Similar Reaction Products Research Articles

The role of carbon textile surface functionalities in reactive adsorption of vapor and liquid 2-chloroethyl ethyl sulfide: Evaluating interactions at the interface

A carbon textile (CT) was chemically modified to increase its surface activity and promote the adsorption and degradation of 2-chloroethyl ethyl sulfide (CEES) - a surrogate for mustard gas. CT was initially subjected to oxidation (CTO), and then heated under ammonia (CTON) or hydrogen sulfide (CTOS) atmosphere to incorporate nitrogen or sulfur functionalities, respectively. Detoxification experiments were performed in closed vials using either vapor or liquid forms of CEES. The maximum vapor weight uptakes on CT, CTO, CTOS, and CTON were 399, 372, 434, and 489 mg/g, respectively. All textiles were able to prevent the vaporization of CEES liquid droplets. Although similar reaction products were detected in both vapor and liquid systems, the marked differences in the extent of CEES chemical transformation on the surfaces of the textiles indicate distinct detoxification pathways influenced by surface chemistry. Even though the heterogeneous surface of CTO, enriched with oxygen surface groups, facilitated various reactions, hydrolysis was the predominant pathway. The thermal treatment, regardless of the atmosphere, reduced the oxygen content, decreasing the extent of hydrolysis. However, incorporating basic surface groups such as pyridines, amines, or weak acids such as thiols promoted dehydrohalogenation as the main detoxification pathway on these samples.

Reactions of Triisobutylaluminum with Unbridged or Bridged Group IV Metallocene Dichlorides

Reactions between zirconocene or hafnocene dichlorides and alkylaluminum activators are involved in several catalytic reactions. This study describes the products formed in reactions between unbridged metallocenes with varying steric profiles (Cp2ZrCl2 (1), Cp2HfCl2 (2), Cp*CpZrCl2 (3), Cp2*ZrCl2 (4), Cp2*HfCl2 (5)) or ansa-zirconocenes (rac-(2-methyl-SBI)ZrCl2 (6), and rac-(EBI)ZrCl2 (7); 2-methyl-SBI = rac-Me2Si(2-methyl-indenyl)2; rac-EBI = rac-C2H4(indenyl)2) with 12 equiv of triisobutylaluminum (TIBA). A 12:1 Al/Zr ratio was chosen because previous results (ACS Cent Sci. 2021, 7, 1225–1231) showed that an unbridged metallocene reacted with 12 equiv of TIBA to form mixtures of bridging metal hydrides in solution. This study shows that sterically open, unbridged metallocenes generate similar reaction products, but sterically crowded metallocenes do not react with TIBA. Rac-(EBI)ZrCl2 reacts with 12 equiv of TIBA to form a mixture of rac-(EBI)Zr(CH2CH(CH3)2)Cl (7a, major, ∼95%) and rac-(EBI)Zr(μ-Cl)(μ-CH2CH2)AliBu2 (7b, minor, ∼5%) after ∼10 min at room temperature. This mixture evolves over the course of ∼2 days to form rac-(EBI)Zr(μ-H)(μ-CH2CH2)AliBu2 (7c), rac-(EBI)ZrH(μ-H)2AliBu2 (7d), rac-(EBI)ZrH(μ-H)2[μ-H(AliBu2)2] (7e), and rac-(EBI)ZrH(μ-H)2[μ-Cl(AliBu2)2] (7f). However, 6 reacts with TIBA to form rac-(2-methyl-SBI)Zr(CH2CH(CH3)2)Cl (6a) as the only product.

Hybrid Cements: Mechanical Properties, Microstructure and Radiological Behavior.

The use of more eco-efficient cements in concretes is one of the keys to ensuring construction industry sustainability. Such eco-efficient binders often contain large but variable proportions of industrial waste or by-products in their composition, many of which may be naturally occurring radioactive materials (NORMs). This study explored the application of a new gamma spectrometric method for measuring radionuclide activity in hybrid alkali-activated cements from solid 5 cm cubic specimens rather than powder samples. The research involved assessing the effect of significant variables such as the nature of the alkaline activator, reaction time and curing conditions to relate the microstructures identified to the radiological behavior observed. The findings showed that varying the inputs generated pastes with similar reaction products (C-S-H, C-A-S-H and (N,C)-A-S-H) but different microstructures. The new gamma spectrometric method for measuring radioactivity in solid 5 cm cubic specimens in alkaline pastes was found to be valid. The variables involved in hybrid cement activation were shown to have no impact on specimen radioactive content. The powder samples, however, emanated 222Rn (a descendent of 226Ra), possibly due to the deformation taking place in fly ash structure during alkaline activation. Further research would be required to explain that finding.

