Long-term outcomes of robot-assisted versus minimally invasive esophagectomy in patients with thoracic esophageal cancer: a propensity score-matched study.

BACKGROUND: Recently, robot-assisted minimally invasive esophagectomy (RAMIE) has gained popularity worldwide. Some studies have compared the long-term results of RAMIE and minimally invasive esophagectomy (MIE). However, there are no reports on the long-term outcomes of RAMIE in Japan. This study compared the long-term outcomes of RAMIE and MIE. METHODS: This retrospective study included 86 patients with thoracic esophageal cancer who underwent RAMIE or MIE at our hospital from June 2010 to December 2016. Propensity score matching (PSM) was employed, incorporating co-variables such as confounders or risk factors derived from the literature and clinical practice. These variables included age, sex, body mass index, alcohol consumption, smoking history, American Society of Anesthesiologists stage, comorbidities, tumor location, histology, clinical TNM stage, and preoperative therapy. The primary endpoint was 5-year overall survival (OS), and the secondary endpoints were 5-year disease-free survival (DFS) and recurrence rates. RESULTS: Before PSM, the RAMIE group had a longer operation time (min) than the MIE group (P = 0.019). RAMIE also exhibited significantly lower blood loss volume (mL) (P < 0.001) and fewer three-field lymph node dissections (P = 0.028). Postoperative complications (Clavien-Dindo: CD ≥ 2) were significantly lower in the RAMIE group (P = 0.04), and postoperative hospital stay was significantly shorter than the MIE group (P < 0.001). After PSM, the RAMIE and MIE groups consisted of 26 patients each. Blood loss volume was significantly smaller (P = 0.012), postoperative complications (Clavien-Dindo ≥ 2) were significantly lower (P = 0.021), and postoperative hospital stay was significantly shorter (P < 0.001) in the RAMIE group than those in the MIE group. The median observation period was 63 months. The 5-year OS rates were 73.1% and 80.8% in the RAMIE and MIE groups, respectively (P = 0.360); the 5-year DFS rates were 76.9% and 76.9% in the RAMIE and MIE groups, respectively (P = 0.749). Six of 26 patients (23.1%) in each group experienced recurrence, with a median recurrence period of 41.5 months in the RAMIE group and 22.5 months in the MIE group. CONCLUSIONS: Compared with MIE, RAMIE led to no differences in long-term results, suggesting that RAMIE is a comparable technique.

Long-term surgical outcomes of gastric neuroendocrine carcinoma and mixed neuroendocrine-non-neuroendocrine neoplasms.

BACKGROUND: Neuroendocrine carcinoma (NEC) and mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN) are extremely rare subtypes of gastric cancer. MiNEN is a mix of carcinomatous components and neuroendocrine neoplasm in the same lesion. NEC and MiNEN have a poor prognosis, are difficult to diagnose, and have no established treatment. Herein, we assessed the clinicopathological characteristics and long-term surgical outcomes of gastric NEC and MiNEN patients in our hospital. METHODS: We retrospectively assessed 1538 patients pathologically diagnosed with gastric cancer and who underwent curative surgical resection at our institution between January 1999 and October 2021. Of these patients, 25 (1.6%) were pathologically diagnosed with neuroendocrine neoplasms. From these 25 patients, we retrospectively analyzed the clinicopathological characteristics and surgical outcomes of 13 (0.8%) patients pathologically diagnosed with NEC or MiNEN. RESULTS: The NEC and MiNEN patients consisted of 11 men and 2 women [mean age, 74 (62-84) years]. The preoperative histological diagnoses were NEC (n = 4) and adenocarcinoma (n = 9). The final pathological diagnoses were large cell neuroendocrine carcinoma (LCNEC; n = 7) and MiNEN (n = 6). Total gastrectomy was the most common surgical procedure (9/13, 69.2%), followed by distal gastrectomy (3/13, 23.1%) and proximal gastrectomy (1/13, 7.7%). Immunohistochemical staining showed 8 CD56-positive patients. All 13 patients were positive for chromogranin A and synaptophysin. The mean Ki-67 value was 64.8 (0-95)%, and the mean mitotic score was 107.9 (0-400). Nine patients survived without recurrence postresection. The median postresection overall survival time was 68.7 (8.0-129) months. The 5-year survival rate was 0.75 ([95% CI] 0.408-0.912). CONCLUSION: The surgical treatment outcomes of NEC and MiNEN patients were relatively favorable. Although evidence concerning the effectiveness of surgery alone is meager, radical resection as part of multidisciplinary treatment including chemotherapy can potentially improve prognosis.

