Deboronation-Induced Turn-on Phosphorescent Sensing of Fluorides by Iridium(III) Cyclometalates with <i>o</i>-Carborane

Nghia, Nguyen Van,Oh, Jihun,Jung, Jaehoon,Lee, Min Hyung American Chemical Society 2017 Organometallics Vol.36 No.14

<P>Heteroleptic tris-cyclometalated Ir(III) complexes bearing an <I>o</I>-carborane at the 4- or 5-position in the phenyl ring of the ppy ligand (<I>closo</I>-<B>1</B> and -<B>2</B>) were prepared and characterized. The X-ray crystal structure of <I>closo</I>-<B>1</B> reveals the <I>fac</I> arrangement of the three C<SUP>∧</SUP>N chelates around the Ir atom. Treatment of <I>closo</I> complexes with fluoride anions led to selective deboronation of the <I>closo</I>-carborane cage, producing the corresponding <I>nido</I>-carborane-substituted complexes (<I>nido</I>-<B>1</B> and <B>-2</B>). Whereas <I>closo</I>-<B>1</B> and -<B>2</B> were almost nonemissive in THF, <I>nido</I>-<B>1</B> and -<B>2</B> were highly phosphorescent (Φ<SUB>PL</SUB> = 0.94–0.95). Theoretical studies suggested that, while the emission quenching in <I>closo</I>-<B>1</B> can be ascribed to the substantial involvement of <I>o</I>-carborane in the <SUP>3</SUP>MLCT excited state, the intraligand charge transfer (<SUP>3</SUP>ILCT) state from the <I>nido</I>-carborane to pyridyl moieties is responsible for the efficient phosphorescence in <I>nido</I>-<B>1</B>. The addition of fluoride to the buffered THF/H<SUB>2</SUB>O solution (1/1, v/v, pH 7) of <I>closo</I>-<B>1</B> and -<B>2</B> under mild heating led to strong emission intensity, allowing the turn-on phosphorescence detection of fluoride in aqueous medium at the ppb level.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/orgnd7/2017/orgnd7.2017.36.issue-14/acs.organomet.7b00139/production/images/medium/om-2017-00139w_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/om7b00139'>ACS Electronic Supporting Info</A></P>

Impact of the number of o-carboranyl ligands on the photophysical and electroluminescent properties of iridium(iii) cyclometalates

Van Nghia, Nguyen,Park, Sunghee,An, Youngjoon,Lee, Junseong,Jung, Jaehoon,Yoo, Seunghyup,Lee, Min Hyung Royal Society of Chemistry 2017 Journal of Materials Chemistry C Vol.5 No.12

<P>A series of iridium(iii) cyclometalates with mono-, bis-, and tris-<I>o</I>-carboranyl ligands,<I>fac</I>-[<I>m</I>-(2-MeCB)ppy]nIr(ppy)3−n(<I>n</I>= 1-3,<I>m</I>= 5 (3a-5a);<I>m</I>= 4 (3b-5b); 2-MeCB = 2-methyl-<I>o</I>-carboran-1-yl; ppy = 2-phenylpyridinato-C<SUP>2</SUP>,N), was prepared to investigate the impact of the number of<I>o</I>-carboranyl ligands on the photophysical and electroluminescent properties. X-ray diffraction analysis of3b-5brevealed that the carboranyl C-C bond distances remained nearly unchanged with different numbers of carboranyl ligands. While the phosphorescence wavelengths of3a-5aand3b-5bwere blue-shifted or red-shifted with respect to that of<I>fac</I>-Ir(ppy)3(6), respectively, both series underwent gradual hypsochromic shifts as the number of carboranyl ligands was increased. All of the complexes exhibited moderate to high phosphorescence quantum efficiencies in toluene with a slightly higher efficiency for the 5-substituted3a-5a(<I>Φ</I>PL= 0.43-0.98) than for the 4-substituted3b-5b(<I>Φ</I>PL= 0.42-0.92). In particular, the quantum efficiency increased as the number of carboranyl ligands increased. Solution-processed green phosphorescent organic light-emitting diodes (PhOLEDs) incorporating the 5-substituted complexes (3a-5a) as emitters exhibited a similar level of high performance, of which the best performance was observed for devices based on4a. Furthermore, vacuum-deposited devices were successfully fabricated with heteroleptic mono- and bis-carboranyl complexes,3aand4a. The resulting devices showed excellent performance, which was improved by<I>ca.</I>40% compared to those of the solution-processed devices. The devices based on4aalso displayed a performance that was superior to those of the devices based on3a(max. CE = 45.8 cd A<SUP>−1</SUP>; PE = 35.4 lm W<SUP>−1</SUP>; EQE = 15.1% for4aat 7 wt% Ir).</P>

