Symmetrical 1,3-diynes were obtained in quantitative yields using the copper(II) acetate catalyzed homocoupling of terminal alkynes in the presence of a stoichiometric amount of piperidine at 25 °C under aerobic conditions. We also accomplished facile syntheses of unsymmetric 1,3-diynes by heterocoupling terminal alkynes in very good yields under the reported reaction conditions. © Georg Thieme Verlag Stuttgart.

Venkitasamy Kesavan

Department Of Biotechnology

COPPER (II)

HETEROCOUPLING

HOMOCOUPLING

PIPERIDINE

SYMMETRIC 1,3-DIYNES

TERMINAL ALKYNE

UNSYMMETRIC 1,3-DIYNES

catalysis

Copper

Acetylene

1,3 DIYNE DERIVATIVE

alkyne derivative

Copper acetate

unclassified drug

aerobic metabolism

article

chemical modification

oxidation

reaction analysis

stoichiometry

synthesis

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Synthesis

The present work describes the photophysical properties of a group of butadiyne bridged pyrene-phenyl molecular hybrids having different substitutions with varying donor and acceptor abilities. In addition to emission from the locally excited (LE) state originating from the pyrene moiety, intramolecular charge transfer (ICT) emissions were observed in molecules with donor-acceptor character. The positions of the ICT emission maxima varied over a wide range of wavelengths (475-600 nm). Pyrene behaved as a donor when a strong acceptor group (-CN) was attached to the phenyl ring and it behaved as an acceptor when the phenyl group contained a strong donor group (-NMe2). In mixed aqueous solvents at higher percentages of water (80-99%), the derivatives showed emissions from the aggregate state in addition to the LE and ICT states. Emissions from the aggregate states of the derivatives were centred in the range 510-560 nm. The aggregate state emissions were found to originate from static excimers involving pyrene moieties. A detailed structure-property relationship of the butadiynyl derivatives was revealed in this study. This journal is © The Royal Society of Chemistry.

Faraday Discussions

On the photophysics of butadiyne bridged pyrene-phenyl molecular conjugates: Multiple emissive pathways through locally excited, intramolecular charge transfer and excimer states

The present work focuses on the current interest in diyne bridged chromophores necessitating a clearer understanding of the photophysics of such molecules. The significance of the diyne moiety in the photophysics has been investigated by synthesizing simple substituted diphenyl butadiynyl derivatives following a quick and efficient microwave assisted Eglinton coupling of terminal alkynes. Emission of the fluorophores is observed from the usual locally excited (LE) state and intramolecular charge transfer (ICT) state. Separation of pure ICT emission from pure LE emission has been carried out by Gaussian/Lorentzian curve fitting. The vibronic coupling in the local transitions appears to be confined to the normal mode involving the C-C triple bond stretching of the diyne moiety. This implies that the LE transition involves the diyne moiety, a conclusion supported by quantum chemical calculations. The resolved ICT emission follows double linear dependence on ET(30) solvent polarity scale. The important role of the diyne moiety in the photophysics of this class of molecules is clearly discernible in this study. © 2013 American Chemical Society.

Journal of Physical Chemistry A

Deciphering the photophysical role of conjugated diyne in butadiynyl fluorophores: Synthesis, photophysical and theoretical study

Green Chem.

An efficient approach to homocoupling of terminal alkynes: Solvent-free synthesis of 1,3-diynes using catalyticCu(ii) and base

The Journal of Organic Chemistry

Influence of Bases and Ligands on the Outcome of the Cu(I)-Catalyzed Oxidative Homocoupling of Terminal Alkynes to 1,4-Disubstituted 1,3-Diynes Using Oxygen as an Oxidant

Tetrahedron Letters

A mild copper-mediated Glaser-type coupling reaction under the novel CuI/NBS/DIPEA promoting system

Organic Letters

Nickel-Catalyzed Oxidative Coupling Reactions of Two Different Terminal Alkynes Using O2as the Oxidant at Room Temperature: Facile Syntheses of Unsymmetric 1,3-Diynes

European Journal of Organic Chemistry

Copper-Zeolites as Catalysts for the Coupling of Terminal Alkynes: An Efficient Synthesis of Diynes

Efficient copper(II) acetate catalyzed homo- and heterocoupling of terminal alkynes at ambient conditions

Journal	Synthesis
ISSN	00397881
Open Access	No