Synthesis and optical characterisation of platinum(ii) poly-yne polymers incorporating substituted 1,4-diethynylbenzene derivatives and an investigation of the intermolecular interactions in the diethynylbenzene molecular precursors?

New Journal of Chemistry Pub Date: 2002-11-25 DOI: 10.1039/B206946F

Abstract

A series of 1,4-diethynylbenzene (1) derivatives, H–C[triple bond, length as m-dash]C–R–C[triple bond, length as m-dash]C–H with R?=?C6H3NH2 (2), C6H3F (3), C6H2F2-2,5 (4), C6F4 (5), C6H2(OCH3)2-2,5 (6) and C6H2(OnC8H17)2-2,5 (7) has been synthesised and their crystal structures determined by single crystal (25) or powder (6, 7) X-ray diffraction. The C[triple bond, length as m-dash]CH?πC[triple bond, length as m-dash]C hydrogen bonds dominating structure 1 are gradually replaced by C[triple bond, length as m-dash]C–H?F ones with the increase of fluorination (3?→?5), or completely replaced by C[triple bond, length as m-dash]CH?N and NH?πC[triple bond, length as m-dash]C bonds in 2, and C[triple bond, length as m-dash]CH?O in 6 and 7. The related platinum-based polymers, trans-[–Pt(PnBu3)2–C[triple bond, length as m-dash]C–R–C[triple bond, length as m-dash]C–]n (R?=?as above and C6H4,) have been prepared and characterised by spectroscopic methods and thermogravimetry, which show that the amino- and methoxy-derivatives have lowest thermal stability while the fluorinated ones exhibit increasing thermal stability with increasing fluorination. Optical spectroscopic measurements reveal that substituents on the aromatic spacer group do not create strong donor–acceptor interactions along the rigid backbone of the organometallic polymers.

Graphical abstract: Synthesis and optical characterisation of platinum(ii) poly-yne polymers incorporating substituted 1,4-diethynylbenzene derivatives and an investigation of the intermolecular interactions in the diethynylbenzene molecular precursors
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