[A Case of Combined Modality Therapy for Progressive Esophagus Cancer with Perforation Due to Preoperative Chemotherapy].

A nearby doctor sensed incongruity in deglutition as a chief complaint from a 56-year-old man. A middle intrathoracic esophagus cancer was subsequently diagnosed and referred to our department. We started FP therapy based on the preoperative chemotherapy guidelines, but perforation of esophageal cancer developed. We conducted chest drainage, and attempted to improve the patient's overall status with antibiotic medical treatment and hyperalimentation; single-stage operations were performed. As tumor invaded the left pleura, surgery occurred for R2 resection of the left lung. Subsequently, we started nivolumab therapy because we give DCF therapy and detected a liver metastasis and we continue it now and survive.

[Combined Modality Therapy for HER2-Positive Progressive Stomach Cancer Metastasis Achieving Treatment Response-A Case Report].

The patient was a 73-year-old man whose chief complaint was a 1-month history of anorexia and weight loss. Pyloric stenosis due to a circumferential type 2 lesion was detected on the pylorus ring from the gastric angle. Close inspection revealed a diagnosis of progressive stomach cancer cT3N+M0, stage Ⅲ. We judged that perioperative radical excision would be impossible and performed gastrojejunal bypass surgery. Postoperatively, the patient was treated with 2 courses of SOX plus trastuzumab and 7 courses of S-1. PR was identified, and a distal-side gastrectomy plus D2 lymph node dissection were performed as conversion surgery. The patient was discharged on postoperative day 9. For 1 year postoperative, no recurrence was noted. The prognosis of the unresectable gastric cancer is poor, but chemotherapy and conversion surgery in this case resulted in a favorable prognosis.

[A Case of Esophageal Malignant Melanoma during Follow-Up of Esophageal Melanosis Metastasis].

Man 62-years-old as for the case. In 2019, he was diagnosed with right hypopharyngeal cancer, and esophageal melanosis was noted on upper gastrointestinal endoscopy before treatment. We did a follow-up upper gastrointestinal endoscopy every year. At a follow-up upper gastrointestinal endoscopy performed in February 2021, he was histologically diagnosed with an esophageal primary malignant melanoma. Computed tomography showed no metastatic lesions. He underwent esophagectomy. He is currently being followed on an outpatient basis and has had no recurrence. Careful follow-up for esophageal melanocytosis is important for early diagnosis of esophageal primary malignant melanoma.

[Duodenal Stent Placement against Anastomotic Stenosis after Esophageal Cancer Resection-A Case Report].

A 53-year-old man was diagnosed as esophageal cancer, and esophagectomy was performed. Anastomotic stenosis was caused due to lymphorrhea and anastomotic leakage after surgery. Dilation was performed, though stenosis did not improved, we placed esophageal stent across the stenotic lesion. Pharyngitis occurred after indwelling esophageal stent, we hence removed the stent. Passage disorder was developed, we placed duodeneal stent which is more flexible. Stenosis is now palliated after placing duodeneal stent. Duodeneal stent could be an option for the tratment of anastomotic stenosis after esophageal surgery.

[A Case of Sigmoid Colon Neuroendocrine Cell Carcinoma Discovered by Defecation Disorder].

A 65-year-old man presented to our hospital with a chief complaint of abdominal pain during defecation. Abdominal contrast-enhanced CT showed circumferential wall thickening with contrast effects in the sigmoid colon, and multiple metastases in the liver. Colonoscopy revealed a type 2 colon tumor that was obstructing the passage. A diagnosis of sigmoid colon cancer and multiple liver metastases was made based on laparoscopic sigmoidectomy plus D3 dissection. Pathologically, the resected specimen was diagnosed as colorectal neuroendocrine cell carcinoma(NEC)that was positive for synaptophysin and CD56. Postoperatively, 8 courses of FOLFOX plus bevacizumab(BV)therapy were administered, but CT showed remarkable increase in liver metastasis, and he died 5 months after the operation. Colorectal NEC is a very rare disease, for which no chemotherapy has been shown to be effective. Since we encounterd a case of sigmoid colon NEC with multiple liver metastases that followed a rapid course, we have presented it along with a literature review.

Clinical Effects of Early Edaravone Use in Acute Ischemic Stroke Patients Treated by Endovascular Reperfusion Therapy.

