Homochiral helical coordination polymers of metallosalen complexes with tunable pitches

Homochiral helical coordination polymers [ML] have been developed via the solvothermal reaction of the chiral di-3-pyridyl-functionalized salen complex (R,R)-(−)-N,N′-bis(3-tert-butyl-5-(3-pyridyl)salicylidene)-1,2-diaminocyclohexane (H2L) with various metal salts MX2 (MX2 = Zn(NO3)2, 1; CoCl2, 2; Ni(NO3)2, 3 and Mn(OAc)2, 4) and characterized by a variety of techniques including microanalysis, IR, thermogravimetric analysis (TGA), circular dichroism (CD) spectroscopy and powder and single-crystal X-ray diffraction. Salen L ligands link adjacent metal centers to form 1D helical chains using tetradentate N2O2 donors and pyridine groups, the pitch lengths of the helices can be tuned by metal cations.