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A woman in her late 70 s was diagnosed with liver injury at a health examination. Despite treatment with ursodeoxycholic acid at a nearby hospital, her transaminase levels elevated in two peaks. She was transferred to our hospital 77 days after the health examination. She weighed 42 kg and had a low body mass index of 19.8 kg/m

A new series of Hofmann-like compounds made with imidazole ligands display interesting properties.

The patient was an 85-year-old man with hepatitis C-related liver cirrhosis and chronic renal failure caused by diabetes mellitus under maintenance hemodialysis (HD) who developed hepatocellular carcinoma (HCC) after achieving a sustained viral response with direct acting antiviral therapy 1 year and 3 months previously. HCC located near the right hepatic vein was treated by radiofrequency ablation (RFA) but recurrent disease accompanied by hepatic vein invasion was detected 3 months after RFA. The recurrent HCC was curatively treated with stereotactic body radiotherapy (SBRT). The patient had additional complications, including grade III AV block controlled by a pacemaker, colonic adenoma resected by endoscopic mucosal resection, and a small cerebral aneurysm, which was untreated. At 2 years after SBRT, there had been no recurrence of HCC. In this old HCC patient with various complications including HD with polypharmacy, multidisciplinary treatment, including SBRT, enabled the patient to achieve complete remission and maintain a good quality of life.

Background and Aim This retrospective study investigated the effect of 48‐week pemafibrate therapy in non‐alcoholic fatty liver disease (NAFLD) with hypertriglyceridemia, as evaluated by the FibroScan‐aspartate aminotransferase (FAST) score. Methods A total of 31 NAFLD patients who were treated with pemafibrate in Gunma Saiseikai Maebashi Hospital and Kusunoki Hospital from September 2018 to April 2020 were included in the current study. We used the FAST score, which is a novel index of steatohepatitis that can be calculated based on the AST value, controlled attenuation parameter (CAP), and liver stiffness measurement (LSM), to evaluate the effect of pemafibrate treatment. Results The median age was 64.0 (interquartile range [IQR] 55.0–75.0) years and 14 patients (45.2%) were male. Median body mass index was 26.8 (IQR 23.8–28.8). Hypertension and diabetes mellitus were detected in 14 (45.2%) and five (16.1%) patients, respectively. Fasting triglyceride and high‐density lipoprotein cholesterol were significantly improved (P, The FibroScan‐aspartate aminotransferase (FAST) score, which stratifies patients with risk of progressive non‐alcoholic steatohepatitis effectively, was significantly improved during pemafibrate treatment. The delta FAST score was correlated with the variations of alanine aminotransferase, which represents the effect of pemafibrate. Pemafibrate may prevent disease progression in non‐alcoholic fatty liver disease patients with hypertriglyceridemia.

The aim of this study was to evaluate the efficacy of zinc acetate treatment for patients with decompensated liver cirrhosis complicated by hypozincemia. We retrospectively analyzed 49 patients with decompensated liver cirrhosis complicated by hypozincemia who received zinc acetate treatment from August 2017 to March 2020. The relationships between serum zinc levels and several parameters including the prognosis, sarcopenia, and immunity were evaluated. Serum zinc levels measured at 3 months post-treatment and the incidence of adverse events were also determined. The median age was 69.0 years (IQR:59.5-78.8) and the male to female ratio was 29:20. Twenty-seven patients had a Child-Pugh classification of B and 22 had a Child-Pugh classification of C; the median Child-Pugh score was 9.0 (IQR, 8.0-11.0). The median serum zinc levels measured at 3 months post-treatment (74.7 (IQR, 50.0-101.0) μg/dL) were significantly elevated in comparison to the pre-treatment levels (43.0 (IQR, 34.0-51.0) μg/dL, P < 0.0001). The overall survival of patients with pre-treatment serum zinc levels of ≥60 μg/dL was significantly better than that of those with pre-treatment serum zinc levels of