Background and Purpose- Although several clinical studies suggested the beneficial effects of edaravone in acute ischemic stroke, most were performed under settings that differ from those in the current treatment strategy, which has dramatically changed with progress in reperfusion therapies. This study aimed to evaluate the efficacy of edaravone in patients with acute ischemic stroke treated by emergent endovascular reperfusion therapy. Methods- We conducted a retrospective observational study using a national administrative database. Patients with acute ischemic stroke treated by emergent endovascular reperfusion therapy were identified and dichotomized by whether edaravone was used within 2 days of admission. We compared the functional independence at hospital discharge, in-hospital mortality, and intracranial hemorrhage after admission between groups, adjusted by a well-validated case-mix adjustment model, in multivariate mixed-effect regression and propensity score matching analyses. Results- Of 11 508 patients eligible for analysis, 10 281 (89.3%) received edaravone therapy. The established risk adjustment model had good predictability for functional independence at hospital discharge, with an area under the receiver operating characteristic curve of 0.74. In the mixed-effect regression analysis, edaravone use was significantly associated with greater functional independence at hospital discharge (32.3% in the edaravone group versus 25.9% in the control group; adjusted odds ratio, 1.21; 95% confidence interval, 1.03-1.41), lower in-hospital mortality (9.9% in the edaravone group versus 17.4% in the control group; adjusted odds ratio, 0.52; 95% confidence interval, 0.43-0.62), and reduced intracranial hemorrhage after admission (1.4% in the edaravone group versus 2.7% in the control group; adjusted odds ratio, 0.55; 95% confidence interval, 0.37-0.82). Results of the propensity score matching analysis corroborated these results. Conclusions- This retrospective analysis of a Japanese nationwide administrative database suggested that combination therapy with edaravone and endovascular reperfusion therapy could be a promising therapeutic strategy in acute ischemic stroke. Further randomized control trials are warranted.

[A Case of Diverticular Perforation of Sigmoid Colostomy during FOLFIRI plus BevacizumabTreatment].

A 61-year-old man with a diagnosis of rectal cancer underwent assisted laparoscopic rectal amputation. Recurrence occurred, and treatment with FOLFIRI plus bevacizumab was initiated at our department. After 12 treatment courses, he developed abdominal pain at home. Emergency surgery was performed for the stoma perforation. We confirmed the diverticular perforation in the resected specimen. In our case, we found a para-stoma hernia and considered it to be the cause of perforation together with bevacizumab administration. Molecular-targeted drugs contribute to improving treatment outcomes in malignant tumors, but specific adverse events such as perforation have been reported. In addition, as causes of sigmoid colon perforation such as that of the stoma, cases associated with intestinal operation, constipation, and para-stoma hernia are suggested. In our case of hyperpolarization due to a para-stoma hernia, administration of bevacizumab was considered the cause of the perforation. This was a case that could be rescued with surgery.

Outcome of traumatic brain injury in patients on antiplatelet agents: a retrospective 20-year observational study in a single neurosurgery unit.

OBJECTIVE: To evaluate the outcomes after Traumatic Brain Injury (TBI) in patients taking Antiplatelet Agents (APAs). METHODS: We reviewed the clinical records of 934 patients with TBI between 1995 and 2014. Multivariate analysis was performed to correlate patient outcome with various factors, including pre-injury APA intake. Cause of death was compared among groups stratified according to APA dose. RESULTS: Increasing doses of APAs were positively associated with mortality rates, however, differences were primarily due to non-traumatic causes. APA therapy before injury was independent of both overall and non-traumatic mortality. In multivariate analysis, mortality was significantly correlated with the Charlson Comorbidity Index (CCI), pupillary abnormalities, age, Glasgow Coma Scale (GCS), head Abbreviated Injury Scale (AIS) and additional AIS >2. Conversely, non-traumatic mortality was associated with age, GCS, additional AIS >2 and CCI, though only CCI was correlated with increasing APA dose. Furthermore, no significant difference was observed when comparing mortalities according to CCI score among APA groups. Thus, mortalities were associated with the severity of pre-existing conditions rather than APA dose. CONCLUSIONS: The outcome of patients with TBI, who were on APAs may be determined by the severity of pre-existing conditions. Aggressive TBI treatment should be implemented when tolerable, regardless of pre-existing APA treatment status.

[A Long-Term Disease-Free Survival Case of Synchronous Pulmonary and Liver Metastasis of Rectal Cancer with Systemic Chemotherapy and Radiofrequency Ablation Therapy for Liver Metastasis].

