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Ruthenium‐catalyzed hydrosilylation of aldehydes with hydrooligosilanes is reported. Among the examined ruthenium catalysts, RuH2(CO)(PPh3)3 gave the best results. The reactions proceed with the Si−Si bonds preserved to afford the corresponding alkoxyoligosilanes in good yields. A series of aryl aldehydes with an electron‐withdrawing group is applicable, whereas those with an electron‐donating group are not suitable for the reaction. Mechanistic considerations suggest that the key points for the preservation of the Si−Si bonds are the formation of zero‐valent ruthenium species and the efficient coordination of the aldehyde to the ruthenium center prior to the oxidative addition of the Si−H bond. [ABSTRACT FROM AUTHOR]

A concise hydrosilylation of alkynes for synthesizing β‐(E)‐vinylsilanes catalyzed by dirhodium(II)/XantPhos has been developed. In this reaction, β‐(E)‐vinylsilanes were generated from the isomerization of β‐(Z)‐vinylsilanes catalyzed by dirhodium(II) hydride species rather than the direct insertion of triple bond into M−H or M−Si bond (traditional Chalk‐Harrod mechanism or modified Chalk‐Harrod mechanism). The hydrosilylation displayed a broad substrate scope for alkynes and tertiary silanes, tolerating diverse functional groups including halides, nitriles, amines, esters, and heterocycles. [ABSTRACT FROM AUTHOR]

Modular access to alkenylsilanes was reported via nickel-catalyzed regiodivergent and stereoselective hydrosilylation of disubstituted alkynes. Herein, strategic use of an amide backbone and the appropriate selection of ligands allows highly regiocontrol and stereocontrol in the key syn -silametallation step. [Display omitted] [ABSTRACT FROM AUTHOR]

Comprehensive Summary Arylidenecyclopropanes (ACPs) are highly strained substrates that can be readily utilized for diverse transformations. This study showcases the outcomes of copper‐catalyzed ring‐opening hydrosilylation and hydroboration reactions of ACPs, showcasing precise cleavage of C—C bonds. The reaction presents an effective and convenient method for producing homoallylic silanes and boronates. [ABSTRACT FROM AUTHOR]

A zirconocene dichloride‐catalyzed alkene hydrosilylation is reported that can be applied to non‐activated and conjugated terminal and internal alkenes. It involves a catalytic Zr‐walk process and leads to a selective conversion to the linear product. Lithium methoxide serves as mild catalyst activating agent, which significantly increases the applicability and operational simplicity in comparison to earlier zirconium(II)‐based protocols. Supported by additional experiments and calculations, a mechanism via zirconium(IV) intermediates is proposed. Due to the benign nature and ready‐availability of the zirconium catalyst, the reaction is an attractive alternative to established alkene hydrosilylation methods. [ABSTRACT FROM AUTHOR]

Hydride abstraction from the borane adduct, (BICAAC) ⋅ BH3 afforded the hydride bridged dinuclear borenium ion equivalent complexes 1 and 2 that have been characterized by various spectroscopic and spectrometric techniques followed by the assessment of Lewis acidity using the Gutmann‐Beckett method. The single crystal X‐ray structure of complex 2 revealed the presence of discrete ions in the solid state. The complex (BICAAC) ⋅ BH2(OTf) (3), obtained from the reaction of (BICAAC) ⋅ BH3 with MeOTf, formed the corresponding boronium cations [(BICAAC) ⋅ BH2(L)]+(OTf)− on reaction with Lewis bases (L= pyridine (4) and DMAP (5)). Complexes 1 and 2 demonstrated notable catalytic activity in the hydrosilylation of a diverse array of carbonyls using 1.0 mol % catalyst loading (achieving the highest turnover frequency (TOFmax) of up to 1200 h−1 with benzaldehyde. A broad substrate scope has been presented for aldehydes and ketones decorated with various electron‐donating and withdrawing substituents along with this the hydrosilylation of a few para‐quinone methides has also been presented. [ABSTRACT FROM AUTHOR]

A mild and highly selective hydrosilylation method was employed to synthesize five novel well-defined Janus ring siloxanes bearing terpenes and terpenoids, which are the main bioactive components of essential oils. The characterization of these new bio-sourced molecular materials, derived from hydrosilyl-substituted all-cis-cyclotetrasiloxane, was conducted through comprehensive analyses using multinuclear NMR, infrared spectroscopy, elemental analysis, and mass spectroscopy. The thermal stability of the newly synthesized Janus rings was investigated, and the siloxane skeleton was shown to confer an enhanced thermal stability compared with free terpenes and terpenoids. [ABSTRACT FROM AUTHOR]

Vinylsilanes are very useful building blocks in organic synthesis and have widespread applications in life sciences and materials chemistry. Here we describe the potential of complex cis‐[Fe(PCP‐iPr)(CH2CH2CH3)(CO)2] as an effective catalyst for the hydrosilylation of both terminal and internal alkynes with SiPhH3 to give vinylsilanes. The reactions were typically performed with a catalyst loading of 1 mol% for 24 h at 70 °C. The catalytic reaction is initiated by migratory insertion of a CO ligand into the Fe─alkyl bond to yield an acyl intermediate, which reacts with silanes to form the 16e− Fe(II) silyl catalyst [Fe(PCP‐iPr)(SiPhH2)(CO)]. In the case of aliphatic terminal alkynes good regioselectivity (anti‐Markovnikov addition) toward the thermodynamically more stable β‐(E)‐vinylsilanes in ratios of up to 10:90 was achieved, while for aromatic alkynes the selectivities were poor with ratios of β‐(Z)‐ to β‐(E)‐vinylsilanes of about 40:60. With internal unsymmetrical alkynes, the two possible regioisomers of the syn‐addition of SiPhH3 were obtained in different ratios with no clear trend toward one regioisomer. Internal symmetrical alkynes yielded exclusively the respective syn‐products in high yields. Mechanistic investigations including deuterium labelling studies were undertaken to provide a reasonable reaction mechanism. [ABSTRACT FROM AUTHOR]

