M. and M. )-1·zn, OAc) 2 : 1 H NMR (400 MHz, CD 2 Cl 2 ) ?? 2

. Hz, 28 (2H, d, J = 9, vol.7

. Hz,

;. Hz, D. 2h, and J. =. , 0 Hz), 8.68 (2H, d, J = 9.0 Hz) ppm. 13 C: After experiment overnight in 500 MHz the signals were not large enough to give an accurate set of peaks

. Mp, , pp.162-167

D. B. Amabilino, 669-670; b) Amabilino, D. B. Chirality at the Nanoscale. Nanoparticles, Surfaces, Materials and more, Chem. Soc. Rev, vol.38, 2009.

B. L. Feringa, W. R. Browne, and B. L. Feringa, 6635-6652; b) Canary, J. W. Redox-triggered chiroptical molecular switches, Molecular Switches, vol.72, pp.121-180, 2007.

V. Balzani, A. Credi, and M. Venturi, Molecular Devices and Machines. Concepts and Perspectives for the Nanoworld, 2008.
DOI : 10.1088/2058-7058/17/11/34

L. You, D. Zha, and E. V. Anslyn, Recent Advances in Supramolecular Analytical Chemistry Using Optical Sensing, Chem. Rev, vol.115, p.7840, 2015.

J. W. Canary, S. Mortezaei, and J. Liang, Transition metal-based chiroptical switches for nanoscale electronics and sensors, Coord. Chem. Rev, vol.254, pp.2249-2266, 2010.
DOI : 10.1016/j.ccr.2010.03.004

D. Zhao, T. M. Neubauer, B. L. Feringa, M. Vlatkovic, B. S. Collins et al., Dynamic control of chirality in phosphine ligands for enantioselective catalysis. Nature Comm. 2015, 6, 6652; see also reviews: b), Chem. Eur. J, vol.22, pp.1247-1277, 2012.

C. Chen and Y. Shen, Helicene Chemistry -From Synthesis to Applications, Rajca, A. Miyasaka, M. In Functional Organic Materials, pp.547-581, 2007.

Y. Shen and C. Chen, Helicenes: Synthesis and Applications, Chem. Rev, vol.112, pp.1463-1535, 2011.
DOI : 10.1021/cr200087r

M. Gingras, N. Saleh, C. Shen, and J. Crassous, Helicene-based transition metal complexes: synthesis, properties and applications, Chem. Soc. Rev, vol.42, p.3680, 2013.

H. Isla and J. Crassous, Helicene-based chiroptical switches, C. R. Chimie, vol.19, pp.39-49, 2016.
DOI : 10.1016/j.crci.2015.06.014

URL : https://hal.archives-ouvertes.fr/hal-01254818

N. Berova, P. L. Polavarapu, and K. Nakanishi, Comprehensive Chiroptical Spectroscopy, vol.1, issue.2, 2012.

J. Lehn, Supramolecular Chemistry: Concepts and Perspectives. VCH: Weinheim, 1995; b) Sauvage, J.-P. Perspectives in Supramolecular Chemistry: Transition Metals in Supramolecular Chemistry, C. Organometallics. Wiley-VCH, 1999.
DOI : 10.1002/3527607439

URL : https://hal.archives-ouvertes.fr/hal-00019531

H. Brunner, H. Amouri, and M. Gruselle, Optically Active Organometallic Compounds of Transition Elements with Chiral Metal Atoms, Chirality in Transition Metal Chemistry: Molecules, Supramolecular Assemblies and Materials, vol.38, pp.302-322, 1999.

J. Crassous, 9684-9692; f) Miyake, H.; Tsukube, H. Coordination chemistry strategies for dynamic helicates: timeprogrammable chirality switching with labile and inert metal helicates, Chem. Soc. Rev, vol.38, pp.6977-6991, 2009.

E. Anger, M. Srebro, N. Vanthuyne, L. Toupet, S. Rigaut et al., Redox-active Chiroptical Switching in Mono-and Bis-Iron-EthynylCarbo[6]Helicenes Studied by Electronic and Vibrational Circular Dichroism and Resonance Raman Optical Activity, remote metal-based tuning and redox switching of the chiroptical properties of a helicene core, vol.134, pp.1673-1681, 2012.

H. Isla, M. Srebro-hooper, M. Jean, N. Vanthuyne, T. Roisnel et al., Conformational changes and chiroptical switching of enantiopure bishelicenic terpyridine upon Zn 2+ binding, Chem. Comm, vol.52, pp.5932-5935, 2016.
URL : https://hal.archives-ouvertes.fr/hal-01301464

K. Sato, . S. Harai, and A. Gayathri, Aron, I. Azahelicenes and other similar tri and tetracyclic helical molecules, Cyclophane chemistry fot the 21st century, vol.1, pp.1-10, 2002.