Synthesis and Characterization of A[W2O2F9] (A = Li – Cs)

Herein, we report upon the in situ formation of WOF4 and its subsequent reaction with AF (A = Li – Cs) in aHF to produce A[W2O2F9] (A = Li – Cs). Structural analysis of the obtained compounds was performed using single‐crystal X‐ray diffraction. A comparison of the single‐crystal structures obtained here to the previously reported A[Mo2O2F9] (A = Li – Cs) and H3O[W2O2F9] salts is given. Additionally, IR and Raman spectroscopy were used to characterize each salt. These spectra were compared to calculated ones for the solid‐state structure of each salt using the DFT‐PBE0 density functional method. The calculated spectra were used to assign bands in the experimental spectra. Both MoOF4 and WOF4 gave similar reaction products under similar reaction conditions. It was concluded that the oxyfluorides show similar Lewis acid‐base reactions with the alkali metal fluorides in aHF solutions.

The role of calcium stearate on regulating activation to form stable, uniform and flawless reaction products in alkali-activated slag cement

In the course of an investigation on using calcium stearate (CaSt) to improve performance of the alkali-activated slag (AAS) cement, the objective of the present work is to discovery its role in the AAS system. Special interest is devoted to understand the influence of CaSt on the reaction process, reaction products and microstructural features of the AAS cement. To achieve this, isothermal calorimetry, impedance characteristics, infrared spectroscopy, X-ray diffraction, thermogravimetry, nitrogen sorption, mercury intrusion porosimetry and scanning electron microscopy were carried out. According to results obtained, the CaSt has three important effects on the AAS cement. Firstly, it inhibited slag reaction with the activator through decreasing activity of alkalis, whereas the amount of C-(A)-S-H gels in the system depended on the usage of CaSt, because the CaSt could have chemical reactions with the alkali-solution and form similar reaction products. Secondly, there is less sodium and more calcium in reaction products of the CaSt added mix, which improve their stability and uniformity. Finally, microstructure characteristics (e.g. pore size distribution, pore connectivity) are optimised and defects are reduced significantly, when CaSt is added in the AAS mix.

Systematic study on the enzymatic decomposition of various dextran fractions

Abstract Investigations on the enzymatic decomposition of dextran with varying initial average molecular masses, aiming at controlled dextran-related process effect mitigation during sugar manufacture, were key to this study. HPLC with size exclusion columns revealed that the enzymatic decomposition follows a gradual pattern leading to a successive reduction of the average molecular mass with the increase of the enzyme level and the incubation time. Affinity chromatography additionally revealed that oligo-, tri- and disaccharides constituted the smallest possible units. The amount of these small-sized saccharides increased with higher enzyme level and extended incubation time. Both effects were found to be further progressed when decomposing T40 as well as an equal-mass mixture of T2000 and T40 compared to exclusively T2000. The decomposition using unusually high enzyme levels leads to very similar reaction products for all substrates investigated. Besides, it was found that the presence of 15% (m/m) sucrose seems to hardly affect the enzyme reaction so that the enzyme application in raw sugar juices seems to be appropriate. The work presented suggests that not only the dextran content, but also the average molecular mass and the polydispersity of dextran are decisive for targeted dextranase applications in sugar industry practice.

Modifications of basic-oxygen-furnace slag microstructure and their effect on the rheology and the strength of alkali-activated binders

Microstructure tailoring of metallurgical slags allows the production of alternative construction binders with customized properties. In this study, the variations of rheology and strength of alkali-activated basic-oxygen-furnace (BOF) slags are quantified. Two modifications of BOF slag were created adding amounts of alumina and silica at high temperature (>1250 °C). The additions, defined by thermodynamic modeling, lowered the liquidus temperature facilitating the generation of amorphous when the slag was fast cooled. The first modification (SAT1) incorporated 5 wt% silica and 11 wt% alumina, while the second (SAT2) included around 13 wt% alumina. Both modifications generated a hybrid microstructure composed of cementitious and non-cementitious crystalline phases and an amorphous fraction. During alkali activation using NaOH solutions of 0.25 M, rheological measurements on fresh paste using SAT2 registered plastic viscosity values 2.3 times higher than those of SAT1. The compressive strength after 28 days for the binder developed from SAT2 slag was 10–30% stronger than the one from SAT1. These binders showed similar crystalline reaction products but compositional differences in the amorphous gel correlated to the initial slag modification. The detected differences in the binder properties are significant enough to justify BOF-slag engineering as a way to deliver customized precursors for alkali activation.

