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π-Extended ullazines were obtained using complementary synthetic approaches based on direct arylation and cycloaddition reactions, respectively. Their strong fluorescence can be tuned by appropriate modifications of substitution and edge expansion.

Cyclobuta[1,2-b:3,4-b′]ditetracene – an analogue of nonacene with a cyclobutadiene unit embedded in the central part has been synthesized by the combination of solution and on-surface chemistry.

This review surveys recent progress in the chemistry of polycyclic heteroaromatic molecules with a focus on structural diversity and synthetic methodology. The article covers literature published during the period of 2016–2020, providing an update to our first review of this topic (Chem. Rev.2017, 117 (4), 3479–3716).

Cellulose has been identified in fossil material, but the preservation potential of hemicelluloses, which are less resistant to decomposition than cellulose, is generally considered very low. Here we present the discovery of hemicellulose in Miocene xylites (fossil wood) and Cretaceous xylo-detritic coals from Poland. The main building blocks of hemicelluloses in softwood are mannose, glucose, xylose with lesser amounts of galactose and arabinose. These saccharides were detected in the coals and xylites using independent geochemical methods. Based on chemical analysis, the lignites contained significant holocellulose (22–37%), α-cellulose (8–29%) and hemicellulose (7–13%). In the smoke from a xylite burn test, levoglucosan and mannosan were dominant, the latter a specific hemicellulose alteration product. Glucose and mannose products dominated after methanolysis, with minor galactose and xylose. The main hemicellulosic polysaccharides in lignite appear to be glucomannan and/or galactoglucomannan but with a lower mannose content, possibly connected to wood degradation by fungi. The preservation of hemicelluloses in fossil material may be due to structural interconnection between lignin, cellulose and hemicellulose (i.e. lignocellulose), common in extant wood. This is the first documentation of hemicelluloses in fossil material. Our results show that not only cellulose, but also hemicelluloses can persist for millions of years under favorable conditions with only minor structural changes due to slow microbial and/or diagenetic decay. In fossil wood, types of hemicellulose can help assess whether the ancient plants were related to gymnosperms or angiosperms.

Tridecacyclene tetraimide, TCTI, an electron-deficient non-benzenoid nanocarbon with a C

Reaction of polycyclic azomethine ylide with norcorrole resulted in a family of chiral antiaromatic stereoisomeric cycloadducts. Oxidative dehydrogenation of some of them gave rise to the dibenzoullazine-extended norcorroles.

Energy-transfer cassettes consisting of naphthaleneimide-fused metalloporphyrin acceptors (M=Zn and Pd) and BODIPY donors have been designed and synthesized. These systems have rigid pseudo-tetrahedral structures with a donor-acceptor separation of ca. 17.5 Å. Spectroscopic investigations, including femtosecond transient absorption measurements, showed efficient excitation energy transfer (EET) occurring according to the Förster mechanism. Strong fluorescence of the donor units and significant spectral overlap of the donor and acceptor subunits are prerequisites for the efficient EET in these systems.

Unsymmetrically fused porphyrins containing one or two naphthalimide subunits were prepared in modular syntheses relying on electron-rich and electron-poor pyrrole building blocks. These new chromophores show progressive changes in their electron-deficient character, while retaining comparably small optical and electrochemical band gaps. The intrinsic curvature and extended optical absorption of these systems make them of interest as mono- and difunctional components of multichromophoric assemblies.

Free base, zinc and palladium π‐extended porphyrins containing fused naphthalenediamide units were employed as photosensitizers in antimicrobial photodynamic therapy (aPDT). Their efficacy, assessed by photophysical and in vitro photobiological studies on Gram‐positive bacteria, was found to depend on metal coordination, showing a dramatic enhancement of photosensitizing activity for the palladium complex., Photo finish it: Antimicrobial photodynamic therapy (aPDT) has been proposed as an alternative approach for the treatment of bacterial infections. Here, free base, zinc and palladium π‐extended porphyrins containing fused naphthalenediamide units were employed as photosensitizers in aPDT, assessed by photophysical and in vitro photobiological studies.

International audience; Boomerang-shaped bipyrroles containing donor-acceptor units were obtained through a tandem palladium-mediated reaction consisting of a cyclization step, involving double C-H bond activation, and a double alpha-oxygenation. The latter reaction can be partly suppressed for the least reactive systems, providing access to alpha-unsubstituted boomerangs for the first time. These "alpha-free" systems are highly efficient fluorophores, with emission quantum yields exceeding 80% in toluene. Preliminary measurements show that helicene-like boomerangs may be usable as circularly polarized luminescent materials.

