Synthesis and Reduction of Nitrogen-Substituted Diaryl Dihydrophenazine Diradical Dications.

A one-pot synthetic approach to form core-extended N,N'-disubstituted diaryl dihydrophenazine (DADHP) diradical dications (DRDCs) via chemical oxidation from aryl-substituted ortho-phenyldiamines is reported. The isolated N,N'-disubstituted DADHP DRDCs were reduced to their neutral counterparts with hydrazine. The model system featuring an unsubstituted fluorene aryl group, 2a, was tested as a photocatalyst for the polymerization of methyl methacrylate using organocatalyzed atom transfer polymerization (O-ATRP), which yielded a polymer with a controlled molecular weight and narrow polydispersity.

Tetracyanocyclopentadienide-Based Stable Poly(aromatic) Anions.

Polyelectrolytes, a class of polymer with ionized functional groups in their repeating units, are widely used in various applications. Many ionized groups have been incorporated into polyelectrolytes, but aromatic anions are rarely investigated. Here, we first successfully incorporate a stable tetracyanocyclopentadienide (TCCp) aromatic anion into polynorbornene (PNb)-based electrolytes (PNb-TCCp) through ring-opening metathesis polymerization (ROMP) with controllable molecular weight and low polydispersity. PNb-TCCp shows a high ionic conductivity of 4.5 × 10-5 S/cm in thin films. Due to its highly stable aromatic anion groups and favorable interactions with aromatic cations, it could improve thermal stability of doped conjugated polymers. Pairing with doped poly(3,4-ethylenedioxythiophene) (PEDOT) through salt metathesis, the generated poly ion complex PEDOT:PNb-TCCp retains its conductivity up to 180 °C.

Combined radical and ionic approach for the enantioselective synthesis of ß-functionalized amines from alcohols.

Chiral amines are among the most important organic compounds and have widespread applications. Enantioselective construction of chiral amines is a major aim in organic synthesis. Among synthetic methods, direct functionalization of omnipresent C-H bonds with common organic nitrogen compounds represents one of the most attractive strategies. However, C-H amination strategies are largely limited to constructing a specific type of N-heterocycles or amine derivatives. To maximize the synthetic potential of asymmetric C-H amination, we report here an approach that unites the complementary reactivities of radical and ionic chemistry for streamlined synthesis of functionalized chiral amines. This synthesis merges the development of an enantioselective radical process for 1,5-C(sp 3)-H amination of alkoxysulfonyl azides via Co(II)-based metalloradical catalysis with an enantiospecific ionic process for ring-opening of the resulting five-membered chiral sulfamidates by nucleophiles. Given that alkoxysulfonyl azides are derived from the corresponding alcohols, this approach offers a powerful synthetic tool for enantioselective ß-C-H amination of common alcohols while converting the hydroxy group to other functionalities through formal nucleophilic substitution.

An Integrated Approach to Selecting a Prepared Medical Decision-Maker.

BACKGROUND: We implemented a systematic multidisciplinary process to engage new outpatients with cancer in selecting and preparing a medical decision-maker. MEASURES: Templated advance care planning notes and medical power of attorney documents were used in the electronic health record by the third office visit. INTERVENTION: Patients were coached to meet with social work from a "culture of yes," viewed a video about the importance of selecting a prepared medical a decision-maker in English or in Spanish, and referenced cards containing simple explanations of advance directives when responding to advance directive questions. OUTCOMES: A total of 351 patients were evaluated. By visit 3, there was no increase in documented social work advance care planning notes in intervention or scanned medical power of attorney documents in the electronic health record. CONCLUSIONS/LESSONS LEARNED: This systematic multidisciplinary approach did not engage new outpatients with cancer in preparing a medical decision-maker. More active physician involvement and varied ways of engagement are needed.

Enantioconvergent Amination of Racemic Tertiary C-H Bonds.

