Mutra, Mohana Reddy’s team published research in Nature Communications in 2022 | CAS: 63069-48-7

4-Chloro-2-iodoaniline(cas: 63069-48-7) belongs to anime. Acylation is one of the most important reactions of primary and secondary amines; a hydrogen atom is replaced by an acyl group (a group derived from an acid, such as RCOOH or RSO3H, by removal of ―OH, such as RC(=O)―, RS(O)2―, and so on). Reagents may be acid chlorides (RCOC1, RSO2C1), anhydrides ((RCO)2O), or even esters (RCOOR′); the products are amides of the corresponding acids.Application In Synthesis of 4-Chloro-2-iodoaniline

In 2022,Mutra, Mohana Reddy; Wang, Jeh-Jeng published an article in Nature Communications. The title of the article was 《Photoinduced ynamide structural reshuffling and functionalization》.Application In Synthesis of 4-Chloro-2-iodoaniline The author mentioned the following in the article:

In this paper, photoinduced radical trigger regio- and chemoselective ynamide bond fission, structural reshuffling and functionalization of 2-alkynyl-ynamides 4-R-2-(CCR1)C6H3N(Ts)CCR2 (R = H, Me, Et, n-bu, Cl, Br; R1 = Ph, n-Bu, cyclopropyl, etc.; R2 = Ph, 2H-1,3-benzodioxol-5-yl, 2-phenylethyl, etc.) to prepare synthetically inaccessible/challenging chalcogen-substituted indole derivatives I [R3 = tosyl, ethanesulfonyl, cyclopropanesulfonyl, etc.; R4 = I, SeC6H5, Se(CH2)4CH3, etc] with excellent step/atom economy were observed The key breakthroughs of this work include, ynamide bond cleavage, divergent radical precursors, broad scope, easy to handle, larger-scale reactions, and generation of multiple bonds (N-C(sp2), C(sp2)-C(sp2), C(sp2)-SO2R/C-SR, and C-I/C-Se/C-H) in a few minutes without photocatalysts, metals, oxidants, additives. Control experiments and 13C-labeling experiments support the conclusion that sulfone radicals contribute to ynamide structural reshuffling processes via a radical pathway. After reading the article, we found that the author used 4-Chloro-2-iodoaniline(cas: 63069-48-7Application In Synthesis of 4-Chloro-2-iodoaniline)

4-Chloro-2-iodoaniline(cas: 63069-48-7) belongs to anime. Acylation is one of the most important reactions of primary and secondary amines; a hydrogen atom is replaced by an acyl group (a group derived from an acid, such as RCOOH or RSO3H, by removal of ―OH, such as RC(=O)―, RS(O)2―, and so on). Reagents may be acid chlorides (RCOC1, RSO2C1), anhydrides ((RCO)2O), or even esters (RCOOR′); the products are amides of the corresponding acids.Application In Synthesis of 4-Chloro-2-iodoaniline

Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com

Xu, Xiaojia’s team published research in Advanced Functional Materials in 2022 | CAS: 15854-87-2

4-Iodopyridine(cas: 15854-87-2) is used as a reagent in the synthesis of indazolylamides as glucocorticoid receptor agonists. 4-Iodopyridine is a halogenated heterocycle that is a building block for proteomics research.Recommanded Product: 4-Iodopyridine

In 2022,Xu, Xiaojia; Ji, Xiaoyu; Chen, Rui; Ye, Fangyuan; Liu, Shuaijun; Zhang, Shuo; Chen, Wei; Wu, Yongzhen; Zhu, Wei-Hong published an article in Advanced Functional Materials. The title of the article was 《Improving Contact and Passivation of Buried Interface for High-Efficiency and Large-Area Inverted Perovskite Solar Cells》.Recommanded Product: 4-Iodopyridine The author mentioned the following in the article:

