A Dormant Ruthenium Catalyst Bearing a Chelating Carboxylate Ligand: In Situ Activation and Application in Metathesis Reactions

Gstrein X., Burtscher D., Szadkowska A., Barbasiewicz M., Stelzer F., Grela K., Slugovc C.

Olefin metathesis catalysts bearing chelating carbene ligands based on 8-vinylquinoline and 5-vinylquinoxaline were examined as initiators for Ring Opening Metathesis Polymerization. Model-polymerizations with these initiators were studied by differential scanning calorimetry and nuclear magnetic resonance. Results revealed a pronounced latency at room temperature and high activity at elevated temperatures. Combined solutions of the initiators and the monomers can even be stored for two weeks at room temperature. While no concomitant polymerization occurred during this time, polymerization of the mixtures took place upon heating.

Barbasiewicz M., Bieniek M., Michrowska A., Szadkowska A., Makal A., Woźniak K., Grela K.

Structural modifications of the Hoveyda-Grubbs ruthenium metathesis complex via electronic and structural withdrawing of the chelating alkoxy ligand were investigated. By decreasing the donor properties of the oxygen atom, an acceleration in catalytic activity was achieved based on facilitation of the initiation step. Conformational constraints of the chelating ether linkage led to the unexpected disturbance of the complex geometry and a vast improvement of the activity.

Tanaka K., Böhm V.P., Chadwick D., Roeper M., Braddock D.C.

A series of Hoveyda−Grubbs benzylidenes, Ru(X)2(IMesH2)(CH-2-(2-PrO)C6H4) (X = Cl, Br, CF3CO2, C2F5CO2; IMesH2 = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) were demonstrated to undergo intermolecular anionic ligand exchange when mixed. The implication is that anionic ligand exchange is occurring between identical ruthenium benzylidenes at all times in solution. A mechanism involving bridged dimers is invoked.

Bieniek M., Bujok R., Cabaj M., Lugan N., Lavigne G., Arlt D., Grela K.

A 95% yield in the cross metathesis of acrylonitrile with a model olefin is achieved at 25 degrees C with only 3 mol % of the new air-stable ruthenium catalyst 1f shown in the enclosed structural diagram. Even more remarkable are the performances of its boosted version 1g incorporating an electron-withdrawing group. Both these new enhanced versions of Hoveyda catalyst are readily available from Grubbs second generation precatalyst upon reaction with a styrenyl ether the end group of which has been functionalized by an ester function. The latter acts as a weakly coordinating ligand allowing to reach a desirable balance between antinomic properties such as the catalyst's stability, a high activity for challenging substrates, and a high initiation rate.

Michrowska A., Mennecke K., Kunz U., Kirschning A., Grela K.

A new concept for noncovalent immobilization of a ruthenium olefin metathesis catalyst is presented. The 2-isopropoxybenzylidene ligand of a Hoveyda-Grubbs carbene is further modified by an additional amino group (7) and immobilization is achieved by treatment with sulfonated polystyrene forming the corresponding ammonium salt. In this novel strategy for the immobilization of ruthenium-based metathesis catalysts, the amino group plays a two-fold role, being first an active anchor for immobilization and second, after protonation, activating the catalysts (electron donating to electron withdrawing activity switch). The polymeric support was prepared by precipitation polymerization which led to small bead sizes (0.2-2 microm) and large surface areas. Compared to commercial resins this tailor-made phase showed superior properties in immobilization of complex 7. This concept of immobilization was applied to glass-polymer composite megaporous Raschig rings. Ru catalyst 7 on Raschig rings was used under batch conditions in various metathesis reactions, including ring-closing (RCM), cross- (CM) and enyne metathesis, to give products of high chemical purity with very low ruthenium contamination levels (21-102 ppm). The same ring can be used for up to 6 cycles of metathesis.

Gułajski Ł., Michrowska A., Bujok R., Grela K.

Synthesis and screening of catalytic activity of two novel ruthenium carbene complexes 9 and 10 bearing substituents in 2-isopropoxybenzylidene ligand is described. These precatalysts constitute excellent tools for RCM and enyne metathesis by combining high stability with a possibility of their on-demand activation by heat and Bronsted (9) or Lewis acids (10).

Barbasiewicz M., Szadkowska A., Bujok R., Grela K.