Matrix Infrared Spectra of Manganese and Iron Isocyanide Complexes.

Mono and diisocyanide complexes of manganese and iron were prepared via the reactions of laser-ablated manganese and iron atoms with (CN)2 in an argon matrix. Product identifications were performed based on the characteristic infrared absorptions from isotopically labeled (CN)2 experiments as compared with computed values for both cyanides and isocyanides. Manganese atoms reacted with (CN)2 to produce Mn(NC)2 upon λ > 220 nm irradiation, during which MnNC was formed mainly as a result of the photoinduced decomposition of Mn(NC)2. Similar reaction products FeNC and Fe(NC)2 were formed during the reactions of Fe and (CN)2. All the product molecules together with the unobserved cyanide isomers were predicted to have linear geometries at the B3LYP level of theory. The cyanide complexes of manganese and iron were computed to be more stable than the isocyanide isomers with energy differences between 0.4 and 4 kcal/mol at the CCSD(T) level. Although manganese and iron cyanide molecules are slightly more stable according to the theory, no absorption can be assigned to these isomers in the region above the isocyanides possibly due to their low infrared intensities.

Effect of Thermal Cycling on Compatibility in CO2 for Concentrated Solar Power Applications

As a first step in evaluating materials for a concentrated solar power (CSP), supercritical CO2 Brayton cycle, experiments are being conducted to simulate the daily operating cycle using 10-h thermal cycles in 1 bar CO2 at 700–800 °C. After 1000-h exposures, the mass gains for commercial Ni-base alloys 740H, 282, 625 and Fe-base alloy 25 were relatively low with correspondingly thin reaction products. At 800 °C, similar reaction products were obtained for thermal cycling in CO2 and dry air, which also could simulate the outside of the primary heat exchanger. In addition, 500-h cycles were conducted at 750 °C, which showed slightly higher mass gains than the 10-h cycles. In general, there were no indications of internal carburization for these four alloys after 1000 h and the measured rate constants are sufficiently low to meet the 30-year CSP lifetime goal.

Supercritical water gasification of RDF and its components over RuO2/γ-Al2O3 catalyst: New insights into RuO2 catalytic reaction mechanisms

Five samples including a composite refuse derived fuel (RDF) and four combustible components of municipal solid wastes (MSW) have been reacted under supercritical water conditions in a batch reactor. The reactions have been carried out at 450°C for 60min reaction time, with or without 20wt% RuO2/gamma-alumina catalyst. The reactivities of the samples depended on their compositions; with the plastic-rich samples, RDF and mixed waste plastics (MWP), giving similar product yields and compositions, while the biogenic samples including mixed waste wood (MWW) and textile waste (TXT) also gave similar reaction products. The use of the heterogeneous ruthenium-based catalyst gave carbon gasification efficiencies (CGE) of up to 99wt%, which was up by at least 83% compared to the non-catalytic tests. In the presence of RuO2 catalyst, methane, hydrogen and carbon dioxide became the dominant gas products for all five samples. The higher heating values (HHV) of the gas products increased at least two-fold in the presence of the catalyst compared to non-catalytic tests. Results show that the ruthenium-based catalyst was active in feedstock steam reforming, methanation and possible direct hydrogenolysis of C–C bonds. This work provides new insights into the catalytic mechanisms of RuO2 during SCWG of carbonaceous materials, along with the possibility of producing high yields of methane from MSW fractions.

Unusual reactivity of MoS2 nanosheets.

The reactivity of the 2D nanosheets of MoS2 with silver ions in solution, leading to their spontaneous morphological and chemical transformations, is reported. This unique reactivity of the nanoscale form of MoS2 was in stark contrast to its bulk counterpart. While the gradual morphological transformation involving several steps has been captured with an electron microscope, precise chemical identification of the species involved was achieved by electron spectroscopy and mass spectrometry. The energetics of the system investigated supports the observed chemical transformation. The reaction with mercury and gold ions shows similar and dissimilar reaction products, respectively and points to the stability of the metal-sulphur bond in determining the chemical compositions of the final products.

