Organoplatinum‐Mediated Synthesis of Cyclic pi‐Conjugated Molecules

Considerable interest has been recently focused on hoop‐shaped π‐conjugated molecules because of their great potentials in molecular electronics. In particular, cycloparaphenylenes (CPPs), consist of para‐linked phenylene unit in a cyclic manner, have become the subject of recent interest in this area.1 We report here the synthesis of CPPs,2) their derivatives,3 and a cage‐like three‐dimensional molecule4 based on the platinum‐mediated assembly of ‐units and subsequent reductive elimination of platinum (Scheme 1). Several unique properties of the prepared compounds are also reportedConsiderable interest has been recently focused on hoop‐shaped π‐conjugated molecules because of their great potentials in molecular electronics. In particular, cycloparaphenylenes (CPPs), consist of para‐linked phenylene unit in a cyclic manner, have become the subject of recent interest in this area.1 We report here the synthesis of CPPs,2) their derivatives,3 and a cage‐like three‐dimensional molecule4 based on the platinum‐mediated assembly of ‐units and subsequent reductive elimination of platinum (Scheme 1). Several unique properties of the prepared compounds are also reportedUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Stochastic Simulation of Controlled Radical Polymerization Forming Dendritic Hyperbranched Polymers

Stochastic simulation of the formation process of hyperbranched polymers (HBPs) based on the reversible deactivation radical polymerization (RDRP) using a branch-inducing monomer, evolmer, has been carried out. The simulation program successfully reproduced the change of dispersities (Đs) during the polymerization process. Furthermore, the simulation suggested that the observed Đs (=1.5–2) are due to the distribution of the number of branches instead of undesired side reactions, and that the branch structures are well controlled. In addition, the analysis of the polymer structure reveals that the majority of HBPs have structures close to the ideal one. The simulation also suggested the slight dependence of branch density on molecular weight, which was experimentally confirmed by synthesizing HBPs with an evolmer having phenyl group

2,3-Bis(2-chloro­benz­yl)naphthalene-1,4-dione

The title disubstituted naphthalene-1,4-dione, C24H16Cl2O2, has the two chloro­benzyl substituents related by a non-crystallographic twofold rotation axis, generating a chiral conformation; both enantiomers are present. The two chlorobenzene rings are nearly perpendicular to the fused ring system, making angles of 88.8 (1) and 77.5 (1)° with it

A donor-acceptor 10-cycloparaphenylene and its use as an emitter in an organic light-emitting diode

We thank JSPS Core-to-Core Program and International Joint Usage/Research Program of Institute for Chemical Research, Kyoto University (grant #2020-37 and 2021-37) for financial support. The St Andrews team would also like to thank EPSRC (EP/P010482/1) for financial support. D.C. thanks the China Scholarship Council (No. 201603780001). The Kyoto team would like to thank JSPS KAKENHI Grant Numbers JP20H05840 (Grant-in-Aid for Transformative Research Areas, “Dynamic Exciton”).Here, we explored the possibility of using cycloparaphenylenes (CPP) within a donor–acceptor TADF emitter design. 4PXZPh-[10]CPP contains four electron-donating moieties connected to a [10]CPP. In the 15 wt % doped in CzSi film, 4PXZPh-[10]CPP showed sky-blue emission with λPL = 475 nm, ΦPL = 29%, and triexponential emission decays with τPL of 4.4, 46.3, and 907.8 ns. Solution-processed OLEDs using 4PXZPh-[10]CPP exhibited sky-blue emission with an λEL of 465 nm and an EQEmax of 1.0%.Publisher PDFPeer reviewe

Phosphorus-containing gradient (block)copolymers via RAFT polymerization and post-polymerization modification

Reversible addition‐fragmentation chain transfer (RAFT) copolymerization of styrene (St) and 4‐(diphenylphosphino)styrene (DPPS) is explored to establish the statistical distribution of the phosphine‐functional monomer within the copolymer. RAFT copolymerization of St and DPPS at a variety of feed ratios provides phosphine‐functional copolymers of low dispersity at moderate monomer conversion (Ð 60%). In all cases, the fraction of DPPS in the resulting polymers is greater than that in the monomer feed. Estimation of copolymerization reactivity ratios indicates DPPS has a strong tendency to homopolymerize while St preferentially copolymerizes with DPPS (rDPPS = 4.4; rSt = 0.31). The utility of the copolymers as macro‐RAFT agents in block copolymer synthesis is demonstrated via chain extension with hydrophilic acrylamide (N,N‐dimethylacrylamide (DMAm)) and acrylate (poly(ethylene glycol) methyl ether acrylate (mPEGA), and di(ethylene glycol) ethyl ether acrylate (EDEGA)) monomers. Finally, access to polymers containing phosphine oxide and phosphonium salt functionalities is shown through postpolymerization modification of the phosphine‐containing copolymers

Dkk4 and Eda Regulate Distinctive Developmental Mechanisms for Subtypes of Mouse Hair

The mouse hair coat comprises protective “primary” and thermo-regulatory “secondary” hairs. Primary hair formation is ectodysplasin (Eda) dependent, but it has been puzzling that Tabby (Eda-/y) mice still make secondary hair. We report that Dickkopf 4 (Dkk4), a Wnt antagonist, affects an auxiliary pathway for Eda-independent development of secondary hair. A Dkk4 transgene in wild-type mice had no effect on primary hair, but secondary hairs were severely malformed. Dkk4 action on secondary hair was further demonstrated when the transgene was introduced into Tabby mice: the usual secondary follicle induction was completely blocked. The Dkk4-regulated secondary hair pathway, like the Eda-dependent primary hair pathway, is further mediated by selective activation of Shh. The results thus reveal two complex molecular pathways that distinctly regulate subtype-based morphogenesis of hair follicles, and provide a resolution for the longstanding puzzle of hair formation in Tabby mice lacking Eda