Abstract
The title compound, di-aqua-[tris-(2-amino-eth-yl)amine]-nickel(II) hexa-aqua-nickel(II) bis-(sulfate), [Ni(C6H18N4)(H2O)2][Ni(H2O)6](SO4)2 or [Ni(tren)(H2O)2][Ni(H2O)6](SO4)2, consists of two octa-hedral nickel complexes within the same unit cell. These metal complexes are formed from the reaction of [Ni(H2O)6](SO4) and the ligand tris-(2-amino-eth-yl)amine (tren). The crystals of the title compound are purple, different from those of the starting complex [Ni(H2O)6](SO4), which are turquoise. The reaction was performed both in a 1:1 and 1:2 metal-ligand molar ratio, always yielding the co-precipitation of the two types of crystals. The asymmetric unit of the title compound, which crystallizes in the space group Pnma, consists of two half NiII complexes and a sulfate counter-anion. The mononuclear cationic complex [Ni(tren)(H2O)2]2+ comprises an Ni ion, the tren ligand and two water mol-ecules, while the mononuclear complex [Ni(H2O)6]2+ consists of another Ni ion surrounded by six coordinated water mol-ecules. The [Ni(tren)(H2O)2] and [Ni(H2O)6] subunits are connected to the SO4 2- counter-anions through hydrogen bonding, thus consolidating the crystal structure.
Highlights
The title compound, diaqua[tris(2-aminoethyl)amine]nickel(II) hexaaquanickel(II) bis(sulfate), [Ni(C6H18N4)(H2O)2][Ni(H2O)6](SO4)2 or [Ni(tren)(H2O)2][Ni(H2O)6](SO4)2, consists of two octahedral nickel complexes within the same unit cell
The asymmetric unit of the title compound, which crystallizes in the space group Pnma, consists of two half NiII complexes and a sulfate counteranion
The mononuclear cationic complex [Ni(tren)(H2O)2]2+ comprises an Ni ion, the tren ligand and two water molecules, while the mononuclear complex [Ni(H2O)6]2+ consists of another Ni ion surrounded by six coordinated water molecules
Summary
Tris(2-aminoethyl)amine (tren) has been used extensively as an ancillary tripodal ligand for capping transition metals to form mononuclear and polynuclear complexes. Metal complexes with a variety of ligands in which tren is coordinating to the metal center have been proposed for applications in catalysis (Ruffin et al, 2017), sensors, and as precursors of bioinorganic reactions (Sakai et al, 1996). Ni(tren) complexes have been proposed for applications in biological systems (Salam & Aoki, 2001) or as a model to study enantioselective synthesis or asymmetric catalysis (Rao et al, 2009), and as coordination polymers in magnetism, electrical conductivity and ion exchange (Park et al, 2001; Tanase et al, 1996). Ni(tren) complexes have been proposed for applications in biological systems (Salam & Aoki, 2001) or as a model to study enantioselective synthesis or asymmetric catalysis (Rao et al, 2009), and as coordination polymers in magnetism, electrical conductivity and ion exchange (Park et al, 2001; Tanase et al, 1996). [Ni(tren)(H2O)2] was reported previously (Chen et al, 2001; Pedersen et al, 2014); to our knowledge, this is the first report of it co-crystallizing with the hexaaquo nickel complex [Ni(H2O)6](SO4)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