Inverted-structured perovskite solar cells (PSCs) mostly employ poly-triarylamines (PTAAs) as hole-transporting materials (HTMs), which generally result in low-quality buried interface due to their hydrophobic nature, shallow HOMO levels, and absence of passivation groups. Herein, the authors molecularly engineer the structure of PTAA via removing alkyl groups and incorporating a multifunctional pyridine unit, which not only regulates energy levels and surface wettability, but also passivates interfacial trap-states, thus addressing above-mentioned issues simultaneously. By altering the linking-site on pyridine unit from ortho- (o-PY) to meta- (m-PY) and para-position (p-PY), they observed a gradually improved hydrophilicity and passivation efficacy, mainly owing to increased exposure of the pyridine-nitrogen as well as its lone electron pair, which enhances the contact and interactions with perovskite. The open-circuit voltage and power conversion efficiency (PCE) of inverted-structured PSCs based on these HTMs increased with the same trend. Consequently, the optimal p-PY as HTM enables facile deposition of uniform perovskite films without complicated interlayer optimizations, delivering a remarkably high PCE exceeding 22% (0.09 cm2). Moreover, when enlarging device area tenfold, a comparable PCE of over 20% (1 cm2) can be obtained. These results are among the highest efficiencies for inverted PSCs, demonstrating the high potential of p-PY for future applications. After reading the article, we found that the author used 4-Iodopyridine(cas: 15854-87-2Recommanded Product: 4-Iodopyridine)

4-Iodopyridine(cas: 15854-87-2) is used as a reagent in the synthesis of indazolylamides as glucocorticoid receptor agonists. 4-Iodopyridine is a halogenated heterocycle that is a building block for proteomics research.Recommanded Product: 4-Iodopyridine

Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com

Zhang, Enshen’s team published research in Organic Chemistry Frontiers in 2022 | CAS: 63069-48-7

4-Chloro-2-iodoaniline(cas: 63069-48-7) belongs to anime. The reaction of alkyl halides, R―X, where X is a halogen, or analogous reagents with ammonia (or amines) is useful with certain compounds. Not all alkyl halides are effective reagents; the reaction is sluggish with secondary alkyl groups and fails with tertiary ones. Its usefulness is largely confined to primary alkyl halides (those having two hydrogen atoms on the reacting site).Quality Control of 4-Chloro-2-iodoaniline

In 2022,Zhang, Enshen; Chen, Chen; Wang, Xueling; Wang, Jian; Shang, Yongjia published an article in Organic Chemistry Frontiers. The title of the article was 《Palladium-catalyzed dearomative 1,4-arylmethylenation of naphthalenes》.Quality Control of 4-Chloro-2-iodoaniline The author mentioned the following in the article:

An efficient palladium-catalyzed construction of E-exocyclic-double-bond-containing spirooxindoles via 1,4-arylmethylenation of naphthalenes has been developed. Aryl aldehyde-derived N-tosylhydrazones were successfully applied as carbene precursors to capture the endocyclic π-allylpalladium intermediate, which was generated via an arylative Heck reaction of the naphthalene-masked conjugated diene, followed by a highly regioselective β-hydride elimination. This reaction features broad functional group tolerance and excellent chemo- and E/Z selectivities. The experimental process involved the reaction of 4-Chloro-2-iodoaniline(cas: 63069-48-7Quality Control of 4-Chloro-2-iodoaniline)

4-Chloro-2-iodoaniline(cas: 63069-48-7) belongs to anime. The reaction of alkyl halides, R―X, where X is a halogen, or analogous reagents with ammonia (or amines) is useful with certain compounds. Not all alkyl halides are effective reagents; the reaction is sluggish with secondary alkyl groups and fails with tertiary ones. Its usefulness is largely confined to primary alkyl halides (those having two hydrogen atoms on the reacting site).Quality Control of 4-Chloro-2-iodoaniline

Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com

Koley, Suvajit’s team published research in Journal of Organic Chemistry in 2022 | CAS: 626-02-8

3-Iodophenol(cas: 626-02-8) belongs to organic iodides. The carbon-iodine bond is weaker than other carbon-halogen bonds due to the poor electronegative nature of the iodine atom. Alkyl iodides react at a faster rate than alkyl fluorides due to the weak C-I bond.Safety of 3-Iodophenol

