title: Synthesis, characterization and oscillator-vibrated near-infrared (NIR) luminescence of two pseudo-polymorphic [Yb4((OH)2-Salophen)4] complexes.
abstract: Through the self-assembly of the (OH)2-Salophen H4L (H4L=N,N'-bis(3-hydroxylsalicylidene)benzene-1,2-diamine) with LnCl3·6H2O or Ln(NO3)3·6H2O (Ln=La, Yb or Gd) in different solvent systems MeCN-EtOH and MeCN-DMF, the mixed (L)(4-) and (H2L)(2-) coordination modes induce the formation of anion-independent while pseudo-polymorphic homoleptic linear tetranuclear complexes [Ln4(H2L)2(L)2(EtOH)2] (Ln=La, 1; Ln=Yb, 2 or Ln=Gd, 3) and [Ln4(H2L)2(L)2(DMF)2] (Ln=La, 4; Ln=Yb, 5 or Ln=Gd, 6), respectively. The result of their photophysical properties shows the characteristic NIR luminescence for both Yb(3+)-based complexes 2 and 5 with emissive lifetimes in microsecond ranges, while the difference of nearby and/or distant oscillator-based (OH and/or CH) vibrations from two coordinated EtOH or DMF molecules within the inner coordination spheres of Yb(3+) ions in the two complexes has a decisive effect on their NIR luminescent properties.
authors.affiliation: School of Chemical Engineering, Shaanxi Key Laboratory of Degradable Medical Material, Northwest University, Xi'an 710069, Shaanxi, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: School of Chemical Engineering, Shaanxi Key Laboratory of Degradable Medical Material, Northwest University, Xi'an 710069, Shaanxi, China.
authors.forename: Heini
authors.initials: H
authors.lastname: Feng
authors.affiliation: School of Chemical Engineering, Shaanxi Key Laboratory of Degradable Medical Material, Northwest University, Xi'an 710069, Shaanxi, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Liu
authors.affiliation: School of Chemical Engineering, Shaanxi Key Laboratory of Degradable Medical Material, Northwest University, Xi'an 710069, Shaanxi, China.
authors.forename: Weixu
authors.initials: W
authors.lastname: Feng
authors.affiliation: School of Chemical Engineering, Shaanxi Key Laboratory of Degradable Medical Material, Northwest University, Xi'an 710069, Shaanxi, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Yu
authors.affiliation: School of Chemical Engineering, Shaanxi Key Laboratory of Degradable Medical Material, Northwest University, Xi'an 710069, Shaanxi, China. Electronic address: 752201351@qq.com.
authors.forename: Xingqiang
authors.initials: X
authors.lastname: Lü
authors.affiliation: Department of Chemistry, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, China.
authors.forename: Wai-Kwok
authors.initials: WK
authors.lastname: Wong
authors.affiliation: Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, TX 78712-0165, United States.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Jones
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D003959:Diamines / Q000737:chemistry; D049449:Luminescence; D049408:Luminescent Agents / Q000138:chemical synthesis / Q000737:chemistry*; D008163:Luminescent Measurements; D008958:Models, Molecular; D012459:Salicylates / Q000138:chemical synthesis / Q000737:chemistry*; D019265:Spectroscopy, Near-Infrared; D015018:Ytterbium / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D003959:Diamines; D049408:Luminescent Agents; D012459:Salicylates; C090416:salophen; D015018:Ytterbium
keywords: Oscillator-vibrated NIR luminescence; Pseudo-polymorphism; Tetranuclear [Ln(4)((OH)(2)-Salophen)(4)]-arrayed complexes