Carbon-rich molecules: synthesis and isolation of aryl/heteroaryl terminal bis(butadiynes) (HC[triple bond]C-C[triple bond]C-Ar-C[triple bond]C-C[triple bond]CH) and their applications in the synthesis of oligo(arylenebutadiynylene) molecular wires

The synthesis, isolation and characterisation are reported for a series of terminal aryl/heteroaryl bis(butadiynes) (HCtriple bond]C-Ctriple bond]C-Ar-Ctriple bond]C-Ctriple bond]CH) 4a-e including the X-ray molecular structure of the 2,5-pyridylene derivative 4d; compound 4a and the mono-protected analogue HCtriple bond]C-Ctriple bond]C-Ar-Ctriple bond]C-Ctriple bond]C-C(OH)Me2] 5a serve as convenient precursors for the synthesis of highly-conjugated oligo(arylenebutadiynylene)s.