Peripheral substitution of a π-extended porphyrin with bulky groups produces a curved chromophore with four helical stereogenic units. The curvature and stereochemistry of such porphyrins can be controlled by varying the substituents, coordinated metal ions, and apical ligands. In particular, when the achiral saddle-shaped free bases are treated with large metal ions, i.e., Cd

Circularly polarized luminescence (CPL) and Raman optical activity (ROA) were observed in a single spectroscopic experiment for a purely organic molecule, an event that had so far been limited to lanthanide-based complexes. The present observation was achieved for [16]cycloparaphenylene lemniscate, a double macrocycle constrained by a rigid 9,9′-bicarbazole subunit, which introduces a chirality source and allows the molecule to be resolved into two configurationally stable enantiomers. Distortion of oligophenylene loops in this lemniscular structure produces a large magnetic transition dipole moment while maintaining the π-conjugation-induced enhancement of the Raman signal, causing the appearance of the CPL/ROA couple. A two-photon mechanism is proposed to explain the population of the lowest-energy excited electronic state prior to the simultaneous emission-scattering event. We thank MINECO/FEDER of the Spanish Government (project reference PGC2018-098533-B-100 and PID2021-127127NB-I00) and the Junta de Andalucía, Spain (UMA18FEDERJA057). We also thank the vibrational spectroscopy unit of the Research Central Services (SCAI) of the University of Málaga. Financial support from the National Science Center of Poland (DEC-2015/19/B/ST5/00612, M.S.) is gratefully acknowledged. L.F. thanks Thomas Vives from the Ecole Nationale Supérieure de Chimie of Rennes, the Shimadzu and Chiral Technology companies for their support regarding the separation of the chiral molecule by supercritical fluid chromatography (SFC). Funding for open access charge: Universidad de Málaga/CBUA

π-Extended acenaphtho[1,2-d][1,2,3]triazoles, the unsubstituted Anta-H and its di-tert-butyl derivative Dibanta-H, as well as 5,6,7,8-tetrahydro-1H-naphtho[2,3-d][1,2,3]triazole Cybta-H were obtained in concise syntheses. In the solid state, Dibanta-H forms an unprecedented hydrogen-bonded cyclic tetrad, stabilized by dispersion interactions of the bulky tBu substituents, whereas a cyclic triad was found in the crystal structure of Anta-H. These cyclic assemblies form infinite slipped stacks in the crystals. Evidence for analogous hydrogen-bonded self-assembly in solution was provided by low-temperature NMR spectroscopy and computational analyses. Kuratowski-type pentanuclear complexes [Zn5 Cl4 (Dibanta)6 ] and [Zn5 Cl4 (Cybta)6 ] were prepared from the respective triazoles. In the Dibanta complexes, the π-aromatic surfaces of the ligands extend from the edges of the tetrahedral Zn5 core, yielding an enlarged structure with significant internal molecular free volume and red-shifted fluorescence.

A hexaradicaloid molecule with alternating Kekule and non-Kekule connectivities between adjacent spin centers was obtained by fusing two conjugation motifs in Chichibabin and Schlenk hydrocarbons into a coronoid structure. 1 H NMR, ESR, and SQUID experiments and computational analyses show that the system has a singlet ground state with a significant hexaradicaloid character (γ0 =0.826, γ1 =γ2 =0.773). It has multiple thermally accessible high-spin states (up to the septet), with uniform energy gaps of ca 1.0 kcal mol-1 between consecutive multiplicities. In line with its open-shell character, the coronoid has a small electronic band gap (ca. 0.8 eV) and undergoes two consecutive one-electron oxidations at low potentials, yielding cationic forms with extended near-infrared absorption. The hexaradicaloid, which combines open-shell and macrocyclic contributions to its π conjugation, is an example of a design strategy for multistate spin switches and redox-amphoteric NIR dyes.

