Multifold Post-Modification of Macrocycles and Cages by Isocyanate-Induced Azadefluorination Cyclisation.

We present the multiple post-modification of organic macrocycles and cages, introducing functional groups into two- and three-dimensional supramolecular scaffolds bearing fluorine substituents, which opens up new possibilities in multi-step supramolecular chemistry employing the vast chemical space of readily available isocyanates. The mechanism and scope of the reaction that proceeds after isocyanate addition to the benzylamine motif via an azadefluorination cyclisation (ADFC) were investigated using DFT calculations, and a series of aromatic isocyanates with different electronic properties were tested. The compounds show excellent chemical stability and were fully characterised. They can be used for subsequent cross-coupling reactions, and ADFC can be used directly to generate cross-linked membranes from macrocycles or cages when using ditopic isocyanates. Single-crystal X-ray (SC-XRD) analysis shows the proof of the formation of the desired supramolecular entity together with the connectivity predicted by calculations and from 19F NMR shifts, allowing the late-stage functionalisation of self-assembled macrocycles and cages by ADFC.

Supramolecular Alloys from Fluorinated Hybrid Tri4 Di6 Imine Cages.

To create innovative materials, efficient control and engineering of pore sizes and their characteristics, crystallinity and stability is required. Eight hybrid Tri4 Di6 imine cages with a tunable degree of fluorination and one fully fluorinated Tri4 Di6 imine cage are investigated. Although the fluorinated and the non-fluorinated building blocks used herein differ vastly in reactivity, it was possible to gain control over the outcome of the self-assembly process, by carefully controlling the feed ratio. This represents the first hybrid material based on fluorinated/hydrogenated porous organic cages (POCs). These cages with unlimited miscibility in the solid state were obtained as highly crystalline samples after recrystallization and even showed retention of the crystal lattice, forming alloys. All mixtures and the fully fluorinated Tri4 Di6 imine cage were analyzed by MALDI-MS, single-crystal XRD, powder XRD and in regard to thermal stability (TGA).

Mechanochemical Release of Non-Covalently Bound Guests from a Polymer-Decorated Supramolecular Cage.

Supramolecular coordination cages show a wide range of useful properties including, but not limited to, complex molecular machine-like operations, confined space catalysis, and rich host-guest chemistries. Here we report the uptake and release of non-covalently encapsulated, pharmaceutically-active cargo from an octahedral Pd cage bearing polymer chains on each vertex. Six poly(ethylene glycol)-decorated bipyridine ligands are used to assemble an octahedral PdII6 (TPT)4 cage. The supramolecular container encapsulates progesterone and ibuprofen within its hydrophobic nanocavity and is activated by shear force produced by ultrasonication in aqueous solution entailing complete cargo release upon rupture, as shown by NMR and GPC analyses.

Peri-implant defect grafting with autogenous bone or bone graft material in immediate implant placement in molar extraction sites-1- to 3-year results of a prospective randomized study.

OBJECTIVES: To evaluate the survival rate, the orobuccal bone resorption and stability of peri-implant hard and soft tissues following immediate implant placement of wide diameter implants in molar extraction sites and peri-implant defect grafting with autogenous bone (AB) or biphasic bone graft material (BBGM) with 1- to 3-year follow-up examinations. MATERIAL AND METHODS: Fifty wide diameter implants were placed in 50 patients immediately into molar extraction sockets by a flapless approach. Peri-implant defect augmentation was performed randomized with either AB or BBGM. Primary outcome variable was implant survival. Marginal bone level changes, orobuccal width of the alveolar crest, probing depths, and implant success were considered as secondary parameters. RESULTS: One implant of the BBGM group was lost, 1 patient withdrew from the study (drop-out). The remaining 48 patients were still in function at a follow-up period up to 31 months after implant insertion. Interproximal marginal bone level regenerated from -7.5 mm to the level of the implant shoulder (AB + 0.38 mm, BBGM + 0.1 mm) at final follow-up. The width of the alveolar crest changed by -0.08 mm (AB) and +0.72 mm (BBGM) at 1 mm, -0.36 mm (AB) and +0.27 mm (BBGM) at 3 mm, -0.36 mm (AB) and +0.31 mm (BBGM) at 6 mm apical to implant shoulder level. Success rate was 87.5% in the AB and 56.3% in the BBGM group (p = .058). CONCLUSIONS: Medium-term results prove a high survival rate, a favorable amount of bone generation in both groups and a low amount of orobuccal resorption in immediate molar implant insertion.

Fast, solvent-free synthesis of ferrocene-containing organic cages via dynamic covalent chemistry in the solid state.

A simple, solvent-free synthetic protocol towards the synthesis of organic self-assembled macromolecules has been established. By employing mechanochemistry using glassware readily available to every organic chemist, we were able to synthesise three novel organic cage compounds exemplarily and to speed up the synthesis of a ferrocene-containing macrocycle by a factor of 288 compared to the solution-based synthesis. The structural investigation of the newly synthesised cages revealed different modes of connectivity from using ferrocene-containing aldehydes caused by the free rotation of the cyclopentadienyl units against each other. By extending the facile solvent-free synthesis to ball-milling, even compounds that show lower reactivity could be employed in the dynamic covalent formation of organometallic cage compounds. The presented protocol gives access to otherwise inaccessible structures, speeds up general synthetic workflows, and simultaneously reduces the environmental impact of supramolecular syntheses.

Clinical and esthetic outcome with immediate insertion and provisionalization with or without connective tissue grafting in presence of mucogingival recessions: A retrospective analysis with follow-up between 1 and 8 years.

BACKGROUND: Recessions following immediate implant insertion are frequently reported in the literature. Data regarding implant installation in presence of mucogingival recessions are rare. PURPOSE: This study observes soft tissue level changes following immediate implant insertion and provisionalization of implants with or without connective tissue grafts in the anterior maxilla in patients with initial mucogingival recession within a follow-up period between one and eight years. MATERIALS AND METHODS: Twenty-six patients with marginal gingival recessions, which were designated for extraction and immediate implant insertion in the anterior zone of the maxilla (13-23), were included. Out of a larger group of immediate implants only single tooth replacements with 1 to 3 mm recession and a pre- and post-op CB-CT were selected. Facial bone deficiencies were grafted flaplessly with autologous bone in all sites. In a group of 13 patients the recessions (mean 2.3 ± 0.7 mm, range 1.0-3.0 mm) were grafted additionally by connective tissue (ABG + CTG), in the remaining 13 patients no soft tissue grafting (mean recession 1.8 ± 0.6 mm, range 1.0-3.0 mm) was performed (ABG). The marginal hard and soft tissue level, the width of the keratinized mucosa, the PES, and implant success were evaluated. RESULTS: After a mean follow-up period of 45 months the recessions were significantly reduced in the ABG group from 1.8 to 0.9 mm. The improvement was even more pronounced in the ABG + CTG group (from 2.3 to 0.5 mm). The PES improved significantly in both groups. At final examination all implants were still in function. Within the observational period, in 5 of 13 implants a marginal bone loss of more than 1 mm was noticed in the ABG, but in none of the ABG + CTG group. CONCLUSIONS: These clinical results provide evidence that immediate implant placement might improve the facial soft tissue level. This was more evident in cases with a greater recession and an additional treatment with connective tissue grafts.