This work details the synthesis and characterization of low-coordinate Zn(II)-based organocations [(NHC)Zn(R)]+ incorporating extremely bulky NHCs [ITr] and [IAd] ([ITr] = ([ITr] = [(HCNCPh3)2C:]; [IAd] = [(HCNAd)2C:], Ad = adamantyl)). Their structural features and particularities are thoroughly assessed as well as their air and water tolerance. Neutral ITr and IAd adducts [(ITr)Zn(R)2] (1, R = Me; 2, R = Et) and [(IAd)Zn(R)2] (3, R = Me; 4, R = Et) were synthesized by reaction of carbene [ITr] or [IAd] with a stoichiometric amount of [ZnR2] and isolated in good yields. Despite the steric bulk of [ITr] and [IAd], neutral compounds 1–4 are robust and the solid state structure of adduct 3 was established through X-ray crystallographic studies as a trigonal monomer Zn(II) species. Adducts 1–4 may readily be ionized by [Ph3C][B(C6F5)4] to afford two-coordinate Zn(II) alkyl cations [(ITr)Zn(Me)]+ ([5]+) and [(ITr)Zn(Et)]+ ([6]+), [(IAd)Zn(Me)]+ ([7]+) and [(IAd)Zn(Me)]+ ([8]+), all isolated in high yields (>80%) as [B(C6F5)4]− salts, which were fully characterized. Remarkably, cation [(ITr)Zn(C6F5)]+ ([9]+), prepared by reaction of [5][B(C6F5)4] with [B(C6F5)3], features π–arene interactions with the electrophilic Zn(II), as deduced from solid state data and further completed by DFT-estimated non-covalent interactions (NCI), indicating that [ITr] may provide substantial steric and electrostatic stabilization. The latter certainly explains the remarkable stability of [(ITr)Zn(C6F5)]+ ([9]+) towards hydrolysis at RT, as it only coordinates H2O to afford an unprecedented stable Zn–OH2 organocation [10]+. Also noteworthy, H2O coordination is reversible allowing recovery of [(ITr)Zn(C6F5)]+ cation, even after prolonged air exposure. Yet, controlled hydrolysis of [(ITr)Zn(C6F5)]+ may occur upon heating with selective protonolysis of the Zn–C6F5 bond to afford structurally characterized dication [(ITr)Zn(OH)]22+ [11]2+. Interestingly, despite steric hindrance, the air-/water-tolerant cation [(ITr)Zn(C6F5)]+ is an effective CO2 hydrosilylation catalyst, and was also shown to mediate imine hydrogenation catalysis. [ABSTRACT FROM AUTHOR]

ABSTRACT NHC pincers (NHC = N‐heterocyclic carbene), which combine the structural benefits of both carbenes and pincer platforms, have shown diverse applications, spanning from fundamental organometallic chemistry to homogeneous catalysis. Although aryl‐bridged bis(NHCs) represent the earliest developed and most studied type of NHC pincers, such [C^C^C]‐platforms have been underutilized in the synthesis of rhodium complexes. In this study, we present several less explored organorhodium(III) complexes featuring [C^C^C]‐pincers. Their synthetic route via a convenient oxidative addition approach has been explored, and the obtained cyclorhodium(III) complexes show versatile coordination geometry (square pyramidal or octahedral). Additionally, these cyclorhodium(III) complexes exhibit very different regioselectivity in catalytic alkyne hydrosilylations compared to known Rh(III) NHC catalytic systems. Finally, a few mechanistic studies have also been conducted, and a plausible mechanism was proposed. [ABSTRACT FROM AUTHOR]

Despite impressive advances in the construction of enantioenriched silacarbocycles featuring silicon‐stereogenic centers via a selection of well‐defined sila‐synthons, the development of a more convenient and economic method with readily available starting materials is significantly less explored and remains a considerable challenge. Herein, we report the first example of copper‐catalyzed sequential hydrosilylation of readily accessible methylenecyclopropanes (MCPs) and primary silanes, affording an efficient and convenient route to a wide range of chiral silacyclopentanes bearing consecutive silicon‐ and carbon‐stereogenic centers with excellent enantio‐ and diastereoselectivities (generally ≥98 % ee, >25 : 1 dr). Mechanistic studies reveal that these reactions combine copper‐catalyzed intermolecular ring‐opening hydrosilylation of aryl MCPs and intramolecular asymmetric hydrosilylation of the resultant Z/E mixture of homoallylic silanes. [ABSTRACT FROM AUTHOR]

Ruthenium‐indane complex, fac‐[Ru(NCMe)3(CO)2(InCl3)] 1Cl reacted with 0.5 equiv. of dppe/dppp to afford dinuclear ruthenium‐indane complexes linked by diphosphine ligand, [{Ru(NCMe)2(CO)2(InCl3)}2{μ2‐Ph2P(CH2)nPPh2}] (n=2: 3, 3: 4). On the other hand, the reaction of fac‐[Ru(NCMe)3(CO)2(InCl3)] 1Cl with 1 equiv. of dppp afforded the corresponding chelate ruthenium(0) indane complex, [Ru(NCMe)(CO)2(InCl3)(dppp)] 5. In the case of dppm, a chelate complex [Ru(NCMe)(CO)2(InCl3)(dppm)] 6 was formed via the dinuclear Ru complex [{Ru(NCMe)2(CO)2(InCl3)}2(μ2‐dppm)]. Complexes 1Cl, 5, and 6 showed a catalytic activity for double‐hydrosilylation of MeCN. Complexes 3–6 were fully characterized using NMR measurements, elemental analyses, and the structures of 1Cl, 3, 5, and 6 were determined by X‐ray crystallography. [ABSTRACT FROM AUTHOR]

The zinc-catalyzed hydrosilylation and hydroboration of cyanamides have been described. Chemoselective reduction of cyanamides with Ph2SiH2 and partial or complete hydroboration of cyanamides with pinacolborane (HBpin) have been successfully carried out. The active catalyst/intermediate in the catalytic reactions, i.e., the bis-guanidinate zinc amidinate compound, has been isolated and structurally characterized. [ABSTRACT FROM AUTHOR]