A 55-year-old woman underwent laparoscopic anterior resection and D2 lymph node dissection for recto-sigmoid colon cancer in November 2014, which was diagnosed as T3N1M1(H3, PUL2), stage IV , for the purpose of preserving the ileus. FOLFOX therapy with panitumumab(Pmab)was started in January 2015.A t the end of 11 courses, pulmonary metastasis changed to CR, and liver metastasis was down-graded to H2 on the CT.Because of the risk of hepatic dysfunction with advanced fatty liver due to chemotherapy and extrahepatic lesions, we chose radiofrequency ablation(RFA)therapy for liver metastasis.Pmab combined FOLFIRI therapy was administered, and maintenance therapy was initiated.This patient is alive 2 years and 7 months after surgery and 10 months after RFA without relapse.It is suggested that RFA therapy for liver metastasis of colon cancer with pulmonary metastasis combined with chemotherapy could be an effective treatment strategy.

[A Case of Successful Collective Treatment of Colon Cancer with Multiple Metachronous Pulmonary Metastases].

A case is a 46-year-old woman visited us with a chief complaint of bloody stools. A diagnosis of rectal cancer(Rs)was made, and laparoscopic resectomy plus D3 was performed. After progressing to pT4a(SE)N2, M0, pStage III b, postoperative adjuvant chemotherapy(6 courses of XELOX)was administered. Two months after initiating chemotherapy, since the CEA value increased, chest abdominal CT was performed. Five nodules were found in the bilateral lungs and diagnosed as lung metastases(PUL2). Systemic chemotherapy(IRIS plus BV)is administered to PUL2(Grade C)of rectal cancer metachronous metastases. After 3 courses, the effect judgment was SD. Based on the recurrence period from postoperative adjuvant chemotherapy and the findings during this time, it was judged that weight loss surgery was appropriate for the rectal cancer lung metastatic lesions in which chemotherapy was ineffective, and partial resection of both lungs under thoracoscopic assistance was performed. Systemic chemotherapy(TAS-102 plus BV)was initiated to prevent postoperative recurrence. The patient is currently alive without relapse after 12 months. We reported a case of metachronous metastasis of colon cancer in which multidisciplinary treatment was successful.

Modulation of a Molecular π-Electron System in a Purely Organic Conductor that Shows Hydrogen-Bond-Dynamics-Based Switching of Conductivity and Magnetism.

New important aspects of the hydrogen-bond (H-bond)-dynamics-based switching of electrical conductivity and magnetism in an H-bonded, purely organic conductor crystal have been discovered by modulating its tetrathiafulvalene (TTF)-based molecular π-electron system by means of partial sulfur/selenium substitution. The prepared selenium analogue also showed a similar type of phase transition, induced by H-bonded deuterium transfer followed by electron transfer between the H-bonded TTF skeletons, and the resulting switching of the physical properties; however, subtle but critical differences due to sulfur/selenium substitution were detected in the electronic structure, phase transition nature, and switching function. A molecular-level discussion based on the crystal structures shows that this chemical modification of the TTF skeleton influences not only its own π-electronic structure and π-π interactions within the conducting layer, but also the H-bond dynamics between the TTF π skeletons in the neighboring layers, which enables modulation of the interplay between the H-bond and π electrons to cause such differences.

A tricky water molecule coordinated to a verdazyl radical-iron(II) complex: a multitechnique approach.

The first iron complexes of high-spin iron(II) species directly coordinated to verdazyl radicals, [Fe(II)(vdCOO)2(H2O)2]·2H2O (1; vdCOO(-) = 1,5-dimethyl-6-oxo-verdazyl-3-carboxylate) and [Fe(II)(vdCOO)2(D2O)2]·2D2O (2), were synthesized. The crystal structure of 1 was investigated by single-crystal X-ray diffraction at room temperature and at 90 K. The compound crystallizes in the P1 space group with no phase transition between 300 and 90 K. The crystals are composed of discrete [Fe(II)(vdCOO)2(H2O)2] complexes and crystallization water molecules. In the complex, two vdCOO(-) ligands coordinate to the iron(II) ion in a head-to-tail arrangement and two water molecules complete the coordination sphere. The Fe-X (X = O, N) distances vary in the 2.069-2.213 Å range at 300 K and in the 2.0679-2.2111 Å range at 90 K, indicating that the iron(II) ion is in its high-spin (HS) state at both temperatures. At 300 K, one of the coordinated water molecules is H-bonded to two crystallization water molecules whereas the second one appears as loosely H-bonded to the two oxygen atoms of the carboxylate group of two neighboring complexes. At 90 K, the former H-bonds remain essentially the same whereas the second coordinated water molecule reveals a complicated behavior appearing simultaneously as tightly H-bonded to two oxygen atoms and non-H-bonded. The (57)Fe Mössbauer spectra, recorded between 300 K and 10 K, give a clue to this situation. They show two sets of doublets typical of HS iron(II) species whose intensity ratio varies smoothly with temperature. It demonstrates the existence of an equilibrium between the high temperature and low temperature forms of the compounds. The solid-state magic angle spinning (2)H NMR spectra of 2 were recorded between 310 K and 193 K. The spectra suggest the existence of a strongly temperature-dependent motion of one of the coordinated water molecules in the whole temperature range. Variable-temperature magnetic susceptibility measurements indicate an antiferromagnetic interaction (J(Fe-vd) = -27.1 cm(-1); H = -J(ij)S(i)S(j)) of the HS iron(II) ion and the radical spins with high g(Fe) and D(Fe) values (g(Fe) = 2.25, D(Fe) = +3.37 cm(-1)) for the HS iron(II) ion. Moreover, the radicals are strongly antiferromagnetically coupled through the iron(II) center (J(vd-vd) = -42.8 cm(-1)). These last results are analysed based on the framework of the magnetic orbitals formalism.

