Synthesis and Oligomerization of CpM(CO)₂

We showcase efficient synthetic protocols of cyclopentadienyl metal dicarbonyl, CpM­(CO)2 (M = Rh and Ir). Reflecting the relativistic effect, the 1H and 13C signals of the Cp ring in CpIr­(CO)2 were upfield shifted when compared with the Rh analogue. A missing dinuclear complex, (CpIr)2(μ-CO)­(CO)2, was spontaneously generated together with [CpIr­(CO)]3 by the loss of CO. The crystallographic analyses unambiguously determined their unique structures with one and three Ir–Ir bonds, respectively

Synthesis and Oligomerization of CpM(CO)₂

We showcase efficient synthetic protocols of cyclopentadienyl metal dicarbonyl, CpM­(CO)2 (M = Rh and Ir). Reflecting the relativistic effect, the 1H and 13C signals of the Cp ring in CpIr­(CO)2 were upfield shifted when compared with the Rh analogue. A missing dinuclear complex, (CpIr)2(μ-CO)­(CO)2, was spontaneously generated together with [CpIr­(CO)]3 by the loss of CO. The crystallographic analyses unambiguously determined their unique structures with one and three Ir–Ir bonds, respectively

Synthesis and Oligomerization of CpM(CO)₂

We showcase efficient synthetic protocols of cyclopentadienyl metal dicarbonyl, CpM­(CO)2 (M = Rh and Ir). Reflecting the relativistic effect, the 1H and 13C signals of the Cp ring in CpIr­(CO)2 were upfield shifted when compared with the Rh analogue. A missing dinuclear complex, (CpIr)2(μ-CO)­(CO)2, was spontaneously generated together with [CpIr­(CO)]3 by the loss of CO. The crystallographic analyses unambiguously determined their unique structures with one and three Ir–Ir bonds, respectively

H₂O/Olefinic‑π Interaction inside a Carbon Nanocage

The H2O/CH2CH2-type hydrogen-bonding (H-bonding) model was experimentally constructed using a water complex of an open-cage C60 derivative, in which an olefinic double bond and a single molecule of H2O are geometrically confined. To investigate OH/π-type H-bonding, that is, H2O···(CC) interaction, we performed 1H NMR spectroscopic studies that demonstrated the monotonic downfield shift of the proton signal corresponding to H2O with remarkable rotational perturbation by lowering the temperature. From the temperature dependence of the angular momentum correlation time (τJ), the interaction energy was quantitatively estimated to be ca. 0.3 kcal/mol. The computational studies were thoroughly conducted to clarify its inherent nature. As a consequence, the orientation of H2O was found to play a prominent role in varying the bonding strength as well as contribution from the electrostatic attraction and orbital–orbital interaction significantly driven by the favorable orbital overlap identified as π­(CC) → σ*­(OH) interaction

Cobalt-Functionalized Open-[60]Fullerenes

Redox noninnocent ligands have drawn considerable attention owing to effective interplay with metal(s) via π–d interactions, enabling magnetic on/off switching as well as redox-controlled catalytic reactions. Herein, we showcase the synthesis of [Co]2 and [Co]1 complexes bearing open-[60]fullerene ligands, whose absorption edges reached 1000 and 1500 nm, respectively. During the reaction, o-dichlorobenzene (solvent) was partly transformed to 2-chlorophenol, with which the Co complexes are most likely to participate in a reductive elimination step. While [Co]2 contains a Co–Co bond identifiable by hybridized dz2 orbitals, [Co]1 possesses a fulvene-conjugated open-[60]fullerene ligand which was generated by a ring-opening metathesis. Theoretical calculations suggested that [Co]1 shows characteristic redox behavior where the ligand works as an electron reservoir

Synthesis and Oligomerization of CpM(CO)₂

We showcase efficient synthetic protocols of cyclopentadienyl metal dicarbonyl, CpM­(CO)2 (M = Rh and Ir). Reflecting the relativistic effect, the 1H and 13C signals of the Cp ring in CpIr­(CO)2 were upfield shifted when compared with the Rh analogue. A missing dinuclear complex, (CpIr)2(μ-CO)­(CO)2, was spontaneously generated together with [CpIr­(CO)]3 by the loss of CO. The crystallographic analyses unambiguously determined their unique structures with one and three Ir–Ir bonds, respectively

Synthesis and Oligomerization of CpM(CO)₂

We showcase efficient synthetic protocols of cyclopentadienyl metal dicarbonyl, CpM­(CO)2 (M = Rh and Ir). Reflecting the relativistic effect, the 1H and 13C signals of the Cp ring in CpIr­(CO)2 were upfield shifted when compared with the Rh analogue. A missing dinuclear complex, (CpIr)2(μ-CO)­(CO)2, was spontaneously generated together with [CpIr­(CO)]3 by the loss of CO. The crystallographic analyses unambiguously determined their unique structures with one and three Ir–Ir bonds, respectively

Cobalt-Functionalized Open-[60]Fullerenes

Redox noninnocent ligands have drawn considerable attention owing to effective interplay with metal(s) via π–d interactions, enabling magnetic on/off switching as well as redox-controlled catalytic reactions. Herein, we showcase the synthesis of [Co]2 and [Co]1 complexes bearing open-[60]fullerene ligands, whose absorption edges reached 1000 and 1500 nm, respectively. During the reaction, o-dichlorobenzene (solvent) was partly transformed to 2-chlorophenol, with which the Co complexes are most likely to participate in a reductive elimination step. While [Co]2 contains a Co–Co bond identifiable by hybridized dz2 orbitals, [Co]1 possesses a fulvene-conjugated open-[60]fullerene ligand which was generated by a ring-opening metathesis. Theoretical calculations suggested that [Co]1 shows characteristic redox behavior where the ligand works as an electron reservoir

Synthesis and Oligomerization of CpM(CO)₂

We showcase efficient synthetic protocols of cyclopentadienyl metal dicarbonyl, CpM­(CO)2 (M = Rh and Ir). Reflecting the relativistic effect, the 1H and 13C signals of the Cp ring in CpIr­(CO)2 were upfield shifted when compared with the Rh analogue. A missing dinuclear complex, (CpIr)2(μ-CO)­(CO)2, was spontaneously generated together with [CpIr­(CO)]3 by the loss of CO. The crystallographic analyses unambiguously determined their unique structures with one and three Ir–Ir bonds, respectively

The Reaction of Fullerene C₆₀ with 4,6-Dimethyl-1,2,3-triazine: Formation of an Open-Cage Fullerene Derivative

A thermal reaction of fullerene C60 with 4,6-dimethyl-1,2,3-triazine (4) in o-dichlorobenzene gave azacyclohexadiene-fused fullerene derivative 5, by the reaction with intermediate azete 11, and then, after flash chromatography over SiO2, open-cage fullerene derivative 6 having an eight-membered ring orifice on the C60 cage. Compound 6 is assumed to be formed via addition of diradical intermediate 13 to C60. Compound 6 underwent a further photochemical reaction with singlet oxygen with the cleavage of one of the double bonds at the rim of the orifice to afford triketone derivative 8 having a 12-membered ring orifice