Novel metathesis catalysts that are derivatives of 8-vinylquinoline, (H2IMes)(Cl)2Ru(CH-κ2(C,N)-8-C9H6N) (1a; H2IMes = 1,3-dimesityl-4,5-dihydroimidzol-2-ylidene), and 5-vinylquinoxaline, (H2IMes)(Cl)2Ru(CH-κ2(C,N)-5-C8H5N2) (2a), which possess five-membered chelate rings, were synthesized in ligand exchange reactions with (H2IMes)(PCy3)(Cl)2RuCHPh. Both 1a and 2a are formed as complexes with the trans-dichloro geometry common for Grubbs-type complexes, while on prolonged storage in dichloromethane they isomerize to the thermodynamically favored cis-dichloro isomers (1b and 2b, respectively). The structures of compounds 1a,b were confirmed by X-ray analysis. The kinetics of trans to cis isomerization were measured by 1H NMR to give the rate constants k1a→1b = 3.2 × 10-2 h-1 and k2a→2b = 5.5 × 10-3 h-1 in dichloromethane-d2 at 23 °C. Investigations of the relative activities of these catalysts in model RCM and enyne reactions showed that catalyst 1a was faster than 1b (and 2a faster than 2b) but that 2a wa...

Monfette S., Fogg D.E.

Olefin metathesis catalysts containing chelating aryloxide donors, RuXX‘(IMes)(py)(CHPh) (5, XX‘ = 3,5-dichloro-2-oxidobenzenesulfonate; 6, XX‘ = catecholate), are accessible in high yield by react...

Conrad J.C., Parnas H.H., Snelgrove J.L., Fogg D.E.

Ruthenium alkylidene complexes containing one aryloxide "pseudohalide" ligand catalyze ring-closing metathesis of diene and ene-yne substrates with exceptionally high efficiency. Chromatographic removal of Ru residues is unexpectedly facile, offering a convenient means of isolating pure organic products in high yields.

Halbach T.S., Mix S., Fischer D., Maechling S., Krause J.O., Sievers C., Blechert S., Nuyken O., Buchmeiser M.R.

The syntheses and reactivity of seven different ruthenium-based metathesis catalysts are described. Ru(CF3COO)2(PCy3)(=CH-2-(2-PrO)C6H4) (1), Ru(CF3COO)2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) (2), and Ru(CF3COO)2(PCy(3))(1,3-dimesityldihydroimidazolin-2-ylidene)(=CHC6H5) (3) were prepared via chlorine exchange by reacting RuCl2(PCy3)2(=CH-2-(2-PrO)C6H4), RuCl2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4), and RuCl2(PCy3)(1,3-dimesityldihydroimidazolin-2-ylidene)(=CHC6H5), respectively, with silver trifluoroacetate (Cy =cyclohexyl). In analogy, Ru(CF3CF2COO)2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) (4) and Ru(CF3CF2CF2COO)2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) (5) were prepared from RuCl2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) via reaction with CF3CF2COOAg and CF3CF2CF2COOAg, respectively. Ru(C6F5COO)2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) (6) and Ru(C6F5O)2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) (7) were prepared from RuCl2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) via reaction with C6F5COOTl and C6F5OTl, respectively. Supported catalysts Ru(PS-DVB-CH2OOCCF2CF2CF2COO)(CF3COO)(PCy3)(1,3-dimesityldihydroimidazolin-2-ylidene)(=CHC6H5) (8), Ru(PS-DVB-CH2OOCCF2CF2CF2COO)(CF3COO)(PCy3)(=CH-2-(2-PrO)C6H4) (9), and Ru(PS-DVB-CH2OOCCF2CF2CF2COO)(CF3COO)(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) (10) were synthesized by reaction of RuCl2(PCy3)(1,3-dimesityldihydroimidazolin-2-ylidene)(=CHC6H5), RuCl2(PCy3)(=CH-2-(2-PrO)C6H4), and RuCl2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4), respectively, with a perfluoroglutaric acid-derivatized poly(styrene-co-divinylbenzene) (PS-DVB) support (silver form). Halogen exchange in PCy3-containing systems had to be carried out in dichloromethane in order to suppress precipitation of AgCl.PCy3. The reactivity of all new catalysts in ring-closing metathesis (RCM) of hindered electron-rich and -poor substrates, respectively, at elevated temperature (45 degrees C) was compared with that of existing systems. Diethyl diallylmalonate (DEDAM, 11), diethyl allyl(2-methylallyl)malonate (12), N,N-diallyl-p-toluenesulfonamide (13), N-benzyl-N-but-1-en-4-ylbut-2-enecarboxylic amide (14), and N-allyl-N-(1-carboxymethyl)but-3-en-1-yl-p-toluenesulfonamide (15) were used as educts. Supported catalysts were prepared with high loadings (2.4, 22.1, and 160 mg of catalyst/g PS-DVB for 8, 9, and 10, respectively). Catalyst 8 showed higher and catalysts 9 and 10 sowed significantly reduced activities in RCM compared to their homogeneous analogues. Thus, with 8, turnover numbers (TONs) up to 4200 were realized in stirred-batch (carousel) RCM experiments. To elucidate the nature of the bound species, catalysts 8-10 were subjected to 13C- and 31P-MAS NMR spectroscopy. These investigations provided evidence for the proposed structures. Leaching of ruthenium into the reaction mixture was low, resulting in ruthenium contents

