Enhancement of bioelectrochemical dioxygen reduction with oxygen-enriching materials

Bioelectrochemical dioxygen reduction reaction (ORR) catalyzed by multi-copper oxidases (MCOs) is a process of paramount importance occurring at the cathode of enzymatic biofuel cells (EBFCs), which is an energy harvester that holds promise of self-sustained implantable and wearable medical devices. The MCO biocathode is, however, frequently the limiting factor of a working EBFC. Besides the operational stability issue, enzymatic biocathodes are largely constrained by the relatively low solubility of dioxygen in aqueous solution. As an emerging topic, we here review the introduction of dioxygen-enriching materials to the cathodic bioelectrode for overcoming the dioxygen supply limitation, leading to improved ORR performance.     

Substituted Tetraaza‐ and Hexaazahexacenes and their N,N′‐Dihydro Derivatives: Syntheses,Properties, and Structures

The palladium‐catalyzed coupling of a substituted o‐diaminoanthracene and a substituted o‐diaminophenazine to substituted 2,3‐dichloroquinoxalines furnishes 10 differently substituted N,N′‐dihydrotetraaza‐ or ‐hexaazahexacenes with the quinoxaline group of the azaacenes carrying fluorine, chlorine, or nitro groups. The N,N′‐dihydrotetraazahexacenes with hydrogen, chlorine, and fluorine subtituents are oxidized to azaacenes, whereas only the parent N,N′‐dihydrohexaazahexacenes, with hydrogen substituents, are oxidized by MnO₂. The resultant azaacenes are characterized by their optical and spectroscopic data. In addition, single‐crystal X‐ray structures have been obtained for the parent tetraazahexacenes and their difluoro‐substituted derivatives. The di‐ and tetrachloro derivatives of the N,N′‐dihydrohexaazahexacene have also been structurally characterized.     

Correlating conductivity and Seebeck coefficient to doping within crystalline and amorphous domains in poly(3-(methoxyethoxyethoxy)thiophene)

Molecular doping of conjugated polymers (CPs) plays a vital role in optimizing organic electronic and energy applications. For the case of organic thermoelectrics, it is commonly believed that doping CPs with a strong dopant could result in higher conductivity (σ) and thus better power factor (PF). Herein, by investigating thermoelectric performance of a polar side-chain bearing CP, poly(3-(methoxyethoxyethoxy)thiophene) (P3MEET), vapor doped with fluorinated-derivative of tetracyanoquinodimethane FnTCNQ (n = 1, 2, 4), we show that using strong dopants can in fact have detrimental effects on the thermoelectric performance of CPs. Despite possessing higher electron affinity, doping P3MEET with F4TCNQ only results in a σ (27.0 S/cm) comparable to samples doped with other two weaker dopants F2TCNQ and F1TCNQ (26.4 and 20.1 S/cm). Interestingly, F4TCNQ-doped samples display a marked reduction in the Seebeck coefficient (α) compared to F1TCNQ- and F2TCNQ-doped samples from 42 to 13 μV/K, leading to an undesirable suppression of the PF. Structural characterizations coupled with Kang-Snyder modeling of the α–σ relation show that the reduction of α in F4TCNQ-doped P3MEET samples originates from the generation of low mobility carrier within P3MEET's amorphous domain. Our results demonstrate that factors such as dopant distribution and doping efficiency within the crystalline and amorphous domains of CPs should play a crucial role in advancing rational design for organic thermoelectrics.     

COSMO-RS predictions of logP in the SAMPL7 blind challenge

Journal of Computer-Aided Molecular Design - We applied the COSMO-RS method to predict the partition coefficient logP between water and 1-octanol for 22 small drug like molecules within the...     

$$\Gamma $$ Γ -evaluations of hypergeometric series

The Ramanujan Journal - In this paper we explore special values of Gaussian hypergeometric functions in terms of products of Euler $$\Gamma $$ -functions and exponential functions of linear...     

Formation and Reactivity of Organo‐Functionalized Tin Selenide Clusters

Reactions of R¹SnCl₃ (R¹=CMe₂CH₂C(O)Me) with (SiMe₃)₂Se yield a series of organo‐functionalized tin selenide clusters, [(SnR¹)₂SeCl₄] ( 1 ), [(SnR¹)₂Se₂Cl₂] ( 2 ), [(SnR¹)₃Se₄Cl] ( 3 ), and [(SnR¹)₄Se₆] ( 4 ), depending on the solvent and ratio of the reactants used. NMR experiments clearly suggest a stepwise formation of 1 through 4 by subsequent condensation steps with the concomitant release of Me₃SiCl. Furthermore, addition of hydrazines to the keto‐functionalized clusters leads to the formation of hydrazone derivatives, [(Sn₂(μ‐R³)(μ‐Se)Cl₄] ( 5 , R³=[CMe₂CH₂CMe(NH)]₂), [(SnR²)₃Se₄Cl] ( 6 , R²=CMe₂CH₂C(NNH₂)Me), [(SnR⁴)₃Se₄][SnCl₃] ( 7 , R⁴=CMe₂CH₂C(NNHPh)Me), [(SnR²)₄Se₆] ( 8 ), and [(SnR⁴)₄Se₆] ( 9 ). Upon treatment of 4 with [Cu(PPh₃)₃Cl] and excess (SiMe₃)₂Se, the cluster fragments to form [(R¹Sn)₂Se₂(CuPPh₃)₂Se₂] ( 10 ), the first discrete Sn/Se/Cu cluster compound reported in the literature. The derivatization reactions indicate fundamental differences between organotin sulfide and organotin selenide chemistry.