Background and Aim We investigated the prognosis of late elderly patients (≥75 years old) after the achievement of a sustained viral response (SVR) by direct‐acting antivirals (DAAs). Methods One hundred and four late elderly patients and 251 young patients (≤74 years old) who had achieved an SVR were included. We compared the cumulative hepatocellular carcinoma (HCC) incidence rates and survival rates after DAA administration. Furthermore, the factors associated with HCC incidence and the causes of death after DAA administration were also investigated. Results The cumulative HCC incidence rates for 1 and 3 years were 2.9% and 11.7% in the late elderly patients and 2.4% and 5.4% in the young patients, respectively. The cumulative survival rates for 1 and 3 years were 100% and 95.6% in the late elderly patients and 100% and 96.4% in the young patients, respectively, with no significant differences in those rates noted (P = 0.133, P = 0.322, respectively). In the late elderly patients, only a history of HCC was a significant factor associated with HCC incidence after DAA administration. Five late elderly patients died after achieving an SVR, and malignant liver tumor was the cause of death in three of those patients. Conclusions The prognosis did not differ markedly between late elderly patients and young patients. The factor most strongly influencing the prognosis of late elderly patients was likely liver disease, including HCC. DAAs should be introduced even in late elderly patients who can be expected to have a relative long‐term survival., One hundred and four late elderly patients (75 years old) and 251 young patients (74 years old) who had achieved a sustained viral response by direct‐acting antivirals (DAAs) were included. The prognosis did not differ markedly between late elderly patients and young patients. The factor most strongly influencing the prognosis of late elderly patients was likely liver disease, including hepatocellular carcinoma. DAAs should be introduced even in late elderly patients who can be expected to have a relative long‐term survival. , Late elderly patients; , young patients.

AIM This study aimed to evaluate the real-world efficacy and safety of 12-week sofosbuvir/velpatasvir (SOF/VEL) treatment for patients with decompensated liver cirrhosis caused by hepatitis C virus (HCV) infection. METHODS A total 72 of patients with Child-Pugh (CP) class B or C were enrolled. We evaluated the sustained virologic response at 12 weeks after the end of treatment (SVR12), adverse events (AEs), and changes in the liver function. RESULTS All participants had genotype 1 or 2 HCV infection. At baseline, the numbers of patients with CP class B and C were 59 and 13, respectively. The overall SVR12 rate was 95.8% (69/72); 94.9% (56/59) in CP class B and 100% (13/13) in CP class C. The serum albumin level, prothrombin time and ascites were significantly improved (P

Sofosbuvir/velpatasvir (SOF/VEL) is expected to be highly effective, even in patients with decompensated liver cirrhosis. However, portal hypertension can be problematic after achieving a sustained viral response (SVR), especially in patients with hepatic encephalopathy (HE) associated with large portal-systemic shunt. Although balloon-occluded retrograde transvenous obliteration (BRTO) is a useful option, whether BRTO or SOF/VEL therapy should be initially performed in patients with a poor liver function reserve is controversial. We herein report a case of refractory HE caused by decompensated liver cirrhosis due to hepatitis C virus (HCV) classified as Child-Pugh class C that was treated by BRTO after SVR with SOF/VEL. A 64-year-old woman with HCV-associated decompensated cirrhosis developed refractory HE. Dynamic contrast-enhanced computed tomography (CT) revealed large portal-systemic shunt. We treated the patient with 12 weeks of SOF/VEL, and she achieved SVR. Although the serum albumin level, edema, and ascites were improved, intractable HE remained. Her general condition had been improved after SVR, so HE was suspected to have been caused by portal-systemic shunting. We, therefore, treated the patient by BRTO. On dynamic contrast-enhanced CT, partial obstruction of the shunt vessel was confirmed after BRTO. Thereafter, her serum ammonia level rapidly improved, and HE did not recur. Interventional radiology such as BRTO following SOF/VEL therapy may be a useful option even in patients with decompensated HCV-associated cirrhosis accompanied by portal-systemic shunt.

We experienced a case of follicular cholangitis that was positive on fluorodeoxyglucose-positron emission tomography (18F-FDG-PET). A 70-year-old man was admitted for jaundice. Endoscopic retrograde cholangiography showed stenosis of the middle to upper choledocus. 18F-FDG-PET depicted a localized hot spot at the stenotic lesion (maximum standardized uptake value = 8.2). Although no malignant findings were found in the cytology or on a bile duct biopsy, malignancy could not be excluded, so surgical treatment was performed. Follicular cholangitis is a new, rare disease that causes severe biliary stricture. Only 11 cases of follicular cholangitis have been reported, including the present case.