Performance at high temperature of alkali-activated slag pastes produced with silica fume and rice husk ash based activators

This study assessed the mechanical properties, and structural changes induced by high temperature exposure, of alkali-silicate activated slag cements produced with sodium silicates derived from silica fume (SF) and rice husk ash (RHA). Similar reaction products were identified, independent of the type of silicate used, but with subtle differences in the composition of the C-S-H gels, leading to different strength losses after elevated temperature exposure. Cements produced with the alternative activators developed higher compressive strengths than those produced with commercial silicate. All samples retained strengths of more than 50 MPa after exposure to 600 °C, however, after exposure to 800 °C only the specimens produced with the RHA-based activator retained measurable strength. This study elucidated that silicate-activated slag binders, either activated with commercial silicate solutions or with sodium silicates based on SF or RHA, are stable up to 600 °C.

The Spectrophotometric Sulfo‐Phospho‐Vanillin Assessment of Total Lipids in Human Meibomian Gland Secretions

Human meibomian gland secretions (meibum) are the major lipid component of the human preocular tear film. The predominant lipid classes found in meibum include waxes (WE), cholesteryl esters (CE), and varying amounts of cholesterol (Chl). The classical sulfo-phospho-vanillin assay (SPVA), adapted for a microplate reader, was used to quantitate lipids in meibum. To account for varying reactivities of different lipids in SPVA, a model meibomian lipid mixture (MMx) that approximated the WE/CE/Chl composition of meibum was developed and used to quantitate meibomian lipids. The overall SPV responses of MMx and meibum were found to be close, with similar intermediate and final reaction products for both. Saturated WE that had not been expected to be reactive were found to be SPV-positive. A reaction mechanism for these compounds in SPVA which involves the formation of alkenyl ethers is proposed and discussed. Tested proteins were non-reactive in SPVA. Thus, by comparing the results of gravimetric analyses of meibum samples with the results of a properly calibrated SPVA, it was estimated that the SPV-reactive lipid content of dry meibum in tested samples was about 78% (w/w). The SPV method can also be adopted for analyzing other types of complex lipids secretions, such as sebum, as well as whole lipid extracts from other lipid-enriched organs and tissues, if proper standards are chosen.

Degradation of 2,4-dichlorophenol and coupling into humic matter by oxidative biomimetic catalysis with iron-porphyrin

We evaluated the activity of a water-soluble iron-porphyrin as catalyst of an oxidative reaction of 2,4-dichlorophenol (2,4-DCP) in the presence of humic molecules, whereby the phenol disappearance should proceed through self-olygomerization and co-polymerization within humic matter. The catalyzed coupling reaction was conducted with H2O2 as oxidizing agent with and without humic matter (HA) and followed by High Performance Liquid Chromatography (HPLC), upon incubation in either dark or daylight conditions. UV- and Fluorescence-detected signals of reaction products separated by HPLC were collected and structurally characterized by GC–MS. The 2,4-DCP degradation by the catalyzed oxidative reaction without addition of HA was complete in both incubation conditions and showed reaction products such as dehalogenated and hydroxylated phenols, and dimers/trimers of the dechlorinated phenol. With the presence of HA, 2,4-DCP was degraded in the dark by only 75% of initial content, whereas degradation was again complete in daylight, which showed similar reaction products as in the dark. These results reveal that the catalyzed oxidative reaction in the presence of HA was less efficient in the dark, possibly because 2,4-DCP was protected from oxidation by absorption into humic hydrophobic domains. Conversely, photo-oxidation combined to chemical oxidation to enhance the coupling reactivity in daylight conditions, most likely through co-polymerization of 2,4-DCP in humic molecules. This work confirms the potentiality of an oxidative coupling reaction catalyzed by iron-porphyrin in co-polymerizing halogenated pollutants into humic matter and detoxifying the environment.

