tetranuclear silver helicates and mesocates were synthesized from the silver-mediated self-assembly of the ligands involving multiple tridentate CNC-type pincer units and NHC coordination sites. The silver helicate was found to be transferred to a gold mesocate upon metal exchange reaction. The metallosupramolecular helicates and mesocates have been fully characterized by single-crystal X-ray crystallography, mass spectrometry, and multinuclear nuclear magnetic resonance spectroscopies. This study provides an example of the selective preparation of poly-NHC-based helicates or mesocates depending on the size of metal ions and the steric effect of ligands.

Unravelling the Roles of Solvophobic Effects and π⋠⋠⋠π Stacking Interactions in the Formation of [2]Catenanes Featuring Di-(N-Heterocyclic Carbene) Building Blocks.

A series of [2]catenanes has been prepared from di-NHC building blocks by utilizing solvophobic effects and/or π⋅⋅⋅π stacking interactions. The dinickel naphthobiscarbene complex syn-[1] and the kinked biphenyl-bridged bipyridyl ligand L2 yield the [2]catenane [2-IL](OTf)4 by self-assembly. Solvophobic effects are pivotal for the formation of the interlocked species. Substitution of the biphenyl-linker in L2 for a pyromellitic diimide group gave ligand L3 , which yielded in combination with syn-[1] the [2]catenane [3-IL](OTf)4 . This assembly exhibits enhanced stability in diluted solution, aided by additional π⋅⋅⋅π stacking interactions. The π⋅⋅⋅π stacking was augmented by the introduction of a pyrene bridge between two NHC donors in ligand L4 . Di-NHC precursor H2 -L4 (PF6 )2 reacts with Ag2 O to give the [Ag2 L4 2 ]2 [2]catenane [4-IL](PF6 )4 , which shows strong π⋅⋅⋅π stacking interactions between the pyrene groups. This assembly was readily converted into the [Au2 L4 2 ]2 gold species [5-IL](PF6 )4 , which exhibits exceptional stability based on the strong π⋅⋅⋅π stacking interactions and the enhanced stability of the Au-CNHC bonds.

Domino hepatocyte transplantation using explanted human livers with metabolic defects attenuates D-GalN/LPS-induced acute liver failure.

BACKGROUND: Explanted livers from patients with inherited metabolic liver diseases possess the potential to be a cell source of good-quality hepatocytes for hepatocyte transplantation (HT). This study evaluated the therapeutic effects of domino HT using hepatocytes isolated from explanted human livers for acute liver failure (ALF). METHODS: Isolated hepatocytes were evaluated for viability and function and then transplanted into D-galactosamine/lipopolysaccharide-induced ALF mice via splenic injection. The survival rate was analyzed by the Kaplan-Meier method and log-rank test. Liver function was evaluated by serum biochemical parameters, and inflammatory cytokine levels were measured by ELISA. The pathological changes in the liver tissues were assessed by hematoxylin-eosin staining. Hepatocyte apoptosis was investigated by TUNEL, and hepatocyte apoptosis-related proteins were detected by western blot. The localization of human hepatocytes in the injured mouse livers was detected by immunohistochemical analyses. RESULTS: Hepatocytes were successfully isolated from explanted livers of 10 pediatric patients with various liver-based metabolic disorders, with an average viability of 85.3% ± 13.0% and average yield of 9.2 × 106 ± 3.4 × 106 cells/g. Isolated hepatocytes had an excellent ability to secret albumin, produce urea, uptake indocyanine green, storage glycogen, and express alpha 1 antitrypsin, albumin, cytokeratin 18, and CYP3A4. Domino HT significantly reduced mortality, decreased serum levels of alanine aminotransferase and aspartate aminotransferase, and improved the pathological damage. Moreover, transplanted hepatocytes inhibited interleukin-6 and tumor necrosis factor-α levels. Domino HT also ameliorates hepatocyte apoptosis, as evidenced by decreased TUNEL positive cells. Positive staining for human albumin suggested the localization of human hepatocytes in ALF mice livers. CONCLUSION: Explanted livers from patients with inheritable metabolic disorders can serve as a viable cell source for cell-based therapies. Domino HT using hepatocytes with certain metabolic defects has the potential to be a novel therapeutic strategy for ALF.