Tuning the photophysical properties of carboranyl luminophores by <i>closo</i>- to <i>nido</i>-carborane conversion and application to OFF-ON fluoride sensing

Nghia, Nguyen Van,Oh, Jihun,Sujith, Surendran,Jung, Jaehoon,Lee, Min Hyung The Royal Society of Chemistry 2018 Dalton Transactions Vol.47 No.48

<P>A family of <I>closo</I>-carborane-appended luminophores (<I>closo</I>-OXD1-2 and <I>closo</I>-DPS1-2) in which 2-R-<I>o</I>-carboranes (R = H, Me) are attached to the diphenyl-1,3,4-oxadiazole (OXD) or diphenyl-sulfone (DPS) acceptor groups were prepared and characterized. Deboronation of the <I>closo</I>-carborane cage produced the corresponding <I>nido</I>-carboranyl luminophores (<I>nido</I>-OXD1-2 and <I>nido</I>-DPS1-2). Whereas the <I>closo</I>-compounds were poorly emissive in THF (<I>Φ</I>PL < 0.01), the <I>nido</I>-luminophores exhibited an intense fluorescence with good quantum yields (<I>Φ</I>PL = 0.1-0.45). Electrochemical studies showed that while the <I>closo</I>-OXD and -DPS compounds displayed only carborane-centred, quasi-reversible reduction, the <I>nido</I>-compounds exhibited the typical features for <I>nido</I>-carborane-centred, irreversible oxidation and acceptor-centred, reversible reduction. Theoretical studies suggested that while the <SUP>1</SUP>ππ* state of <I>closo</I>-compounds is nonemissive due to the contribution of <I>closo</I>-carborane to the LUMO in the S1 excited state, the intramolecular charge transfer (ICT) state from the <I>nido</I>-carborane to acceptor moieties in <I>nido</I>-compounds leads to an efficient fluorescence. Finally, THF solutions of <I>closo</I>-OXD1 and -DPS1 showed strong fluorescence upon the addition of fluoride anions under mild heating, but were intact to other anions, including cyanide, allowing the selective OFF-ON fluorescence sensing of fluoride.</P>

Real-time Multi-People Tracking for Embedded Computing Environments

Van Ngoc Nghia Nguyen(응웬반응억냐),Sang-hyuck Bae(배상혁),Sun-Tae Chung(정선태) 대한전자공학회 2018 대한전자공학회 학술대회 Vol.2018 No.11

Real-time Multiple Pedestrians Tracking for Embedded Smart Visual Systems

Van Ngoc Nghia Nguyen,Thanh Binh Nguyen,정선태 한국멀티미디어학회 2019 멀티미디어학회논문지 Vol.22 No.2

Even though so much progresses have been achieved in Multiple Object Tracking (MOT), most of reported MOT methods are not still satisfactory for commercial embedded products like Pan-Tilt–Zoom (PTZ) camera. In this paper, we propose a real-time multiple pedestrians tracking method for embedded environments. First, we design a new light weight convolutional neural network(CNN)-based pedestrian detector, which is constructed to detect even small size pedestrians, as well. For further saving of processing time, the designed detector is applied for every other frame, and Kalman filter is employed to predict pedestrians’ positions in frames where the designed CNN-based detector is not applied. The pose orientation information is incorporated to enhance object association for tracking pedestrians without further computational cost. Through experiments on Nvidia’s embedded computing board, Jetson TX2, it is verified that the designed pedestrian detector detects even small size pedestrians fast and well, compared to many state-of-the-art detectors, and that the proposed tracking method can track pedestrians in real-time and show accuracy performance comparably to performances of many state-of-the-art tracking methods, which do not target for operation in embedded systems.

