Crystalline multicomponent compounds involving hexaammine cobalt( iii ) cations

Abstract

A new series of multicomponent compounds containing the cation [Co(NH3)6]3+ and various organic N-, N,O-, and O-donor moieties has been synthesized and crystallized. The series involves [Co(NH3)6]Cl3·2(phen)·3H2O (1), [Co(NH3)6](Hbdc)(bdc)·3H2O (2), [Co(NH3)6]Cl2(Hpht)·3H2O (3), [Co(NH3)6]Cl(Hpht)2·3H2O (4), [Co(NH3)6]Cl(2,3-pdc)·H2O (5), [Co(NH3)6]11[Co(2,5-pdc)3]8Cl·84H2O (6), [Co(NH3)6][Co(3,5-pdc)2(H2O)4]Cl·3H2O (7), [Co(NH3)6]Cl(sb)·4H2O (8), and [Co(NH3)6]2(sb)3·EtOH·2.5H2O (9) (where phen = 1,10-phenanthroline, H2bdc = diphenyl-4,4′-dicarboxylic acid, H2pht = o-phthalic acid, H2pdc = 2,3-/2,5-/3,5-pyridinedicarboxylic acid, H2sb = 4-sulfobenzoic acid). Single crystal X-ray diffraction studies have revealed that in these compounds the [Co(NH3)6]3+ cation serves as a building block for the incorporation of various anions/molecules and promotes the formation of multicomponent compounds with extended charge-supported networks between cations and anions and others such as H-bonds between charged⋯neutral and neutral⋯neutral components as well as π–π stacking interactions. In addition to the [Co(NH3)6]3+ cations, compounds 1–9 contain in changing composition Cl−, deprotonated phthalate, diphenyldicarboxylate, pyridinedicarboxylate, and sulfonate anions or complex [Co(2,5-pdc)3]4− and [Co(3,5-pdc)2(H2O)4]2− anions, as well as neutral 1,10-phenanthroline and ethanol and water molecules as components of the crystallization. Hirshfeld surface analysis was also performed to discuss the strength of hydrogen bonds and to quantify the inter-contacts. Energy decomposition analysis of the intermolecular interaction energy was performed using the SAPT method to study the non-covalent bonding interactions of [Co(NH3)6]3+ cations with mono-, dianions and neutral molecules, and it was found that the calculated bonding energy for compound 1 is minimal. Compounds 1–9 were tested in vitro against Rhizobium (Agrobacterium) vitis, an oncogenic bacterium that causes tumor formation in plants. Compound 1, comprising hexaammine cobalt(III) chloride and 1,10-phenanthroline, showed the highest inhibitory potential and is thus qualified for an application against bacterial cancer in plants.