A hybrid nanocarbon receptor consisting of a calix[4]arene and a bent oligophenylene loop ("molecular squid"), was obtained in an efficient, scalable synthesis. The system contains an electron-rich cavity with an adaptable shape, which can serve as a host for electron deficient guests, such as diquat, 10-methylacridinium, and anthraquinone. The new receptor forms inclusion complexes in the solid state and in solution, showing a dependence of the observed binding strength on the shape of the guest species and its charge. The interaction with the methylacridinium cation in solution was interpreted in terms of a 2:1 binding model, with K11 = 5.92(7) × 103 M-1. The solid receptor is porous to gases and vapors, yielding an uptake of ca. 4 mmol/g for methanol at 293 K. In solution, the receptor shows cyan fluorescence (λmaxem = 485 nm, ΦF = 33%), which is partly quenched upon binding of guests. Methylacridinium and anthraquinone adducts show red-shifted emission in the solid state, attributable to the charge-transfer character of these inclusion complexes.

A diindenophenanthrene biradicaloid, formally derived from Chichibabin's hydrocarbon, is obtained in a short, scalable synthesis. The present system is electron-rich and devoid of conjugated substituents, and still exhibits very good stability under ambient conditions. The introduction of the diindeno[1,2-a:2′,1′-i] phenanthrene ring framework results in a singlet biradicaloid system with an easily accessible triplet state (ΔES–T = −1.30 kcal mol−1) and a small electronic bandgap (1.39 V). The stability limits of the title hydrocarbon were explored systematically in the solid state, to reveal an unusual thermally initiated hydrogen-scrambling oligomerization process.

Cel – Celem opracowania jest identyfikacja i opis zalezności ujawnien w zakresie dokumentacji cen transferowych a sprawozdawczością finansową podmiotow gospodarczych. Metodologia badania – W artykule zawarto monograficzną metodologie badania, wykorzystując infor-macje w formie jakościowo - opisowej. Poddano metodzie analizy i konstrukcji logicznej piśmiennictwo istniejące w zakresie badanego zagadnienia, uwzgledniając istniejący zakres prawa podatkowego. Wynik – Wynikiem badan jest kwantyfikacja roznic i podobienstw w zakresie ujawnien aktywow, funkcji, ryzyk i realizowanych przez podmiot strategii w obszarze prawa podatkowego i bilansowego. Oryginalnośc/Wartośc – Jednym z elementow szeroko rozumianego otoczenia ekonomicznego, jest sys-tem rachunkowości dostarczający odbiorcom informacji o wynikach jednostki i sytuacji majątkowo-finansowej. Do szeroko rozumianego otoczenia ekonomicznego zaliczamy rowniez otoczenie fiskalne. Prawo podatkowe, sluząc glownie celom fiskalnym panstwa, realizuje jedną z podstawowych funkcji systemu podatkowego, do ktorych nalezy funkcja fiskalna. Prawo bilansowe sluzy glowne do informowania wlaścicieli kapitalow jednostki o szeroko rozumianych wynikach finansowych uzyskiwanych przez jednostki gospodarcze. Zmiany w zakresie ujawnien danych ekonomicznych w zidentyfikowanych dwoch systemach, stanowią istotny element zarządzania generowanymi przez podmiot informacjami zarowno w zakresie podatkow jak i sprawozdawczości finansowej.

The antiaromatic ring of norcorrole, a contracted tetrapyrrolic porphyrinoid, was subjected to [2+3] dipolar cycloaddition of iminonitriles. The paratropic character of the resulting chiral chlorins was retained. The chlorins were easily dehydrogenated in the presence of air, yielding pyrazole-fused norcorroles with markedly enhanced paratropicity.

Recent advances in the chemistry of electron-poor polycyclic aromatic molecules are reviewed with a focus on new structural designs and emerging synthetic methods. We review various classes of building blocks, notably those based on rylene imides, and highlight the application of the most successful C–C bond-forming reactions, e.g., tandem Pd-catalyzed couplings, photocyclizations, and the glyoxylic Perkin condensation. These advances are presented in the context of the electronic properties of the resulting materials, which are of high current interest as n-type organic semiconductors.

A 139-π-electron nanographenoid radical was obtained by expanding the periphery of a naphthalimide–azacoronene hybrid with a methine bridge. The radical was isolated in the form of its σ-dimer, which was shown to possess a conformationally restricted two-layer structure both in the solid state and in solution. The dimer is cleaved into its parent radicals when exposed to ultraviolet or visible radiation in toluene solutions but is resistant to thermally induced dissociation. Under inert conditions, the radicals recombine quantitatively into the σ-dimer with observable kinetics, but they are oxidized into a ketone derivative in the presence of atmospheric oxygen. Combined structural, spectroscopic, and theoretical evidence shows that the σ-dimer contains a weak C(sp3)–C(sp3) bond, but is stabilized against thermal dissociation by a very strong dispersive interaction between the overlapping π surfaces.