Van Veldhuizen J.J., Campbell J.E., Giudici R.E., Hoveyda A.H.

A new chiral bidentate N-heterocyclic carbene (NHC) ligand has been designed and synthesized. The NHC ligand bears a chiral diamine backbone and an achiral biphenol group; upon metal complexation (derived from Ag(I), Ru(II), or Cu(II)), the diamine moiety induces >98% diastereoselectivity such that the biaryl unit coordinates to the metal center to afford the desired complex as a single atropisomer. Because the ligand does not require optically pure biaryl amino alcohols, its synthesis is significantly shorter and simpler than the related first generation ligands bearing a chiral binaphthyl-based amino alcohol. The chiral NHC ligand can be used in the preparation of highly effective Ru- and Cu-based complexes (prepared and used in situ from the Ag(I) carbene) that promote enantioselective olefin metathesis and allylic alkylations with scope that is improved from previously reported protocols. In many cases, transformations promoted by the chiral NHC-based complexes proceed with higher enantioselectivity and reactivity than was observed with previously reported complexes.

Slugovc C., Burtscher D., Stelzer F., Mereiter K.

The synthesis, characterization, and ROM polymerization activity of two ruthenium-based metathesis initiators bearing chelating carbene ligands with imine functionalities and N-heterocyclic carbene ligands are presented.

Kingsbury J.S., Hoveyda A.H.

Two isotopically and structurally labeled Ru-based carbenes (2-d4 and 13) have been prepared and attached to the surface of monolithic sol-gel glass. The resulting glass-supported complexes (18-dn and 19) exhibit significant catalytic activity in promoting olefin metathesis reactions and provide products of high purity. Through analysis of the derivatized glass pellets used in a sequence of catalytic ring-closing metathesis reactions mediated by various supported Ru carbenes, it is demonstrated that free Ru carbene intermediates in solution can be scavenged by support-bound styrene ether ligands prior to the onset of competing transition metal decomposition. The observations detailed herein provide rigorous evidence that the initially proposed release/return mechanism is, at least partially, operative. The present investigations shed light on a critical aspect of the mechanism of an important class of Ru-based metathesis complexes (those bearing a bidentate styrene ether ligand).

Mayr M., Wang D., Kröll R., Schuler N., Prühs S., Fürstner A., Buchmeiser M.

