Magnetic and Sorption Properties of Supramolecular Systems Based on Pentanuclear Copper(II) 12‐Metallacrown‐4 Complexes and Isomeric Phthalates: Structural Modeling of the Different Stages of Alcohol Sorption

Metathesis of the perchlorate anions in [Cu 5 (ahpha) 4 ](ClO 4 ) 2 · 4H 2 O, where ahpha 2– is the dianion of 3‐amino‐3‐hydroximinopropane hydroxamic acid, with m ‐ and p ‐phthalates resulted in formation of [Cu 5 (ahpha) 4 ( m ‐C 8 H 4 O 4 )(H 2 O)] · 9H 2 O ( 1 ), [Cu 5 (ahpha) 4 ( m ‐C 8 H 4 O 4 )(H 2 O)] · 2MeOH · DMF ( 1a ) and [Cu 5 (ahpha) 4 ( p ‐C 8 H 4 O 4 )(H 2 O) 2 ] 2 · 14H 2 O ( 2 ). Molecules in the structures of 1 , 1a and 2 are held together by noncovalent interactions, and the lattices contain voids filled with water molecules. Compounds 1 and 1a differ in the mode of m ‐phthalate coordination, solvent type, and crystal lattice content. Desolvated 1 and 2 sorb gaseous MeOH and EtOH. Whereas the MeOH sorption capacity was very similar for 1 and 2 (about 0.14 cm 3 /g at PP S –1 = 0.9, where P is the current methanol pressure and P S the saturation vapor pressure of methanol at 293 K), the capacity of 2 to sorb EtOH was about 1.5 times as high as that of 1 . To a certain extent, the structures of 1 and 1a can be considered as models of compounds that can form at different stages during alcohol sorption by desolvated 1 . The χ M T vs. T data for 1 and 2 could be fitted with a model based on the Hamiltonian H (Cu II 5 ) = –2 J 1 (S 1 · S 2 + S 1 · S 3 + S 1 · S 4 + S 1 · S 5 ) – 2 J 2 (S 2 · S 5 + S 2 · S 3 + S 3 · S 4 + S 4 · S 5 ), where S 1 represents the spins of the central Cu II ions and S 2 –S 4 correspond to the spins of the peripheral Cu II ions. The best fits corresponded to J 1 = –129(3) cm –1 , J 2 = –66(1) cm –1 and zJ′ = –2.5(2) cm –1 at g Cu = 2.12(1) for 1 , and J 1 = –163(3) cm –1 , J 2 = –78(1) cm –1 and zJ′ = –1.5(1) cm –1 at g Cu = 2.05(1) for 2 .