Novel Layering of Aqua and Imidazolidinyl Phenolate Bridged Cationic [CuII 2(μ-L)(μ-H2O) 3H2O]2 Units Over CuINCS Based One-Dimensional Anionic Parallel Chains as Diamagnetic Coordination Framework Host

The hetero valence copper-based metal-organic framework structure {[CuII2(μ-L)(μ-H2O) 3H2O][CuI- (1,3-NCS)2]}n (2) was constructed from the aqua-bridged [Cu2] complex [Cu2(μ-L)(μ-H2O)]ClO4 3 1.5H2O (1 3 1.5H2O) of the N4O3 coordinating heptadentate imidazolidinyl phenolate Schiff base ligand, H3L (2-(20hydroxyphenyl)-1,3-bis[4-(2-hydroxyphenyl)-3-azabut-3-enyl]-1,3-imidazolidine). Thiocyanate coordination induced aqua bridge cleavage and reductive extrusion lead to the formation of Cu(NCS)2 - anions as a molecular building block and generation of one-dimensional (1D) anionic chains as an extended coordination framework host in 2 and quantitatively replace all the ClO4 - ions from 1 3 1.5H2O via anion metathesis. Once formed these chains trap the original [Cu2] cationic units in a layer. The copper atoms of 2 are in a distorted square-pyramidal environments around copper ions and are held together by phenolate, imidazolidinyl, and aqua bridges at 3.29 A ° intrametallic CuII 3 3 3 CuII separation. Within the anionic part the presence of two “symmetric” end-to-end thiocyanate bridges with CuI-SCN and CuI-NCS distances of 2.61 A ° (av.) and 1.924 A ° (av.), respectively, results in a CuI 3 3 3 CuI separation of 5.51 A ° (av.) within the linear chain. The cationic part of 2 exhibits a weak ferromagnetic exchange interaction (J/kB=þ13.0(5) K or J=þ9.0 cm-1 and g=2.25(1)) between the two CuII ions (S=1/2) and implies that the complex possesses an ST=1 spin ground state in good agreement with theMvs H data below 8 K