Helical Ni-Cluster Organic Framework Constructed from Enantiopure Lactate Derivative: Synthesis, Structure and Properties

Under hydrothermal condition, lactate derivative ( R )-4-(1- carboxyethoxy)-2-methylbenzoic acid (( R )-H 2 cma) as chiral synthon assembled with 4,4′-di(1H-imidazol-1-yl)-1,1′-biphenyl (4,4’-dib) and Ni(II) ions to obtain complex {[Ni 2 (( R )-cma) 2 (4,4’-dib) 2 (H 2 O)] ⋅ 2H 2 O} n ( HU20- R ). In complex HU20- R , carboxyl group from lactate unit of ( R )-cma 2− anion and coordinating H 2 O molecule adopt a μ 2 -coordination mode to obtain dinuclear [Ni 2 (CO 2 ) 2 (H 2 O)] 2+ cluster. ( R )-cma 2− anions and Ni(II) ions build single left-handed ( R )-cma-Ni-chain, while 4,4’-dib ligands are bridged by different Ni(II) centers to form double left-handed 4,4’-dib-Ni-chain. These helical secondary structures are further connected together to result in an 8-connected 3D framework. PXRD tests indicated that complex HU20- R has well hydro-stability. UV-vis absorption experiment confirmed that HU20- R is a semi-conducting material with strong absorption capacity for ultraviolet-visible (UV-vis) light. Additionally, electrochemical experiment revealed that HU20- R has low impedance and high charge transport capacity. Further test results confirm that HU20- R has noticeable photo-catalytic effect in photodegradation of Rhodamine B (RhB) and antiferromagnetic property.