The anion fac-[Fe(CO)3I3]− undergoes rapid decomposition to release CO and involve iodine radical. The CO-release can be tuned by its cations. The radical causes severe cytotoxicity which may endow the anion a great potential as an anticancer drug.

Four iron(II) carbonyl complexes, fac-[Fe (CO) 3 X 2 (py)] (X = I − , 1 and Br − , 3), fac-[{Fe (CO) 3 X 2 } 2 (bipy)] (X = I − , 2 and Br − , 4), were facilely synthesized by reacting cis-[Fe (CO) 4 X 2 ] (X = I − , Br −) with pyridine (py) and 4,4 0-dipyridine (bipy) ligands, respectively, in good yields (70%85%). These complexes were fully characterized, and the structures of Complexes 2 and 3 were crystallographically analyzed. In dimethyl sulfoxide, they decomposed rapidly to release carbon monoxide (CO), and in methanol, they showed better stability which allowed kinetically analyzing their decomposing behaviors. The selfdecomposing in methanol fitted first-order kinetics with a half-time ranging from several minutes to 1 h. Our results suggested that the ligand with great conjugation (bipy) and strong electron-donating capability (iodide) could stabilize the iron(II) carbonyl complexes. The decomposition of the iodo complexes (1 and 2) involved the production of iodine radicals. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assessments revealed that the efficacy against human bladder carcinoma cell line (RT112) is in the following trend: 1 > 2 > 3 > 4. The relatively strong efficacy of Complexes 1 and 2 is mainly contributed to the in situ generated iodine radicals. The combination of the cytotoxicity of the in situ generated radicals with the anticancer activity of CO as reported in literatures may lead to developing novel anticancer drugs with enhanced efficacy. K E Y W O R D S anticancer activity, carbon monoxide release and kinetics, iodine radical, iron carbonyl compounds, solvolysis Zhuming Guo and Jing Jin contributed equally to this work.

Non-typhoidal Salmonella (NTS) typically causes self-limiting diarrheal disease but may occasionally lead to invasive infection. This study investigated the epidemiology and antimicrobial resistance of children with NTS infection between 2012 and 2019. We retrospectively analyzed pediatric patients with NTS infections, confirmed by positive cultures, in a tertiary medical center in Taiwan in 2012 and 2019. Clinical features and laboratory data of the patients were collected. Changes in the serogroup category and antimicrobial resistance were also analyzed. Of the total 797 isolates collected, 55 had NTS bacteremia. Compared with the resistance rates in 2012, the rates of resistances to third-generation cephalosporin and ciprofloxacin were significantly higher in 2019 (4.1% vs 14.3%, P < 0.001; 1.9% vs 28.6%, P < 0.001), especially in groups B, D, and E. Moreover, we observed significantly higher antimicrobial resistance (25.3%) to third-generation cephalosporin, and approximately half the NTS isolates in the infant group were multidrug resistant – a higher rate than those of other age groups in 2019. Invasive NTS often presented with a longer fever duration, lower hemoglobin level and with no elevated C-reactive protein (P < 0.05). Non-invasive NTS isolates in 2019 were significantly more resistant to ceftriaxone (P < 0.001) and ciprofloxacin (P < 0.001) than those in 2012. The antimicrobial resistance of NTS in children has increased progressively in the past decade, and different serogroups exhibited different resistance patterns. During this period, infants showed the highest risk to get a third-generation cephalosporin-resistant NTS infection. The high rates of antimicrobial resistance among children with NTS in Taiwan merit continual surveillance.

No abstract