S1 Supplementary Information Ferrocenyl helquats: unusual chiral organometallic nonlinear optical chromophores Laura E. R. Buckley, a Benjamin J. Coe, a Daniela Rusanova, a Sergio Sánchez, a Michael Jirásek, b Vishwas D. Joshi, b Jan Vávra, b Dushant Khobragade, b Lubomír Pospíšil, c Šárka Ramešová, c Ivana Císařová, d David Šaman, b Radek Pohl, b Koen Clays, e Nick Van Steerteghem, e Bruce S. Brunschwig f and Filip Teplý b a School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK. b The Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo n. 542/2, 166 10 Prague 6, Czech Republic. c J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, 18223 Prague 8, Czech Republic d Department of Inorganic Chemistry, Charles University, Hlavova 2030/8, 128 43 Prague 2, Czech Republic e Department of Chemistry, University of Leuven, Celestijnenlaan 200 D, B-3001, Belgium f Molecular Materials Research Center, Beckman Institute, MC 139-74, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States 1. Crystallographic Study ································································· S2 2. Spectroscopic Studies··································································· S3 3. Electrochemical Studies ······························································ S12 4. Theoretical Studies ···································································· S14 Electronic Supplementary Material (ESI) for Dalton Transactions. This journal is © The Royal Society of Chemistry 2017