베트남 물관리의 현황과 미래 전략

( Nguyen Chi Nghia ),( Do Truong Sinh ),( Nguyen Van Kenh ),( Tong Thanh Tung ),( Dinh Thi Thuong ) 한국수자원공사 2017 저널 물 정책·경제 Vol.28 No.-

베트남에서 수자원은 새로운 분야다. 2003년까지는 농업ㆍ농촌지역개발부(Ministry of Agriculture and Rural Development)가 지표수를 수문학적 관점에서 산정하여 관리하였으며, 지질ㆍ광물자원부터(the General Department of Geology and Minerals)에서 지하수를 조사하고 산정하였다. 이때까지 베트남에서는 `수자원`이라는 개념은 존재하지 않았으며, 물을 자원으로 생각하지 않아서 수자원 정책이나 수자원관리 체계가 마련되지 않은 상황이었다. 2003년 자연자원환경부(Ministry of Natural Resources and Environment) 수립 이후로, 수자원관리 체계가 점차 정립되었다. 2010년부터 베트남의 수자원관리는 크게 발전하였다. 2013년에는 수자원법이 발효되었고, 수자원 관련기관들이 설립되었다. 이후 수자원부문에 대한 투자 가치가 인정되어, 수자원부문에 대한 국가 예산 투자가 상당히 증가하였다. 구체적으로 수자원법수행 및 제도 구축을 위한 투자가 있었는데, 이와 관련하여 5개의 시행령, 22개의 시행규칙 및 20개의 국무총리 고시가 발표되었다. 또한 수자원관리를 위하여 조직 체질개선, 수자원 기초조사 등의 수자원 조사ㆍ감독 역량 강화, 수질오염 제한 및 수자원 보호, 수자원 개발ㆍ이용에 대한 효율적 관리, 국제 협력, 수자원부문의 과학 및 기술 발전, 수자원 법에 대한 선전, 국민의 수자원에 대한 인식 제고 등 다양한 노력이 있었다. 향후 2016-2020년 동안, 베트남 자연자원환경부는 수자원의 계량화, 수자원 인프라 투자 및 거버넌스 구축을 위한 국제협력 강화 등 수자원관리 역량을 향상시키기 위하여 필요한 사항을 점검하고 이에 집중할 것이다. 본 연구는 베트남의 지난 국가수자원계획의 성과를 평가해보고 그 한계점을 파악한 후, 2016-2020 국가수자원계획에 반영할 개선점을 진단하였다. 따라서 본 연구는 베트남 수자원 분야의 협력개발 및 프로젝트에 있어 훌륭한 기반이 될 것이다.

Effect of nanobubbles (oxygen, ozone) on the Pacific white shrimp (Penaeus vannamei), Vibrio parahaemolyticus and water quality under lab conditions

Nguyen Huu Nghia,Nguyen Thi Nguyen,Phan Trong Binh,Le Thi May,Tong Tran Huy,Pham Thai Giang,Sophie St-Hilaire,Phan Thi Van 한국수산과학회 2022 Fisheries and Aquatic Sciences Vol.25 No.8

This study assessed the effects of oxygen and ozone nanobubbles on gill morphology, weight gain, and mortality of Pacific white shrimp (Penaeus vannamei), as well as the level of Vibrio parahaemolyticus and water quality of shrimp culture tanks under lab conditions. Two experiments were carried out with oxygen macrobubble, ozone macrobubble, oxygen nanobubble, ozone nanobubble, and control treatments (air-stone macrobubble). Experiments were done in triplicate in 100 L tanks with 15‰ saline water, and 20 shrimp per tank. Tanks in Experiment 1 were not inoculated with bacteria; tanks in Experiment 2 were inoculated with V. parahaemolyticus at a concentration of 106 CFU/mL. The results revealed that short treatments with ozone nanobubbles had minimal impact on shrimp gills, mortality, and growth rates, reduced V. parahaemolyticus concentration in water compared to the other groups, and improve water quality. These laboratory results indicate that ozone nanobubble treatment may be useful for controlling V. parahaemolyticus. More work is needed to find the best protocol to apply the technology on a commercial scale.

Triarylboryl-Functionalized Oxadiazole as a Host Material with Electron Transporting Property for Green PhOLEDs

Nguyen Van Nghia,김종웅,김영민,이민형 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.6

A triarylboryl-functionalized oxadiazole compound, 2,5-bis-(m-dimesitylboryl-phenyl)-1,3,4-oxadiazole (1) was prepared and characterized to investigate multi-functional properties in phosphorescent OLEDs (PhOLEDs). X-ray crystal structure revealed that two Mes2B groups are oriented toward the same side and the entire fragments of oxadiazole, phenylene, and trigonal boron are in a nearly coplanar arrangement. From the optical and electrochemical measurements, 1 was shown to possess high triplet energy (ET = 2.75 eV) and deep HOMO (E HOMO = 6.02 eV) and low LUMO levels (E LUMO = 2.53 eV), which are suitable for electron transporting (ETM) and/or host materials in PhOLEDs. Green PhOLED devices incorporating 1 as electron transporting material (ETM), host, or host/ETM were fabricated and compared their performance with that of the devices based on the well-known CBP (9,9′-(1,1′-biphenyl)-4,4′-diylbis-9H-carbazole) host and TPBi (1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene) ETM. Among them, the devices based on 1 as host/ETM showed the highest performance that is comparable to that of the reference device.