Racemization is considered to be an intrinsic stereochemical feature of free radical chemistry as can be seen in traditional radical halogenation reactions of optically active tertiary C-H bonds. If the facile process of radical racemization could be effectively combined with an ensuing step of bond formation in an enantioselective fashion, then it would give rise to deracemizative functionalization of racemic tertiary C-H bonds for stereoselective construction of chiral molecules bearing quaternary stereocenters. As a demonstration of this unique potential in radical chemistry, we herein report that metalloradical catalysis can be successfully applied to devise Co(II)-based catalytic system for enantioconvergent radical amination of racemic tertiary C(sp3)-H bonds. The key to the success of the radical process is the development of Co(II)-based metalloradical catalyst with fitting steric, electronic, and chiral environments of the D2-symmetric chiral amidoporphyrin as the supporting ligand. The existence of optimal reaction temperature is recognized as an important factor in the realization of the enantioconvergent radical process. Supported by an optimized chiral ligand, the Co(II)-based metalloradical system can effectively catalyze the enantioconvergent 1,6-amination of racemic tertiary C(sp3)-H bonds at the optimal temperature, affording chiral α-tertiary amines in excellent yields with high enantiocontrol of the newly created quaternary stereocenters. Systematic studies, including experiments utilizing optically active deuterium-labeled C-H substrates as a model system, shed light on the underlying mechanistic details of this new catalytic process for enantioconvergent radical C-H amination. The remarkable power to create quaternary stereocenters bearing multiple functionalities from ubiquitous C-H bonds, as showcased with stereoselective construction of bicyclic N-heterocycles, opens the door for future synthetic applications of this new radical technology.

Extension of refocus depth range in digital holographic microscopy.

Digital holographic microscopy (DHM) suffers from a limited refocus depth range due to the employed microscope objective. The relationship between the refocus depth range of the DHM system and its optical parameters is studied theoretically and experimentally, and a method is proposed that combines wavefront coding with bicubic interpolation and extrapolation iteration to extend the refocus depth range. For obtaining a uniform point spread function on the refocus plane, a propagator kernel in numerical reconstruction is multiplied by a numerical logarithmic phase mask, and a deviation of the refocus distance is made. To improve the resolution of the refocused image, the size of the hologram is doubly enlarged. This approach can extend the refocus depth range from 0.9 up to 1.5 mm. This work provides important guidance for high-resolution imaging with a large refocus depth range in DHM.

Enantioselective Radical Construction of 5-Membered Cyclic Sulfonamides by Metalloradical C-H Amination.

Both arylsulfonyl and alkylsulfonyl azides can be effectively activated by the cobalt(II) complexes of D2-symmetric chiral amidoporphyrins for enantioselective radical 1,5-C-H amination to stereoselectively construct 5-membered cyclic sulfonamides. In addition to C-H bonds with varied electronic properties, the Co(II)-based metalloradical system features chemoselective amination of allylic C-H bonds and is compatible with heteroaryl groups, producing functionalized 5-membered chiral cyclic sulfonamides in high yields with high enantioselectivities. The unique profile of reactivity and selectivity of the Co(II)-catalyzed C-H amination is attributed to its underlying stepwise radical mechanism, which is supported by several lines of experimental evidence.

Systematic Approach to Selecting and Preparing a Medical Power of Attorney in the Gynecologic Oncology Center.

PURPOSE: Advance care planning (ACP) supports national priorities of patient engagement, person-centered care, and safety. A systematic approach is uncommon in most care settings. Our institution offers all patients with cancer new to the institution an opportunity to select and prepare a medical decision maker (MDM) after social work counseling. The goals of this study were to determine the success of a systematic institutional process for selecting a prepared MDM. The primary objectives were that (1) 70% or more of new patients would have one or more documented social work ACP discussions by the third office visit within 4 months, and (2) there would be a two-fold increase in scanned medical power of attorney (MPOA) documents available in the electronic health record (EHR). The secondary objectives were (1) improved surrogate preparedness for medical decision making, and (2) to determine whether patients with metastatic disease demonstrated greater readiness for selection of an MDM than those with localized disease. MATERIALS AND METHODS: We conducted a retrospective chart review of consecutive gynecology oncology outpatients. RESULTS: Of 133 patients, 93 (70%) had metastatic disease. The median number of visits was two (one to three). Forty-seven patients (39.3%) met with social work by visit 3. Review of ACP notes suggested that most patients were in the early stages of selecting a prepared MDM. At visit 1, 39 (29.3%) reported having an advance directive document; 14 (10.5%) had an MPOA in the EHR. There was no increase by visit 3. Fewer patients with metastatic disease than those with localized cancer (32.3% v 67.5%; P = .001) had three visits; no other parameter, including presence of MPOA documents in the EHR, achieved statistical significance between groups. CONCLUSION: Current processes fail to engage patients in selecting and preparing an MDM.

Asymmetric Induction and Enantiodivergence in Catalytic Radical C-H Amination via Enantiodifferentiative H-Atom Abstraction and Stereoretentive Radical Substitution.

