@misc{kricheldorf_cyclic_ladder_2005, 
author={Kricheldorf, H.R.,Fritsch, D.,Vakhtangishvili, L.,Schwarz, G.},
title={Cyclic Ladder Polymers by Polycondensation of Silylated Tetrahydroxy-tetramethylspirobisindane with 1,4-Dicyanotetrafluorobenzene},
year={2005},
howpublished = {journal article},
doi = {https://doi.org/10.1002/macp.200500280},
abstract = {5,5’,6,6’-Tetra(trimethylsiloxy)4,4,4,4’-tetramethyl-1,1-spirobisindane (TTSBI),was polycondensed with 1,4-dicyanotetrafluorobenzene (DCTB) under variation of solvent,temperature, time and feed ratio. Under optimized reaction conditions, all products detectable by MALDI-TOF mass spectrometry (up to masses around 8 000 Da) proved to be cyclic ladder oligomers and polymers. In N-methylpyrrolidone and dimethylsulfoxide oddnumbered,cycles were formed in addition to the prevailing even-numbered ones. However, in sulfolane exclusively even-numbered cycles were obtained (detectable up to masses around,10 000 Da), together with even-numbered linear chains. Temperatures above 100°C enhanced,the molecular weights by side reactions. With the less reactive cyano-2,3,5,6-,tetrafluorobenzene (CTB) again cycles were formed, but their content and the conversions,were lower. Polycondensation of CTB up to 160°C and all polycondensations of,cyanopentafluorobenzene gave crosslinked products.},
note = {Online available at: \url{https://doi.org/10.1002/macp.200500280} (DOI). Kricheldorf, H.; Fritsch, D.; Vakhtangishvili, L.; Schwarz, G.: Cyclic Ladder Polymers by Polycondensation of Silylated Tetrahydroxy-tetramethylspirobisindane with 1,4-Dicyanotetrafluorobenzene. Macromolecular Chemistry and Physics. 2005. vol. 206, no. 22, 2239-2247. DOI: 10.1002/macp.200500280}}