title: X-ray structure and spectroscopy of novel trans-[Ni(L)(NO(3))(2)] and [Ni(L)](ClO(4))(2)·2H(2)O complexes.
abstract: Ni(L)(NO(3))(2) (complex 1) and [Ni(L)](ClO(4))(2)·2H(2)O (complex 2) [L=3,14-diethyl-2,6,13,17-tetraazatricyclo(16.4.0.0(7,12))docosane] have been prepared and structurally characterized by single-crystal X-ray diffraction at 200K. For these constrained macrocycle complexes, nickel(II) exists in a distorted octahedral environment with the four nitrogen atoms of the macrocyclic ligands and two oxygen atoms from nitrate in axial positions in complex 1. The macrocyclic ligand in complex 1 adopts the most stable trans-III conformation. The Ni-N distances in both the complex 1 (2.094(4)-2.051(4)Å) and complex 2 (2.042(8)-1.996(7)Å), are typical but the axial ligands are coordinating, with NiO bond length, 2.198(3)Å for complex 1. The complex 2 adopts square planner geometry around the Ni(II) with four nitrogen atoms from macrocyclic ligand. The crystals are stabilized in a 3-D network by intra and intermolecular hydrogen bonds that are formed among the secondary nitrogen hydrogen atoms and nitrate in 1, and intermolecular hydrogen bonds are formed by perchlorate and NH groups in 2. The electronic absorption, IR and PL spectral properties are also discussed.
authors.affiliation: Department of Chemistry, Shah Jalal University of Science and Technology, Sylhet, Bangladesh; Department of Chemistry, Andong National University, Andong 760-749, Republic of Korea. Electronic address: subhan-che@sust.edu.
authors.forename: Md Abdus
authors.initials: MA
authors.lastname: Subhan
authors.affiliation: Department of Chemistry, Andong National University, Andong 760-749, Republic of Korea. Electronic address: jhchoi@andong.ac.kr.
authors.forename: Jong-Ha
authors.initials: JH
authors.lastname: Choi
mesh_terms: D000473:Alkanes / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008024:Ligands; D047028:Macrocyclic Compounds / Q000737:chemistry*; D008958:Models, Molecular; D009532:Nickel / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000473:Alkanes; D056831:Coordination Complexes; D008024:Ligands; D047028:Macrocyclic Compounds; D009532:Nickel; C470023:docosane
keywords: Crystal structure; Macrocyclic ligand; Nickel(II); Spectroscopic properties; trans-III Conformation