Applications of Magnetite Nanoparticles for Water Treatment and for DNA and Cell Separation

Nguyen Hoang Hai,Nguyen Chau,Nguyen Hoang Luong,Nguyen Thi Van Anh,Phan Tuan Nghia 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.3

Magnetic nanoparticles with a diameter of 15 nm prepared by using the coprecipitation method have been applied to enforce the sedimentation of the solid waste, to adsorb the arsenic ions in water, to increase the DNA concentration by using a magnetic eld for the electrochemical DNA sensor and to separate the helper CD4+ T cells to determine the number of the cells in blood. A combination of magnetic nanoparticles and alum makes the solid waste in water under a magnetic field aggregate a dozen times faster than under the gravity alone. A concentration of 0.1 mg/l of arsenic in water was reduced to a value lower than the permissible concentration of 0.01 mg/l after few minutes of stirring. The particles functionalized with 3-aminopropyl triethoxysilane were used to enrich the DNA of the Herpes virus, which extended the sensitivity of an electrochemical sensor down to a concentration lower than nM/l. The particles coated with fluorescent-labeled antiCD4 antibody were used to count the helper CD4+ T cells. The fluorescence signals of the particle/cell system were two times stronger than those of the uorescence antiCD4 cell system. This can be used for the treatment of an HIV-infected patient with a simple fluorescent microscope. Magnetic nanoparticles with a diameter of 15 nm prepared by using the coprecipitation method have been applied to enforce the sedimentation of the solid waste, to adsorb the arsenic ions in water, to increase the DNA concentration by using a magnetic eld for the electrochemical DNA sensor and to separate the helper CD4+ T cells to determine the number of the cells in blood. A combination of magnetic nanoparticles and alum makes the solid waste in water under a magnetic field aggregate a dozen times faster than under the gravity alone. A concentration of 0.1 mg/l of arsenic in water was reduced to a value lower than the permissible concentration of 0.01 mg/l after few minutes of stirring. The particles functionalized with 3-aminopropyl triethoxysilane were used to enrich the DNA of the Herpes virus, which extended the sensitivity of an electrochemical sensor down to a concentration lower than nM/l. The particles coated with fluorescent-labeled antiCD4 antibody were used to count the helper CD4+ T cells. The fluorescence signals of the particle/cell system were two times stronger than those of the uorescence antiCD4 cell system. This can be used for the treatment of an HIV-infected patient with a simple fluorescent microscope.

<i>In situ</i> growth of flower-like V₂O₅ arrays on graphene@nickel foam as high-performance electrode for supercapacitors

Van Hoa, Nguyen,Quyen, Tran Thi Hoang,Nghia, Nguyen Huu,Van Hieu, Nguyen,Shim, Jae-Jin Elsevier 2017 Journal of alloys and compounds Vol.702 No.-

<P><B>Abstract</B></P> <P>Hierarchical flower-like V<SUB>2</SUB>O<SUB>5</SUB> growth on graphene and nickel foam electrodes was fabricated by using chemical vapor deposition and hydrothermal methods for electrochemical capacitors. Taking advantages of the high conductivity of graphene, high capacitance of well-defined V<SUB>2</SUB>O<SUB>5</SUB> flower-like structure and open framework of three-dimensional nickel foam, the resulting electrodes exhibited rapid electron and ion transport, large electroactive surface area, and excellent structural stability. The specific capacitance was as high as 1235 F g<SUP>−1</SUP> at a current density of 2 A g<SUP>-1</SUP>, suggesting its potential as a high performance electrode for supercapacitors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hierarchical flower-like V2O5/graphene/nickel foam electrodes was fabricated. </LI> <LI> The electrodes exhibited rapid electron and ion transport, large electroactive surface area. </LI> <LI> The specific capacitance was as high as 1235 A g−1 at a current density of 2 A g−1. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>