Structural and magnetic study of N-2, NO, NO2, and SO2 adsorbed within a flexible single-crystal adsorbent of [Rh-2(bza)(4)(pyz)](n)

The crystalline one-dimensional compound, [Rh-2(II)(bza)(4)(pyz)](n) (1) (bza=benzoate, pyz=pyrazine) demonstrates gas adsorbency for N-2, NO, NO2, and SO2. These gas-inclusion crystal structures were characterized by single-crystal X-ray crystallography as 1.1.5N(2) (298K) 1.2.5N(2) (90K), and 1-1.95 NO (90 K) under forcible adsorption conditions and 1-2 NO2 (90 K) and 1(.)3 SO2 (90 K) under ambient pressure. Crystal-phase transition to the P (1) over bar space group that correlates with gas adsorption was observed under N-2, NO, and SO2 conditions. The C2/c space group was observed under NO2 conditions without phase transition. All adsorbed gases were stabilized by the host lattice. In the N-2, NO, and SO2 inclusion crystals at 90 K, short interatomic distances within van der Waals contacts were found among the neigh-boring guest molecules along the channel. The adsorbed NO molecules generated the trans-NO... NO associated dimer with short intermolecular contacts but without the conventional chemical bond. The magnetic susceptibility of the NO inclusion crystal indicated antiferromagnetic interaction between the NO molecules and paramagnetism arising from the NO monomer. The NO, inclusion crystal structure revealed that the gas molecules were adsorbed in the crystal in dimeric form, N2O4.