Adenocarcinoma which develops in the jejunal pouch has rarely been reported, but most of such cases tend to be a recurrence of primary cancer due to the presence of residual or disseminated cancer cells. Primary jejunal pouch cancer is extremely rare. We experienced an autopsy case of primary jejunal pouch cancer which occurred 14 years after proximal gastrectomy for gastric cancer. A female in her late 60s was admitted because of hypoglycemia with liver dysfunction. She underwent total gastrectomy for fundic cancer and had been reconstructed by jejunal pouch interposition 14 years prior to this presentation. Hypoglycemia recovered by nutritional support. Computed tomography demonstrated severe fatty liver and liver biopsy proved non-alcoholic steatohepatitis, which was supposed to have been induced by malnutrition. Screening esophagogastroduodenoscopy (EGD) revealed no tumorous lesions in the jejunal pouch at this time. However, her anorexia gradually progressed and the symptom of bowel obstruction appeared. EGD performed 5 months after the previous EGD revealed adenocarcinoma which extended from the anastomosis of the interposed jejunum. Then liver metastasis developed and jejunal pouch cancer invaded the abdominal wall and protruded with ulcer formation. Finally, the patient died of malnutrition. An autopsy revealed adenocarcinoma which had developed in the interposed jejunal pouch and protruded through the abdominal wall accompanied with lung and liver metastasis. We herein describe this rare case of primary interposed jejunal pouch cancer and discuss our findings including a review of the pertinent literature.

The changes in portal hypertension after achieving a sustained viral response (SVR) by direct-acting antivirals (DAAs) have not been fully elucidated. Consequently, noninvasive and inexpensive predictors need to be investigated. We therefore explored factors associated with the progression of EVs after the achievement of an SVR with DAAs in patients with chronic hepatitis C.Eighty-nine patients, who had achieved an SVR with DAAs and could have their esophagogastroduodenoscopy (EGD) findings compared between before DAAs administration and after achieving an SVR achievement were enrolled in this study. We compared the patients with and without EVs progression. Furthermore, the cumulative progression rates of EVs were also analyzed.The fibrosis-4 index (FIB-4) before DAAs administration was the only significant factor for the progression of EVs after an SVR (odds ratios: 1.2, 95% confidence intervals: 1.05-1.38,As patients with FIB-4 ≥ 8.41 may have progressions of EVs, periodic surveillance by EGD should be continued in such cases, even after an SVR is achieved.

The clinical significance of mac-2 binding protein glycosylation isomer (M2BPGi) levels based on virological responses due to antiviral therapy has not been fully evaluated. We compared the change before and 24 weeks after the therapy with daclatasvir and asunaprevir (DCV+ASV) of M2BPGi levels with those of other fibrosis markers in 73 chronic hepatitis C cases. Moreover, we examined the association between M2BPGi levels and hepatocarcinogenesis in sustained virological response (SVR) and non-SVR cases. M2BPGi levels were significantly improved at post-treatment week 24 (PTW24) in SVR but not non-SVR cases, whereas the changes of other fibrosis markers showed the same tendency in both SVR and non-SVR cases. M2BPGi levels were well correlated with other fibrosis markers at baseline but not PTW24. The incidence of hepatocellular carcinoma (HCC) was significantly associated with M2BPGi levels at PTW24. The achievement of SVR significantly affected the improvement of M2BPGi levels that best reflected the effect of direct-acting antivirals among the fibrosis markers. Furthermore, M2BPGi levels at PTW24 were also associated with the incidence of HCC in only SVR cases. However, the rapid decrease of M2BPGi levels might reflect the amelioration of liver inflammation rather than the improvement of liver fibrosis, which should be further elucidated.