In 2022,Koley, Suvajit; Cayton, Kaylee T.; Gonzalez-Montiel, Gisela A.; Yadav, M. Ramu; Orsi, Douglas L.; Intelli, Andrew J.; Cheong, Paul Ha-Yeon; Altman, Ryan A. published an article in Journal of Organic Chemistry. The title of the article was 《Cu(II)-Catalyzed Unsymmetrical Dioxidation of gem-Difluoroalkenes to Generate α,α-Difluorinated-α-phenoxyketones》.Safety of 3-Iodophenol The author mentioned the following in the article:

A Cu-based catalyst system convergently couples gem-difluoroalkenes with phenols under aerobic conditions to deliver α,α-difluorinated-α-phenoxyketones, an unstudied hybrid fluorinated functional group. Composed of α,α-difluorinated ketone and α,α-difluorinated ether moieties, these compounds have rarely been reported as a synthetic intermediate. Computational predictions and later exptl. corroboration suggest that the phenoxy-substituted fluorinated ketone’s sp3-hybridized hydrate form is energetically favored relative to the resp. nonether variant and that perturbation of the electronic character of the ketone can further encourage the formation of the hydrate. The more facile conversion between ketone and hydrate forms suggests that analogs should readily covalently inhibit proteases and other enzymes. Further functionalization of the ketone group enables access to other useful fluorinated functional groups.3-Iodophenol(cas: 626-02-8Safety of 3-Iodophenol) was used in this study.

3-Iodophenol(cas: 626-02-8) belongs to organic iodides. The carbon-iodine bond is weaker than other carbon-halogen bonds due to the poor electronegative nature of the iodine atom. Alkyl iodides react at a faster rate than alkyl fluorides due to the weak C-I bond.Safety of 3-Iodophenol

Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com

Sun, Bozheng’s team published research in Chemistry – A European Journal in 2022 | CAS: 591-18-4

1-Bromo-3-iodobenzene(cas: 591-18-4) has been used in the preparation of 1-(3′-bromophenyl)-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodec-1-ene and 1-(3′-bromophenyl)-3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooct-1-ene.Reference of 1-Bromo-3-iodobenzene Further, it is involved in the preparation of oxygen-tethered 1,6-enynes.

In 2022,Sun, Bozheng; Oakley, Meagan S.; Yoshida, Kota; Yang, Yanwen; Tommasini, Matteo; Zanchi, Chiara; Lucotti, Andrea; Ferguson, Michael J.; Hampel, Frank; Klobukowski, Mariusz; Tykwinski, Rik R. published an article in Chemistry – A European Journal. The title of the article was 《The Effects of Ring Strain on Cyclic Tetraaryl[5]cumulenes》.Reference of 1-Bromo-3-iodobenzene The author mentioned the following in the article:

Cyclic tetraaryl[5]cumulenes I (n = 1, 2, 3, 4, 5, 6) have been synthesized and studied as a function of increasing ring strain. The magnitude of ring strain is approximated by the extent of bending of the cumulenic core as assessed by a combination of X-ray crystallog. anal. and DFT calculations In particular, the exptl. HOMO-LUMO gap is not appreciably affected by bending of the [5]cumulene framework from ca. 174°λmax = 504 nm in I (n = 1) to ca. 178° λmax = 494 nm in I (n = 6). In addition to this study using 1-Bromo-3-iodobenzene, there are many other studies that have used 1-Bromo-3-iodobenzene(cas: 591-18-4Reference of 1-Bromo-3-iodobenzene) was used in this study.

1-Bromo-3-iodobenzene(cas: 591-18-4) has been used in the preparation of 1-(3′-bromophenyl)-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodec-1-ene and 1-(3′-bromophenyl)-3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooct-1-ene.Reference of 1-Bromo-3-iodobenzene Further, it is involved in the preparation of oxygen-tethered 1,6-enynes.

Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com

Liu, Yunting’s team published research in Chinese Journal of Chemistry in 2021 | CAS: 15854-87-2

4-Iodopyridine(cas: 15854-87-2) is a halogenated heterocycle that is a building block for proteomics research. 4-Iodopyridine is used as a reagent in the synthesis of indazolylamides as glucocorticoid receptor agonists.Product Details of 15854-87-2

Liu, Yunting; Wang, Zihan; Guo, Na; Liu, Pengbo; Liu, Guanhua; Gao, Jing; Zhang, Lei; Jiang, Yanjun published an article in 2021. The article was titled 《Polydopamine-Encapsulated Dendritic Organosilica Nanoparticles as Amphiphilic Platforms for Highly Efficient Heterogeneous Catalysis in Water》, and you may find the article in Chinese Journal of Chemistry.Product Details of 15854-87-2 The information in the text is summarized as follows:

Herein, a type of amphiphilic core-shell catalysts with a hydrophilic polydopamine (PDA) shell and a hydrophobic dendritic organosilica nanoparticle (DON) core for heterogeneous catalysis in water was synthesized. The hydrophilic shell allowed the catalyst dispersing well in water, and the hydrophobic core facilitated the absorption of organic reactants. The hierarchical core-shell structure facilitated rational arrangement of the location of catalytic species to match the reaction sequence. The obtained metal, enzyme and metal-enzyme amphiphilic catalysts demonstrated improved stability, selectivity and activity in aqueous reactions, including Pd-catalyzed cross-couplings (Suzuki, Liebeskind-Srogl, Heck and Sonogashira), enzymic enantioselective reduction, chemoenzymic cascade synthesis of chiral compounds and chemoenzymic cascade degradation of organophosphates. The amphiphilic catalysts were easily recovered and their high catalytic performance was sustained for five cycles.4-Iodopyridine(cas: 15854-87-2Product Details of 15854-87-2) was used in this study.

4-Iodopyridine(cas: 15854-87-2) is a halogenated heterocycle that is a building block for proteomics research. 4-Iodopyridine is used as a reagent in the synthesis of indazolylamides as glucocorticoid receptor agonists.Product Details of 15854-87-2

Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com

Ogata, Aya’s team published research in Bioorganic & Medicinal Chemistry in 2017 | CAS: 3993-79-1

2-Amino-5-iodopyrimidin-4(1H)-one(cas: 3993-79-1) belongs to anime. In organic chemistry, amines are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (NH3), wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group (these may respectively be called alkylamines and arylamines; amines in which both types of substituent are attached to one nitrogen atom may be called alkylarylamines).Application In Synthesis of 2-Amino-5-iodopyrimidin-4(1H)-one

《Synthesis of antisense oligonucleotides containing acyclic alkynyl nucleoside analogs and their biophysical and biological properties》 was written by Ogata, Aya; Maeda, Yusuke; Ueno, Yoshihito. Application In Synthesis of 2-Amino-5-iodopyrimidin-4(1H)-one And the article was included in Bioorganic & Medicinal Chemistry on April 1 ,2017. The article conveys some information:

The synthesis of oligonucleotide (ON) analogs, which can be used as antisense mols., has recently gained much attention. Here, we report the synthesis and properties of an ON analog containing acyclic thymidine and cytidine analogs with a 4-pentyl-1,2-diol instead of the D-ribofuranose moiety. The incorporation of these analogs into the ON improved its nuclease resistance to 3′-exonucleases. Furthermore, it was found that the incorporation of the acyclic thymidine analog into a DNA/RNA duplex accelerates the RNA cleavage of a DNA/RNA duplex by Escherichia coli RNase H. In the part of experimental materials, we found many familiar compounds, such as 2-Amino-5-iodopyrimidin-4(1H)-one(cas: 3993-79-1Application In Synthesis of 2-Amino-5-iodopyrimidin-4(1H)-one)