Control of enantioselectivity remains a major challenge in radical chemistry. The emergence of metalloradical catalysis (MRC) offers a conceptually new strategy for addressing this and other outstanding issues. Through the employment of D2-symmetric chiral amidoporphyrins as the supporting ligands, Co(II)-based MRC has enabled the development of new catalytic systems for asymmetric radical transformations with a unique profile of reactivity and selectivity. With the support of new-generation HuPhyrin chiral ligands whose cavity environment can be fine-tuned, the Co-centered d-radicals enable to address challenging issues that require exquisite control of fundamental radical processes. As showcased with asymmetric 1,5-C-H amination of sulfamoyl azides, the enantiocontrol of which has proven difficult, the judicious use of HuPhyrin ligand by tuning the bridge length and other remote nonchiral elements allows for controlling both the degree and sense of asymmetric induction in a systematic manner. This effort leads to successful development of new Co(II)-based catalytic systems that are highly effective for enantiodivergent radical 1,5-C-H amination, producing both enantiomers of the strained five-membered cyclic sulfamides with excellent enantioselectivities. Detailed deuterium-labeling studies, together with DFT computation, have revealed an unprecedented mode of asymmetric induction that consists of enantiodifferentiative H-atom abstraction and stereoretentive radical substitution.

Next-Generation D2 -Symmetric Chiral Porphyrins for Cobalt(II)-Based Metalloradical Catalysis: Catalyst Engineering by Distal Bridging.

Novel D2 -symmetric chiral amidoporphyrins with alkyl bridges across two chiral amide units on both sides of the porphyrin plane (designated "HuPhyrin") have been effectively constructed in a modular fashion to permit variation of the bridge length. The CoII complexes of HuPhyrin, [Co(HuPhyrin)], represent new-generation metalloradical catalysts where the metal-centered d-radical is situated inside a cavity-like ligand with a more rigid chiral environment and enhanced hydrogen-bonding capability. As demonstrated with cyclopropanation and aziridination as model reactions, the bridged [Co(HuPhyrin)] functions notably different from the open catalysts, exhibiting significant enhancement in both reactivity and stereoselectivity. Furthermore, the length of the distal alkyl bridge can have a remarkable influence on the catalytic properties.

Catalytic Radical Process for Enantioselective Amination of C(sp3 )-H Bonds.

A new catalytic radical system involving CoII -based metalloradical catalysis is effective in activating sulfamoyl azides for enantioselective radical 1,6-amination of C(sp3 )-H bonds, affording six-membered chiral heterocyclic sulfamides in high yields with excellent enantioselectivities. The CoII -catalyzed C-H amination features an unusual degree of functional-group tolerance and chemoselectivity. The unique reactivity and stereoselectivity is attributed to the underlying stepwise radical pathway. The resulting optically active cyclic sulfamides can be readily converted into synthetically useful chiral 1,3-diamine derivatives without loss in enantiopurity.

Asymmetric Radical Bicyclization of Allyl Azidoformates via Cobalt(II)-Based Metalloradical Catalysis.

Cobalt(II)-based metalloradical catalysis has been successfully applied to radical bicyclization of allyl azidoformates to construct aziridine/oxazolidinone-fused bicyclic structures. The Co(II) complex of D2-symmetric chiral amidoporphyrin 3,5-DitBu-QingPhyrin has been identified as an effective metalloradical catalyst for the intramolecular radical aziridination of this type of carbonyl azides, allowing for high-yielding formation of synthetically useful chiral [3.1.0]-bicyclic aziridines with high diastereo- and enantioselectivity.

Homogenous Electrocatalytic Oxygen Reduction Rates Correlate with Reaction Overpotential in Acidic Organic Solutions.

Improved electrocatalysts for the oxygen reduction reaction (ORR) are critical for the advancement of fuel cell technologies. Herein, we report a series of 11 soluble iron porphyrin ORR electrocatalysts that possess turnover frequencies (TOFs) from 3 s-1 to an unprecedented value of 2.2 × 106 s-1. These TOFs correlate with the ORR overpotential, which can be modulated by changing the E1/2 of the catalyst using different ancillary ligands, by changing the solvent and solution acidity, and by changing the catalyst's protonation state. The overpotential is well-defined for these homogeneous electrocatalysts by the E1/2 of the catalyst and the proton activity of the solution. This is the first such correlation for homogeneous ORR electrocatalysis, and it demonstrates that the remarkably fast TOFs are a consequence of high overpotential. The correlation with overpotential is surprising since the turnover limiting steps involve oxygen binding and protonation, as opposed to turnover limiting electron transfer commonly found in Tafel analysis of heterogeneous ORR materials. Computational studies show that the free energies for oxygen binding to the catalyst and for protonation of the superoxide complex are in general linearly related to the catalyst E1/2, and that this is the origin of the overpotential correlations. This analysis thus provides detailed understanding of the ORR barriers. The best catalysts involve partial decoupling of the influence of the second coordination sphere from the properties of the metal center, which is suggested as new molecular design strategy to avoid the limitations of the traditional scaling relationships for these catalysts.

