The thiolate-bridged diiron carbonyl complex [{Fe(μ-PyBPT-κ 3 N,C,S)(CO) 2 }Fe(CO) 3 ] (1) consists of two units, Fe(PyBPT)(CO) 2 and Fe(CO) 3 , where the N,C,S-pincer ligand PyBPT is a doubly deprotonated form of 3′-(2″-pyridyl)-1,1′-biphenyl-2-thiol. The two Fe complex units are connected through a thiolate S atom, π coordination, and an Fe−Fe bond. Diiron complex 1 reacted with 1 equiv of dimethylphenylphosphine to form the CO substitution product [{Fe(μ-PyBPT-(2), which has a polarized Fe−Fe bond. A further reaction of 3 with PMe 2 Ph produced the N,C,S-pincer iron(II) complex trans-[Fe(PyBPT-κ 3 N,C,S)(CO)(PMe 2 Ph) 2 ] (4) and the iron(0) complex trans-[Fe(CO) 3 (PMe 2 Ph) 2 ]. 1,2-Bis(diphenylphosphino)benzene (dppbz) abstracted the Fe(CO) 3 unit from 1 to give the dimeric diiron(II,II) complex [{Fe(μ-PyBPT-κ 3 N,C,S)(CO) 2 } 2 ] (7) and the iron(0) complex [Fe(CO) 3 (dppbz)]. The asymmetric bridging ligand PyBPT and coordination of the phosphines induce polarization of the Fe−Fe bond, which leads to the formation of the iron(II) and iron(0) complexes via heterolytic Fe−Fe cleavage. Electrochemical properties of 3 and 4 were investigated by cyclic voltammetry. Complex 3 showed two one-electron-reduction processes, the potentials of which are ca. 0.4 V more negative than those of 1. Electrocatalytic proton reduction by 3 was investigated, and the efficiency was comparable to that of 1.

A thermal reaction of 6-(4''-dibenzothienyl)-2,2'-bipyridine (bpyDBT) with [Ru(3)(CO)(12)] produced a sulfur-bridged triruthenium complex via double carbon-sulfur bond cleavage and CO insertion, while a diiron(I,I) complex containing a thiametallacycle was obtained by a photochemical reaction of bpyDBT with [Fe(CO)(5)].

CrystEngComm COMMUNICATION Tsunehisa Kimura et al. Single-crystal structure determination from microcrystalline powders (~5 µm) by an orientation attachment mountable on an in-house X-ray diffractometer

A technique for collecting single-crystal X-ray diffraction data using a suspension of microcrystalline powder is reported. The technique developed is based on the three-dimensional alignment of microcrystals by the intermittent rotation of the suspension under static magnetic field, in combination with in situ X-ray measurements. The magnetic attachment required to perform these in situ measurements is significantly simplified because the shutter system equipped with the magnetic system in the previous reported attachment is not necessary in the current technique owing to the application of intermittent rotation. Using this technique, the measurement time is significantly decreased in comparison to that required in our previous procedure. The successful performance of this technique is demonstrated by the structural determination of L-alanine from its microcrystalline powder.

In this study, the magnetically oriented microcrystal suspension (MOMS) method is combined with the shutterless continuous rotation method. In the MOMS method, the suspension has to be rotated to maintain the three‐dimensional orientation of microcrystals. This means that it is compatible with the continuous rotation method, which also utilizes sample rotation. The time constants of the two methods should match to allow their successful combination. The conditions required for the MOMS method for combination with the continuous rotation method are investigated. Experiments are performed with a complementary metal–oxide semiconductor (CMOS) detector and the restriction imposed on the time constant for the MOMS method by the continuous rotation method is examined. The combination of these two methods is a promising approach for realizing the structure analyses of biomolecules from their microcrystalline powders.

