CuAAC and RuAAC with Alkyne-functionalised Dihydroazulene Photoswitches and Determination of Hammett σ-Constants for Triazoles

Dihydroazulene (DHA)–vinylheptafulvene (VHF) photoswitches have attracted attention as potentially useful components in molecular electronics. The π-conjugated dihydroazulene system is a rigid structure and can be strategically functionalised to place handles for further elaboration. Here we show that alkyne-functionalised dihydroazulenes can be subjected to copper and ruthenium catalysed azide–alkyne cycloadditions (CuAAC and RuAAC) with tolylazide, furnishing 1,4- and 1,5-disubstituted triazoles. The rates of ring-closure of the corresponding vinylheptafulvenes were compared with those of reference systems, which allowed determination of Hammett substituent constants (meta and para) for N-tolyl-substituted 1,2,3-triazoles.

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Polarographic and spectrophotometric behaviour of some N-p-phenyl substituted benzamidines

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19912791 ◽

1991 ◽

Vol 56 (12) ◽

pp. 2791-2799 ◽

Cited By ~ 1

Author(s):

Juan A. Squella ◽

Luis J. Nuñez-Vergara ◽

Hernan Rodríguez ◽

Amelia Márquez ◽

Jose M. Rodríguez-Mellado ◽

...

Keyword(s):

Spectrophotometric Study ◽

Absorption Bands ◽

Electrochemical Parameters ◽

Wide Ph Range ◽

Group A ◽

Substituent Constants ◽

Ph Range ◽

The Waves

Five N-p-phenyl substituted benzamidines were studied by DC and DP polarography in a wide pH range. Coulometric results show that the overall processes are four-electron reductions. Logarithmic analysis of the waves indicate that the process are irreversible. The influence of the pH on the polarographic parameters was also studied. A UV spectrophotometric study was performed in the pH range 2-13. In basic media some variations in the absorption bands were observed due to the dissociation of the amidine group. A determination of the pK values was made by deconvolution of the spectra. Correlations of both the electrochemical parameters and spectrophotometric pK values with the Hammett substituent constants were obtained.

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Determination of the Hammett σ-Constants for the Picryl Group

The Journal of Organic Chemistry ◽

10.1021/jo01012a523 ◽

1965 ◽

Vol 30 (1) ◽

pp. 319-320 ◽

Cited By ~ 2

Author(s):

Howard E. Ruskie ◽

Lloyd A. Kaplan

Keyword(s):

Hammett Σ Constants

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ChemInform Abstract: DETERMINATION OF POSITIONAL WEIGHTING FACTORS FOR THE SWAIN AND LUPTON SUBSTITUENT CONSTANTS F AND R

Chemischer Informationsdienst ◽

10.1002/chin.197615071 ◽

1976 ◽

Vol 7 (15) ◽

pp. no-no

Author(s):

S. G. WILLIAMS ◽

F. E. NORRINGTON

Keyword(s):

Weighting Factors ◽

Substituent Constants

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New Investigation on the Geometry of the Contact in Gear Generation

Volume 4: 9th International Power Transmission and Gearing Conference, Parts A and B ◽

10.1115/detc2003/ptg-48087 ◽

2003 ◽

Author(s):

Marco Gabiccini ◽

Massimo Guiggiani ◽

Francesca Di Puccio

Keyword(s):

Reference Frame ◽

Relative Position ◽

Geometric Approach ◽

Gear Ratio ◽

Reference Systems ◽

Geometric Properties ◽

Envelope Surface ◽

Enveloping Surface ◽

Contact Matrix

Based on a recently developed geometric approach to the theory of gearing that does not make use of any reference systems [1], this paper presents some useful relations between the geometric properties of the enveloping surface and those of its envelope. Treating vectors as such, that is without expressing their components in any reference systems, it is possible to obtain compact expressions for the coefficients of the first and second fundamental forms of the envelope surface. These coefficients show to be central in the determination of the contact matrix between mating surfaces. Moreover, since this approach is coordinate free, it is valid regardless of the reference frame actually employed to perform calculations and allows a, hopefully, clearer understanding of the roles played by the intrinsic geometric properties of the enveloping surface, the relative position of the gear axes and the gear ratio.

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A Terrestrial Reference System Consistent with WGRS

International Astronomical Union Colloquium ◽

10.1017/s025292110006379x ◽

1991 ◽

Vol 127 ◽

pp. 211-214 ◽

Cited By ~ 2

Author(s):

C. Boucher ◽

Z. Altamimi

Keyword(s):

Reference System ◽

Terrestrial Reference Frame ◽

Reference Systems ◽

International Earth Rotation Service ◽

Earth Orientation Parameters ◽

Terrestrial Reference System ◽

Definition Of ◽

Orientation Parameters ◽

Evolution With Time

AbstractThe IAU and IUGG has jointly established in 1988 an International Earth Rotation Service (IERS) which is in charge of the realization of conventional celestial and terrestrial reference systems, together with the determination of earth orientation parameters which connect them.The theoretical definition of the terrestrial reference system which is realized by IERS through a conventional terrestrial reference frame formed by SLR, LLR, VLBI and GPS stations is presented. In particular its origin, scale, orientation and evolution with time are reviewed, taking into account relativistic and deformation effects.

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