Intramolecular Radical Aziridination of Allylic Sulfamoyl Azides by Cobalt(II)-Based Metalloradical Catalysis: Effective Construction of Strained Heterobicyclic Structures.

Cobalt(II)-based metalloradical catalysis (MRC) has been successfully applied for effective construction of the highly strained 2-sulfonyl-1,3-diazabicyclo[3.1.0]hexane structures in high yields through intramolecular radical aziridination of allylic sulfamoyl azides. The resulting [3.1.0] bicyclic aziridines prove to be versatile synthons for the preparation of a diverse range of 1,2- and 1,3-diamine derivatives by selective ring-opening reactions. As a demonstration of its application for target synthesis, the metalloradical intramolecular aziridination reaction has been incorporated as a key step for efficient synthesis of a potent neurokinin 1 (NK1 ) antagonist in 60 % overall yield.

Intramolecular 1,5-C(sp3)-H Radical Amination via Co(II)-Based Metalloradical Catalysis for Five-Membered Cyclic Sulfamides.

Co(II)-based metalloradical catalysis (MRC) proves effective for intramolecular 1,5-C-H amination of sulfamoyl azides under neutral and nonoxidative conditions, providing a straightforward approach to access strained 5-membered cyclic sulfamides with nitrogen gas as the only byproduct. The metalloradical amination system is applicable to different types of C(sp3)-H bonds and has a high degree of functional group tolerance. Additional features of the Co(II)-catalyzed 1,5-C-H amination include excellent chemoselectivity toward allylic and propargylic C-H bonds. The unique reactivity and selectivity profile of the Co(II)-catalyzed 1,5-C-H amination is attributed to the underlying radical mechanism of MRC.

Self-assembly approach toward chiral bimetallic catalysts: bis-urea-functionalized (salen)cobalt complexes for the hydrolytic kinetic resolution of epoxides.

A series of novel bis-urea-functionalized (salen)Co complexes has been developed. The complexes were designed to form self-assembled structures in solution through intermolecular urea-urea hydrogen-bonding interactions. These bis-urea (salen)Co catalysts resulted in rate acceleration (up to 13 times) in the hydrolytic kinetic resolution (HKR) of rac-epichlorohydrin in THF by facilitating cooperative activation, compared to the monomeric catalyst. In addition, one of the bis-urea (salen)Co(III) catalyst efficiently resolves various terminal epoxides even under solvent-free conditions by requiring much shorter reaction time at low catalyst loading (0.03-0.05 mol %). A series of kinetic/mechanistic studies demonstrated that the self-association of two (salen)Co units through urea-urea hydrogen bonds was responsible for the observed rate acceleration. The self-assembly study with the bis-urea (salen)Co by FTIR spectroscopy and with the corresponding (salen)Ni complex by (1)H NMR spectroscopy showed that intermolecular hydrogen-bonding interactions exist between the bis-urea scaffolds in THF. This result demonstrates that self-assembly approach by using non-covalent interactions can be an alternative and useful strategy toward the efficient HKR catalysis.

Development of bifunctional aza-bis(oxazoline) copper catalysts for enantioselective Henry reaction.

Base-functionalized aza-bis(oxazoline) ligands were prepared to explore the concept of dual activation through the Lewis acid and a tethered tertiary amine base. The catalytic activity of the Cu complex was evaluated for the asymmetric Henry reaction. Compared with a corresponding unfunctionalized copper complex with external 1-benzyl-4-ethylpiperazine base, the ethylpiperazine-functionalized aza-bis(oxazoline) copper catalyst resulted in rate acceleration (2.5 times) as well as improved enantioselectivity (72% ee vs 92% ee).

A red-emitting phosphor and its luminescent properties.

Under 616 nm monitoring, excitation peaks at 395, 465, and 535 nm were observed for the red-emitting phosphor Li(0.3)Y(0.82)Mo(0.1)W(0.9)O(4+delta): 0.08Eu(3+) (LYMW), which was synthesized using the solid-state method. Particularly in the range of 250 to 420 nm, excited peaks can be assigned to the transitions of O(2-)-->Mo(6+)/W(6+)/Eu(3+) and four sharp peaks can be assigned to the 4f-4f transition of Eu(3+) (approximately 360 nm from the (7)F(0)-->(5)D(4) transition, approximately 380 nm from the (7)F(0)-->(5)L(7) transition, approximately 395 nm from the (7)F(0)-->(5)(L6) transition, and approximately 415 nm from the (7)F(0)-->(5)D(3) transition).