Background Hepatocellular carcinoma (HCC) may lead to extrahepatic metastasis (EHM). Most patients with EHM had either intrahepatic stage III or IVA tumor at the site of metastases. Herein, we present the case of a fairly rare 1.5-cm small-diameter HCC with right adrenal gland tumor having an inferior vena cava (IVC) tumor thrombus. Case presentation A 75-year-old man had a 1.5-cm hepatocellular carcinoma (HCC) in segment 8 of the liver and a 3.0-cm right adrenal gland tumor with inferior vena cava (IVC) tumor thrombus. He underwent partial hepatectomy, right adrenalectomy, and IVC tumor thrombectomy. Tumor resection was successful, but the tumor progressed rapidly, and the patient died 8 months after the operation. Immunohistochemical staining revealed that both HCC cells and adrenal tumor cells were positive for HCC markers Glypican-3 and alpha-fetoprotein. In terms of adrenal carcinoma markers vimentin and Melan-A, vimentin was negative in the HCC and adrenal tumor, and Melan-A was negative in the HCC. In adrenal tumor, slight positivity of Melan-A was observed, but the intensity of staining was clearly weak compared with that in normal adrenal glands. CD133, one of the stem cell markers, was positive in both HCC and adrenal tumor cells. Next-generation amplicon sequencing analyses were performed using DNA derived from the HCC, adrenal tumor, and normal liver tissue. After exome data analyses for representative HCC-related genes as TERT, CTNNB1, TP53, and ARID2, TP53 mutation (exon3: c.G351 T: p.R117S) was found in both HCC cells and adrenal tumor cells. Conversely, no significant mutations in other genes were observed. These pathological findings and sequencing results showed that the adrenal tumor might be an adrenal metastasis of HCC in spite of small primary tumor size. Conclusions This case suggests that the right adrenal tumor was a metastasis of HCC. Immunohistochemical staining and gene mutation analyses using NGS are very useful in differentiating the tumor origin.

The patient was an 86-year-old man who was admitted with obstructive jaundice. Computed tomography revealed a tumor in the hilar choledochus with peripheral hepatic duct dilatation. Endoscopic cholangiography (ERC) demonstrated the defect in the choledochus. Brushing cytology during ERC showed Orange-G-philic keratinized atypical cells, which led to a diagnosis of squamous cell carcinoma. Chemotherapy with tegafur-gimeracil-oteracil potassium was ineffective and was discontinued due to adverse effects. The patient died 5 months after the diagnosis and autopsy revealed tubular adenocarcinoma of the hilar bile duct with squamous cell carcinoma component. Progression of the disease might influence the distribution of adenosquamous carcinoma. The clinicopathological sequence of adenosquamous carcinoma of the choledochus was documented.

A 76-year-old woman with spontaneous reactivation of hepatitis B virus (HBV) without any immunosuppressants who had been successfully treated with tenofovir alafenamide fumarate (TAF) was reported. The patient was admitted to our hospital because of acute exacerbation of the liver function and jaundice. She had been found to have chronic HBV infection with a normal liver function and had been treated for lifestyle-related diseases, such as diabetes mellitus, dyslipidemia and hypertension, for over 10 years at a local clinic. At admission, her serum HBV DNA was high (7.3 log IU/mL), and anti-hepatitis B core protein immunoglobulin M was slightly elevated (1.47 S/CO). Due to the absence of known risk factors for HBV reactivation, the reactivation was regarded as "spontaneous". After the initiation of the nucleotide analog TAF, her liver function gradually improved with a decrease in the HBV DNA load. Her HBV genome was typed as subgenotype B1 and possessed a frameshift mutation due to an insertion of T after nucleotide (nt) 1817 and G to A mutations at nt 1896 and nt 1899 (G1896A/G1899A) in the precore region as well as serine to glutamine substitution of amino acid 21 in the core protein. In addition to these viral mutations, aging and complications of lifestyle-related diseases in the present case may have been responsible for the spontaneous HBV reactivation. Careful observation and management of aged HBV carriers with underlying diseases are needed even when persistent HBV infection is free from symptoms and liver dysfunction and no immunosuppressive conditions are involved.

PURPOSE Helicobacter pylori (HP) infection is reported to increase 18 F-fluoro-2-deoxyglucose (FDG) accumulation in the stomach. The accumulation of FDG by positron-emission tomography (FDG-PET) in the stomach for the voluntary health examinees of cancer checkup was examined before and after the HP eradication. SUBJECTS AND METHODS From March 2013 to October 2015, eighty-one subjects were performed FDG-PET to detect cancer at the health checkup. All of them were also surveyed by esophagogastroduodenoscopy. Subjects were classified as the 33 cases of HP positive (group A), 38 cases of originally negative (group B), and the 10 negative cases by HP eradication therapy (group C). Group A was treated by combination of amoxicillin, clarithromycin, and proton pump inhibitor for a week, and all of them eradicated HP. A part of group A (n = 7) was serially performed FDG-PET one to five years after the treatment and compared the maximum standard uptake value of FDG (SUV) around the fundic gland region. RESULTS SUV of group A (3.55 ± 0.69) was significantly higher than those of both group B (2.96 ± 0.72) and group C (2.89 ± 0.51) (p