The selective, transition metal‐free hydrosilylation of CO2 to CH2(OSiEt3)2 has been achieved under mild conditions and in high isolated yields (up to 90%) by using Et3SiH and the simple, easily prepared borohydride catalyst Li+[HB(C6F5)3]−. The resulting CO2‐derived bis(silyl)acetal product—whose mechanism of formation has been interrogated through detailed computational and experimental studies—can be rapidly valorized through the facile synthesis of N‐heterocyclic carbenes, via their corresponding imidazolium salts. By using relatively inexpensive, isotopically enriched 13CO2 this protocol can be exploited to prepare NHC isotopologues that are selectively 13C labelled at the key, ligating C2 position. This provides an electronically responsive 13C NMR spectroscopic handle with dramatically enhanced sensitivity, which can directly benefit reactivity studies in both organo‐ and organometallic catalysis, where NHC use is ubiquitous. [ABSTRACT FROM AUTHOR]

ABSTRACT Silylene metal complexes exhibit excellent catalytic activity and selectivity in homogeneous catalysis. However, there are relatively few examples of silylene metal complexes as catalysts for the hydrosilylation of alkenes. In order to study the effect of a silylene ligand on the catalytic performance of [PSiP] pincer Co(II) chloride for alkene hydrosilylation, the PMe3 ligand in (MeSi(C6H4‐PPh2)2)Co (PMe3)Cl (1) was replaced by a silylene ligand, and a silylene [PSiP] pincer Co(II) chloride, (MeSi(C6H4‐PPh2)2)Co (PhC (NtBu)2Si)Cl (2), was used as catalyst to study its catalytic activity in alkene hydrosilylation. It was confirmed that silylene Complex 2 has excellent catalytic activity for alkene hydrosilylation with Ph2SiH2 as a hydrogen source. For alkene hydrosilylation, compared to phosphine Complex 1, silylene Complex 2 does not need NaBHEt3 as an additive. In addition, for aromatic alkenes, silylene Complex 2 has anti‐Markovnikov selectivity, while phosphine Complex 1 provides Markovnikov products in the presence of NaBHEt3. [ABSTRACT FROM AUTHOR]

Transition metal catalysis plays a pivotal role in chemical synthesis. Noble metals often grab significant attention in organometallic catalysis due to their high reactivity. However, the serious issues associated with these metals such as low abundance, toxicity, geopolitical limitations, and volatile prices are driving the scientific community to discover sustainable alternatives. In this context, iron appears to be the first choice as an alternative metal due to its unique properties, including a range of stable oxidation states, Lewis acidity, high abundance in the earth's crust, and low toxicity. Over the past two decades, substantial progress has been made in iron catalysis. This overview examines the recent developments in iron‐catalyzed industrially relevant transformations such as hydroformylation, olefin isomerization, hydrosilylation, hydrophosphination, carbonylation, Wacker‐type oxidation, and plastic depolymerization. As witnessed throughout this review, the performance of iron can be significantly altered by suitable ligand selection and by tailoring the electronic and steric properties of the iron center. While noble metals remain the industry work‐horse, iron is inching closer and with extensive scientific understanding, it may replace noble metals in the near future. [ABSTRACT FROM AUTHOR]

Air‐stable palladium(II) and copper(I) complexes containing the 4,4′,6,6′‐tetramethoxybiphenyl‐2,2′‐diyl)bis(diphenylphosphine) ligands, (R)‐Ph‐Garphos ((R)‐L1) and ((S)‐Ph‐Garphos ((S)‐L1), were synthesized and characterized by 1H‐, 13C‐, and 31P{1H} NMR spectroscopy and elemental analyses. The PdCl2((R)‐Ph‐Garphos) ((R)‐1) and PdCl2((S)‐Ph‐Garphos) ((S)‐1) complexes were assessed for the Suzuki‐Miyaura cross‐coupling of aryl halides with phenylboronic acid under ambient conditions, or naphthyl substrates under reflux. X‐ray crystal structures of the copper complexes revealed that [Cu((R)‐Ph‐Garphos)I] ((R)‐2) crystallized as a three‐coordinate monomer in the orthorhombic space group P212121 whereas [Cu((S)‐Ph‐Garphos)I] ((S)‐2) crystallized as a tetrahedral (μ‐I) dimer in the same crystal system. The synthesis of the analogous [Cu((R)‐Ph‐Garphos)OAc] ((R)‐3) is also described. Complexes (R)‐2 and (R)‐3 were evaluated for the asymmetric hydrosilylation of ketones wherein enantioselectivities of up to 83 % ee were achieved. [ABSTRACT FROM AUTHOR]

The success of platinum-based chemotherapeutic drugs for clinical cancer treatments has inspired tremendous research efforts on developing new metallic anticancer agents with improved cytotoxic activity and reduced side effects. 2,2′;6′,2″-Terpyridine and its 4′-substituted derivatives have showed great potential as ligand compartments for designing new anticancer drug candidates involving base metals. In this work, we synthesized a series of cobalt and iron coordination compounds based on 4′-pyridyl-2,2′;6′,2″-terpyridine, including homoleptic complexes, a dinuclear bridged complex and 1- and 2-dimensional coordination polymers/networks. The polymorphism of two homoleptic CoII and FeII complexes has been described along with the structural characterization of a CoII coordination polymer and dinuclear FeIII complex by X-ray crystallography. These compounds were tested preliminarily as precatalysts for the regioselective hydrosilylation of styrene. Their cytotoxic activities against two human breast cancer cell lines (MCF-7 and MDA-MB 468) and a normal breast epithelial cell line (MCF-10A) were investigated in order to observe the best-performing drug candidates. [ABSTRACT FROM AUTHOR]