Wellbore integrity in carbon sequestration environments: 1. Experimental study of Cement–Sandstone/Shale–Brine–CO2

Abstract It is important to determine the geochemical reactions between common cements used in wellbore construction, formation mineralogy, and supercritical CO 2 stored in deep saline reservoirs, because abandoned and completed wells provide a pathway for release of the stored CO 2 back to overlying aquifers and to the atmosphere. Although it is known that alkaline cements readily react with acidic CO 2 -rich waters, the influence of the formation and cement mineralogy on the bonding of the wellbore cement to the caprock at pressure and temperature conditions associated with saline CO 2 storage reservoirs is uncertain. We reacted end member components of the heterolithic sandstone and shale unit that forms the upper section of the carbon storage reservoir at the Krechba Field, In Salah, Algeria with supercritical CO 2 and class G cement in a representative brine at 95 °C and 10 MPa in gold bag autoclaves to identify geochemical reactions that occur in the wellbore environment. The experimental system allows reaction progress of complex geochemical environments to be tracked by sampling the aqueous phase periodically over the two-month long experiments. Analysis of the solution chemistry over time and the solid products show that the wellbore environment is dominated by reactions between cement, carbonate, and clay minerals when exposed to CO 2 -rich fluid. Reaction of the hydrated cement with synthetic brine equilibrated with supercritical CO 2 rapidly forms amorphous silica, calcite, and aragonite. Similar reaction products were observed when cement reacted with sandstone and CO 2 (reservoir). However in the vicinity of the shale (caprock) cement minerals altered to calcium carbonate minerals and smectite (clay).

Streptococcal serum opacity factor increases the rate of hepatocyte uptake of human plasma high-density lipoprotein cholesterol.

Serum opacity factor (SOF), a virulence determinant of Streptococcus pyogenes, converts plasma high-density lipoproteins (HDL) to three distinct species: lipid-free apolipoprotein (apo) A-I, neo HDL, a small discoidal HDL-like particle, and a large cholesteryl ester-rich microemulsion (CERM) that contains the cholesterol esters (CE) of up to ∼400000 HDL particles and apo E as its major protein. Similar SOF reaction products are obtained with HDL, total plasma lipoproteins, and whole plasma. We hypothesized that hepatic uptake of CERM-CE via multiple apo E-dependent receptors would be faster than that of HDL-CE. We tested our hypothesis using human hepatoma cells and lipoprotein receptor-specific Chinese hamster ovary (CHO) cells. The uptake of [(3)H]CE by HepG2 and Huh7 cells from HDL after SOF treatment, which transfers >90% of HDL-CE to CERM, was 2.4 and 4.5 times faster, respectively, than from control HDL. CERM-[(3)H]CE uptake was inhibited by LDL and HDL, suggestive of uptake by both the LDL receptor (LDL-R) and scavenger receptor class B type I (SR-BI). Studies in CHO cells specifically expressing LDL-R and SR-BI confirmed CERM-[(3)H]CE uptake by both receptors. RAP and heparin inhibit CERM-[(3)H]CE but not HDL-[(3)H]CE uptake, thereby implicating LRP-1 and cell surface proteoglycans in this process. These data demonstrate that SOF treatment of HDL increases the rate of CE uptake via multiple hepatic apo E receptors. In so doing, SOF might increase the level of hepatic disposal of plasma cholesterol in a way that is therapeutically useful.

Photochemical Reactions of Regioisomeric 2,2‐Dimethyl‐5,5‐diphenyl‐ and 5,5‐Dimethyl‐2,2‐diphenyl‐Substituted Diazo Ketones of a Tetrahydrofuran Series

AbstractThe principal direction of conventional photolysis of the regioisomeric 2,2‐dimethyl‐5,5‐diphenyl‐ and 5,5‐dimethyl‐2,2‐diphenyl‐substituted 4‐diazodihydrofuran‐3(2H)‐ones 1a and 1b, respectively, is the Wolff rearrangement, while other photochemical processes, which are giving rise to the formation of CH‐insertion, 1,2‐alkyl‐ or ‐aryl‐shifts, as well as H‐atom‐abstraction products occur to a much lower degree (Schemes 2 and 3). The ratio of similar reaction products from both regioisomers 1a and 1b is essentially independent of their structure, and a substantial effect of the relative position of the Ph and diazo group to each other on the yield of CH‐insertion products does not occur. Based on stereochemical considerations, the Wolff rearrangement of diazodihydrofuran‐3(2H)‐ones apparently proceeds in a concerted manner, whereas the appearance in the reaction mixture of 1,2‐shift and H‐atom‐abstraction products points to the parallel generation during photolysis of singlet and triplet carbenes (Schemes 4 and 5).

