Abstract:Carbon ligands have long played an important role in organometallic chemistry. However, previous examples of all-carbon chelating ligands are limited. Herein, we present a novel complex with an eleven-atom carbon chain as a polydentate chelating ligand. This species was formed by the [2+2+2] cycloaddition reaction of two equivalents of an alkyne with an osmapentalyne that contains the smallest carbyne bond angle (127.9°) ever observed. Density functional calculations revealed that electron-donating groups play… Show more
“…4), a series of reactant osmapentalynes (1b-1g) were synthesized by the treatment of carbon ligands (L2-L7) with multiyne chains with OsCl 2 (PPh 3 ) 3 and PPh 3 , the different substituents at different positions appear not to affect the reaction (3,(31)(32)(33)(34)(35)(36). For instance, the R′ substituent can be styryl (3), phenyl (31)(32)(33), thienyl (34) or hydrogen (35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46), and the Y group can be CH 2 (31,34), O (32,35) or C(COOMe) 2 (33,36). The structures of all the above complexes were confirmed by NMR spectroscopy, EA and HRMS ( Supplementary Figs.…”
Section: Resultsmentioning
confidence: 99%
“…The high ring strain associated with this small carbyne angle promoted us to investigate the reactivity of 1a and 2a with alkynes. In our previous work, only cycloaddition reactions based on similar osmapentalyne complexes were reported 27 , 30 , 31 . Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The reactions of M≡C and C≡C bonds tend to afford cycloaddition intermediates or products on account of their high degree of unsaturation. For example, the alkyne metathesis undergoes metallacyclobutadiene intermediates process 12-14 , and [2+2], [2+2+1], and [2+2+2] cycloaddition products have been widely published [26][27][28][29][30][31][32][33][34][35][36][37] . Acyclic products, however, have never been reported.…”
The metal-carbon triple bonds and carbon-carbon triple bonds are both highly unsaturated bonds. As a result, their reactions tend to afford cycloaddition intermediates or products. Herein, we report a reaction of M≡C and C≡C bonds that affords acyclic addition products. These newly discovered reactions are highly efficient, regio- and stereospecific, with good functional group tolerance, and are robust under air at room temperature. The isotope labeling NMR experiments and theoretical calculations reveal the reaction mechanism. Employing these reactions, functionalized dπ-pπ conjugated systems can be easily constructed and modified. The resulting dπ-pπ conjugated systems were found to be good electron transport layer materials in organic solar cells, with power conversion efficiency up to 16.28% based on the PM6: Y6 non-fullerene system. This work provides a facile, efficient methodology for the preparation of dπ-pπ conjugated systems for use in functional materials.
“…4), a series of reactant osmapentalynes (1b-1g) were synthesized by the treatment of carbon ligands (L2-L7) with multiyne chains with OsCl 2 (PPh 3 ) 3 and PPh 3 , the different substituents at different positions appear not to affect the reaction (3,(31)(32)(33)(34)(35)(36). For instance, the R′ substituent can be styryl (3), phenyl (31)(32)(33), thienyl (34) or hydrogen (35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46), and the Y group can be CH 2 (31,34), O (32,35) or C(COOMe) 2 (33,36). The structures of all the above complexes were confirmed by NMR spectroscopy, EA and HRMS ( Supplementary Figs.…”
Section: Resultsmentioning
confidence: 99%
“…The high ring strain associated with this small carbyne angle promoted us to investigate the reactivity of 1a and 2a with alkynes. In our previous work, only cycloaddition reactions based on similar osmapentalyne complexes were reported 27 , 30 , 31 . Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The reactions of M≡C and C≡C bonds tend to afford cycloaddition intermediates or products on account of their high degree of unsaturation. For example, the alkyne metathesis undergoes metallacyclobutadiene intermediates process 12-14 , and [2+2], [2+2+1], and [2+2+2] cycloaddition products have been widely published [26][27][28][29][30][31][32][33][34][35][36][37] . Acyclic products, however, have never been reported.…”
The metal-carbon triple bonds and carbon-carbon triple bonds are both highly unsaturated bonds. As a result, their reactions tend to afford cycloaddition intermediates or products. Herein, we report a reaction of M≡C and C≡C bonds that affords acyclic addition products. These newly discovered reactions are highly efficient, regio- and stereospecific, with good functional group tolerance, and are robust under air at room temperature. The isotope labeling NMR experiments and theoretical calculations reveal the reaction mechanism. Employing these reactions, functionalized dπ-pπ conjugated systems can be easily constructed and modified. The resulting dπ-pπ conjugated systems were found to be good electron transport layer materials in organic solar cells, with power conversion efficiency up to 16.28% based on the PM6: Y6 non-fullerene system. This work provides a facile, efficient methodology for the preparation of dπ-pπ conjugated systems for use in functional materials.
