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Among the plethora of polycyclic structures that have emerged in recent years, indenofluorenes comprise a unique class of compounds due to their potential in organic electronic systems such as OLEDs, OFETs, and OPVCs. However, the synthesis of fully conjugated indenofluorenes without bulky groups on the apical carbons under standard chemistry conditions is not easily accessible. In this regard, on-surface synthesis has appeared as a newly developing field of research, which exploits the use of well-defined solid surfaces as confinement templates to initiate and develop chemical reactions. Here, we demonstrate the successful fabrication of indeno[1,2-b]fluorene p-conjugated polymers linked via cumulene-like connections on well-defined metallic surfaces under ultra-high vacuum conditions. The structure and electronic properties of the formed polymers have been precisely characterized by scanning tunneling microscopy, noncontact atomic force microscopy and scanning tunneling spectroscopy, complemented by computational investigations, Comunidad de Madrid, Ministerio de Ciencia e Innovación, MINECO, Depto. de Química Orgánica, Fac. de Ciencias Químicas, TRUE, pub

Antiferromagnetic spintronics is a rapidly emerging field with the potential to revolutionize the way we store and process information. One of the key challenges in this field is the development of novel two-dimensional antiferromagnetic materials. In this paper, we report the first on-surface synthesis of a Co-directed metal-organic network in which the Co atoms are strongly antiferromagnetically coupled, while featuring a perpendicular magnetic anisotropy. This material is a promising candidate for future antiferromagnetic spintronic devices, as it combines the advantages of twodimensionality and metal-organic chemistry with strong antiferromagnetic order and perpendicular magnetic anisotropy.

On-surface synthesis has recently emerged as a powerful strategy to design conjugated polymers previously precluded in conventional solution chemistry. Here, an N-containing pentacene-based precursor (tetraazapentacene) is ex-professo synthesized endowed with terminal dibromomethylene (:CBr2) groups to steer homocoupling via dehalogenation on metallic supports. Combined scanning probe microscopy investigations complemented by theoretical calculations reveal how the substrate selection drives different reaction mechanisms. On Ag(111) the dissociation of bromine atoms at room temperature triggers the homocoupling of tetraazapentacene units together with the binding of silver adatoms to the nitrogen atoms of the monomers giving rise to a N-containing conjugated coordination polymer (P1). Subsequently, P1 undergoes ladderization at 200 degrees C, affording a pyrrolopyrrole-bridged conjugated polymer (P2). On Au(111) the formation of the intermediate polymer P1 is not observed and, instead, after annealing at 100 degrees C, the conjugated ladder polymer P2 is obtained, revealing the crucial role of metal adatoms on Ag(111) as compared to Au(111). Finally, on Ag(100) the loss of :CBr2 groups affords the formation of tetraazapentacene monomers, which coexist with polymer P1. Our results contribute to introduce protocols for the synthesis of N-containing conjugated polymers, illustrating the selective role of the metallic support in the underlying reaction mechanisms., Funding Agencies|European Research Council (ERC CoG ELECNANO) [766555]; Comunidad de Madrid [project QUIMTRONIC-CM] [Y2018/NMT-4783]; Ministerio de Ciencia e Innovacion [PID2019-108532GB-I00]; "Severo Ochoa" Programme for Centers of Excellence in RD (MINECO) [SEV-2016-0686]; European Unions Horizon 2020 research and innovation programme under the Marie Skodowska-Curie grant [886314]; Swedish Research Council; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]