Optimal management of perioperative analgesia regarding immediate and short-term outcomes after liver transplantation - A systematic review, meta-analysis and expert panel recommendations.

BACKGROUND: Adequate pain control is essential for patients undergoing liver transplantation (LT). Multiple analgesic strategies have been implemented during the perioperative period. There is no consensus on the optimal perioperative analgesia management. OBJECTIVES: To provide recommendations, on the optimal perioperative analgesia management for LT. DATA SOURCES: Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central. METHODS: A systematic review and meta-analysis following PRISMA guidelines and recommendations using GRADE. Studies describing outcomes, morbidity, mortality, pain scores, intensive care unit and hospital length of stay in patients that received different pain management techniques during and after LT were included (CRD42021243282). RESULTS: One thousand nine hundred ten articles were screened, but only two randomized controlled trials, one prospective and six retrospective studies were included. The opioid-avoidance protocols included, thoracic epidural analgesia (TEA), Transversus Abdominis Plane (TAP) block, as well as other non-opioid analgesics, resulted in improved short-term outcomes. Mortality was reduced in this group versus control cohorts (OR = 0.51; CI 0.14, 1.83; P = 0.350), Time to extubation, and intensive care unit LOS were shorter; pain scores after surgery were lower in opioid-avoidance group (percentage decrease, 35%, 12%, and 55%, respectively). However, hospital LOS was longer (percentage increase 8%). CONCLUSIONS: Opioid-avoidance analgesia management for LT results in improved short-term outcomes. (Quality of Evidence; Moderate to low | Grade of Recommendation; Weak). Medications such as acetaminophen(paracetamol), gabapentin, ketamine, tramadol and local anesthesia may be used instead of, or as adjuncts to opioids for postoperative analgesia. Overall evidence remains weak and more robust studies are required.

N-Heterocyclic carbenes and their precursors in functionalised porous materials.

Though N-heterocyclic carbenes (NHCs) have emerged as diverse and powerful discrete functional molecules in pharmaceutics, nanotechnology, and catalysis over decades, the heterogenization of NHCs and their precursors for broader applications in porous materials, like metal-organic frameworks (MOFs), porous coordination polymers (PCPs), covalent-organic frameworks (COFs), porous organic polymers (POPs), and porous organometallic cages (POMCs) was not extensively studied until the last ten years. By de novo or post-synthetic modification (PSM) methods, myriads of NHCs and their precursors containing building blocks were designed and integrated into MOFs, PCPs, COFs, POPs and POMCs to form various structures and porosities. Functionalisation with NHCs and their precursors significantly expands the scope of the potential applications of porous materials by tuning the pore surface chemical/physical properties, providing active sites for binding guest molecules and substrates and realizing recyclability. In this review, we summarise and discuss the recent progress on the synthetic methods, structural features, and promising applications of NHCs and their precursors in functionalised porous materials. At the end, a brief perspective on the encouraging future prospects and challenges in this contemporary field is presented. This review will serve as a guide for researchers to design and synthesize more novel porous materials functionalised with NHCs and their precursors.

A Molecular "A-Type" Tangled Metallocube.

Tangled cubes feature the topology of typical Platonic cubes, with their "faces" traversed by edges in different ways. This study generates an "A-type" tangled metallocube from the reaction of binuclear gold-NHC complex and H2 S. The tangled cube topology was validated by multinuclear nuclear magnetic resonance (NMR) spectroscopy, high-resolution electrospray-ionization (HR-ESI) mass spectrometry, and single-crystal X-ray diffraction analysis. This study offers a simple and effective approach to designing and fabricating new, topologically unique molecular structures.

Coordination-Induced Emission from Tetraphenylethylene Units and Their Applications.