Manganese catalysis has attracted significant attention in the last few years. In comparison with the extensively studied Mn complexes bearing phosphine‐based pincer ligands, catalysis with Mn containing N‐heterocyclic carbenes (NHC) is poorly developed. In this work, new manganese(I) complexes bearing an NHC ligand with picolyl wingtip substituents (an N,C,N ligand) have been synthesized and fully characterized. The structure of fac‐[Mn(CO)3(κ2N,C,N)Br] and fac‐[Mn(CO)3(κ3N,C,N)](OTf) complexes with a bidentate and tridentate coordination of the N,C,N ligand, respectively, has been elucidated by single crystal X‐ray diffraction studies. These Mn complexes were applied as catalysts for the visible light‐induced hydrosilylation of ketones. The mild protocol operated efficiently at room temperature under visible light irradiation (blue LED), enabling the conversion of a wide variety of aromatic ketones to their respective alcohols in high yields. Evidence for radical intermediates and the participation of Mn‐H species has been demonstrated by a series of trapping experiments. [ABSTRACT FROM AUTHOR]

Photocatalyzed hydrosilication has the advantages of high reaction efficiency and environmental friendliness. However, the cost of photosensitive platinum catalysts is very high, hindering their applications. In this work, a novel and cost-effective photosensitive platinum catalyst is synthesized and can effectively catalyze the hydrosilylation reaction under ultraviolet light. It is found that Pt catalysts exhibit catalytic activity under ultraviolet light when the ratio of Platinum chloride bonding and cyclopentadienyl (Pt-Cl:Cp) is higher than 1:1.2. The cost is reduced by 50%. The structure of this platinum catalyst is characterized using FTIR and NMR techniques. Under ultraviolet light, the new photosensitive platinum catalyst's catalytic efficiency increases from approximately 5% to 60%. The viscosity of prepared silicone rubber was measured. Results show that the prepared silicone rubber has a storing time of over 30 days in shaded environments, and can be completely cured within 2 min under ultraviolet light. The thermal decomposition residual mass of photocured silicone rubber products is as high as 70%, having good thermal stability. As the content of the platinum catalyst increases from 20 to 100 ppm, the reaction conversion rate of the hydrosilylation reaction increases from 43 to 60%. The hardness of the silicone rubber also increases from the initial 11 degrees to 20 degrees. This novel photosensitive platinum catalyst has potential applications in 3D printing and electronic packaging. [ABSTRACT FROM AUTHOR]

The preparation of cationic bis(hydrosilane)–coinage‐metal complexes by chloride abstraction from the neutral metal chloride precursors with Na[BArF4] is described. Unlike previously reported hydrosilane‐stabilized copper and silver complexes, the presented complexes are cationic and feature two bidentate (ortho‐silylphenyl)phosphine ligands. These complexes were fully characterized by NMR spectroscopy and X‐ray diffraction analysis, revealing that both Si−H bonds are activated by the Lewis acidic cationic metal center. The new complexes were found to be effective in catalytic carbonyl hydrosilylation, leading to the corresponding silyl ethers under mild conditions without the addition of an external base. Combined mechanistic control experiments and quantum chemical calculations support an ionic outer‐sphere mechanism, in which a neutral metal alkoxide species instead of a metal hydride is the key intermediate that interacts with the silylcarboxonium ion to generate the silyl ether. [ABSTRACT FROM AUTHOR]

Development of mild, robust and metal‐free catalytic approach for the hydrosilylation of alkenes is critical to the advancement of modern organosilicon chemistry given their powerful capacity in the construction of various C−Si bonds. Herein, we wish to disclose a visible light‐triggered organophotocatalytic strategy, which proceeds via a triplet energy transfer (EnT)‐enabled radical chain pathway. Notably, this redox‐neutral protocol is capable of accommodating a broad spectrum of electron‐deficient and ‐rich alkenes with excellent functional group compatibility. Electron‐deficient alkenes are more reactive and the reaction could be finished within a couple of minutes even in PBS solution with extremely low concentration, which suggests its click‐like potential in organic synthesis. The preparative power of the transformations has been further highlighted in a number of complex settings, including the late‐stage functionalization and scale‐up experiments. Furthermore, although only highly reactive (TMS)3SiH is suitable hydrosilane substrate, our studies revealed the great reactivity and versatility of (TMS)3Si− group in diverse C−Si and Si−Si bond cleavage‐based transformations, enabling the rapid introduction of diverse functional groups and the facile construction of valuable quaternary silicon architectures. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Heteronuclear metal complexes have played an increasingly important role in both small molecules activation and catalytic transformation due to the potential metal‐metal synergies. In this work, we reported that the well‐defined Mg‐Ni‐Mg complex [(LMg)2Ni(C2H4)2] {L = [(DippNCMe)2CH]−, Dipp = 2,6‐iPr2C6H3} was capable of catalyzing the conversion of a diverse array of terminal alkenes to hydrosilylated products in anti‐Markovnikov fashion using PhSiH3 as the silicon source. The stoichiometric reaction of heterometallic Mg‐Ni‐Mg complex with one equivalent PhSiH3 obtained a silyl‐nickel‐monohydride complex [(LMg)2NiH(C2H4)(SiHPhEt)] featuring a Ni‐Si‐H‐Mg interaction. Moreover, treatment of heterometallic Mg‐Ni‐Mg complex with three equivalents PhSiH3 provided the silyl‐nickel‐trihydride complex [(LMg)2NiH3(SiHPhEt)] with three hydride‐bridged at Mg‐Ni‐Mg fragment. Further reactions of the resultant silyl‐nickel complexes with alkenes, e.g., ethylene and styrene, yielded the corresponding alkene‐coordinated Mg‐Ni‐Mg complexes [(LMg)2Ni(C2H4)2], [(LMg)2NiH2(C2H4)] and [(LMg)2NiH2(CH2CHPh)], respectively, with the elimination of PhEtSiH2. Based on the control experiments, both silyl‐nickel‐monohydride and silyl‐nickel‐trihydride complexes were considered as active intermediates in the catalytic hydrosilylation reaction. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Heteronuclear metal complexes have played an increasingly important role in both small molecules activation and catalytic transformation due to the potential metal‐metal synergies. In this work, we reported that the well‐defined Mg‐Ni‐Mg complex [(LMg)2Ni(C2H4)2] {L = [(DippNCMe)2CH]−, Dipp = 2,6‐iPr2C6H3} was capable of catalyzing the conversion of a diverse array of terminal alkenes to hydrosilylated products in anti‐Markovnikov fashion using PhSiH3 as the silicon source. The stoichiometric reaction of heterometallic Mg‐Ni‐Mg complex with one equivalent PhSiH3 obtained a silyl‐nickel‐monohydride complex [(LMg)2NiH(C2H4)(SiHPhEt)] featuring a Ni‐Si‐H‐Mg interaction. Moreover, treatment of heterometallic Mg‐Ni‐Mg complex with three equivalents PhSiH3 provided the silyl‐nickel‐trihydride complex [(LMg)2NiH3(SiHPhEt)] with three hydride‐bridged at Mg‐Ni‐Mg fragment. Further reactions of the resultant silyl‐nickel complexes with alkenes, e.g., ethylene and styrene, yielded the corresponding alkene‐coordinated Mg‐Ni‐Mg complexes [(LMg)2Ni(C2H4)2], [(LMg)2NiH2(C2H4)] and [(LMg)2NiH2(CH2CHPh)], respectively, with the elimination of PhEtSiH2. Based on the control experiments, both silyl‐nickel‐monohydride and silyl‐nickel‐trihydride complexes were considered as active intermediates in the catalytic hydrosilylation reaction. [ABSTRACT FROM AUTHOR]