Conductive π-conjugated polymers were electrochemically generated from a variety of donor–acceptor pyrroles containing fused perimidine subunits. Alternating oxidative and reductive polarization of...

In this issue of Chem, Jishan Wu and colleagues provide the first examples of annulene-within-an-annulene (AWA) structures in which the inner and outer conjugated circuits are formally fully decoupled. Existing models of AWA aromaticity might need to be revised to account for the exceptional behavior of these novel structures.

Oxidative transformation of hexapyrrolylbenzenes into azacoronenes using bromine electrophiles as alternative coupling agents is shown to occur according to a distinct mechanism, different from those proposed for typical high-potential oxidants. It is shown that consecutive cyclizations do not involve brominated intermediates and can be rationalized by assuming a relayed arenium cation attack followed by deprotonation and conjugate elimination. The final cyclization is incompatible with this mechanism and is found to involve double-electrophilic bromination followed by thermal elimination of dibromine. These findings provide insight into the reactivity of sterically congested aromatic systems and may help in designing new methods of C-C bond formation.

International audience; A cycloparaphenylene-based molecular lemniscate (CPPL) was obtained in a short synthesis involving masked p-phenylene equivalents. The strained figure-eight geometry of CPPL is sustained by the incorporated 9,9'-bicarbazole subunit, which also acts as a stereogenic element. The shape of the distorted [16]cycloparaphenylene nanohoop embedded in CPPL is accurately approximated with a Booth lemniscate. The structure of CPPL, investigated using NMR and Raman spectroscopic methods, revealed strain-dependent features, consistent with the variable curvature of the ring. The electronic and optical properties of CPPL combine features more characteristic of smaller cycloparaphenylenes, such as a reduced optical bandgap and red-shifted fluorescence. CPPL was resolved into enantiomers, which are configurationally stable and provide strong chiroptical responses, including circularly polarized luminescence.

W artykule przedstawiono perspektywy rozpoznawania i oceny relacji występujących pomiędzy pomiędzy aktualnie obowiązującymi przepisami prawa bilansowego i podatkowego w obszarze działalności badawczo-rozwojowej, która jest wymiarem innowacyjności przedsiębiorstw W artykule nie zaprezentowano wszystkich aspektów oddziałujących na innowacyjność przedsiębiorstw. Autorzy skupili się na powyżej zasygnalizowanych obszarach działalności przedsiębiorstw. Całość prezentowanych rozważań została podzielona na dwie zasadnicze części. Pierwsza część artykułu podkreśla problem identyfikacji, klasyfikacji, oceny i prezentacji działalności badawczo-rozwojowej z punktu widzenia prawa bilansowego. Rozważania przedstawione w drugiej części charakteryzują działalność badawczo-rozwojową przedsiębiorstw w zakresie podatków. Zastosowanymi metodami badawczymi są studia literaturowe, analiza przepisów prawnych oraz analiza opisowej.

Purpose – The purpose of this article is identification and description of risks, which constitute an inherent element of the tax documentation. Design/Methodology/approach – This article includes monographic research methodology using information in qualitative and descriptive form. Analysis and logical structure method has been applied to the literature on the subject taking into account existing scope of the tax law. The practical part of this article includes case study. Findings – The research result is quantification of tax risks resulting from cooperation of related companies in the aspect of the transfer prices documentation. Originality/value – One of the elements of widely understood economic environment is the fiscal environment. The tax law which mainly serve to fiscal purposes, performs one of the basic tax system functions to which the fiscal function belongs. However, the tax law gives companies the opportunity to choose, for example, the form of cooperation especially between companies with capital, organizational and personal links. Business links significantly influence the opportunities of cooperation and at the same time they are a source of the tax risk. Identification and description of the tax risk in the aspect of reliability of the transfer prices documentation seems to be an important problem.