Helicobacter pylori (HP) infection is reported to increaseFrom March 2013 to October 2015, eighty-one subjects were performed FDG-PET to detect cancer at the health checkup. All of them were also surveyed by esophagogastroduodenoscopy. Subjects were classified as the 33 cases of HP positive (group A), 38 cases of originally negative (group B), and the 10 negative cases by HP eradication therapy (group C). Group A was treated by combination of amoxicillin, clarithromycin, and proton pump inhibitor for a week, and all of them eradicated HP. A part of group A (n = 7) was serially performed FDG-PET one to five years after the treatment and compared the maximum standard uptake value of FDG (SUV) around the fundic gland region.SUV of group A (3.55 ± 0.69) was significantly higher than those of both group B (2.96 ± 0.72) and group C (2.89 ± 0.51) (p 0.01, respectively). Groups B and C are almost comparable and showed no significant difference during the course. In group A, HP eradication significantly decreased the SUV to 3.1 ± 0.43 (P .01). SUV after the eradication was significantly reduced (P .01) in the mild to moderate atrophy (C1-C3) group according to Kimura and Takemoto classification of chronic gastritis of group A. Although SUV in the advanced atrophy group (O1-O3) tended to decline after the eradication, the change was not significant.HP-infected stomach showed higher FDG uptake in the fundic gland region and HP eradication decreased the uptake in the mild to moderate atrophic gastritis but not in the severe atrophic gastritis.

Cholangiolocellular carcinoma (CoCC) is a rare primary liver cancer that is difficult diagnose due to a lack of specific imaging findings. We herein report a case of CoCC accompanied by severe alcoholic cirrhosis. Dynamic computed tomography showed a low-density tumor with a faint surrounding enhancement. Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging revealed iso-intensity in the hepatobiliary phase and a maximum tumor diameter of 53 mm. 18F-fluoro-2-deoxyglucose position-emission tomography was moderately positive (maximum standardized uptake value: 4.3). CoCC was diagnosed based on the pathological findings, including immunohistochemistry. We discuss the diagnostic imaging findings and review previous reports.

Broncho-biliary fistula (BBF) is a rare but severe disorder defined as abnormal communication between the biliary system and bronchial tree. Cases of BBF have occasionally been reported, but no standard treatment has been established. We report two cases of BBF that developed after the treatment of hepatocellular carcinoma (HCC) and reviewed the relevant literature. Case 1, a man in his early eighties was diagnosed with BBF 4 months after undergoing surgical resection for HCC (diameter, 7 cm; location, segments 4 and 5). Percutaneous drainage and endoscopic nasobiliary drainage (ENBD) improved BBF without recurrence for more than a year. Case 2, a woman in her late sixties was diagnosed with BBF after percutaneous radiofrequency ablation for HCC. Although the BBF was treated with ENBD, bronchial occlusion, and percutaneous transhepatic portal vein embolization, these treatments were unsuccessful and the patient died. Although non-invasive treatments have been developed, refractory BBF still exists. The prediction of BBF and the development of more effective treatments are necessary to improve outcomes.

We experienced a case of follicular cholangitis that was positive on fluorodeoxyglucose-positron emission tomography (

The treatment for hepatocellular carcinoma (HCC) adjacent to the portal vein and/or bile duct requires considerable caution to avoid the complications, such as hepatic infarction and obstructive jaundice. Carbon ion radiotherapy (CIRT) has been attempted for HCC and has become accepted as a promising modality for minimizing hepatic damage with good local tumor control. We experienced two elder cases of HCC adjacent to intrahepatic vessels successfully treated by CIRT. Case 1, a 75-year-old man, was treated by CIRT for a 2-cm HCC near the porta hepatis adjacent to the right first portal branch. The treatment was sufficiently effective, and no vascular damage was demonstrated after CIRT. The liver function transiently deteriorated after CIRT, but recovered quickly. Alpha-fetoprotein transiently increased after the treatment and decreased thereafter. Tumor stain persisted for 3 months after CIRT, so a liver tumor biopsy was performed. However, no viable carcinoma cells were detected. There was no local recurrence or complications for 17 months. Case 2, 76-year-old male HCC patient, showed dilation of the peripheral bile duct in the left lobe, suggesting tumor invasion to the duct. The tumor was hypovascular and was found to be well-differentiated HCC by a tumor biopsy. He was treated with CIRT, because he had a history of cerebral infarction and was being administered an antiplatelet agent daily. He achieved complete remission, and no adverse events were observed after the treatment for 3 years.