Two metathesis catalysts, RuCl2(PCy3)- (NHC)(CHPh) (1) (NHC ¼ 1-(2,4,5-trimethylphen- yl)-3-(6-hydroxyhexyl)-imidazol-2-ylidene) and Mo(N-2,6-i-Pr2-C6H3)(CHCMe2Ph)(BIPHEN) (2) (BIPHEN ¼ (R)-3,3'-di-t-butyl-5,5',6,6'-tetramethyl- 2,2'-biphenolate) have been immobilized on polymer- ic, monolithic discs using a grafting protocol. Monolithic discs were prepared via ring-opening metathesis polymerization (ROMP) from norborn-2- ene (NBE), tris(norborn-5-ene-2-ylmethyleneoxy)- methylsilane ((NBE-CH2O)3-SiCH3), 2-propanol, tol- uene and RuCl2(PCy3)2(CHPh). Catalyst loadings of 0.55 and 0.7 wt %, respectively, were obtained. Mon- olithic disc-immobilized 1 was used in various meta- thesis-based reactions including ring-closing metathe- sis (RCM), ring-opening cross metathesis and enyne metathesis. Using 0.23 - 0.59 mol % of supported 1, turnover numbers (TONs) up to 330 were achieved. Monolithic disc-immobilized 2 was used in various enantioselective RCM and desymmetrization reac- tions. Using 9 - 13 mol % of supported catalyst, excel- lent yields up to 100% and high enantiomeric excess (eeX88%) were observed. In both cases, metal leach- ing was low (X 3a ndX2%, respectively). In addition, 1 catalyzed the cyclopolymerization of diethyl dipro- pargylmalonate (DEDPM) to yield poly(ene)s consist- ing of 5-membered rings, i.e., cyclopent-1-ene-1-vinyl- ene units. The polymerization proceeded via non-stoi- chiometric initiation yielding polymers with unimodal molecular weight distribution. Using a catalyst to mon- omer ratio of 1 : 170, molecular weights of Mw ¼ 16,400 and Mn ¼ 11,700 g/mol, PDI ¼ 1.40 were obtained.

Astruc D.

Metathesis is one of the most spectacular recent improvements in synthetic strategies for organic synthesis and polymer science. The historical aspects and modern developments of the metathesis reactions are summarized here. In particular, emphasis is placed on the leading role played by the mechanistic work and proposals of Yves Chauvin and on the history of the efficient catalysts discovered by the groups of R. R. Schrock and R. H. Grubbs. It is pointed out how the Chauvin metathesis mechanism, with formation of a metallacyclobutane, has been generalized to many organometallic reactions that also involve square intermediates comprising a metal atom. Subsequently, the progressive development of ideas by Schrock and Grubbs during the last three decades has brought the field to the forefront of synthetic chemistry. The quest for efficient metathesis catalysts is a success story, starting from organometallic mechanisms, that has now invaded the worlds of organic synthesis and polymer science. Indeed, the Schrock’ and Grubbs’ catalysts and their derivatives are now the most efficient catalysts compatible with functional groups for the metathesis reactions. They considerably shorten synthetic schemes by affording new routes and therefore have changed the way chemists think about synthesis.

Kinugawa T., Mitsusada S., Orito N., Matsuo T.

Antonova Alexandra S., Zubkov Fedor I.

Catalytic olefin metathesis using Hoveyda-Grubbs type ruthenium complexes is a powerful tool for creating complex molecules possessing a variety of practically useful properties. This method is also applied for obtaining modern polymer materials from low-demand petroleum products. Among all ruthenium complexes containing five- or six-membered chelate rings, the commercially available HG-II catalyst is the most common. In addition, other Hoveyda-Grubbs type complexes, which include a Het→Ru donor–acceptor bond in the chelate ring, often exhibit metathesis activity equal to or superior to that of HG-II. This review considers second-generation N-heterocyclic ruthenium carbene Hoveyda-Grubbs type complexes with donor–acceptor bonds such as O→Ru, S→Ru, Se→Ru, N→Ru, P→Ru and Hal→Ru in the chelate ring. Methods of preparation, analysis of stability and catalytic activity of such complexes are compared, and examples of the application of these organometallic ruthenium derivatives in the synthesis of practically relevant products are provided. The literature from 2010 to 2023 is summarized, making this review useful for a broad audience of chemists working in heterocyclic and organometallic chemistry, as well as practitioners involved in the production of catalysts and polymers.The bibliography includes 174 references.

Nadirova M., Zieliński A., Malinska M., Kajetanowicz A.

Two new ruthenium complexes with chelating-ether benzylidene ligands bearing a furan moiety were synthesized and characterized, including X-ray crystallography. They initiated fast, also at 0 °C, and were found to be highly active in a variety of ring-closing, ene-yne, and cross-metathesis reactions, including an active pharmaceutical ingredient (API) model, which makes them good candidates for the transformation of complex polyfunctional compounds that require mild reaction conditions.

Patrzałek M., Zieliński A., Pasparakis G., Vamvakaki M., Ruszczyńska A., Bulska E., Kajetanowicz A., Grela K.