Thanks to the potential of aggregation-induced emission (AIE) phenomena, improved stabilities, and the good selectivity and sensitivity of the chemical responses exhibited by the products, coordination-driven self-assembly with tetraphenylethylene (TPE) units has recently received much attention and has been widely investigated for application in chemical sensors, cell imaging agents, light-harvesting systems, and others. Several reviews have emerged on the topics of AIE chemistry and aggregation-induced emission luminogen (AIEgen)-based supramolecular assembles, however, there is still a distinct lack of full overviews of emission enhancement from the viewpoint of metal-coordination effects. Thus, this minireview offers recent advances that have been made in the design and application of TPE-based metallacycles, metallacages, metal-organic frameworks (MOFs) and coordination polymers (CPs).

Early transjugular intrahepatic portosystemic shunt for acute variceal bleeding: a systematic review and meta-analysis.

OBJECTIVES: The alleged benefit of early placement of transjugular intrahepatic portosystemic shunt (TIPS) in patients with cirrhosis and acute variceal bleeding (AVB) remains controversial. This meta-analysis was conducted to evaluate the therapeutic effect of early TIPS on cirrhotic patients with AVB. METHODS: MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases were searched for relevant literatures. Data from included studies were extracted, and random-effects meta-analyses were performed. RESULTS: Three randomized control trials and six observational studies involving 2878 participants were included. Compared with those undergoing standard treatment, patients undergoing early TIPS had a significantly lower all-cause mortality (RR, 0.64; 95% CI, 0.52-0.79). Furthermore, early TIPS was associated with a significantly reduced incidence of failure to control bleeding (RR, 0.15; 95% CI, 0.07-0.29) and rebleeding (RR, 0.40; 95% CI, 0.23-0.71), without increasing the risk of hepatic encephalopathy (RR, 1.13; 95% CI, 0.92-1.38). In a stratification analysis based on Child-Pugh classification, the survival benefit was observed in Child-Pugh B patients with active bleeding (RR, 0.53; 95% CI, 0.31-0.93) and Child-Pugh C patients (RR 0.55, 95% CI, 0.37-0.82), but not in low-risk patients (Child-Pugh A and Child-Pugh B without active bleeding) (RR, 0.93; 95% CI, 0.55-1.57). CONCLUSION: Early TIPS is a feasible therapeutic option for cirrhotic patients with AVB, especially benefiting high-risk patients in terms of improved survival. Given the current low utilization rate in clinical practice, this study favors the placement of early TIPS in a wider range of patients with cirrhosis and AVB, especially high-risk patients. KEY POINTS: • Early TIPS is associated with improved survival in high-risk patients (Child-Pugh B plus active bleeding at endoscopy or Child-Pugh C 10-13) with cirrhosis and acute variceal bleeding. • Current utilization rate of early TIPS is low in clinical practice.

EBV-specific cytotoxic T lymphocytes for refractory EBV-associated post-transplant lymphoproliferative disorder in solid organ transplant recipients: a systematic review.

The use of Epstein-Barr virus-specific cytotoxic T lymphocytes (EBV-CTLs) in adoptive immunotherapy in hematopoietic stem cell transplantation (HSCT) patients with post-transplantation lymphoproliferative disorder (PTLD) has demonstrated safety and effectiveness. EBV-CTLs might also be the effective treatment of refractory PTLD of solid organ transplantation (SOT) recipients. Two independent assessors searched Pubmed, Embase, Cochrane Library, and Web of Science from their inception to November 2020. Eleven studies with 76 patients (42, 55% male) were included. We extracted the data and completed the quality assessments. Most of the studies were from Europe and the USA. Liver and kidney transplantation accounted for most of the transplant types. Thirty-five (46.1%) patients were diagnosed with monomorphic PTLD, and B lymphocyte type was the most common. All the patients received primary treatment for PTLD while it was ineffective. CTLs included autologous EBV-CTLs (15/76, 22%) and HLA-matched third-party EBV-CTLs (61/76, 78%). The response rate for EBV-CTL treatment of refractory PTLD was 66%. Of 50 patients, 36 achieved complete remission and 14 achieved partial remission. EBV-DNA level decreased in 39 patients. Adverse reactions were rare and mild. We conclude that adoptive therapy with EBV-specific CTLs is safe, well-tolerated, and effective in PTLD.

