The first example of evolution of an iridanaphthalene into an indanone through an intermediate indenyl is reported, serving as a good example of starting material to obtain indanones. Two new iridanaphthalenes are obtained by intramolecular C−H activation of a phenyl ring of a carbene ligand in [IrCp*{C(OMe)CHCPh 2 }(L)]PF 6 (L = PPh 2 Me, PMe 3 ) complexes. It is demonstrated that these iridanaphthalene complexes can undergo a thermal reaction to give indenyl complexes and 3-phenylindanone.M etallacyclic aromatic compounds incorporating transition metals are a subject of great interest, since they display a behavior that includes properties from both aromatic organic and organometallic compounds. Although many metallabenzenes of osmium, iridium, platinum, and ruthenium are known, to the best of our knowledge only two metallanaphthalenes have been reported, one with osmium 1 and another with iridium. 2 The importance of this type of metal-organic functionality is emphasized by the fact that metal cyclopentadienyls can be formed from transitory metallabenzenes. 3 Analogously, an osmanaphthalene has been proposed as intermediate leading to an indenyl complex. 4 Recently, we have reported that the new (methoxy)-alkenylcarbeneiridium complex [IrCp*Cl{C(OMe)CH CPh 2 }(PPh 2 Me)]PF 6 (1a) reacts with amines to undergo the unexpected cleavage of the O−CH 3 bond instead of the usual aminolysis. 5 This peculiar behavior has prompted us to further explore the reactivity of these types of compounds. Here, we report that treatment of [IrCp*Cl{C(OMe)CHCPh 2 }-(L)]PF 6 (L = PPh 2 Me (1a), PMe 3 (1b)) with AgPF 6 gives high yields of the iridanaphthalene complexes [IrCp*{C(OMe)-CHC(o-C 6 H 4 )(Ph)}(L)]PF 6 (L = PPh 2 Me (2a), PMe 3 (2b)) through an intramolecular C−H activation of one of the phenyl rings of the carbene ligand (eq 1).The structures of both iridanaphthalene complexes have been confirmed by single-crystal X-ray diffraction (see the Supporting Information). Figure 1 shows the complex cation 2a. The iridium atom becomes part of a metallanaphthalene moiety and the metal coordination sphere is completed with a pentamethylcyclopentadienyl (Cp*) and a phosphane ligand.The NMR spectra support the solid-state structures of 2a,b (see the Supporting Information).Remarkably, the iridanaphthalene moiety is not stable and refluxing 2 in 1,2-dichloroethane or toluene for 24 h gives 3-phenylindanone (4) (eq 2). The same transformation occurs also at longer reaction times in dichloromethane at 35°C (eq 2).
Several theoretical studies have proposed strategies to reach helical molecular orbitals (Hel-MOs) in [n]cumulenes. While chiral even-[n] cumulenes feature Hel-MOs, odd-[n] cumulenes may also present them if the terminal groups lie on different planes. However, the hitherto proposed systems have been either experimentally unfeasible or resulted in opposite pseudodegenerated Hel-MOs, impeding their use in real applicatons. To overcome this challenge, we hereby demonstrate the introduction of a remarkable energy difference between helical orbitals of opposite twist by fixing the torsion angle between the terminal groups in butadiyne fragments. In order to experimentally lock the conformation of the terminal groups, we designed cyclic architectures by combining acetylenes with chiral spirobifluorenes. A straightforward synthetic strategy along with the high stability allowed the isolation and full characterization of systems presenting distinct helical orbitals. Finally, a thorough computational analysis revealed that the most significant optical responses of these systems originate mainly from the exciton coupling between the featured diphenylbutadiyne fragments. This novel strategy opens now access to the development of systems with distinct helical molecular orbitals suitable for their implementation into chiroptical and optoelectronic applications Scheme 1. General representation of acetylene (top left), [2]cumulene (top center), [3]cumulene (top right) and schematic representation of two possible paths for the formation of helical orbitals in [2]cumulenes (bottom left) and acetylenes (bottom right). Black spheres represent functional groups that can be the same or different and grey lobes stand for p atomic orbitals.
Spirobifluorene derivatives find use in many end-user applications. Therefore, furthere xpansiono f their scopei st he focus of many research studies. However,a lthough the optical properties of spirobifluorenes can be greatly tuned through incorporation of metal complexes,t od ate, spirobifluorene metallaaromatics remain unknown. Ta king advantage of the versatility of our methodologyf or the synthesis of metallaaromatic systems, this work reports the first metallaaromatic spirobifluorene compound. The presence of an Ir atom was found to redshift the absorption maximum by ca. 1.1 eV comparedt o bare spirobifluorene. Additionally,X -ray analysisa sw ell as anisotropy of the current-induced density calculations revealed this compound to be of aromatic nature.T he high stabilityi ns olution, solids tate, under air,a nd at high temperature, as well as distinct optical properties of this new class of compounds are expected to open new frontiers for chiroptical and optoelectronica pplications.
The activation of tetrafluoropropenes at rhodium silyl and germyl complexes revealed various reaction pathways such as the generation of organic derivatives of the substrate and a rhodium fluorido complex or the formation of rhodium vinyl complexes.
The reaction of [Rh(H)(PEt 3 ) 3 ]( 1)w ith the refrigerant HFO-1234yf (2,3,3,3-tetrafluoropropene) affords an efficient route to obtain [Rh(F)(PEt 3 ) 3 ]( 3)b yC À Fb ond activation. Catalytic hydrodefluorinations were achieved in the presence of the silane HSiPh 3 .Inthe presence of afluorosilane, 3 provides aC ÀHb ond activation followed by a1 ,2-fluorine shift to produce [Rh{(E)-C(CF 3 )=CHF}(PEt 3 ) 3 ]( 4). Similar rearrangements of HFO-1234yf were observed at [Rh(E)-(PEt 3 ) 3 ][E= Bpin (6), C 7 D 7 (8), Me (9)].The ability to favor C À Hb ond activation using 3 and fluorosilane is also demonstrated with 3,3,3-trifluoropropene.S tudies are supported by DFT calculations.
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