Traditionally, olefin metathesis (OM) is carried out in organic solvents such as dichloromethane or toluene. Due to the development of water-resistant or even water-soluble ruthenium catalysts in the last two decades, considerable progress on OM in aqueous media has been made. However, the removal of ruthenium from the product of OM reactions performed in water remains a substantial challenge. In the present work, selected approaches to purify the reaction mixtures after aqueous homogeneous olefin metathesis (AHOM) reactions have been probed to address this shortcoming. It was found that elimination of a water-soluble Ru catalyst after AHOM conducted in neat water can be achieved via addition of thiocyanate ions (with or without support of charcoal additive). The developed purification method can make the aqueous metathesis methodology more practical, allowing easier separation of a spent water-soluble catalyst from the water-soluble metathesis products. Unfortunately, this methodology did not provide satisfactory results in the case of AHOM reactions performed in water/alcohol mixtures. To allow separation of a Ru catalyst in the latter case, a method utilizing a stimuli-responsive polymer was tested, leading however to limited success.

Herz K., Elser I., Buchmeiser M.R.

Abstract This article covers the basic principles of modern, well‐defined group 6 and group 8 metal alkylidene catalysts and their use in ring‐opening metathesis polymerization (ROMP). In this context, the expression “well‐defined” refers to catalytic systems that are characterized by a uniform and stoichiometric composition and for which the actual propagating species is well known and characterized. Such catalysts allow for the controlled, sometimes living, ROMP, which is of advantage for a variety of purposes. Generally, one particularity of ROMP is the formation of either cis ‐ or trans ‐double bonds along the polymer chain. Their formation during ROMP is strongly related to the catalyst used. In addition, tactic ROMP‐derived polymers are accessible. The influence of the alkylidene configuration and chirality of the catalysts on the microstructure of the resulting polymers as well as the different mechanisms that lead to tactic structures are outlined.

Wei W., Jia G.

The coordination chemistry of ruthenium, osmium, technetium and rhenium with carbon-based ligands covering the literature from 2003 to 2018 is discussed. These metals form a vast number of coordination compounds with carbon-based ligands ranging from a single carbon atom (a carbido ligand) to polydentate hydrocarbon chains, and from monodentate organometallic ligands such as carbenes to multidentate ligands such as pincers and macrocycles. Particular focus of this review is given to syntheses, properties and applications of complexes with popular carbon-based ligands such as monodentate N-heterocyclic carbenes (NHCs), cyclometallated bidentate ligands, tridentate pincers and porphyrin-like macrocycles.

Shapovalov S.S., Skabitskii I.V.

The heterometallic complex (L1)Ru(κ2-O2CC5H4)Mn(CO)3(O2CC5H4)Mn(CO)3) (I) (L1 is the pivalate ligand) is synthesized by the reaction of the ruthenium(II) complex (L1)Ru(κ2-O2CCMe3)(O2CCMe3) with cymantrenylcarboxylic acid (HO2CC5H4)Mn(CO)3. The consecutive reactions of nickel acetate with cymantrenenecarboxylic acid and diimine 1,4-di-tert-butyl-1,4-diazabutadiene-1,3 affords the complex (L2)Ni(κ2-O2CC5H4Mn(CO)3)2 (II) (L2 = tBu–N=CH–CH=N–tBu). Complexes I and II are identified by the elemental and X-ray diffraction analyses data (СIF files CCDC nos. 2001354 (I) and 2001355 (II)).

Masoud S.M., Vorobyeva D.V., Petropavlovskikh D.A., Bruneau C., Osipov S.N.

The review summarizes literature data on the methods for the introduction of fluorine atoms and fluoralkyl groups into different ligands to construct metathesis-active ruthenium carbene complexes. It also analyzes the influence of fluorinated ligands on the catalytic activity of the complexes. The choice, structure and positions of fluorinated substituents in NHC ligands are generally dictated by the desire to increase the electrophilicity of the ruthenium atom due to the electron-withdrawing effect of fluorine atoms and fluoroalkyl groups, resulting, as a rule, in an increase in the activity of the ruthenium complex. In catalysts with unsymmetrical fluorine-containing NHC ligands, there is a possibility of additional Ru–F coordination, making the complexes much more stable and, consequently, more active. The presence of fluorine in chelating alkylidene ligands provides an increase in the catalyst initiation rate due to a weakening of the ruthenium – heteroatom bond. Besides, the introduction of polyfluoroalkyl groups into ligands solves the problem of catalyst recovery using fluorous biphasic systems for reuse. The bibliography includes 172 references.