In situ transmission Fourier transform infrared (FT-IR) spectroscopy investigations of the surface chemistry of gettering common gases in vacuum systems with a common commercial flashed getter alloy as a function of temperature

Studies of gettering reactions of a commercial flashed metal alloy commonly used in vacuum electronics with common gases found in vacuum electronic systems (CO, CO 2, CH 4, and O 2) have been carried out in situ using Fourier transform infrared spectroscopy (FT-IR) to better understand the nature of these reactions as a function of temperature. Flashed alloy was found to adsorb CO at temperatures greater than −5 ± 5 °C across a pressure range from 3 to 50 Torr of CO. Multivariate curve resolution (MCR) was needed to extract the pure component spectra and temperature profiles for signals having intensities 10–200 times less than the background. No spectral evidence for adsorbed CO 2 or CH 4 was observed but both CO and CO 2 were found to react with the barium film at temperatures above 77 ± 5 °C forming what is likely a combination of Ba(OH) 2, Sr(OH) 2, and other trace metal oxides and hydroxides. Again MCR was needed to resolve the pure spectral components and temperature profiles of these highly overlapped components. The production of metal hydroxides is likely caused by the presence of H 2 sorbed to the getter during the flash as low temperature, <−50 °C, experiments with O 2 showed similar reaction products. In the case of CH 4 no reaction is seen with the flashed alloy surface up to 120 °C. However, in the presence of what is NiO (Ni is a trace impurity in the getter) and potentially BaO, CH 4 does react at temperatures greater than 55 °C to produce CO 2 which in turn reacts with the alloy film as outlined above.

1,4,9,10-Anthradiquinone as precursor for antitumor compounds

1,4,9,10-Anthradiquinone 5 was reacted with enamines 6 in the Nenitzescu reaction to yield unexpected 3,3a,6,12-tetrahydro-3a,7-dihydroxy-2-methyl-6,12-dioxo-naphtho[2,3- d]indol-1-carboxylates 8A. However, anthracycline-like naphtho-condensed 5-hydroxyindoles were not obtained from this diquinone. It yielded similar reaction products of the Nenitzescu reaction like other quinones activated by two electron-withdrawing groups. Furthermore, these new compounds 8A were found to constitute precursors for the synthesis of azonines. The conversion to dibenzoazonines 13 occurred in an unusual and up to now unknown way consisting of isomerization, ring opening, and re-closure. 2-Chloro-anthradiquinone 19 reacted with enamines 6 as vinylogeous acid chloride to pyrroloanthraquinone 20. No substitution of chlorine was observed. Naphtho-condensed indoles 26 were obtained by the reactions of unsubstituted 1,4-anthraquinone 25 with enamines 6 via the normal Nenitzescu route. Indoles 26 were converted to Mannich bases, reacting further to dimers by the Diels–Alder reaction of intermediate o-quinone methides. Most of the synthesized heterocycles were evaluated for their anticancer properties in the NCI’s human-disease oriented in vitro anticancer screen. Particularly, carbinolamines 8A exhibited inhibitory activity of tumor cell growth and thus they constitute a new class of lead structures for anticancer drug design.

Mechanistic information on the reaction of cis- and trans-[RuCl 2(DMSO) 4] with d(T 2GGT 2) derived from MALDI-TOF and HPLC studies

Reactions of trans and cis isomers of the Ru II complex [RuCl 2(DMSO) 4] with single-stranded hexanucleotide d(T 2GGT 2) were studied in aqueous solutions in the absence and presence of excess chloride by high performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionisation time of flight mass spectrometry (MALDI-TOF MS). Despite the different reactive species formed from the two isomers in aqueous solution, similar reaction products are obtained in their interaction with d(T 2GGT 2). Both [RuCl 2(DMSO) 4] isomers bind to the oligonucleotide in the bidentate mode to form thermodynamically stable bis-guanosine adducts, Ru(G-N7) 2. Significant differences were observed in the reaction rates, however the reaction with trans- [RuCl 2(DMSO) 4] is ca. 5–10 times faster in comparison to that observed for the cis analogue. This difference is interpreted in terms of different rate-limiting steps for the trans and cis complexes, respectively. It is suggested that the rate of the reaction with the trans isomer is controlled by dissociation of a Cl − ligand from the initially formed trans,cis,cis-[RuCl 2(DMSO) 2(H 2O) 2]. In the contrast, release of a dimethyl sulfoxide molecule from the reactive species cis,fac-[RuCl 2(DMSO) 3(H 2O)] is likely to be rate limiting for the cis analogue. Significant influence of electrostatic interactions on the reaction rate was observed for the trans isomer. Mechanistic interpretation of the observed reactivity trends based on data obtained from UV–Vis spectroscopy, HPLC and MALDI-TOF MS studies is presented and discussed within the paper.