Platinum(II) metalla‐N‐heterocyclic carbene complexes featuring pyridyl heterocyclic moiety demonstrate remarkable catalytic efficiency in alkyne hydrosilylation under green light irradiation. The photocatalytic properties of complexes are rationalised by the photo‐induced charge transfer occurring in extended condensed system identified with the help of various experimental (UV/vis and emission spectroscopy, cyclic voltammetry) and theoretical methods (DFT/TD‐DFT, IFCT analysis). [ABSTRACT FROM AUTHOR]

CO2 is an abundant C1 resource but a green‐house gas and chemically inert. Thus, its utilization has been a promising but challenging project. Herein, we report the unprecedented polymerization of CO2 and C6H4(SiMe2H)2 using B(C6F5)3 alone under mild conditions to give poly(silphenylene siloxane) accompanied by releasing CH4. The copolymerization can be extended to comonomers of phenylene silanes bearing functional groups. Moreover, it combines with Piers‐Rubinsztajn reaction to establish a tandem polymerization system to achieve super thermal resistant poly(siloxane‐co‐silphenylene siloxane)s. Density functional theory reveals that B(C6F5)3 is activated by silanes to form free HB(C6F5)2, which is the true active species for CO2 reducing to borylformate, the rate controlling step of the polymerization procedure. The subsequent multiple reductions of borylformate to CH4 and the step‐growth to poly(silphenylene siloxane)s can be fulfilled by both B(C6F5)3 and HB(C6F5)2, and the former shows a slightly higher activity. This work opens a new avenue of utilizing CO2 to fabricate polysiloxanes that is unable to access using current manners. [ABSTRACT FROM AUTHOR]

The chemistry of transition‐metal (TM) complexes with monoanionic bidentate (κ2‐L,Si) silyl ligands has considerably grown in recent years. This work summarizes the advances in the chemistry of TM‐(κ2‐L,Si) complexes (L=N‐heterocycle, phosphine, N‐heterocyclic carbene, thioether, ester, silylether or tetrylene). The most common synthetic method has been the oxidative addition of the Si−H bond to the metal center assisted by the coordination of L. The metal silicon bond distances in TM‐(κ2‐L,Si) complexes are in the range of metal‐silyl bond distances. TM‐(κ2‐L,Si) complexes have proven to be effective catalysts for hydrosilylation and/or hydrogenation of unsaturated molecules among other processes. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) have shown great research and application value in various types of hydrosilylation reactions. However, studies on photocatalysis‐induced hydrosilylation using MOFs are extremely rare. Metal nanoparticles (MNPs)@MOFs are extensively studied for their excellent structural tunability and photocatalytic activity, but there are few reports on their application in photocatalytic hydrosilylation. Here, a novel photocatalyst consisting of platinum (Pt) nanoparticles immobilized in a MOF framework is synthesized and used for photocatalytic hydrosilylation. The effects of various factors on hydrosilylation conversion are investigated, including catalyst concentration, substrate ratio, and irradiation intensity. Furthermore, the photoreactivity of the synthesized Pt catalyst is evaluated in the presence of different concentrations of 2‐chlorothixanthone as a photosensitizer. It is noteworthy that the conversion of the reaction increases with increasing catalyst concentration or photosensitizer concentration, whereas increasing the polymethylhydrosiloxane content does not lead to a significant increase in conversion. This study demonstrates the potential of MNPs@MOFs as efficient photocatalysts for photoinduced hydrosilylation reactions and paves the way for future applications in this area. [ABSTRACT FROM AUTHOR]

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The mechanochromic materials can respond to environmental changes by altering the optical properties of the system, which has garnered significant attention in recently. The utilization of these materials for the purpose of sensing tensile and compressive stress has been extensively documented. However, the mechanochromic polymer that can effectively discriminate hardness of inorganic particles is still rarely reported. In this article, a force‐sensitive organic polysiloxane was developed by introducing triethenyl‐substituted rhodamine derivatives crosslinker into the polymethylhydrosiloxane network through hydrosilylation addition reaction. The results demonstrated that the grinding of the crosslinked polysiloxane effectively facilitated the transmission of external force to the polymeric network, leading to an open ring isomerization of rhodamine accompanied by significant alterations in visible and fluorescent color. In addition, we found that the optical properties of the system showed distinct variations when the inorganic particles with different Moh's hardness were co‐ground with the polysiloxane. High Moh's hardness particles, such as Al2O3, could effectively trigger the mechanochromic behavior of the polymer, while Na2SO4 particles with low hardness failed to induce the corresponding change. Therefore, this organic polysiloxane could be used as a potential fluorescent indicator for hardness recognition. [ABSTRACT FROM AUTHOR]

