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Tetramethoxy resorcinarens as platforms for fluorescent and halogen bonding systems
No full textThe synthesis and characterization of new tetramethoxy resorcinarene
derivatives are described. The new compounds are obtained and characterized
in solution and solid state, along with halogen bonded networks. In the coming
pages the structural and photophysical properties of newly synthesized
tetramethodxy resorcinarene derivatives will be presented.
A previously unknown derivative of the tetramethoxy resorcinarene
platform, methyl tetramethoxy resorcinarene, was synthesized completing the
family of tetramethoxy resorcinarenes. Methyl C1- and ethyl C2-tetramethoxy
resorcinarenes were used as platforms for the syntheses of five different
pyridine and benzyl functionalized resorcinarene tetrapodands, and for the
crown-ether bridged benzofuran resorcinarene derivative. The structural
properties of these compounds were studied in solution by NMR spectroscopy
and in the solid state by X-ray crystallography. Only one carbon difference in
the lower rim alkyl groups, methyl vs. ethyl, was observed to affect the
dynamic behavior of resorcinarene podands in solution. In the solid state,
methyl tetramethoxy resorcinarene obeyed compact “brick”-like packing made
possible by the small methyl group at the lower rim.
The pyridine functionalized resorcinarene podands were used in the
construction of solid state halogen bonded architectures with halobenzene
linkers. The structural characteristics of the resorcinarene scaffold and the
podand arms allowed the formation of multidimensional networks showing
potentially porous properties. In solution, although no formation of larger
assemblies were observed, halogen bonding between resorcinarenes and the
linkers was confirmed; and the observed interactions were supported by
computational methods.
In the synthesis of crown bridged resorcinarenes, a side product was
isolated that contained an unusual benzofuran fused macrocyclic structure. The
modified macrocycle had characteristic fluorescence properties and the study
showed that emission/excitation matrix spectroscopy is a valid tool for
structure analysis in solution.unknown accessibilityei tietoa saavutettavuudest
Resorsinareenien metallikompleksit
No full textTämän pro gradu -tutkielman kirjallisuusosa käsittelee resorsinareenien metallikomplekseja. Tarkastelussa on keskitytty erityisesti resorsinareenien metallikompleksien rakenteeseen ja koordinaatiogeometriaan. Tutkielma on jaoteltu siirtymä- ja alkalimetalleihin sitoutuviin resorsinareeneihin, ja nämä on jaoteltu vielä tarkemmin resorsinareenien mukaan.
Kokeellisen osan tarkoituksena oli syntetisoida terpyridiinifunktionalisoitu resorsinareeni, joka pystyy muodostamaan metallikomplekseja. Aromaattiset amiinit ovat typpiatomiensa takia mielenkiintoisia substituenttiryhmiä. Yhdisteen terpyridiinisillat ovat hyviä koordinoitumaan useisiin eri metalleihin, kuten sinkkiin ja kupariin, juuri typpiatomiensa ansiosta.unknown accessibilityei tietoa saavutettavuudest
A perspective to resorcinarene crowns
No full textIn this report, we have summarized different synthesis methods of the resorcinarene crowns, discussed their
structural and complexation properties together with the possible application aspects.peerReviewe
Influence of lower rim C-methyl group on crystal forms and metal complexation of resorcinarene bis-crown-5
No full textC-methyl resorcinarene bis-crown-5 (1) with pendant methyl groups at the lower rim was
prepared and crystallized in various solvent mixtures with and without selected metal salts.
The crystal structures of two polymorphic forms of unsolvated 1 (1-I and 1-II), three solvates
(acetonitrile, chloroform and dichloromethane-methanol), and three metal complexes with
silver and cesium salts were obtained. The lower rim methyl groups and the block shape of the
host promote crystal packing in brick-wall type assemblies, in which the binding cavities are
efficiently filled by the crown bridges. Thus, solvents are found in the interstitial space or
coordinated to the crown bridges on top of the cavity, whereas more strongly binding metal
cations are able to occupy the cavity. The chloroform solvate proved to be a relatively labile
crystal form, which transformed to unsolvated form (1-I) over time. Resorcinarene monocrown-5
(2) was obtained as a minor product of the bridging reaction. Two solvate structures
(acetonitrile and chloroform-water) of 2 are also reported, providing an example of the effect
of the missing crown bridge on the solvate structures.peerReviewe
The Effect of Halogen Bonding on the Packing of Bromine Substituted Pyridine and Benzyl Functionalized Resorcinarene Tetrapodands in the Solid State
No full textThe synthesis and characterization of new bromine-substituted pyridine and benzyl functionalized tetramethoxy resorcinarene tetrapodands are described and their solid-state structural properties and interactions were studied by single crystal X-ray crystallography. Three different crystal structures were obtained for the pyridine derivative and one for the benzyl derivative, which revealed that the interactions of the bromine substituent have an explicit effect on the crystal packing of the resorcinarene molecules. One of the structures obtained had very interesting halogen–halogen interactions with the same geometry as is generally found for compounds used in nonlinear optical studies.peerReviewe
4,4-Difluoro-2,3;5,6-bis(tetramethylene)-4-bora-3a,4a-diaza-s-indacene (LD540)
No full textThe title compound, C18H21BF2N2, is a lipophilic dye based on
a BODIPY fluorophore backbone, which was developed for
microscopic imaging of lipid droplets; the molecule has a
planar BODIPY core [dihedral angle between the pyrrole
rings = 2.3 (3)] and two tetramethylene substituents at the
2,3- and 5,6-positions in a half-chair conformation. One of the
tetramethylene substituents is disordered over two two sets of
sites with site occupancies of 0.5. In the crystal, pairs of C—
HF interactions link the molecules into inversion dimers.
Neighbouring dimers are linked by further C—HF interactions,
forming an infinite array. C—H and –
[centroid–centroid distance = 4.360 (3) A˚ ] interactions are
observed between the BODIPY core and the tetramethylene
substituents of neighbouring dimer pairs.peerReviewe
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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