Correction: 57Fe Mössbauer spectroscopy and high-pressure structural analysis for the mechanism of pressure-induced unique magnetic behaviour in (cation)[FeIIFeIII(dto)3] (cation = Ph4P and nPrPh3P; dto = 1,2-dithiooxalato).

Correction for '57Fe Mössbauer spectroscopy and high-pressure structural analysis for the mechanism of pressure-induced unique magnetic behaviour in (cation)[FeIIFeIII(dto)3] (cation = Ph4P and nPrPh3P; dto = 1,2-dithiooxalato)' by Ryosuke Taniai et al., Dalton Trans., 2023, 52, 8368-8375.

Clinical complete response after trastuzumab deruxtecan 6th-line treatment for postoperative gastric cancer recurrence: a case report.

BACKGROUND: Despite the recent developments in the treatment of advanced or recurrent gastric cancer, the median survival time remains shorter than 15 months. Herein, we report a case of postoperative gastric cancer recurrence in which a complete clinical response was achieved with trastuzumab deruxtecan as 6th-line treatment. CASE PRESENTATION: A 70-year-old man underwent abdominal contrast-enhanced computed tomography (CT) during follow-up after rectal cancer surgery. The CT revealed an enlarged perigastric lymph node. After further examination, the patient's condition was diagnosed as gastric cancer cT2N1H0P0M0 cStage IIA. The patient underwent distal gastrectomy and D2 lymph node dissection. The resulting pathological diagnosis was pT1bN3aH0P0 pStageIIB, HER2 score 3+. Abdominal contrast-enhanced CT 19 months postoperatively revealed para-aortic lymph node recurrence, thus systemic chemotherapy courses were planned. The primary treatment was a combination of S-1, cisplatin, and trastuzumab administered in 11 courses. However, there was an enlargement of the para-aortic lymph node which was evaluated as progressive disease. Systematic chemotherapy with various regimens was continued until the 5th-line treatment. However, therapeutic benefits were not achieved and lung metastasis was observed. Trastuzumab deruxtecan (TDXD) was initiated as 6th-line treatment. Abdominal contrast-enhanced CT at 4 months after the start of treatment showed marked shrinkage of the enlarged para-aortic lymph node and disappearance of the lung metastasis in the right upper lung lobe, which was evaluated as partial response (PR). The para-aortic lymph node metastasis was evaluated as PR with only a slight accumulation of SUV-Max 2.66 with a shrinking trend by positron emission tomography-computed tomography (PET-CT) performed after 1 year. Tumor markers CEA, CA19-9, and CA125 also improved significantly. PET-CT after 1 year and 4 months showed no lymph node enlargement or accumulation, indicating a complete response (CR). All tumor markers also normalized. The patient has maintained clinical CR without additional treatment to date. CONCLUSIONS: We report the apparent first case of postoperative gastric cancer recurrence successfully treated with TDXD, achieving clinical CR with TDXD as a 6th-line treatment.

A series of weak ferromagnets based on a chromium-acetylide-TTF type complex: correlation of the structures and magnetic properties and origin of the weak ferromagnetism.