The success of platinum-based chemotherapeutic drugs for clinical cancer treatments has inspired tremendous research efforts on developing new metallic anticancer agents with improved cytotoxic activity and reduced side effects. 2,2′;6′,2″-Terpyridine and its 4′-substituted derivatives have showed great potential as ligand compartments for designing new anticancer drug candidates involving base metals. In this work, we synthesized a series of cobalt and iron coordination compounds based on 4′-pyridyl-2,2′;6′,2″-terpyridine, including homoleptic complexes, a dinuclear bridged complex and 1- and 2-dimensional coordination polymers/networks. The polymorphism of two homoleptic CoII and FeII complexes has been described along with the structural characterization of a CoII coordination polymer and dinuclear FeIII complex by X-ray crystallography. These compounds were tested preliminarily as precatalysts for the regioselective hydrosilylation of styrene. Their cytotoxic activities against two human breast cancer cell lines (MCF-7 and MDA-MB 468) and a normal breast epithelial cell line (MCF-10A) were investigated in order to observe the best-performing drug candidates.

Abstract We present a methodology for the synthesis of inorganic-organic Janus-type molecules based on mono-T8 and difunctionalized double-decker silsesquioxanes (DDSQs) via hydrosilylation reactions, achieving exceptionally high yields and selectivities. The synthesized compounds were extensively characterized using various spectroscopic techniques, and their sizes and spatial arrangements were predicted through molecular modelling and density functional theory (DFT) calculations. Quantum chemical calculations were employed to examine the interactions among four molecules of the synthesized compounds. These computational results allowed us to determine the propensity for molecular aggregation, identify the functional groups involved in these interactions, and understand the changes in interatomic distances during aggregation. Understanding the aggregation behaviour of silsesquioxane molecules is crucial for tailoring their properties for specific applications, such as nanocomposites, surface coatings, drug delivery systems, and catalysts. Through a combination of experimental and computational approaches, this study provides valuable insights into the design and optimization of silsesquioxane-based Janus-type molecules for enhanced performance across various fields.

We report herein a blue‐light‐promoted iron‐catalyzed reduction of carboxamides and carboxylic esters. Conducting the reaction under hydrosilylation conditions and blue light (2×24 W, 450–460 nm) in the presence of an iron(0) based pre‐catalyst, Fe(CO)4(IMes), amines and alcohols were obtained, respectively, notably at ambient conditions, whereas using white light, higher reaction temperatures up to 100 °C were required. Preliminary mechanism studies highlighted the crucial role of blue light not only to generate the catalytic active species, but also in some steps of the catalytic cycle. [ABSTRACT FROM AUTHOR]

Benzyne derived from hexadehydrogenated Diels Alder (HDDA) reactions was found to be an efficient hydrosilylation acceptors. Various silanes can react smoothly with HDDA‐derived benzyne to give the arylation products. Lewis acid such as boron trifluoride etherate can accelerate these hydrosilylation reactions. Polyhydromethylsiloxane (PHMS), a widely used organosilicon polymer, was also successfully modified using our method. About 5 % of Si−H bonds in the polymer were inserted by benzynes, giving a functional PHMS with much more solubility in methanol and with a blue‐emitting fluorescence behavior. Mechanism research shows that the insertion of benzyne into the Si−H bond probably undergoes a synergistic pathway, which is quite different from the traditional radical‐initiated hydrosilylation or transition‐metal‐catalyzed hydrosilylation. [ABSTRACT FROM AUTHOR]

A facile esterification of α,β-unsaturated aldehydes with alcohols has been developed for the synthesis of esters by using bulky N-heterocyclic (NHC) carbene as a metal-free and eco-friendly organocatalyst. This new protocol has been proved to be effective with a wide substrate scope, giving selective esters in yields greater than 84% under mild conditions. Moreover, proposed synthetic strategy enables modification of various types of silsesquioxanes (SQ) which cannot or are technically difficult to be carried out with known protocols. For the first time, a one-pot sequential esterification/hydrosilylation has been successfully carried out. [ABSTRACT FROM AUTHOR]

A series of air‐stable cobalt(III)salen complexes Co‐1 to Co‐4 have been synthesized and employed in the hydrosilylation of ketones. Notably, the most intricately tailored Co‐3 pre‐catalyst exhibited exceptional catalytic activity under mild reaction conditions. The developed catalytic hydrosilylation protocol proceeded with an unusual ppm level (5 ppm) catalyst loading of Co‐3 and achieved a maximum turnover number (TON) of 200,000. A wide variety of aromatic, aliphatic, and heterocyclic ketones encompassing both electron‐donating and electron‐withdrawing substituents were successfully transformed into the desired silyl ethers or secondary alcohols in moderate to excellent yields. [ABSTRACT FROM AUTHOR]

The hydrosilylation reactions of dihydrosilylium ion 2, stabilized by coordination of a σ‐donating Ni(0) fragment, has been investigated. Complex 2 with two reactive sites, dihydrosilylium and Ni(0) centers, readily reacts with diphenylacetylene via a selective mono‐hydrosilylation reaction to afford the corresponding Ni(0)‐stabilized (hydro)(vinyl)silylium ion 6. In the case of ethylene, three equivalents of olefin are consumed to give a cationic Ni(II)‐complex 7 featuring a Bu‐Si+‐NiII‐Et moiety with a NHC‐supported Si atom. DFT calculations indicate that the hydrosilylation proceeds by a classical (Chalk‐Harrod type) mechanism with the assistance of NHC ligand moving between Si and Ni centers according to their stabilization requirements. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: By rational modification of electronic and steric properties of pincer ligands, a Co/Fe dual catalyst system is developed for one‐pot sequential Markovnikov alkyne hydrosilylation and stereoselective alkene isomerization. The protocol provides an atom‐economical and efficient approach to trisubstituted (E)‐alkenyl silanes from widely accessible terminal alkynes with high regio‐ and stereoselectivities under mild conditions. The utility of this reaction was demonstrated by gram‐scale synthesis and derivatization of bioactive molecules. The radical clock and trapping experiments indicated that radical pathway might be operative in the alkene isomerization step. [ABSTRACT FROM AUTHOR]