Cases of autoimmune liver diseases complicated with hepatitis C (HCV) infection have occasionally been reported. However, the efficacy and safety of direct acting antivirals for chronic hepatitis C (CHC) complicated with autoimmune liver diseases remain unclear. A 74-year-old woman was referred to our hospital for an acute exacerbation of liver dysfunction. She had been diagnosed with CHC 10 years previously. Laboratory data showed elevated immunoglobulin G (IgG), and she was positive for antinuclear antibody (ANA), anti-mitochondrial M2 antibody, and HCV-RNA (genotype 2a). Liver biopsy revealed significant infiltration of lymphocytes and plasma cells in the portal triad, moderate interface hepatitis with mild bridging fibrosis, and chronic non-suppurative destructive cholangitis. She was diagnosed with chronic active hepatitis and primary biliary cholangitis (PBC). Combination therapy with glecaprevir/pibrentasvir (GLE/PIB) rapidly improved her serum transaminase and HCV-RNA levels. A sustained viral response was achieved 24 weeks after GLE/PIB. No adverse events were observed, and her IgG and ANA levels were normalized 6 months after GLE/PIB. The second liver biopsy performed 10 months after GLE/PIB demonstrated the remarkable improvement of active hepatitis. However, the findings suggesting PBC were remained and the AMA-M2 titer was decreased but positive at that time. GLE/PIB is an effective and tolerated choice for the treatment in cases of CHC complicated by PBC.

We herein report a unique case of hepatitis C virus (HCV)-associated renal disease without cryoglobulinemia that showed proteinuria, hypoproteinemia, ascites, and edema. Due to combination therapy with daclatasvir and asunaprevir, the patient achieved sustained virological response at week 24 of the therapy. Furthermore, the therapy caused marked amelioration of her proteinuria, ascites, edema, and hypoalbuminemia, and finally improved her estimated glomerular filtration rate. There were no adverse events, and the combination therapy was well-tolerated. We recommend that HCV eradication with antiviral therapy using direct-acting antiviral agents be attempted first for all renal disease with HCV infection, regardless of cryoglobulinemia, considering the existence of resistance-associated variants.

Hepatitis E, which is caused by hepatitis E virus (HEV), is a public health concern in Japan, where the zoonotic food-borne transmission of HEV from domestic pigs and wild boars plays an important role. A 44-year-old Japanese man with autochthonous sporadic acute hepatitis E was admitted with general fatigue and moderate liver dysfunction. In the present study, two distinct HEV strains were recovered from the patient, who had consumed the raw or undercooked pig liver and intestine two or three times per week for 3 months before the disease onset. The recovered HEV strains were segregated into two clusters within subgenotype 3b, the open reading frame (ORF)1 and ORF2 sequences of which each showed ~10% difference, indicating HEV mixed infection. Because most notified patients with clinical HEV infection in Japan are diagnosed based on the detection of IgA-class HEV antibodies and because serum samples from only a limited number of HEV-infected patients are subjected to HEV RNA detection and nucleotide sequencing, it is very likely that patients with HEV mixed infection remain largely overlooked. The identification of sources of autochthonous HEV infection remains an important goal. Continued efforts to trace the sources of acute or chronic autochthonous HEV infection are warranted.

New FeII guest-dependent spin crossover (SCO) coordination polymers, {FeII4-(3-pentyl)pyridine2[AuI(CN)2]2·(guest)}n (guest = 4-(3-pentyl)pyridine (1a), non-guest (1b)) has been prepared and investigated by magnetic measurement and X-ray structure analysis. The adsorbed state has a two-step transition with a broad temperature-range intermediate state, whereas the desorbed state has a one-step transition. 1b is maintained HS state down to around 200 K. Below this temperature, 1b displays nearly 50% one-step transition. The first transition of 1a starts below ca. 280 K and almost completes at ca. 210 K. Below around 120 K, second transition starts and completes around 65 K, which 50% of high-spin is remaining. Interlayer spaces between two dimensional sheets are greater than other similar 2D Hoffman-like clathrates.