Specyfika dziel technicznych polega na tym, ze z zalozenia sluzą one realizacji celow pragmatycznych. Uzytkowy charakter dziel technicznych wplywa na proces ksztaltowania treści i formy utworu. Na „dzialalnośc tworczą o indywidulanym charakterze” mają wplyw takie okoliczności, jak ograniczenia technologiczne, przewidywalnośc spodziewanego rezultatu dzialalności czy praktyka postepowania. W konsekwencji dziela techniczne mozna przeciwstawic „klasycznie” pojmowanym utworom sluzącym zaspokojeniu potrzeb duchowych czlowieka. Analiza polskiej doktryny i orzecznictwa sądow polskich prowadzi do wniosku, ze o ile przeslanka dzialalności tworczej w przypadku dziel technicznych co do zasady bedzie spelniona, o tyle wątpliwe jest, na ile proces tworczy, stratyfikowany czynnikami obiektywnymi, pozwala na indywidualne uksztaltowanie dziela technicznego. W rezultacie kwestia ochrony prawnoautorskiej dziela technicznego w wiekszości przypadkow sprowadzac sie bedzie do odpowiedzi na pytanie, czy spelnia ono przeslanke indywidualnego charakteru utworu. Ustawowa przeslanka indywidulanego charakteru musi uwzgledniac kazdy przejaw dzialalności tworczej czlowieka, w tym taki, ktory nalezy do szeroko rozumianej sfery dziel niefikcjonalnych (dzielo techniczne, naukowe). W konsekwencji swoisty charakter dziel technicznych rodzi pytania zarowno o to, w jakim stopniu przeslanka indywidualności realizuje sie w przypadku dziel technicznych, jak i o to, jakie jest samo znaczenie indywidualnego charakteru utworu w polskim prawie autorskim.

The paper is aiming to determinate the extent of the north eastern arm of Kozłowicka buried valley on the grounds of own re search by means of electrical resistivity tomography- ERT and avail able archival researches. On the Hydro-geological map of Poland, Żyrardów sheet (Felter and Nowicki, 1998a, b) Kozłowicka buried valley was differentiated as an individual hydro-geological unit. The results of the anal y sis show that the ex tent of the structure, defined by its up per boundary, differs significantly from the one suggested on the sheet of Hydrogeological map of Poland. Since there was no data avail able in the north eastern part of the dis cussed arm of Kozłowicka buried valley, the northern boundary was defined only based on avail able geoelectrical sounding profiles (Czerwiñska, 1988; Topolewska, 2015). In order to confirm suggested solution, geoelectrical re search by means of electrical resistivity tomography (ERT) was con ducted. The measurements were per formed along 3 pro files located in the area of interest. The authors would like to point out the need of the us age of ERT in map ping and studying buried structures that might be ground water reservoirs. As a result, one obtains quasi-continuous image of electrical resistivity of the subsurface. Due to the contrast of electrical properties of sediments, it is possible to determine upper and bottom surfaces of buried structures, formed within glacial deposits.

Octulene, the higher homologue of kekulene and septulene, was synthesized using the fold-in method. This new hydrocarbon macrocycle contains a large 24-membered inner circuit, which is peripherally fused to 24 benzene rings. Such an arrangement produces considerable hyperbolic distortion of the π-conjugated surface. The consequences of distortion in octulene were explored using photophysical methods, which revealed a reduced electronic band gap and greater flexibility of the π system. Octulene contains a functional cavity with a diameter larger than 5.5 A that is capable of efficiently binding the chloride anion in a nonpolar solvent (Ka= 2.2(4)×104 m−1, 1 % dichloromethane (DCM) in benzene). The octulene–chloride interaction is stabilized by eight weak C(sp2)H⋅⋅⋅Cl bonds, providing the first example of a hydrocarbon-based anion receptor.

The paper presents spatial analysis and numerical methods to describe the hydrodynamic and hydrochemical conditions in a groundwater system. The research was conducted in the northern part of the Białystok High Plane, eastern Poland, within a Quaternary multi-aquifer system. Spatial analysis was used for imaging the quasi-continuous structure of the system based on a discrete set of hydrogeological data. A high-resolution regional flow model was used to identify the groundwater discharge and discharge zones of the individual aquifers. Calculations have shown a marked asymmetry of the flow system. Deeply incised river valleys in the Niemen River basin more strongly affect the groundwater than the discharge zones in the valleys of the Vistula River basin. As a result, the underground watershed in deeper aquifers is clearly shifted westward in relation to the morphological watershed. The hydrodynamic conditions of the system determined by numerical methods were used to identify the points along the groundwater flow-path for the hydrochemical study. It was the basis for the identification of points located along the groundwater flow direction, which were used in the hydrochemical study. Computational schemes of water solution models were calculated for the quasi-equilibrium state of chemical reactions between the solution and the solid and gaseous phases. Presentation of the chemical reactions allowed determining the origin of changes in the concentrations of individual components dissolved in groundwater. It was found that kaolinitization, i.e. chemical weathering of feldspars and plagioclases is the basic process that most affects the groundwater chemistry.