This concept addresses the main economic, environmental, scientific and technological issues associated with the use of homogeneous Pt‐catalysts in the important industrial hydrosilylation process. The development of biphase catalysis is proposed as the most promising approach. One solution we suggest is the use of ethylene glycol (EG) as a medium in biphase catalysis. We have previously shown that EG in Pt‐catalyzed hydrosilylation serves not only as a medium but also as a mild reducing agent of Pt‐ions to Pt0, as well as an effective ligand for the preparation of mononuclear Pt01‐complexes. These zero valent platinum complexes are single‐atom catalysts (SAC) and have high activity in hydrosilylation, stability during storage and the ability to be recycled multiple times (~40 times). This option of using an atomic catalyst allows us to combine the advantages of homogeneous and heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

Cobalt complexes featuring triazine‐based PNP ligands have proven to be exceptionally active and chemoselective pre‐catalysts in facilitating the dehydrogenative coupling between silanes and amines, leading to the synthesis of diverse aminosilanes. Notably, even challenging substrates exhibited high reactivity. The catalyst's unique feature of avoiding coupling with tertiary silanes enhances process chemoselectivity. It facilitates a more precise synthesis of silylamines possessing of SiH2−N and SiH−N motifs, overcoming challenges associated with broader reactivity seen in previous systems. In terms of its remarkable chemoselectivity, it is also noteworthy that the catalytic system exhibits both versatility and efficacy in converting substrates with untouched double and triple carbon‐carbon bonds. This accomplishment is particularly significant, given previous challenges brought about by the activity of commonly employed catalysts in the competitive hydrosilylation process. [ABSTRACT FROM AUTHOR]

The selective conversion of unsaturated compounds has emerged as a crucial method in chemical synthesis, enabling the synthesis of functional organic molecules. In recent decades, transition metal‐catalyzed hydrosilylation has emerged as a highly successful exemplar of industrialization within the realm of organic chemistry for the production of organosilanes, which have a pivotal role in organic chemistry and materials science. Precious metal complexes are typically employed as catalysts in most industrial hydrosilylation processes. The exploration of Earth‐abundant alternatives has emerged as a focal point of considerable research attention due to the high cost, poor selectivity, and many side reactions reported for precious metal catalysts. Ligand skeleton construction, selectivity, and mechanism research are areas where cobalt catalysts have more potential than iron and nickel. This review discusses the recent advances in cobalt‐catalyzed hydrosilylation across carbon‐carbon, carbon‐oxygen, and carbon‐nitrogen multiple bonds from 2019 to 2023. [ABSTRACT FROM AUTHOR]

The report introduces simple yet highly reactive calcium salt, Ca[Al(ORF)4]2 (RF=C(CF3)3), 1, which effectively catalyses olefin hydrosilylation through an unusual mechanism involving the activation of the alkene molecule. Upon dissolution in o‐difluorobenzene (oDFB), 1 forms a highly Lewis acidic [Ca(oDFB)6]2+ complex. Our DFT calculations reveal that fluoride ion affinity is comparable to SbF5. Reactivity tests show that it effectively catalyses the hydrosilylation of olefins with high regioselectivity, also in reactions involving sterically demanding substrates like (iPr)3SiH or tetrasubstituted olefins. Experimental and computational results point to the mechanism where the olefin molecule forms a complex with Ca2+, which significantly facilitates the attack of H‐SiR3 on the C=C double bond. [ABSTRACT FROM AUTHOR]

Fluorinated arylborane‐based Lewis acid catalysts have shown remarkable activity and serve as ideal examples of transition metal‐free catalysts for diverse organic transformations. However, their homogeneous nature poses challenges in terms of recyclability and separation from reaction mixtures. This work presents an efficient technique for the heterogenization of boron Lewis acid catalysts by anchoring Piers' borane to allyl‐functionalized iron oxide. This catalyst demonstrates excellent activity in the hydrosilylation of imines and the reductive amination of carbonyls using various silanes as reducing agents under mild reaction conditions. The catalyst exhibits broad tolerance towards a wide range of functional substrates. Furthermore, it exhibits good recyclability and can be easily separated from the products using an external magnetic field. This work represents a significant advance in the development of sustainable heterogenous metal‐free catalysts for organic transformations. [ABSTRACT FROM AUTHOR]

We present a methodology for the synthesis of inorganic-organic Janus-type molecules based on mono-T8 and difunctionalized double-decker silsesquioxanes (DDSQs) via hydrosilylation reactions, achieving exceptionally high yields and selectivities. The synthesized compounds were extensively characterized using various spectroscopic techniques, and their sizes and spatial arrangements were predicted through molecular modelling and density functional theory (DFT) calculations. Quantum chemical calculations were employed to examine the interactions among four molecules of the synthesized compounds. These computational results allowed us to determine the propensity for molecular aggregation, identify the functional groups involved in these interactions, and understand the changes in interatomic distances during aggregation. Understanding the aggregation behaviour of silsesquioxane molecules is crucial for tailoring their properties for specific applications, such as nanocomposites, surface coatings, drug delivery systems, and catalysts. Through a combination of experimental and computational approaches, this study provides valuable insights into the design and optimization of silsesquioxane-based Janus-type molecules for enhanced performance across various fields. [ABSTRACT FROM AUTHOR]

