Fig 4 - uploaded by Serhii I. Vasylevskyi
Content may be subject to copyright.
a) Solid state photoluminescence (PL) and photoluminescence excitation (PLE) spectra recorded at 298 K for trphe-H (λ ex = 370 nm, λ em = 490 nm) and complex 2 (λ ex = 340 nm, λ em = 465 nm). The inset shows emission decay curves recorded for trphe-H (λ em = 450 nm) and 2 (λ em = 470 nm) under excitation at 375 nm using a picosecond diode laser; b) diffuse reflectance spectra of trphe-H, trala-H and complex 2.
Source publication
![Fig. 1. Formation of layered structural motifs in [Ag(μ 4-trala)]·H 2 O...](profile/Serhii-Vasylevskyi/publication/283649482/figure/fig2/AS:524870668779520@1502150327770/Formation-of-layered-structural-motifs-in-Agm-4-tralaH-2-O-a-and-Agm_Q320.jpg)
![Fig. 2. a), b) The unsymmetrical [Ag 4 (μ 4-trala) 4 ] supramolecular...](profile/Serhii-Vasylevskyi/publication/283649482/figure/fig3/AS:524870669029376@1502150327903/a-b-The-unsymmetrical-Ag-4-m-4-trala-4-supramolecular-container-is-perfectly_Q320.jpg)
![Scheme 1. a) [–N–N–]-tr linkage is isosteric with μ 2-η 1 :η 1...](profile/Serhii-Vasylevskyi/publication/283649482/figure/fig1/AS:524870671110144@1502150327692/Scheme-1-a-N-N--tr-linkage-is-isosteric-with-m-2-e-1-e-1-carboxylate-bridge-b_Q320.jpg)
Several -amino acids, (l,d)-alanine and (l,d)-phenylalanine were utilized, as precursors for synthesis of 1,2,4-triazolyl carboxylic acids (l,d)-trala-H and (l,d)-trphe-H, which were explored as angular bifunctional building blocks for engineering Ag(I)-coordination polymers. Two complexes, [Ag(μ4-trala)]H2O (1), [Ag(μ4-trphe)]H2O (2), were prepare...
Contexts in source publication
Context 1
... 2 was selected to study photoluminescence properties. The solid state PL and PLE spectra recorded at 298 K for the complex and for the protonated ligand trphe-H are shown in Fig. 4a. Both the emission and excitation bands are very similar for the protonated ligand trphe-H and complex 2, however, a shift of the band positions toward shorter wavelengths can be noticed for the latter. The maximum of the excitation band is observed at 407 nm for trphe-H and at 365 nm for 2. The emission maxima are observed at 458 nm ...
Context 2
... for the protonated ligand trphe-H and complex 2, however, a shift of the band positions toward shorter wavelengths can be noticed for the latter. The maximum of the excitation band is observed at 407 nm for trphe-H and at 365 nm for 2. The emission maxima are observed at 458 nm and at 433 nm for trphe-H and compound 2, respectively. The inset in Fig. 4a shows the emission decay curves recorded at 298 K for trphe-H and complex 2. In both cases the decay curves are biexponential and the determined time constants are: t 1 = 2.7 ns, t 2 = 8.5 ns for trphe-H, and t 1 = 3.1 ns, t 2 = 9.6 ns for 2. There is only a small increase in the decay times observed for the complex as compared to the ...
Context 3
... emission bands of trphe-H should be assigned as n−π* or π−π* transitions. Based on the observed similarity of excitation and emission bands of the protonated ligand and the Ag-complex, the emission of 2 should be assigned to intraligand transitions. The reflectance spectra presented in Fig. 4b are very similar for the protonated ligand and complex 2. In the spectrum recorded for trala-H the absorption band at about 260 nm, observed for trphe-H and 2, is missing, which indicates that it should be assigned to a phenyl ring of the phenylalanine substituent, whereas other bands are due to absorption transitions of triazole ...
Similar publications
La découverte fortuite en octobre 1845 à Larnaca (Chypre) de la stèle de Sargon II d’Assyrie aujourd’hui à Berlin (Vorderasiatisches Museum) a suscité au cours des années des recherches pour localiser le vrai site de découverte et retracer l’histoire de son acquisition par les Königliche Museen de Berlin. Elle passe généralement pour avoir été trou...
Citations
... In this context, Chen et al. (2011) used 1,2,4-triazolyl isophthalate as a ligand in the synthesis of a series of Ag I -Ln III heterometallic coordination polymers. Second, in the 'cooperative' role, tr/ COO serves as a heteroleptic bridge between the metal centers ( Vasylevs'kyy et al. 2015). ...
