New Hypercoordinating Organostannanes for the Modular Functionalization of Mono- and Polystannanes: Synthetic and Computational Studies

In this paper we outline two major findings. The first is that we describe how designer hypercoordinate stannanes can be made from simple substitutions, and by extension, designer tin polymers, at least partially, using these methods. The second is that using advanced DFT methods, 119Sn NMR frequencies have been accurately calculated for select hypercoordinate tin compounds. This accuracy provides a means for further investigation of an important bonding interaction in the solution phase, and is of significant interest to small molecule tin chemists.

CO2 Derivatives of Molecular Tin Compounds. Part 2: Carbamato, Formato, Phosphinoformato and Metallocarboxylato Complexes

Single-crystal X-ray diffraction structures of organotin compounds bearing hemicarbonate and carbonate ligands were recently reviewed by us—“CO2 Derivatives of Molecular Tin Compounds. Part 1: Hemicarbonato and Carbonato Complexes”, Inorganics2020, 8, 31—based on crystallographic data available from the Cambridge Structural Database. Interestingly, this first collection revealed that most of the compounds listed were isolated in the context of studies devoted to the reactivity of tin precursors towards carbon dioxide, at atmospheric pressure or under pressure, thus highlighting the suitable disposition of Sn to fix CO2. In the frame of a second part, the present review carries on to explore CO2 derivatives of molecular tin compounds by describing successively the complexes with carbamato, formato, and phosphinoformato ligands, and obtained from insertion reactions of carbon dioxide into Sn–X bonds (X = N, H, P, respectively). The last chapter is devoted to X-ray structures of transition metal/tin CO2 complexes exhibiting metallocarboxylato ligands. As in Part 1, for each tin compound reported and when described in the original study, the structural descriptions are supplemented by synthetic conditions and spectroscopic data.

Respiratory Protection Programs (RPP) Implementation at Production Unit of A Tin Smelter at Bangka Belitung Islands Province

The fume generated from the reaction of flux and molten tin produces tin compounds in the atmosphere which potentially lead to stanosis or also known as tin pneumoconiosis after chronic inhalation and prolonged exposure in the workplaces e.g. in smelter industries. The risk can be minimized by implementing Respiratory Protection Program (RPP). This study aimed to evaluate the implementation of RPP at one smelter industries in Bangka Belitung Province. This is a evaluation study that qualitatively evaluate the implementation of RPP. eigth RPP elements from National safety Council (NSC) Australia was used as guideline. The secondary data from Occupational Health and Safety inspection and monitoring report at one of tin smelter from Department of Manpower (Disnaker), Banga Belitung Island province. It was found that several RPP elements have not been fully implemented, which were (1) compliance with respirator standards, (2) no selection of respirators procedure, (3) no protective clothing, (4) no fit testing execution, (5) improper management of cleaning and inspections, and (6) no evaluation of respirator usage. Moreover, specific work process that need Supplied Air Respirator (SAR) has not been anticipated, and improvement in the training materials, periodic training schedule and evaluation of the Respiratory Protection Program were emphasized. There were 3 informants in this study consisting of company managers, safety officers, and labor inspector. The implementation of RPP at PT X. Tin needs to be enhanced. Continuous coaching, monitoring, inspection, and evaluation related to the Respiratory Protection Program must be carried out more intensively both internally and externally from the government.

The Effect of Tin Compounds on the Lipid Peroxidation Level of Russian Sturgeon Fresh and Cryopreserved Sperm

The effect of organotin compounds (OTs) on the accumulation of the lipid peroxidation (LPO) carbonyl by-products, which react with thiobarbituric acid (TBARS) in fresh and cryopreserved sperm of Russian sturgeon, was studied. It was found that incubation (1 hour) of Russian sturgeon sperm with OTs (CH3SnCl3, (CH3)2SnCl2, (CH3)3SnCl, (n-C4H9)2SnCl2, (n-C4H9)3SnCl, (C6H5)2SnCl2, (C6H5)3SnCl) in concentration 0.1 mM led to the promotion of the accumulation of TBARS in native semen. Dimethyl- (DMT) and diphenyltin dichlorides (DPT) exhibited the greatest promoting activity, and the LPO level of both native and cryopreserved sperm of Russian sturgeon, including those in modified Stein's cryomedium, increased in the presence of these compounds. It was found that Russian sturgeon's cryopreserved sperm had lower sensitivity to the promotion of sperm LPO by DMT and DPT compared with the native sperm. The protective effect of Stein’s cryomedium decreased in the presence of the studied OTs. The results suggest that accumulation of OTs by gonad of fish is another stress factor affecting the cell productivity in the cryopreservation process.