Two spin crossover (SCO) coordination polymers assembled by combining FeII octahedral ion, 4-cyanopyridine (4-CNpy) and [Au(CN)2]&minus, liner unit are described. These compounds, Fe(4-CNpy)2[Au(CN)2]2&middot, 1/2(4-CNpy) (1a) and {Fe(4-CNpy)2[Au(CN)2]2}-{Fe(H2O)2[Au(CN)2]2} (1b), present quite different supramolecular networks that show different magnetic behaviors. Compound 1a crystallizes in the centrosymmetric space group Pbcn. The asymmetric unit contains two 4-CNpy, one type of Fe2+, and two types of crystallographically distinct [Au(CN)2]&minus, units which form Hofmann-like two dimensional layer structures with guest spaces. The layers are combined with another layer by strong gold-gold intermetalic interactions. Compound 1b crystallizes in the centrosymmetric space group Pnma. The bent bismonodentate [AuI(CN)2] units and FeII ions form a complicated interpenetrated three dimensional structure. In addition, 1b exhibits ferromagnetic interaction.

In a series of Hofmann-like spin crossover complexes, two new compounds, {Fe(3-F-4-Methyl-py)2[Au(CN)2]2} (1) and {Fe(3-Methyl-py)2[Au(CN)2]2} (2) (py = pyridine) are described. The series maintains a uniform 2-dimentional (2-D) layer structure of {Fe[Au(CN)2]2}. The layers are combined with another layer by strong aurophilic interactions, which results in a bilayer structure. Both coordination compounds 1 and 2 at 293 K crystallize in the centrosymmetric space groups P21/c. The asymmetric unit contains two pyridine derivative ligands, one type of Fe2+, and two types of crystallographically distinct [Au(CN)2]− units. Compound 1 undergoes a complete two-step spin transition. On the other hand, 2 maintains the characteristic of the high-spin state. The present compounds and other closely related bilayer compounds are compared and discussed in terms of the cooperativity and critical temperature. The bilayer structure is able to be further linked by substituent-substituent contact resulting in 3-dimentional (3-D) network cooperativity.

The synthesis, crystal structures, and magnetic properties of a new two-dimensional (2D) Hofmann-like series, FeII(L)2[AgI(CN)2]2 (L = 3-cyano-4-methylpyridine (1), allyl isonicotinate (2), phenyl-isonicotinate (3), and benzyl nicotinate (4)) were studied. These compounds have a 2D sheet structure because of their strongly determinate self-assembly process. An octahedral FeII ion is coordinated with the nitrogen atoms of[AgI(CN)2 linear units at equatorial positions and monodentate pyridine derivatives at the axial position. The layers construct a parallel stacking array. Compounds 1&ndash, 3 show pairs of layers constructed by intermetallic Ag&middot, &middot, Ag interactions. Compound 4 shows a mono-layer structure. The substituent bulk of the ligands affects the interlayer space. Compounds 1&ndash, 4 undergo a 100% spin transition. However, compound 1, incorporating a smaller group, has a relatively lower critical temperature (Tc = 182 K (1), Tc = 221 K (2), Tc = 227 (3) and Tc1 = 236 K, Tc2 = 215 K (4)). We investigated the correlations between our systematic crystal design, substituent size, and the spin crossover profiles.

Sandwich compounds often exhibit various phase transitions, including those to plastic phases. To elucidate the general features of the phase transitions in metallocenium salts, the thermal properties and crystal structures of [Fe(C5 Me5 )2 ]X ([1]X), [Co(C5 Me5 )2 ]X ([2]X), and [Fe(C5 Me4 H)2 ]X ([3]X) have been investigated, where the counter anions (X) are Tf2 N (=(CF3 SO2 )2 N- ), OTf (=CF3 SO3- ), PF6 , and BF4 . The Tf2 N salts commonly undergo phase transitions from an ordered phase at low temperatures to an anion-disordered phase, followed by a plastic phase and finally melt at high temperatures. All these salts exhibit a phase transition to a plastic phase, and the transition temperature generally decreases with decreasing cation size and increasing anion size. The crystal structures of these salts comprise an alternating arrangement of cations and anions. About half of these salts exhibit phase transitions at low temperatures, which are mostly correlated with the order-disorder of the anion.