Here, we introduce a new class of titanocene catalysts for epoxide hydrosilylation that frustrates their hydridicity and thereby emphasizes their electron transfer reactivity. This unique attenuation of hydridicity is accomplished by introducing Lewis acidic silicon centers to the cyclopentadienyl ligands for an intramolecular coordination of the titanium‐bound hydride. The superiority of our rationally designed catalysts over classic titanocenes with alkyl‐substituted cyclopentadienyl ligands is demonstrated in the dramatically improved regioselectivity of the hydrosilylation of monosubstituted epoxides to primary alcohols. [ABSTRACT FROM AUTHOR]

The hydrosilylation reaction is a suitable route to prepare efficient, transparent, and low‐viscose silicone surfactants with low surface tension. Initial materials, the catalyst used, and experimental conditions are highly effective variables to achieve the maximum efficiency of the reaction, reduce the consumption of the catalyst, and prevent side reactions. To draw a comprehensive conclusion on the effect of these variables, a series of trimethylsiloxy‐terminated poly (methylhydro‐dimethyl)siloxanes copolymer (abbreviated as RSiH with different preceding numbers) and two unsaturated polyethylene glycols (UPEG200 and UPEG400) were selected, and the reactions in the presence of two platinum‐based catalysts, namely, hexachloroplatinic acid and ammonium hexachloroplatinate, were statistically studied by Design of Experiment. After initial pre‐investigations, the amounts of reactant and catalyst were subjected to analysis of variance using response surface methodology (RSM). Based on the results, low‐viscose and low‐surface tension silicone surfactants were obtained using UPEG400, RSiH105, and (NH4)2PtCl6 as catalysts, at temperatures over 170 °C. The best results were obtained with a relatively low concentration of the catalyst between 2.57 × 10−6 and 2.72 × 10−6 equivalent catalyst per UPEG. The relative equivalent ratio of [UPEG]/[RSiH] at the optimum condition was 1.6, which provided a surface tension below 21 mN/m together with a minimum amount of unreacted RSiH (less than 3%). The silicone surfactant was characterized as a pure product by a series of spectroscopic methods, such as FT‐IR and 1H NMR spectroscopies, as well as bromine number index. These excellent properties make this compound a new alternative in various industries. [ABSTRACT FROM AUTHOR]

Few‐atom metal clusters (FAMCs) exhibit superior performance in catalyzing complex molecular transformations due to their special spatial environments and electronic states, compared to single‐atom catalysts (SACs). However, achieving the efficient and accurate synthesis of FAMCs while avoiding the formation of other species, such as nanoparticles and SACs, still remains challenges. Herein, we report a two‐step strategy for synthesis of few‐atom platinum (Pt) clusters by predeposition of zinc single‐atom‐glue (Zn1) on MgO nanosheets (Ptn−Zn1/MgO), where FAMCs can be obtained over a wide range of Pt contents (0.09 to 1.45 wt %). Zn atoms can act as Lewis acidic sites to allow electron transfer between Zn and Pt through bridging O atoms, which play a crucial role in the formation and stabilization of few‐atom Pt clusters. Ptn−Zn1/MgO exhibited a high selectivity of 93 % for anti‐Markovnikov alkene hydrosilylation. Moreover, an excellent activity with a turnover frequency of up to 1.6×104 h−1 can be achieved, exceeding most of the reported Pt SACs. Further theoretical studies revealed that the Pt atoms in Ptn−Zn1/MgO possess moderate steric hindrance, which enables high selectivity and activity for hydrosilylation. This work presents some guidelines for utilizing atomic‐scale species to increase the synthesis efficiency and precision of FAMCs. [ABSTRACT FROM AUTHOR]

Carbene–metal–amide (CMA) complexes of gold, silver, and copper have been studied extensively for their photochemical/photocatalytic properties and as potential (pre-)catalysts in organic synthesis. Herein, the design, synthesis, and characterization of five bench-stable Au-, Ag-, and Cu-NHC complexes bearing the benzotriazolyl anion as an amide donor, are reported. All complexes are synthesized in a facile and straightforward manner, using mild conditions. The catalytic activity of the Ag and Cu complexes was studied in propargylamide cycloisomerization and carbonyl hydrosilylation reactions. Both CMA-catalyzed transformations proceed under mild conditions and are highly efficient for a range of propargylamides and carbonyl compounds, respectively, affording the desired corresponding products in good to excellent yields. [ABSTRACT FROM AUTHOR]

We report the stepwise synthesis of a novel series of heterometallic gold(I)/palladium(II) complexes supported by heteroditopic imidazol‐2‐ylidene/triazol‐5‐ylidene ligands. All new compounds were characterized by means of 1H and 13C NMR spectroscopy, melting points, and elemental analyses. The versatility of the ligand platforms, additionally allows for the preparation of cationic chelate biscarbenic palladium(II) complexes through full deprotonation of the mixed azolium precursors. Characterization studies were completed by the determination of the molecular structures of some synthetic intermediates. The new biscarbenic palladium(II) complexes were tested as catalysts in the cross‐coupling of boronic acid to a variety of chloroarenes and the hydrosilylation of terminal alkynes. Both catalytic processes provide good to excellent yields under low catalyst loadings. [ABSTRACT FROM AUTHOR]

A sterically encumbered dinuclear amidinato magnesium hydride 3 with bridging hydrido ligands was synthesized from the metalation of the corresponding amidine 1 with dibutylmagnesium and subsequent treatment with phenylsilane. This complex reacts stoichiometrically with 1 atm of carbon dioxide at room temperature in tetrahydrofuran (THF) to the corresponding bis(thf) adduct of the dinuclear formate complex 4‐2 thf with bridging formate anions. This complex is stable in THF at 60 °C for more than 16 hours but decomposes into the amidine 1 upon removal of ligated thf ligands. Complex 3 efficiently catalyzes the reduction of carbon dioxide with 9‐BBN, yielding bis(boryl)acetal (R2BO)2CH2, and with silanes H4‐nSiPhn (n=1, 2, and 3). The bis(silyl)acetal is quantitatively accessible for Ph3SiH (n=3) whereas during the reduction of CO2 with hydrogen‐richer silanes (n=1, 2) siloxanes form and methane evolves. [ABSTRACT FROM AUTHOR]