“…The metal-carbon triple bond possesses an "alkyne-like" character and can react with an external metal precursor to generate bimetallic adducts, in which osmium-carbon triple bond coordinated with the coinage metal center. Xia reported that osmapentalyne 44 [48] was treated with cuprous chloride to afford hetero bimetallic adduct 45, in which the chloride bonded to osmium also coordinated with copper atoms. As different silver or gold precursors were subjected to osmapentalyne 44, the corresponding hetero bimetallic adduct 46 or 47 was formed in a similar way.…”
Section: Formation Of Osmapentalyne-coinage Metal Complexesmentioning
confidence: 99%
“…Recently, Xia and coworkers documented a series of five-membered cyclic metal carbyne complexes, i.e., osmapentalynes [47][48][49][50][51] and ruthenapentalynes [52]. The carbine-carbon bond angles in the metallapentalynes are around 130 • , which are much smaller than those of the acyclic metal carbynes (180 • ).…”
Section: Reactivity Of Five-membered Metallapentalynesmentioning
The acyclic organic alkynes and carbyne bonds exhibit linear shapes. Metallabenzynes and metallapentalynes are six- or five-membered metallacycles containing carbynes, whose carbine-carbon bond angles are less than 180°. Such distortion results in considerable ring strain, resulting in the unprecedented reactivity compared with acyclic carbynes. Meanwhile, the aromaticity of these metallacycles would stabilize the ring system. The fascinating combination of ring strain and aromaticity would lead to interesting reactivities. This mini review summarized recent findings on the reactivity of the metal–carbon triple bonds and the aromatic ring system. In the case of metallabenzynes, aromaticity would prevail over ring strain. The reactions are similar to those of organic aromatics, especially in electrophilic reactions. Meanwhile, fragmentation of metallacarbynes might be observed via migratory insertion if the aromaticity of metallacarbynes is strongly affected. In the case of metallapentalynes, the extremely small bond angle would result in high reactivity of the carbyne moiety, which would undergo typical reactions for organic alkynes, including interaction with coinage metal complexes, electrophilic reactions, nucleophilic reactions and cycloaddition reactions, whereas the strong aromaticity ensured the integrity of the bicyclic framework of metallapentalynes throughout all reported reaction conditions.
Metallacyclobutadienes (MCBDs) are key intermediates of alkyne metathesis reactions. There are in principle two isomerization pathway from kinetic to thermodynamic MCBDs, intermolecular and intramolecular. However, systems that simultaneously isolate two kinds of MCBD isomers have not been achieved, thus restricting the mechanistic studies of the isomerization. Here the reactivity of a metallapentalyne that contains an M≡C bond within the aromatic ring, with alkynes to afford a series of MCBD‐fused metallapentalenes is studied. In some cases, both kinetic and thermodynamic products are isolated in the same system, which has never been observed in previous MCBD reactions. Furthermore, the isomerization of MCBD‐fused metallapentalenes is investigated both experimentally and theoretically, indicating that it is an intramolecular process involving a metallatetrahedrane (MTd) intermediate. This research provides experimental evidence demonstrating that one MCBD can undergo intramolecular rearrangement to transform into another.
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