2-Amino-5-iodopyrimidin-4(1H)-one(cas: 3993-79-1) belongs to anime. In organic chemistry, amines are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (NH3), wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group (these may respectively be called alkylamines and arylamines; amines in which both types of substituent are attached to one nitrogen atom may be called alkylarylamines).Application In Synthesis of 2-Amino-5-iodopyrimidin-4(1H)-one

Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com

Hsiao, Pu-Yen’s team published research in Journal of Organic Chemistry in 2022 | CAS: 15854-87-2

4-Iodopyridine(cas: 15854-87-2) is a halogenated heterocycle that is a building block for proteomics research. 4-Iodopyridine is used as a reagent in the synthesis of indazolylamides as glucocorticoid receptor agonists.Recommanded Product: 4-Iodopyridine

Recommanded Product: 4-IodopyridineIn 2022 ,《Synthesis and Mechanistic Investigation of Bipyrazolo[1,5-a]pyridines via Palladium-Catalyzed Cross-Dehydrogenative Coupling of Pyrazolo[1,5-a]pyridines》 appeared in Journal of Organic Chemistry. The author of the article were Hsiao, Pu-Yen; Chang, Rong; Sue, Andrew C.-H.; Chu, Jean-Ho; Liao, Guan-Wei; Lee, Yi-Hsin; Huang, Jui-Yang. The article conveys some information:

The synthesis of a range of 3,3′-bipyrazolo[1,5-a]pyridine derivatives via direct cross-dehydrogenative coupling of pyrazolo[1,5-a]pyridine precursors was herein presented. This simple and efficient methodol. involving palladium(II)-catalyzed C-H bond activation showed good functional group tolerance and product yield (up to 94%). Through the mechanistic insights gained from both kinetic isotope effect exptl. studies and d. functional theory calculations, a plausible reaction mechanism was outlined. Furthermore, subsequent derivatizations of the resulting 7,7′-diaryl-3,3′-bipyrazolo[1,5-a]pyridines, executed by performing palladium-mediated ortho C-H bond activation followed by hypervalent iodine-induced chlorination, rendered this series of compounds more extended π-conjugation and twisted conformations. The study on these bipyrazolo[1,5-a]pyridine-based luminogens provided new opportunities for tailor-made organic luminescent materials.4-Iodopyridine(cas: 15854-87-2Recommanded Product: 4-Iodopyridine) was used in this study.

4-Iodopyridine(cas: 15854-87-2) is a halogenated heterocycle that is a building block for proteomics research. 4-Iodopyridine is used as a reagent in the synthesis of indazolylamides as glucocorticoid receptor agonists.Recommanded Product: 4-Iodopyridine

Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com

Chen, Xiao-Chao’s team published research in Chemistry – An Asian Journal in 2021 | CAS: 624-73-7

1,2-Diiodoethane(cas: 624-73-7) is one of organic iodides. The carbon-iodine bond is weaker than other carbon-halogen bonds due to the poor electronegative nature of the iodine atom. In general, organic iodides are light-sensitive and turn yellow during storage, owing to the formation of iodine. Organic iodides can be alkyl, alkenyl, or alkynyl, and all of them are very reactive toward with many kinds of nucleophiles.Quality Control of 1,2-Diiodoethane

Quality Control of 1,2-DiiodoethaneIn 2021 ,《Cooperative Catalysis of Ru(III)-Porphyrin in CO2-Involved Synthesis of Oxazolidinones》 appeared in Chemistry – An Asian Journal. The author of the article were Chen, Xiao-Chao; Yao, Yin-Qing; Zhao, Kai-Chun; Liu, Lei; Lu, Yong; Liu, Ye. The article conveys some information:

Herein, a Ru(III)-porphyrin catalyst (RuCl3·3H2O-H2TPP) was found highly efficient in the three-component reaction of CO2, aliphatic amines and dichloroethane (or its derivative) for synthesis of oxazolidinones in the yields of 71∼91%. It was indicated by means of the control experiments and UV-vis spectra that CO2 was stoichiometrically activated by the involved aliphatic amine substrates to form a stable carbamate salt while 1,2-dichloroethane (or its derivative) was independently activated by the involved Ru(III)-porphyrin catalyst. The combination of CO2-activation by aliphatic amines with 1,2-dichloroethane activation by Ru(III)-porphyrin catalyst cooperatively contributed to this successful transformation. In the part of experimental materials, we found many familiar compounds, such as 1,2-Diiodoethane(cas: 624-73-7Quality Control of 1,2-Diiodoethane)

