Octamethoxydibenzochrysene: Isolation and X-ray Crystallographic Characterization of a Twisted Polyaromatic Cation Radical

The isolation and X-ray crystal structure determination of octamethoxydibenzochrysene (3) cation radical together with DFT calculations allow us to delineate evidence that the complex structural changes (i.e. elongation and shortening of various bonds) in a polyaromatic hydrocarbon can be predicted based on the positioning of the largest bonding and antibonding character of the HOMO

FHBC, a Hexa‐\u3cem\u3eperi\u3c/em\u3e‐hexabenzocoronene–Fluorene Hybrid: A Platform for Highly Soluble, Easily Functionalizable HBCs with an Expanded Graphitic Core

Materials based upon hexa‐peri‐hexabenzocoronenes (HBCs) show significant promise in a variety of photovoltaic applications. There remains the need, however, for a soluble, versatile, HBC‐based platform, which can be tailored by incorporation of electroactive groups or groups that can prompt self‐assembly. The synthesis of a HBC–fluorene hybrid is presented that contains an expanded graphitic core that is highly soluble, resists aggregation, and can be readily functionalized at its vertices. This new HBC platform can be tailored to incorporate six electroactive groups at its vertices, as exemplified by a facile synthesis of a representative hexaaryl derivative of FHBC. Synthesis of new FHBC derivatives, containing electroactive functional groups that can allow controlled self‐assembly, may serve as potential long‐range charge‐transfer materials for photovoltaic applications

X-ray Structural Characterization of Charge Delocalization onto the Three Equivalent Benzenoid Rings in Hexamethoxytriptycene Cation Radical

Definitive X-ray crystallographic evidence is obtained for a single hole (or a polaron) to be uniformly distributed on the three equivalent 1,2-dimethoxybenzenoid (or veratrole) rings in the hexamethoxytriptycene cation radical. This conclusion is further supported by electrochemical analysis and by the observation of an intense near-IR transition in its electronic spectrum, as well as by comparison of the spectral and electrochemical characteristics with the model compounds containing one and two dimethoxybenzene rings

From Intramolecular (Circular) in an Isolated Molecule to Intermolecular Hole Delocalization in a Two‐Dimensional Solid‐State Assembly: The Case of Pillarene

To achieve long‐range charge transport/separation and, in turn, bolster the efficiency of modern photovoltaic devices, new molecular scaffolds are needed that can self‐assemble in two‐dimensional (2D) arrays while maintaining both intra‐ and intermolecular electronic coupling. In an isolated molecule of pillarene, a single hole delocalizes intramolecularly via hopping amongst the circularly arrayed hydroquinone ether rings. The crystallization of pillarene cation radical produces a 2D self‐assembly with three intermolecular dimeric (sandwich‐like) contacts. Surprisingly, each pillarene in the crystal lattice bears a fractional formal charge of +1.5. This unusual stoichiometry of oxidized pillarene in crystals arises from effective charge distribution within the 2D array via an interplay of intra‐ and intermolecular electronic couplings. This important finding is expected to help advance the rational design of efficient solid‐state materials for long‐range charge transfer

Design, Synthesis and Study of Polycyclic Aromatic Hydrocarbons and their Cation Radicals

The unifying theme of most of optoelectronic devices revolves around the charge carrier mobility of the organic materials used in the conductive layers, which is a measure of how easily the electron/hole moves in a particular pi conjugated organic material. When pi conjugated materials are incorporated in these devices, molecules are generally layered in random orientation. Consequently, the efficiency of charge transport in the conducting layers of these devices is governed not only by the intramolecular electron/hole transport through the backbone of the molecule but also by the intermolecular electron/hole transport between the molecules and hence packing of these molecules plays a critical role in the efficiency of these devices. Although significant progress has been made in understanding the charge transport mechanisms in various polycyclic aromatic hydrocarbons (PAHs), the usefulness of such materials in functional devices remains limited; hence design and synthesis of new PAHs to better understand the charge transport mechanisms remains an active area of research. A novel series of methoxydibenzochrysenes was designed and synthesized utilizing ferric chloride mediated oxidative cyclodehydrogenation as a key step. We have also shown that numerous 9,10-diarylphenanthrenes and dibenzo[g,p]chrysenes can be prepared from a readily available tetraarylethylenes using 1 and 2 equivalents of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), respectively. A similar oxidative cyclodehydrogenation strategy was used for synthesizing a highly soluble, larger derivative of hexa-peri-hexabenzocoronene (HBC), where twelve carbon-carbon bonds are formed in a single step. Deployment of fluorenes at the periphery of the HBC core not only imparts solubility to the structure, but also allows the new PAHs to be functionalized further to make bigger PAHs. X-ray crystal structure determination of octamethoxydibenzochrysene cation radical and 1,4,5,8-tetramethoxyanthracene dimer cation radical, in addition to their neutral structures, allowed us to delineate the effect of electron removal on their bond length changes. Definitive X-ray crystallographic evidence is obtained for a single hole to be uniformly distributed on the three equivalent 1,2-dimethoxybenzenoid (or veratrole) rings in the hexamethoxytriptycene cation radical. This conclusion is further supported by electrochemical analysis and by the observation of an intense near-IR transition in its electronic spectrum, as well as by comparison of the spectral and electrochemical characteristics with the model compounds containing one and two dimethoxybenzene rings. A new class of intervalance cation radicals from p-diaryloxybenzenes was also studied