A family of bandgap-tunable pyrroles structurally related to rylene dyes was computationally designed and prepared using robust, easily scalable chemistry. These pyrroles show highly variable fluorescence properties and can be used as building blocks for the synthesis of electron-deficient oligopyrroles. The latter application is demonstrated through the development of π-extended porphyrins containing naphthalenediamide or naphthalenediimide units. These new macrocycles exhibit simultaneously tunable visible and near-IR absorptions, an ability to accept up to 8 electrons via electrochemical reduction, and high internal molecular free volumes. When chemically reduced under inert conditions, the most electron-deficient of these macrocycles revealed reversible formation of eight charged states, characterized by remarkably red-shifted optical absorptions, extending beyond 2200 nm. Such features make these oligopyrroles of interest as functional chromophores, charge-storage materials, and tectons for crystal engineering.

Two-dimensionally extended, polycyclic heteroaromatic molecules (heterocyclic nanographenes) are a highly versatile class of organic materials, applicable as functional chromophores and organic semiconductors. In this Review, we discuss the rich chemistry of large heteroaromatics, focusing on their synthesis, electronic properties, and applications in materials science. This Review summarizes the historical development and current state of the art in this rapidly expanding field of research, which has become one of the key exploration areas of modern heterocyclic chemistry.

The purpose of this study was to investigate 3,4-diarylpyrrole electropolymerization and simultaneous or subsequent intramolecular oxidative coupling leading to poly(phenanthropyrrole). Small amounts of π-conjugated products were obtained only under the conditions of increased concentration of the monomer and increased rate of potential sweep, which enabled both processes − monomer oxidation and deprotonation of the σ-dimer. The combined electrochemistry, UV-vis-NIR, ESR and TD-DFT results show, that the α,α'-coupling of 3,4-diarylpyrrole derivatives is inhibited by the stability of the σ-dimer dication, inhibition of the deprotonation and the reversal of the σ bond formation resulting in regeneration of the monomer. The addition of pyridine did not result in σ–dimer deprotonation in 2- and 2'-position.

Chiral heteroaromatic propellers based on radially π-extended hexapyrrolohexaazacoronenes were obtained in a concise synthesis from suitably functionalized donor-acceptor monopyrroles. To overcome steric hindrance, a new cyclodehydrogenation method was developed, and it uses bromine electrophiles as oxidative coupling agents instead of the commonly employed high-potential oxidants. The new reaction offers high yields of propeller-shaped targets, even for electron-deficient precursors, and shows electrophile-dependent stereoselectivity, with N-bromosuccinimide and dibromine yielding, respectively D6 - and C2 -symmetric products. The propeller azacoronenes are chiral and can be separated into configurationally stable enantiomers. In addition to providing steric bulk, peripheral functionalization considerably affects the electronic properties of the propellers, which exhibit reduced optical and electrochemical band gaps, and a more clearly defined electroreduction behavior.

[4]Chrysaorene, a fully conjugated carbocyclic coronoid, is shown to be a low-bandgap π-conjugated system with a distinct open-shell character. The system shows good chemical stability and can be oxidized to well-defined radical cation and dication states. The cavity of [4]chrysaorene acts as an anion receptor toward halide ions with a particular selectivity toward iodides (Ka = 207 ± 6 M–1). The interplay between anion binding and redox chemistry is demonstrated using a 1H NMR analysis in solution. In particular, a well-resolved, paramagnetically shifted spectrum of the [4]chrysaorene radical cation is observed, providing evidence for the inner binding of the iodide. The radical cation–iodide adduct can be generated in thin solid films of [4] chrysaorene by simple exposure to diiodine vapor.

This review summarizes recent advances in the chemistry of curved aromatic molecules. By focusing on the key accomplishments of the last decade, we provide a general overview of synthetic methods capable of efficient induction of internal strain in π-conjugated frameworks. The review is structured according to the topology change involved in the strain-inducing reaction step (cyclizations, eliminations, ring expansions and contractions), and highlights the striking diversity of structures achievable with modern synthetic methodology.