1,2-Diiodoethane(cas: 624-73-7) is one of organic iodides. The carbon-iodine bond is weaker than other carbon-halogen bonds due to the poor electronegative nature of the iodine atom. In general, organic iodides are light-sensitive and turn yellow during storage, owing to the formation of iodine. Organic iodides can be alkyl, alkenyl, or alkynyl, and all of them are very reactive toward with many kinds of nucleophiles.Quality Control of 1,2-Diiodoethane

Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com

Wang, Can’s team published research in ACS Applied Materials & Interfaces in 2022 | CAS: 589-87-7

1-Bromo-4-iodobenzene(cas: 589-87-7) is mainly used as the OLED pharmaceutical intermediate, as reagent for in situ desilylation and coupling of silylated alkynes, as substrate in copper-free Sonogashira coupling in aqueous acetone..COA of Formula: C6H4BrI It is also used in synthesis of β,β,dibromostyrenes, as starting reagent in the total syntheses of ent-conduramine A and ent-7-deoxypancratistatin (alkaloids)

In 2022,Wang, Can; Xiong, Qiu; Zhang, Zilong; Meng, Lingyi; Li, Feng; Yang, Longkai; Wang, Xiaobing; Zhou, Qin; Fan, Weihang; Liang, Lusheng; Lien, Shui-Yang; Li, Xin; Wu, Jihuai; Gao, Peng published an article in ACS Applied Materials & Interfaces. The title of the article was 《Deciphering the reduced loss in high fill factor inverted perovskite solar cells with methoxy-substituted poly(triarylamine) as the hole selective contact》.COA of Formula: C6H4BrI The author mentioned the following in the article:

A dopant-free polymeric hole selective contact (HSC) layer is ubiquitous for stable perovskite solar cells (PSCs). However, the intrinsic nonwetting nature of the polymeric HSC impedes the uniform spreading of the perovskite precursor solution, generating a terrible buried interface. Here, we dexterously tackle this dilemma from the perspective of dispersive and polar component surface energies of the HSC layer. A novel triarylamine-based HSC material, poly[bis(4-phenyl)(2,4-dimethoxyphenyl)amine] (2MeO-PTAA), was designed by introducing the polar methoxy groups to the para and ortho positions of the dangling benzene. These nonsym. substituted electron-donating methoxy groups enhanced the polar components of surface energy, allowing more tight interfacial contact between the HSC layer and perovskite and facilitating hole extraction When utilized as the dopant-free HSC layer in inverted PSCs, the 2MeO-PTAA-based device with CH3NH3PbI3 as the absorber exhibited an encouraging power conversion efficiency of 20.23% and a high fill factor of 84.31% with negligible hysteresis. Finally, a revised detailed balance model was used to verify the drastically lessened surface defect-induced recombination loss and shunt resistance loss in 2MeO-PTAA-based devices. This work demonstrates a facile and efficient way to modulate the buried interface and shed light on the direction to further improve the photovoltaic performance of inverted PSCs with other types of perovskites. The experimental part of the paper was very detailed, including the reaction process of 1-Bromo-4-iodobenzene(cas: 589-87-7COA of Formula: C6H4BrI)

1-Bromo-4-iodobenzene(cas: 589-87-7) is mainly used as the OLED pharmaceutical intermediate, as reagent for in situ desilylation and coupling of silylated alkynes, as substrate in copper-free Sonogashira coupling in aqueous acetone..COA of Formula: C6H4BrI It is also used in synthesis of β,β,dibromostyrenes, as starting reagent in the total syntheses of ent-conduramine A and ent-7-deoxypancratistatin (alkaloids)

Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com