C. Kaes, A. Katz, M. W. Hosseini, and . Bipyridine, The Most Widely Used Ligand. A Review of Molecules Comprising at Least Two 2,2'-Bipyridine Units, Chem. Rev, vol.100, pp.3553-3590, 2000.

J. M. Fox and T. J. Katz,

K. Deshayes, R. D. Broene, I. Chao, C. B. Knobler, F. Diederich et al., Helical Chiral Pyridine N-Oxides: A New Family of Asymmetric Catalysts, Angew. Chem. Int. Ed, vol.64, pp.9708-9710, 1991.

J. Chen, B. Captain, and N. Takenaka, Helical Chiral 2,2?-Bipyridine NMonoxides as Catalysts in the Enantioselective Propargylation of Aldehydes with Allenyltrichlorosilane, Org. Lett, vol.13, pp.1654-1657, 2011.

N. Saleh, M. Srebro, T. Reynaldo, N. Vanthuyne, L. Toupet et al.,

. Chem, J. Comm-;-klívar, M. ?ámal, A. Jan?a?ík, J. Vacek et al., Asymmetric Synthesis of Diastereo-and Enantiopure Bioxahelicene 2,2?-Bipyridines, Eur. J. Org. Chem, vol.51, pp.5164-5178, 2015.

E. Negishi, Magical Power of Transition Metals: Past, Present, and Future (Nobel Lecture), Angew. Chem. Int. Ed, vol.50, pp.6738-6764, 2011.

D. A. Lightner, D. T. Hefelfinger, T. W. Powers, G. W. Frank, K. N. Trueblood et al., Absolute configuration, P*,P*)-1 means the racemic mixture of (P,P)-and (M,M, vol.94, p.1, 1972.

K. N. Solovyov and E. A. Borisevich, ) a) Autschbach, J. Computing chiroptical properties with first-principles theoretical methods: background and illustrative examples, Annu. Rev. Phys. Chem, vol.48, issue.19, pp.399-420, 2005.

J. Rebek, J. Trend, J. E. Wattley, R. V. Chakravorti, S. Rebek et al., Allosteric effects. Remote control of ion transport selectivity, J. Am. Chem. Soc, vol.101, pp.4853-4854, 1979.

J. Rebek, T. Costello, L. Marshall, R. Wattley, R. C. Gadwood et al., Allosteric effects in organic chemistry: binding cooperativity in a model for subunit interactions, Angew. Chem. Int. Ed, vol.107, pp.3635-3638, 1985.

, Metal-Ion-Driven Molecular Hinges with Adjustable Amplitude, Chem. Eur

J. Suzuki, Y. Nakamura, T. Iida, H. Ousaka, N. Yashima et al., Allosteric Regulation of Unidirectional Spring-like Motion of Double-Stranded Helicates, J. Am. Chem. Soc, vol.15, pp.4852-4859, 2009.

H. Maeda, Y. Bando, J. Kumar, T. Nakashima, T. Kawai et al., Circularly Polarized Luminescence in Chiral Molecules and Supramolecular Assemblies, Recent progress in research on stimuliresponsive circularly polarized luminescence based on ?-conjugated molecules, vol.85, pp.13488-13500, 1967.

R. Aoki, R. Toyoda, J. F. Kögel, R. Sakamoto, J. Kumar et al., Bis(dipyrrinato)zinc(II) Complex Chiroptical Wires: Exfoliation into Single Strands and Intensification of Circularly Polarized Luminescence, Switching of Circularly Polarized Luminescence by Oxophilic Interaction of Homochiral SulfoxideContaining o-OPEs with Metal Cations, vol.139, pp.13985-13988, 2017.

M. P. Mitoraj, A. Michalak, and T. Ziegler, A Combined Charge and Energy Decomposition Scheme for Bond Analysis, J. Chem. Theory Comput, vol.5, pp.962-975, 2009.

M. Srebro, J. Autschbach, M. El-sayed-moussa, M. Srebro, E. Anger et al., 455-465; c) Friese, D. H.; Hättig, C. Optical rotation calculations on large molecules using the approximate coupled cluster model CC2 and the resolution-of-the-identity approximation, Phys. Chem. Chem. Phys, vol.8, pp.5942-5951, 2012.

K. Takaishi, M. Yasui, and T. Ema, For a recent example of acid-base triggered CPL switch see, J. Am. Chem. Soc, vol.140, pp.5334-5338, 2018.

I. Alkorta, J. Elguero, and C. Roussel, A theoretical study of the conformation, basicity and NMR properties of 2,2?-, 3,3?-and 4,4?-bipyridines and their conjugated acids, Comput. Theor. Chem, vol.966, pp.334-339, 2011.

Y. Nakai, T. Mori, K. Sato, and Y. Inoue, Theoretical and Experimental Studies of Circular Dichroism of Mono-and Diazonia[6]helicenes, J. Phys. Chem. A, vol.117, pp.5082-5092, 2013.