Matsuo T.

Hoveyda–Grubbs-type complexes, ruthenium catalysts for olefin metathesis, have gained increased interest as a research target in the interdisciplinary research fields of chemistry and biology because of their high functional group selectivity in olefin metathesis reactions and stabilities in aqueous media. This review article introduces the application of designed Hoveyda–Grubbs-type complexes for bio-relevant studies including the construction of hybrid olefin metathesis biocatalysts and the development of in-vivo olefin metathesis reactions. As a noticeable issue in the employment of Hoveyda–Grubbs-type complexes in aqueous media, the influence of water on the catalytic activities of the complexes and strategies to overcome the problems resulting from the water effects are also discussed. In connection to the structural effects of protein structures on the reactivities of Hoveyda–Grubbs-type complexes included in the protein, the regulation of metathesis activities through second-coordination sphere effect is presented, demonstrating that the reactivities of Hoveyda–Grubbs-type complexes are controllable by the structural modification of the complexes at outer-sphere parts. Finally, as a new-type reaction based on the ruthenium-olefin specific interaction, a recent finding on the ruthenium complex transfer reaction between Hoveyda–Grubbs-type complexes and biomolecules is introduced.

Momin M., Musso J.V., Frey W., Buchmeiser M.R.

We report the synthesis of O- and N-chelated hexacoordinated molybdenum imido alkylidene N-heterocyclic carbene (NHC) bistriflate and pentacoordinated molybdenum imido alkylidene NHC monotriflate monoalkoxide complexes and their use as thermally latent and in some cases air-stable precatalysts in the ring-opening metathesis polymerization (ROMP) of dicyclopentadiene (DCPD). Introduction of electron- withdrawing and electron-donating groups at the O-chelated alkylidene ligand allowed for the tuning of both the onset temperature of polymerization (Tonset) and the temperature of the exotherm maximum (Texo,max). In addition, N-chelated complexes were synthesized using easily available 2-vinylpyridine or 2-vinyl- N,N-dimethylaniline to yield five-membered and, for the first time, four-membered molybdenum imido alkylidene NHC chelates. With these precatalysts, Tonset and Texo,max could be varied between 52 and 142 °C and between 99 and 174 °C, respectively. All primary data files and processed data of the journal article from the Buchmeiser group. Tuning the Latent Behavior of Molybdenum Imido Alkylidene N-Heterocyclic Carbene Complexes in Dicyclopentadiene Polymerization. Nuclear magnetic resonance (NMR) spectra are uploaded. Also differential scanning calorimetry (DSC) data are available.

Jatmika C., Goshima K., Wakabayashi K., Akiyama N., Hirota S., Matsuo T.

The reactivities of Hoveyda–Grubbs-type complexes are tunable through second-coordination sphere effects caused by a functional group in the ligand.

Kovačič S., Slugovc C.

This review article summarises the academic work in the fields of initiator development, polymer chemistry and physics, composites, self-healing composites, novel processing opportunities and macro-as well as microporous materials.

Shen C., Zheng A., Huang M., Tang Q., Gong C., Chow C.

Prussian blue bimetallic analog (PBA)-modified TiO2 particles (NP1–3) were explored as a new generation of latent catalytic materials for the simultaneous detection and removal of cyanide using the indicator/catalytic displacement approach (ICDA).

Zieliński A., Szczepaniak G., Gajda R., Woźniak K., Trzaskowski B., Vidović D., Kajetanowicz A., Grela K.

Gawin A., Małecki P., Dranka M., Zachara J., Skompska M., Kajetanowicz A., Grela K.

Upon activation with C2Cl6 known latent Ru metathesis catalyst LatMet (13) exhibited activity in RCM and in ROMP of DCPD. A by-product of such activation, an aryloxybenzylidene ruthenium(III) complex 17 have been independently synthesised by reacting 13 with C2Cl6. This unique complex was characterised by spectroscopic and electrochemical methods, and by X-ray crystallography. To the best to our knowledge, this is the first isolated and structurally determined Ru(III) alkylidene complex reported.