Cadmium-1,4-cyclohexanedicarboxylato coordination polymers bearing different di-alkyl-2,2'-bipyridines: syntheses, crystal structures and photoluminescence studies
Por:
Rosales-Vazquez, Luis D., Sanchez-Mendieta, Victor, Dorazco-Gonzalez, Alejandro, Martinez-Otero, Diego, Garcia-Orozco, Ivan, Morales-Luckie, Raul A., Jaramillo-Garcia, Jonathan, Tellez-Lopez, Antonio
Publicada:
7 oct 2017
Categoría:
Inorganic chemistry
Resumen:
Four coordination polymers have been synthesized using self-assembly
solution reactions under ambient conditions, reacting Cd(II) ions with
1,4-cyclohexanedicarboxylic acid in the presence of different
2,2'bipyridine co-ligands: {[Cd(H2O)(e,
a-cis-1,4-chdc)(2,2'-bpy)].H2O(n) (1); [Cd-2(H2O) 2(e,
a-cis-1,4chdc)(2)(4,4'-dmb)(2)] (n) (2); {[Cd(e,
a-cis-1,4-chdc)(5,5'-dmb)] u H2O.CH3OH (n) (3) and {[Cd(e,
e-trans-1,4-chdc) (4,4'-dtbb)].CH3OH n (4), where 1,4-chdc =
1,4-cyclohexanedicarboxylato, 2,2'-bpy = 2,2'-bipyridine, 4,4'-dmb =
4,4'-dimethyl-2,2'-bipyridine, 5,5'-dmb = 5,5'-dimethyl-2,2'-bipyridine
and 4,4'-dtbb = 4,4'di-tert-butyl-2,2'-bipyridine. Crystallographic
studies show that compound 1 has a 1D structure propagating along the
crystallographic b-axis; the Cd ion in 1 is six-coordinated with a
distorted-octahedral coordination sphere. Compound 2 has two
crystallographic different Cd ions and both are six-coordinated with a
distorted-octahedral coordination sphere. Compound 3 exhibits a
seven-coordinated Cd ion having a distinctive distorted-monocapped
trigonal prismatic geometry. In compound 4, the Cd ion is also
seven-coordinated in a distorted monocapped octahedral geometry.
Compounds 2, 3 and 4 possess rhombic-shaped dinuclear units (Cd2O2) as
nodes to generate larger cycles made up of four dinuclear units, a Cd-4
motif, bridged by four 1,4-chdc ligands, accomplishing, thus, 2D
structures. Remarkably, in compound 4 the 1,4-chdc ligand conformation
changes to the equatorial, equatorial trans, unlike the other compounds
where the bridging ligand conformation is the more typical equatorial,
axial cis. The solid state luminescence properties of 1-4 were
investigated; polymers 3 and 4 exhibited a strong blue emission
(lambda(em) = 410-414 nm) compared to 1 and 2; structure-related
photoluminescence is attributed to the degree of hydration of the
compounds. Furthermore, Cd-polymer 3 suspended in acetone allows the
fluorescence selective sensing of acetonitrile over common organic
solvents such as alcohols and DMF, based on turn-on fluorescence
intensity with a limit of 53 mu mol L-1.
Filiaciones:
Univ Autonoma Estado Mexico, Fac Quim, Toluca 50120, Estado De Mexic, Mexico
UNAM, UAEM, Ctr Conjunto Invest Quim Sustentable, Carretera Toluca Ixtlahuaca Km 14-5, Toluca, Estado De Mexic, Mexico
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