Collision of Two Rotating Hayward Black Holes

We investigate the spin interaction and the gravitational radiation thermally allowed in a head-on collision of two rotating Hayward black holes. The Hayward black hole is a regular black hole in a modified Einstein equation, and hence it can be an appropriate model to describe the extent to which the regularity effect in the near-horizon region affects the interaction and the radiation. If one black hole is assumed to be considerably smaller than the other, the potential of the spin interaction can be analytically obtained and is dependent on the alignment of angular momenta of the black holes. For the collision of massive black holes, the gravitational radiation is numerically obtained as the upper bound by using the laws of thermodynamics. The effect of the Hayward black hole tends to increase the radiation energy, but we can limit the effect by comparing the radiation energy with the gravitational waves GW150914 and GW151226.Comment: 25 pages, 43 figures, published version in EPJ

Synthesis and Hydrolysis of Cationic Palladium(II) 2,6-Diacetylpyridine Dimethyl Ketal Complexes. Cyclopalladation of 2,6-Diacetylpyridine. Palladium-Catalyzed Synthesis of a 1,5-Benzodiazepine

The complex [Pd­(<i>O</i>¹,<i>N</i>¹,<i>C</i>¹-L)­(OClO₃)] (L = monoanionic ligand resulting from deprotonation of the acetyl group of the dimethyl monoketal of 2,6-diacetylpyridine) reacts with neutral ligands L¹ (phosphines, isocyanides, CO, N-donor ligands) to give the complexes [Pd­(<i>O</i>¹,<i>N</i>¹,<i>C</i>¹-L)­L¹]­ClO₄, [Pd­(<i>N</i>¹,<i>C</i>¹-L)­L¹₂]­ClO₄, and [Pd­(<i>C</i>¹-L)­L¹₃]­ClO₄. The complex [Pd­(<i>N</i>¹,<i>C</i>¹-L)­(pda)]­ClO₄ (pda = NH₂C₆H₄NH₂-2) can be used as a catalyst for the synthesis of 2′,2′,4′-trimethyl-2′,3′-dihydro-1<i>H</i>-1′,5′-benzodiazepine (Bzdiaz) from pda and acetone. The intermediate [Pd­(<i>O</i>¹,<i>N</i>¹,<i>C</i>¹-L)­(Bzdiaz)]­ClO₄ has been isolated from an acetone solution of [Pd­(<i>N</i>¹,<i>C</i>¹-L)­(pda)]­ClO₄. The ligand L in some of the above complexes hydrolyzes to give [Pd­(<i>O</i>¹,<i>N</i>¹,<i>C</i>¹-L′)­L¹]­ClO₄ (L′ = monoanionic ligand resulting from the deprotonation of one acetyl group of 2,6-diacetylpyridine, L¹ = MeCN, ^<i>t</i>BuNC). These complexes are best prepared by reacting L¹ with [Pd­(<i>O</i>¹,<i>N</i>¹,<i>C</i>¹-L′)­(NCMe)]­ClO₄, which, in turn, can be obtained from 2,6-diacetylpyridinium perchlorate and Pd­(OAc)₂ in MeCN. When THF is used as solvent, [Pd­(<i>O</i>¹,<i>N</i>¹,<i>C</i>¹-L′)­(OH₂)]­ClO₄ can be isolated. The crystal structures of [Pd­(<i>O</i>¹,<i>N</i>¹,<i>C</i>¹-L′)­(NCMe)]­ClO₄ and [Pd­(<i>O</i>¹,<i>N</i>¹,<i>C</i>^<i>1</i>-L)­(CNXy)]­ClO₄ have been determined

Room-Temperature Direct β‑Arylation of Thiophenes and Benzo[<i>b</i>]thiophenes and Kinetic Evidence for a Heck-type Pathway

The first example of a regioselective β-arylation of benzo­[<i>b</i>]­thiophenes and thiophenes at room temperature with aryl iodides as coupling partners is reported. This methodology stands out for its operational simplicity: no prefunctionalization of either starting material is required, the reaction is insensitive to air and moisture, and it proceeds at room temperature. The mild conditions afford wide functional group tolerance, often with complete regioselectivity and high yields, resulting in a highly efficient catalytic system. Initial mechanistic studies, including ¹³C and ²H KIEs, suggest that this process occurs via a concerted carbo-palladation across the thiophene double bond, followed by a base-assisted anti-elimination

Pd-Catalyzed C(sp³)–H Functionalization/Carbenoid Insertion: All-Carbon Quaternary Centers via Multiple C–C Bond Formation

A Pd-catalyzed C­(sp³)–H functionalization/carbenoid insertion is described. The method allows for the rapid synthesis of bicyclic frameworks, generating all-carbon quaternary centers via multiple C–C bond formations in a straightforward manner

Kinetically-Controlled Ni-Catalyzed Direct Carboxylation of Unactivated Secondary Alkyl Bromides without Chain Walking

Herein, we report the direct carboxylation of unactivated secondary alkyl bromides enabled by the merger of photoredox and nickel catalysis, a previously inaccessible endeavor in the carboxylation arena. Site-selectivity is dictated by a kinetically controlled insertion of CO2 at the initial C(sp3)–Br site by the rapid formation of Ni(I)–alkyl species, thus avoiding undesired β-hydride elimination and chain-walking processes. Preliminary mechanistic experiments reveal the subtleties of stereoelectronic effects for guiding the reactivity and site-selectivity

Kinetically-Controlled Ni-Catalyzed Direct Carboxylation of Unactivated Secondary Alkyl Bromides without Chain Walking

Herein, we report the direct carboxylation of unactivated secondary alkyl bromides enabled by the merger of photoredox and nickel catalysis, a previously inaccessible endeavor in the carboxylation arena. Site-selectivity is dictated by a kinetically controlled insertion of CO2 at the initial C(sp3)–Br site by the rapid formation of Ni(I)–alkyl species, thus avoiding undesired β-hydride elimination and chain-walking processes. Preliminary mechanistic experiments reveal the subtleties of stereoelectronic effects for guiding the reactivity and site-selectivity