[0001] The present invention refers to a periacene π-conjugated biradical polymer of formula (I), to a method for its synthesis and uses therefrom. The biradical π-conjugated polymers have quinoid-like character, based on periacene monomers linked through cumulene bridges featuring semiconductor behavior.
1. A π-conjugated polymer of formula (I): <img class="EMIRef" id="707917052-ib0016" /> wherein, each occurrence of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11 and R12 is independently selected from the group consisting of H, OH, I, Br, Cl, F, -CN, -NO<2>, optionally substituted C<1>-C<6> alkyl group, optionally substituted C<3>-C<7> saturated or partially saturated mono- or bicyclic aliphatic group, optionally substituted 3- to 10-membered heterocyclyl, optionally substituted C<6>-C<12> aryl, optionally substituted (C<6>-C<12>)aryl(C<1>-C<6>)alkyl, and optionally substituted 3- to 10-membered heteroaryl; each occurrence of the integer a is independently selected from 0, 1 or 2; each occurrence of the integers b1, b2, b3, b4, b5 and b6 is independently selected from 0, 1, 2, 3 or 4 wherein b1 + b2 is ≤ 4, b3 + b4 is ≤ 4, b5 + b6 is ≤ 4 and b1 + b2 + b3 + b4 + b5 + b6 > 0; c is an integer comprised between 0 and 100; each occurrence of the dashed bonds inside each monomer unit is independently a bond or absence of a bond; and each circular dot depicted next to the terminal carbon atoms represents one unpaired electron. 2. The π-conjugated biradical polymer according to claim 1, wherein at least one of b1 + b2, b3 + b4 or b5 + b6 is ≥ 2. 3. The π-conjugated biradical polymer according to any one of claims 1 or 2, wherein each occurrence of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11 and R12 is independently selected from the group consisting of H, OH, I, Br, Cl, F, -CN, -NO<2>, optionally substituted C<6>-C<12> aryl and optionally substituted 3- to 10-membered heteroaryl. 4. The π-conjugated biradical polymer according to any one of claims 1 to 3, wherein each occurrence of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11 and R12 is independently selected from the group consisting of H, OH, I, Br, Cl, F, -CN and - NO<2>. 5. A method for the synthesis of a π-conjugated polymer comprising the steps of: a. providing, on a solid substrate, at least two polycyclic aromatic hydrocarbon monomer precursor units of formula (II), <img class="EMIRef" id="707917052-ib0017" /> wherein, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11 and R12 are independently selected from the group consisting of H, OH, I, Br, Cl, F, -CN, -NO<2>, optionally substituted C<1>-C<6> alkyl group, optionally substituted C<3>-C<7> saturated or partially saturated mono- or bicyclic aliphatic group, optionally substituted 3- to 10-membered heterocyclyl, optionally substituted C<6>-C<12> aryl, optionally substituted (C<6>-C<12>)aryl(C<1>-C<6>)alkyl, and optionally substituted 3- to 10-membered heteroaryl; the integer a is selected from 0, 1 or 2; the integers b1, b2, b3, b4, b5 and b6 are independently selected from 0, 1, 2, 3 or 4 wherein b1 + b2 is ≤ 4, b3 + b4 is ≤ 4, b5 + b6 is ≤ 4 and b1 + b2 + b3 + b4 + b5 + b6 > 0; and X1, X2, X3 and X4 is independently selected from a leaving group consisting of I, Br, Cl, F, sulfonate, phosphonate, boronate, azo, silane or stannane, preferably Br; b. polymerizing the monomer precursor of the previous step on the solid substrate by dehalogenation and subsequent C-C coupling; and c. at least partially cyclodehydrogenating the polymer obtained in the previous step. 6. The method according to claim 5, wherein the surface of the solid substrate onto which the precursor of formula (II) is provided, is a surface comprising Au, Ag, Cu, Al, Pt, Pd, W, Ni, Si, Ge, GaAs, SiC, MoS<2>, BN, NaCl, CaCO<3>, silicon oxide, silicon oxynitride, hafnium silicate, nitrided hafnium silicates (HfSiON), zirconium silicate, hafnium dioxide, zirconium dioxide, aluminum oxide, copper oxide, iron oxide, strontium titanate, lead titanate, barium titanate, molybdenum diselenide, molybdenum diteluride, tungsten disulfide, tungsten diselenide, phosphorene or combinations thereof. 7. The method according to any one of claims 5 or 6, wherein the surface of the solid substrate onto which the precursor of formula (II) is provided, is a surface selected to induce a unidirectional growth orientation of the polymer. 8. The method according to any one of claims 5 to 7, wherein in step (a), the provision of the monomer precursor on a solid substrate is performed by vacuum deposition, spin coating, spray coating, dip coating, printing, electrospray deposition, laser induced desorption or a direct surface-to-surface transfer. 9. The method according to any one of claims 5 to 8, wherein steps (a), (b) and (c) are carried out at a total gas phase pressure comprised between 1×10<-1> and 1×10<-11> mbar. 10. The method according to any one of claims 5 to 9, wherein step (b) is induced by thermal activation at a temperature comprised between -100 and 500°C. 11. The method according to any one of claims 5 to 10, wherein step (c) is induced by thermal activation at a temperature which is higher than the temperature of step (b), but not higher than 600°C. 12. A π-conjugated polymer obtainable according to the method of any one of claims 5 to 11. 13. The π-conjugated polymer according to claim 12, wherein at least one of the periacene monomer units comprises at least five benzene fused rings in the transverse direction. 14. The π-conjugated polymer according to any one of claims 1 to 4, or according to any one of claims 12 or 13, wherein the polymer has a band gap comprised between 0.01 eV and 2 eV. 15. Use of the π-conjugated polymer according to any one of claims 1 to 4, or according to any one of claims 12 or 13, in semi-conductors, light-emitting devices, photovoltaics, organic field-effect transistors, photocatalysis, sensors, organic spintronics, near infrared, nonlinear optics and topological quantum memories.