The crystal structures and magnetic properties of a series of new weak ferromagnets containing a chromium-acetylide-tetrathiafulvalene (TTF) type complex, [CrCyclam(C≡C-5-methyl-4'5'-ethylenedithio-TTF)2](2+) ([1](2+)), were investigated. The six new isostructural weak ferromagnets [1][BF4]2(PhF)2(MeCN), [1][ClO4]2(PhF)2(MeCN), [1][ReO4]2(PhCl)2(MeCN), [1][ClO4]2(PhBr)3, [1][ReO4]2(PhBr)3, and [1][ClO4]2(PhI)3 contain ferrimagnetic chain structures of [1](2+)∞ with different interchain distances that are dependent on the sizes of the anions and solvent molecules. Magnetic measurements of the salts revealed that the weak ferromagnetic transition temperature gradually increases from 14.5 to 26.0 K as the interchain distance decreases from 3.997(2) to 3.803(2) Å, while the remanent magnetization at 2 K decreases from 0.0215 to 0.0079 µB. The observed magnetic properties and crystal structures suggest that the weak ferromagnetism originates from the single-ion anisotropy of [1](2+), where a stronger interchain antiferromagnetic interaction not only causes a higher transition temperature but also suppresses the noncollinear canted spin alignment.

Malignant Melanoma Arising from Esophageal Melanosis and Synchronous with Esophageal Squamous Cell Carcinoma.

BACKGROUND Primary malignant melanoma of the esophagus is a rare disease. However, its exact etiology and progression from melanosis to malignant melanoma have not been elucidated due to its rarity. CASE REPORT We report a case of esophageal melanosis that progressed to malignant melanoma and was synchronous with esophageal squamous cell carcinoma. A male patient in his 60s was diagnosed with right hypopharyngeal cancer. Cervical dissection and chemoradiation therapy were performed. Esophageal melanosis was discovered using gastrointestinal endoscopy during a pre-treatment screening 2 years later and revealed a 0-Ia tumor in the middle thoracic esophagus, coinciding with the esophageal melanosis site. A biopsy revealed malignant melanoma. We performed thoracoscopic total thoracic esophagectomy. The resected specimen showed a 0-Ia lesion, and the invasion depth of the esophageal malignant melanoma was submucosal (pT1b-SM3), N0, Stage I. A 0-IIc lesion was found in the resected specimen [squamous cell carcinoma in situ, intraepithelial mucosal (pTis/T1a-EP), N0, Stage 0]. The patient has been recurrence-free for 18 months post-surgery without postoperative adjuvant chemotherapy and is still receiving outpatient followup. CONCLUSIONS The close relationship between esophageal melanosis and primary malignant melanoma of the esophagus has implicated the melanosis as the origin of the malignant melanoma. The coexistence of esophageal melanosis and esophageal cancer warrants improved patient followup, including biopsy and multiple endoscopic examinations after esophageal melanosis diagnosis.

Investigation of the unique magnetic behaviours of isomers in a 1,2-dithiooxalato-bridged diiron(II) complex.

1,2-Dithiooxalate (dto) can be employed as a bridging ligand and it exhibits symmetric (O,S-chelation) or asymmetric (O,O- and S,S-chelation) coordination forms. In this study, we prepared a novel dto-bridged diiron(II) complex, [{Fe(TPA)}2(µ-dto)](ClO4)2 (1), where TPA is tris(2-pyridylmethyl)amine. Interestingly, the bridging dto ligand exhibited not only the asymmetric form but also a linkage isomer and a diastereomer within the same crystal. Notably, the three isomers of 1 exhibited different magnetic properties, resulting in a multi-step spin crossover behaviour.

57Fe Mössbauer spectroscopy and high-pressure structural analysis for the mechanism of pressure-induced unique magnetic behaviour in (cation)[FeIIFeIII(dto)3] (cation = Ph4P and nPrPh3P; dto = 1,2-dithiooxalato).

A mixed-valence iron(II,III) coordination polymer, (Ph4P)[FeIIFeIII(dto)3] (2; Ph4P = tetraphenylphosphonium, dto = 1,2-dithiooxalato), exhibits a thermal hysteresis loop and a low temperature shift of the ferromagnetic phase transition temperature, with increasing pressure. The latter magnetic behaviour can also be observed in a novel compound (nPrPh3P)[FeIIFeIII(dto)3] (3; nPrPh3P = n-propyltriphenylphosphonium). To understand the structural information under pressure, we performed high-pressure powder X-ray diffraction, and the result suggests that there was no structural phase transition for either compound. Considering the 57Fe Mössbauer spectroscopy studies, both 2 and 3 may have a high transition entropy, and this finding is caused by pressure-induced unique magnetic behaviours.