Mono-, oligo- and polymers comprising a 2,6-azulene group and their use as charge transport materials

A mono-, oligo- or polymeric compound comprising one or more identical or different recurring units of formula I

• -[(A)a-(B)b-(C)c]- I
• wherein
• A and C are independently of each other and independently in each occurrence —CX1═CX2—, —C≡C—, optionally substituted arylene, optionally substituted heteroarylene, or is substituted or unsubstituted azulene-2,6-diyl, [2,6′]-bisazulene-6,2′-diyl, [2,2′]-bisazulene-6,6′-diyl, [6,6′]-bisazulene-2,2′-diyl, or a mirror image of one of these groups,
• X1 and X2 are independently of each other H, F, Cl or CN,
• B is independently in each occurrence azulene-2,6-diyl, [2,6′]-bisazulene-6,2′-diyl, [2,2′]-bisazulene-6,6′-diyl, [6,6′]-bisazulene-2,2′-diyl, all of which are substituted or unsubstituted, or a mirror image of one of these groups, and
• a, b and c are independently of each other 0, 1, 2 or 3, with a+b+c>0,
• with the proviso that the mono-, oligo- or polymer comprises at least two azulene-2,6-diyl groups or at least one [2,6′]-bisazulene-6,2′-diyl, [2,2′]-bisazulene-6,6′-diyl or [6,6′]-bisazulene-2,2′-diyl group.