CO2 Derivatives of Molecular Tin Compounds. Part 1: Hemicarbonato and Carbonato Complexes

This review focuses on organotin compounds bearing hemicarbonate and carbonate ligands, and whose molecular structures have been previously resolved by single-crystal X-ray diffraction analysis. Most of them were isolated within the framework of studies devoted to the reactivity of tin precursors with carbon dioxide at atmospheric or elevated pressure. Alternatively, and essentially for the preparation of some carbonato derivatives, inorganic carbonate salts such as K2CO3, Cs2CO3, Na2CO3 and NaHCO3 were also used as coreagents. In terms of the number of X-ray structures, carbonate compounds are the most widely represented (to date, there are 23 depositions in the Cambridge Structural Database), while hemicarbonate derivatives are rarer; only three have so far been characterized in the solid-state, and exclusively for diorganotin complexes. For each compound, the synthesis conditions are first specified. Structural aspects involving, in particular, the modes of coordination of the hemicarbonato and carbonato moieties and the coordination geometry around tin are then described and illustrated (for most cases) by showing molecular representations. Moreover, when they were available in the original reports, some characteristic spectroscopic data are also given for comparison (in table form). Carbonato complexes are arbitrarily listed according to their decreasing number of hydrocarbon substituents linked to tin atoms, namely tri-, di-, and mono-organotins. Four additional examples, involving three CO2 derivatives of C,N-chelated stannoxanes and one of a trinuclear nickel cluster Sn-capped, are also included in the last part of the chapter.

Experimental and Theoretical Study on the False Positive of Monomethyltin Determination in Toys Based on Gastric Juice Migration

Background. Organic tin compounds (OTCs), a group of high-risk hazardous substances, are highly concerned in safety regulation of consumer products especially for toys because they can cause serious damage to organs after prolonged or repeated exposure. Gastric juice migration is nowadays widely implemented to assess organic tin intake from toys or food-contact materials; however, the followed up detection method using sodium tetraethylborate [NaB(Et4)] as a derivatization agent may directly lead to false positive of monomethyltins (MMT). Objective. In order to avoid the phenomena of false positive of MMT in the course of laboratory testing of toys, it is necessary and important to perform relative experimental and theoretical studies to reveal the cause of false positive of MMT. Method. With metal tin powder as a representative of inorganic tin which existed in real samples, it was treated with artificial gastric juice (0.07 mol/L·HCl), followed by ethyl derivatization using sodium tetraethylborate [NaB(Et)4] and then analyzed by gas chromatography-mass spectrometry (GC-MS) according to the procedure specified in the standard of EN 71-3:2013+A3:2018 issued by the European Committee for Standardization (CEN). Results. Without any OTCs in the starting materials, MMT false positive can be reproduced by detecting 0.56 mg/L of triethylmethyltin (TEMT) together with approximately 1000 mg/L of tetraethyltin (TeET), which is similar to real samples. Further, it is demonstrated that the detected amount of TEMT is linearly related with the added amount of NaB(Et)4, and that the formation of TEMT (methyl derivative) is easier than TeET (ethyl derivative) even though the ethyl group is present in a larger amount than the methyl group. Conclusions. The phenomena of MMT false positive which occurred in the laboratory testing of toys is mainly because that TEMT is highly likely to be obtained from the reaction of inorganic tin and trace level of methylation agent impurities contained in the derivatization reagent—NaB(Et)4. To avoid MMT false positive, it is concluded that the maximum acceptable mole ratio of methylation agent impurities contained in NaB(Et)4 is approximately 0.028%. This research is helpful to be aware of methylation impurities and is favorable to avoid false judgment caused by MMT false positive in routine analysis of toys.

Hydrogen rich water ameliorate Trimethyltin induced spatial learning and memory impairment by regulation of Siah-1

Background: As an important member of organic tin compounds, Trimethyltin (TMT) exists widely in industrial and agricultural productions. TMT can induce significant neurodegeneration in the limbic system, particular in hippocampus. However, the molecular mechanisms in TMT-induced learning and memory impairment are not fully clear. Thus, this research was to explore the role of Synaptophysin (SYP) and Ubiquitin-ligating enzyme Siah-1 in TMT-induced nerve impairment and the protective effect of hydrogen rich water (HRW). Methods: Male BALB/c mice were randomly divided into 4 groups: control group (saline, 4 ml/d, i.p.for seven days), HRW group (4 ml/d, i.p.for seven days) , TMT group (2.25mg/kg, i.p. at the seventh day ), and HRW plus TMT group. The spatial learning and memory was tested by Morris water maze, the protein level of SYP and Siah-1were determined by western blot& immunocytochemical analysis, and the tin contents were detected by ICP-MS. Results: The TMT-treated mice showed significant learning and memory disability. Moreover, TMT increased the level of Siah-1, reduced the expression of SYP in hippocampus and cortex. After 7 days of continuous pretreatment with HRW, the mice showed better memory ability, the expression of Siah-1 and tin content decreased accompanied with the increase of SYP. Conclusions: These results showed that HRW ameliorated the decrease of SYP and the nerve impairment induced by TMT, reduced tin content and up-regulated the expressions of Siah-1, and it might be an important role in the protection of neurodegenerative diseases induced by TMT.