Fluorene-containing polymers and compounds useful in the preparation thereof

A process for preparing polymers having at least three fluorene groups in its backbone, which comprises heating a mixture of compounds of the formulas:

• X—A—X (VII)
• and
• Z—A—Z (VIII)
• wherein A is independently in each occurrence a conjugated group, provided that A, in at least three occurrences, is a unit of the formulas:
• or a combination thereof;
• wherein R1 is independently in each occurrence C1-20 hydrocarbyl or C1-20 hydrocarbyl containing one or more S, N, O, P or Si atoms, C4-16 hydrocarbyl carbonyloxy, C4-16 aryl(trialkylsiloxy) or both R1 may form with the 9-carbon on the fluorene ring a C5-20 ring structure or a C4-20 ring structure containing one or more heteroatoms of S, N or O;
• R2 is independently in each occurrence C1-20 hydrocarbyl, C1-20 hydrocarbyloxy, C1-20 thioether, C1-20 hydrocarbylcarbonyloxy or cyano;
• R3 is independently in each occurrence C1-20 hydrocarbyl or C1-20 hydrocarbyl substituted with di(C1-20 alkyl)amino, C1-20 hydrocarbyloxy or C1-20 hydrocarbyl or tri(C1-10 alkyl)siloxy;
• a is independently in each occurrence 0 or 1;
• Z is independently in each occurrence
• —B(OH)2, or —B(OR4)2, wherein R4 is independently in each occurrence a C1-10 alkyl group and R5 is independently in each occurrence a C2-10 alkylene group;
• and X is independently in each occurrence a halogen moiety, under reaction conditions sufficient to form the corresponding alternating copolymer.