Our previous studies detected the presence of a photoinitiator 2-methyl-4′-(methylthio)-2-morpholinopropiophenone (MTMP) in an intravenous (i.v.) injection bag solution. Importantly, MTMP has demonstrated cytotoxicity for normal human peripheral blood (PB) mononuclear cells (MNC). Cell death pathways have two well-known modes, apoptosis and necrosis. But it has not been clear whether MTMP induced apoptosis or necrosis in normal human PB MNC. In the present in vitro study, we examined normal human PB MNC for the frequencies of apoptosis and necrosis and changes upon exposure to MTMP. We observed time-dependent changes in MNC viability with MTMP. We also assessed the activity of caspases-3/7. The results demonstrated that MTMP induced apoptosis in normal human PB MNC after 24 h. In addition, MTMP induced caspases-3/7 in a time-dependent manner. In conclusion, we suggest that MTMP induces apoptosis in a caspase-dependent pathway in vitro.Key words photoinitiator; apoptosis; caspase-3; caspase-7; cytotoxicity; human mononuclear cell Photoinitiators are used in a broad range of commercial and biological applications such as printing, 1) dentistry, 2) encapsulation of pancreatic islet cells, 3,4) and blood vessel adhesives.5) Thus, a high level of daily exposure to photoinitiators is possible. In previous in vitro studies, it was reported that photopolymerizing agents were cytotoxic. The photoinitiators Sarcat CD 1012, Araidite GY 281 and Epon 825 were cytotoxic to L929 cells, 6) and 4-octylphenyl phenyliodoniumhexafluoroantimonate (OPIA) also was severely cytotoxic.7) In other studies, Irgacure 2959 was found to be the least toxic photoinitiator while 1-hydroxycyclohexyl phenyl ketone (Irgacure 184) and 2,2-dimethoxy-2-phenylacetophenone (Irgacure 651) were significantly more toxic to human fetal osteoblasts. 8)In our recent study, we detected the presence of the photoinitiator 2-methyl-4′-(methylthio)-2-morpholinopropiophenone (MTMP) at approximately 2.8 mg/bag (5.6 µg/mL) in an intravenous (i.v.) injection bag solution. We demonstrated that MTMP was cytotoxic to normal human peripheral blood (PB) mononuclear cells (MNC). 9)

In previous studies, we detected the photoinitiators 1-hydroxycyclohexyl phenyl ketone (1-HCHPK) and 2-methyl-4'-(methylthio)-2-morpholinopropiophenone (MTMP) in an intravenous injection solution. Importantly, 1-HCHPK and MTMP have been demonstrated to be cytotoxic to normal human peripheral blood (PB) mononuclear cells (MNC). Cell death (apoptosis) pathways can be classified into two modes, caspase-dependent and -independent pathways. However, it is unclear whether methyl 2-benzoylbenzoate (MBB) induces the caspase-dependent and/or -independent pathway in normal human PBMNC. In the present in vitro study, we examined the levels of MBB in a solution from an intravenous fluid bag and the cytotoxicity of MBB towards normal human PBMNC via the caspase-8-, caspase-9-, or apoptosis-inducing factor (AIF)-mediated apoptosis pathways. We found that extracts from the injection solution had been contaminated with approximately 80 μM of the photoinitiator MBB. In addition, MBB induced apoptosis in the high concentration range in normal human PBMNC in vitro. Moreover, we found that MBB-induced apoptosis occurs via the caspase-9 pathway, but not the AIF pathway. In conclusion, we suggest that MBB has cytotoxic effects on normal human PBMNC in vitro, which are mediated via the caspase-dependent pathway.

Dichloromethane (DCM) and 1,2-dichloropsropane (DCP) have various uses, including being solvents for paint removers. Photoinitiators are also used in a wide range of commercial applications such as printing. These chemicals have been shown to induce cytotoxic effects. In the present study, we evaluated the combined effects of DCM or DCP from paint removers and photoinitiators used in printing on normal human embryonic lung fibroblasts with the aim of preventing occupational injuries. We showed that DCP, 2,2-dimethoxy-2-phenylacetophenone (2,2-DMPAP), 2-ethylhexyl-4-(dimethylamino) benzoate (2-EHDAB), 1-hydroxycyclohexyl phenyl ketone (1-HCHPK), and methyl 2-benzoylbenzoate (MBB) induced cytotoxicity, whereas DCM and 2-isopropylthioxanthone (2-ITX) did not. In addition, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone (MTMP) caused a slight increase in cytotoxicity. The combination of DCP and the four photoinitiators (2,2-DMPAP, 2-EHDAB, MBB, and MTMP) significantly induced cytotoxicity and also led to apoptosis. In conclusion, the combination of DCP and photoinitiators may increase the risk of respiratory diseases.