Discotic liquid crystals of transition metal complexes. Part 32.1 Synthesis and liquid-crystalline properties of doubledeckers and tripledeckers based on cerium complexes of bis- and tetrakis(3,4-dialkoxyphenyl)porphyrinElectronic supplementary information (ESI) available: yields, elemental analysis data and electronic absorption spectral data. See http://www.rsc.org/suppdata/jm/b1/b109998c/

Novel sandwich-type doubledecker and tripledecker cerium complexes, bis[5,15-bis(3,4-dialkoxyphenyl)porphyrinato]cerium(IV) (2: [(CnO)4BPP]2Ce; n = 14), bis[5,10,15,20-tetrakis(3,4-dialkoxyphenyl)porphyrinato]cerium(IV) (5: [(CnO)8TPP]2Ce; n = 8,10,12,14,16,18), and tris[5,10,15,20-tetrakis(3,4-dialkoxyphenyl)porphyrinato]cerium(IV) (6: [(CnO)8TPP]3Ce2; n = 10), have been synthesized by using the corresponding metal free derivatives, 5,15-bis(3,4-dialkoxyphenyl)porphyrin (1: (CnO)4BPPH2) and 5,10,15,20-tetrakis[3,4-bis(octadecyloxy)phenyl]porphyrins (4: (CnO)8TPPH2) which were previously reported to show a discotic lamellar(DL) mesophase. The mesophase structures of all these sandwich-type cerium complexes have been characterized in detail by microscopic observation, DSC measurements and temperature-dependent X-ray diffraction studies. We have investigated the critical molecular structure changing from lamellar mesophase-showing porphyrins to columnar mesophase-showing ones. We found that these sandwich-type multideckers may exhibit a columnar mesophase, when the central core is substituted by more than twelve alkoxy chains.