Incidence of de novo autoimmune hepatitis in children and adolescents with increased autoantibodies after liver transplantation: a meta-analysis.

The objective of this meta-analysis was to assess the incidence of de novo autoimmune hepatitis (AIH) in children and adolescents with increased autoantibodies after liver transplantation. We systematically retrieved studies from PubMed, Embase, Central, CNKI, VIP and Wanfang published before February 1, 2020. All analyses were conducted using R-4.0.1 statistical package (Meta). Seven studies with high quality were pooled in our final analysis (N = 251 participants). The incidence of de novo AIH was 9% [95% confidence interval (CI) 1-23%, I2  = 86%]. Subgroup analysis suggested that publications not using the International Autoimmune Hepatitis Group (IAIHG) criteria have marginally significantly higher incidence of de novo AIH than those using IAIHG criteria (P for interaction = 0.08). The incidence of chronic rejection was 8% (95% CI 2-17%, I2  = 72%). Meta-regression indicated significant correlation (P = 0.04; estimate: 1.51) between the incidence of de novo AIH and the rate of increase of antibodies to liver/kidney microsome (anti-LKM). It is still challenging to distinguish de novo AIH and chronic rejection in children and adolescents with increased autoantibodies after liver transplantation. The diagnostic criteria for de novo AIH in children and adolescents and the role of anti-LKM in the development of de novo AIH deserve future investigation.

Post-transplant lymphoproliferative disorder after paediatric liver transplantation.

OBJECTIVE: The purpose of this study was to analyse the clinical and pathological characteristics, treatments and outcomes of post-transplant lymphoproliferative disorder (PTLD) in paediatric liver transplant recipients. METHOD: A retrospective analysis of records from nine paediatric liver transplant recipients with PTLD who were treated at our Liver Transplant Center over the period from June 2013 to August 2018. RESULT: Of these nine patients, seven received liver transplantation in our centre and the remaining two patients at other hospitals. The overall incidence of PTLD in paediatric liver transplant recipients in our centre was 1.4% (7/485). The median onset of PTLD after liver transplantation was 11 months. Three cases were classified as infectious mononucleosis PTLD, one case was plasmacytic hyperplasia PTLD, one case was polymorphic PTLD and two cases were Burkitt lymphoma. One case showed diffuse large B-cell lymphoma and one was classical Hodgkin lymphoma-like PTLD. These patients presented with different clinical manifestations including fever, anaemia, diarrhoea, hypoproteinaemia, enlargement of lymph nodes, hepatosplenomegaly, jaundice, bowel obstruction and even intestinal perforation. Nine patients were positive for EBV-DNA in serum. After diagnosis, immunosuppressants were reduced or discontinued in all cases. Eight patients received anti-CD20 monoclonal antibody (Rituximab) therapy, four cases were treated with a combination of chemotherapy (R-CHOP, ABVD, COPP/ABV) and one case was combined with radiotherapy. Two cases received surgical treatment due to bowel obstruction. Eight of these patients achieved a complete remission and remained healthy when assessed at the time of final follow-up. One patient died as a result of PTLD progression. CONCLUSION: PTLD is one of the most serious and fatal complications after liver transplantation. The definitive diagnosis requires histopathology. Treatment varies and basically includes immunosuppression reduction, anti-CD20 antibody, surgery, radiotherapy and chemotherapy.

Risk factors for portal vein stenosis in pediatric liver transplantation.

OBJECTIVE: To analyze the incidence and risk factors of portal vein stenosis (PVS) in pediatric liver transplantation (LT). METHODS: This retrospective analysis of 396 cases of pediatric LT (patients aged ≤ 14 years old) was conducted at the Liver Transplantation Center of Beijing Friendship Hospital (China) from June 2013 to December 2017. We collected relevant data and calculated the incidence. We analyzed a total of 23 risk factors for PVS children during the perioperative period. RESULTS: The incidence of PVS in pediatric LT was 6.6%. The following were identified as risk factors for PVS in pediatric LT: Preoperative portal hypertension was complicated, weight (≤7 kg), recipients of portal vein diameter ≤4 mm, GRWR (≥3.5%), the use of cold preservation vein grafts, anastomosis in the region of superior mesenteric vein and splenic vein and reverse blood flow in the portal vein shown in preoperative ultrasound examination. Recipients of portal vein diameter ≤4 mm and the use cold preservation grafts were independent risks factors for PVS in pediatric LT. CONCLUSION: For recipients with the risk factors identified in this study, we strongly recommend a strict follow-up and the provision of suitable interventions when indicated.

