Search

Multicopper active sites for small molecule activation in materials and enzymatic systems rely on controlled but adaptable coordination spheres about copper clusters for enabling challenging chemical transformations. To translate this constrained flexibility into molecular multicopper complexes, developments are needed in both ligand design for clusters and synthetic strategies for modifying the cluster cores. The present study investigates the chemistry of a class of pyridyldiimine-derived macrocycles with geometrically flexible aliphatic linkers of varying lengths (nPDI2, n = 2, 3). A series of dicopper complexes bound by the nPDI2 ligands are described and found to exhibit improved solubility over their parent analogs due to the incorporation of 4-tBu groups on the pyridyl units and the use of triflate counterions. The ensuing synthetic study investigated methods for introducing various bridging ligands (µ-X; X = F, Cl, Br, N3, NO2, OSiMe3, OH, OTf) between the two copper centers within the macrocycle-supported complexes. Traditional anion metathesis routes were unsuccessful, but the abstraction of bridging halides resulted in "open-core" complexes suitable for capturing various anions. The geometric flexibility of the nPDI2 macrocycles was reflected in the various solid-state geometries, Cu–Cu distances, and relative Cu coordination spheres on variation in the identity of the captured anion. [ABSTRACT FROM AUTHOR]

Herein we report a method for pyrrole synthesis via iron-catalyzed carboamination/copper-mediated cyclization that is completely regioselective for the formation of 1,2,4-trisubstituted products. This two-step, one-pot process offers significant improvements to previously reported conditions including the use of a readily available copper(I) source and a markedly less arduous experimental procedure. Exploration of the substrate scope reveals a variety of arylacetylenes undergo pyrrole formation to afford single isomer products. Isotopic labelling data points to a mechanism involving activation of the alkyne moiety by the copper(I) reagent during the cyclization step. [ABSTRACT FROM AUTHOR]

Next generation mobile devices and computing architectures would benefit from ultra-high bandwidth technologies that efficiently transport and process optical signals. Subsurface fabrication can address this challenge by forming volumetric photonic integrated circuits with a more compact aerial footprint than planar on-chip circuits. These 3D optical systems may utilize densely packed low-loss, freeform optical interconnects for high volume data transfer. In this Perspective, we provide a comparative overview of the two main methods for subsurface fabrication, including our recently developed SCRIBE process, and assess the advantages and future directions of each approach. After analyzing the underlying technologies, we provide a roadmap of important steps to transition from laboratory demonstrations of individual elements to industrial-scale production of subsurface volumetric photonic integrated circuits. [ABSTRACT FROM AUTHOR]

The article focuses on the use of porous metal augments in the reconstruction of large cavitary defects in complex revision knee replacement. According to the article, the use of trabecular metal cone augments have reported favorable results and showed no signs of loosening or change in component position. However, complications are comparable to those seen in other revision total knee replacements although there are suggestions of likely better component fixation with trabecular metal cone augments.

Periprosthetic fracture with preexisting severe loss of bone stock is a challenging condition to treat. Available surgical options can be divided into three categories: complex reconstruction of the deficient proximal femur with secure distal fixation; segmental substitution of the proximal femur with a megaprosthesis or allograft/stem composite; and distally fixed replacement with a modular stem, which acts as a scaffold around which the remaining deficient proximal bone can be assembled, to unite and possibly reconstitute.

The management of severe bone loss in a patient with a chronically infected total hip arthroplasty is a complex surgical challenge. The surgical alternatives are numerous and include the use of allografts, both structural and morcellized; cemented and cementless femoral components; and segmental replacement megaprostheses.

Muscle damage that can occur during minimally invasive total hip replacement is an important concern. Minimizing this iatrogenic injury can help achieve the goals of the minimally invasive approach: decreased postoperative pain, decreased blood loss, and faster rehabilitation. Knowledge of particular aspects of minimally invasive anterolateral total hip arthroplasty is important, with focus on the nuances that aid in reducing muscle injury.