Development of an adaptive fuzzy logic controller for HVAC system

An adaptive approach to control a cooling coil chilled water valve operation, called adaptive fuzzy logic control (AFLC), is developed and validated in this study. The AFLC calculates the error between the supply air temperature and supply air temperature set point for air in an air handling unit (AHU) of a heating, ventilating, and air conditioning (HVAC) system and determines optimal fuzzy rule matrix to minimize the hydronic energy consumption while maintaining occupant comfort. The AFLC uses genetic algorithms and evolutionary strategies to determine the fuzzy rule matrix and fuzzy membership functions for an AHU in HVAC systems;Cooling coil models are developed using neural network, general regression neural network and lump capacitance methods to predict the supply air temperature. These models helped with the development of the adaptive fuzzy logic controller;Two types of validation experiments were conducted, one with cyclically changing supply air temperatures and the second with cyclically changing supply air flow rates. Experiments conducted on two identical real HVAC systems were used to compare the performances of the AFLC to a conventional proportional, integral and derivative (PID) controller. To remove bias between the testing systems, the controllers were switched from one system to the other;The validation experiments indicate that the HVAC system operated under the AFLC consumes 1 to 7 % less hydronic energy when compared with a conventional PID controlled system. More actuator travel distance was observed when using the AFLC. The AFLC maintained better occupant comfort conditions when compared with the conventional PID controller. It was observed that the controlled variable for the AFLC system required 0 to 185% more rise time, had 9 to 68% less overshoot and required 11 to 45% less settling time as compared to the conventional PID controlled system

Performance Evaluation of Fuzzy based Congestion Control for TCP/IP Networks

It by and large acknowledged that the trouble of system congestion control stays a basic issue and a high need, particularly given the developing size, request, and speed (transfer speed) of the inexorably coordinated administrations systems. In spite of the examination endeavors spreading over several decades and accordingly the sizable measure of different plans proposed, there are no generally worthy control arrangements. Current arrangements in existing systems are progressively getting insufficient, and it's commonly acknowledged that these arrangements can only with significant effort extent even with different proposed "fixes". In this paper, a Fuzzy based congestion control is talked about to manage the congestion control issue. The exhibition of the controlled framework is assessed by means of reenactment

Implementing Informatics Tools with Data Management Plans for Disease Area Research

Data Management Plans (DMPs) are essential to a research data life cycle. The DMPs should be developed as part of the research programs to be effective. For disease area research, integrating research community-recommended data standards during collection can enhance the likelihood of data reuse. Informatics tools are required as part of DMPs with the aim of data being findable, accessible, interoperable, and reusable. The US National Institutes of Health supports various disease area research programs and has recently finalized the Data Management and Sharing Policy. The policy highlights the importance of sharing data and metadata, including information on various elements such as data types, standards, storage repositories, access, services, and tools used for a proposed research project. The present paper provides Traumatic Brain Injury (TBI) and Parkinson’s Disease (PD) research as examples of where the elements of the policy are being supported. The software tools that have been developed for the TBI and PD plans are available through the Biomedical Research Informatics Computing System. A Protocol and Form Research Management System (ProFoRMS) facilitates researchers to manage research protocols when collecting clinical data. The ProFoRMS also supports automatic validation with the data dictionaries for TBI and Parkinson’s disease. Detailed information on the functionality of the software tools used for preserving data within TBI and PD repositories is openly available on their respective websites