Backbone-Directed Self-Assembly of Interlocked Molecular Cyclic Metalla[3]Catenanes.

The efficient backbone-directed self-assembly of cyclic metalla[3]catenanes by the combination of tetrachloroperylenediimide (TCPDI)-based dinuclear rhodium(III) clips and 4,4'-diazopyridine or 4,4'-dipyridylethylene ligands is realized in a single-step strategy. The topology and coordination geometry of the cyclic metalla[3]catenanes are characterized by NMR spectroscopy, ESI-TOF-MS spectrometry, UV/Vis-NIR spectroscopy, and X-ray diffraction studies. The most remarkable feature of the formed cyclic metalla[3]catenane is that it contains π-aggregates (ca. 2.6 nm) incorporating six TCPDIs. Further studies revealed that cyclic metalla[3]catenanes can be converted reversibly to their corresponding sodium adducts and precursor building blocks, respectively. This strategy opens the possibility of generating unique supramolecular structures from discrete functional π-aggregates with precise arrangements.

Synthesis, Characterization, and Properties of Tetraphenylethylene-Based Tetrakis-NHC Ligands and Their Metal Complexes.

The development of highly emissive dinuclear AgI or AuI complexes [M2 L](PF6 )2 (L=2 a, 2 b; M=Ag, Au) derived from tetraphenylethylene (TPE)-based tetrabenzimidazolin-2-ylidene ligands is reported. The new complexes exhibit a remarkable fluorescence enhancement compared to their parent benzimidazolium salts. The quantum yield (ΦF ) value for salt H4 -2 a(PF6 )4 in dilute solution (c=10-5 m) was found to be less than 1 %, whereas its metal complexes show ΦF values up to 55 % at similar solution concentration. This observation can be attributed to the rigidification of the TPE skeleton upon metalation resulting in a restriction of the intramolecular rotation of the phenyl groups. Functionalization of the complexes [M2 2 b](PF6 )2 (M=Ag, Au) with terminal coumarin groups and subsequent photoirradiation yielded the complexes [M2 3 b](PF6 )2 (M=Ag, Au) bearing a new type of ligand with an unaffected TPE moiety.

C3 -Symmetric Assemblies from Trigonal Polycarbene Ligands and MI Ions for the Synthesis of Three-Dimensional Polyimidazolium Cations.

Metallosupramolecular poly-NHC-metal assemblies were prepared from trigonal hexakis (H6 -1 a(PF6 )6 and H6 -1 b(PF6 )6 ) or nonakis (H9 -3(BF4 )9 ) imidazolium salts and Ag2 O. Complexes [Ag6 (1 a)2 ](PF6 )6 and [Ag6 (1 b)2 ](PF6 )6 are built from six Ag+ ions sandwiched between two trigonal hexacarbene ligands with an inner and an outer NHC donor in each of the three ligand arms. The metal atoms are arranged in two triangles. The hexakis-NHC ligands bear cinnamic ester groups at the outlying NHC donors, used in postsynthetic [2+2] cycloaddition reactions linking two hexakis-NHC ligands by three cyclobutane units to give complexes [Ag6 (2 a)](PF6 )6 and [Ag6 (2 b)](PF6 )6 bearing a dodecacarbene ligand. From the related nonakisimidazolium salt H9 -3(BF4 )9 , complex [Ag9 (4)](BF4 )9 bearing an octadecacarbene ligand was obtained. Removal of the template metals yielded very large, stable, polyimidazolium cations with 12 or 18 internal imidazolium groups.