The heterobifunctional organic ligand, 3-(1,2,4-triazol-4-yl)adamantane-1-carboxyl-ate (tr-ad-COO- ), was employed for the synthesis of the title silver(I) coordination polymer, {[Ag(C13H16N3O2)]·2H2O}
n
, crystallizing in the rare ortho-rhom-bic C2221 space group. Alternation of the double μ2-1,2,4-triazole and μ2-η2:η1-COO- (chelating, bridging mode) bridges between AgI cations supports the formation of sinusoidal coordination chains. The AgI centers possess a distorted {N2O3} square-pyramidal arrangement with τ5 = 0.30. The angular organic linkers connect the chains into a tetra-gonal framework with small channels along the c-axis direction occupied by water mol-ecules of crystallization, which are inter-linked via O-H⋯O hydrogen bonds with carboxyl-ate groups, leading to right- and left-handed helical dispositions.
A 1,2,4-triazol-4-yl-acetic acid ( trGly-H ) was used for the synthesis of Ag I and Ag I /U VI coordination polymers. The composition space diagram was built for the AgNO 3 / trGly-H /UO 2 (NO 3 ) 2 ·6H 2 O system shows the crystallization fields of two Ag I /U VI -compounds were found.
2‐(4H‐1,2,4‐triazol‐4‐yl)acetic acid (trglyH) and (dl)‐4‐methyl‐2‐(4H‐1,2,4‐triazol‐4‐yl)pentanoic acid (trleuH) were used as ligands for the development of MoO3 coordination hybrids for catalytic applications. Coordination polymers [Mo2O6(Htrgly)] ⋅ H2O (1) and [MoO3(trleuH)] ⋅ 0.5H2O (2) were prepared and structurally characterized. Compound 1 adopts a structure in which edge‐sharing MoO6 octahedra are organized in a ribbon motif via μ3‐O bridges. The Htrgly ligand exists as a zwitterion: −CO2⁻ links two MoVI in a μ2‐η¹ : η¹ mode, while positively charged triazolium is left uncoordinated. In 2, Mo atoms are joined in a chain through μ2‐O. The more hydrophobic trleuH appears in a nonionized form and its [N−N] sites serve as a “clamp” for supporting the [−OMo(O)2−OMo(O)2(tr)2]n sequence. The complexes were explored for liquid phase catalytic epoxidation of cis‐cyclooctene, using H2O2 or tert‐butylhydroperoxide as oxidants. The hybrids showed good catalytic activity, and 2 behaved as a reaction‐induced self‐separating catalyst for olefin epoxidation with H2O2, presenting advantages of homogeneous and heterogeneous catalysis.
A new heterofunctional ligand (Me2trGly-H = 3,5-dimethyl-(1,2,4-triazol-4-yl)-acetic acid)was employed for the synthesis of two coordination polymers [Ag4(Me2trGly-H)2.25(Me2trGly)1.75(NO3)2](NO3)0.25⋅6H2O (1) and [Ag4(UO2)(H2O)(Me2trGly)4(NO3)2]⋅5H2O (2). In compound 1, the triazole functional groups interact with Ag⁺ forming the stable tetranuclear rhombic {Ag4(Me2tr)4} motif, while the partially deprotonated carboxylic functions are left uncoordinated. NO3⁻ anions are located between the equatorial positions of the Ag⁺ coordination cores resulting in 2D coordination layers. In a mixture of Ag⁺/UO2²⁺ (compound 2) the triazole groups interact with silver(I) centers in the similar mode linking in a zig-zag chain. The COO⁻ moieties show strict affinity toward “hard” Pearson’s acid UO2²⁺ that reveals a pentagonal bipyramidal environment {UO7} in a 3D framework. Analysis of thermal stability reveals the structure intactness of 1 till 100 °C and 2 till 180 °C. Loss of water molecules causes phase transformation, while total decomposition is observed above 230 °C.
Chiral Na[(S)-LR] (R = Me, 1a; iPr, 1b; CH2iPr, 1c, and (S)-secBu, 1d) and Na[(R) LR] (R = Me, 1a’) compounds were synthesised following standard procedures. New compounds 1d and 1a’ were analytical and spectroscopically characterised. 1a and 1c were structurally identified by single-crystal X ray diffraction methods as homochiral 2D coordination polymers {Na(H2O)[(S)-LMe]}n and {Na[(S)-LCH2iPr]}n, respectively. Both (S) 2alkyl,2-(1H-imidazol-1-yl)acetate anions displayed unprecedented coordination modes in these coordination polymers: 32OO’ for 1a and 42O2O’ for 1c. Enantiomeric species 1a’, {Na(H2O)[(R)-LMe]}n, showed the same X ray powder diffractogram (XRPD) that 1a, in agreement with a similar crystal structure. DFT calculations on the [LR]- anions confirmed their coordination capabilities as ditopic linkers. In fact, the reaction of Na[LR] with several metal salts yielded the following coordination polymers: {Ag[(S)-LMe]}n, 2a, {Ag[(R)-LMe]}n, 2a’, {Cu[(S)-LR]2}n (R = Me, 3a; iPr, 3b), {Cu[(R)-LMe]}n, 3a’, {Zn[(S)-LR]2}n (R = Me, 4a; iPr, 4b; (S)-secBu, 4d) and {Zn[(R)-LMe]2}n, 4a’. For known 3a and 4a, this procedure is a new synthetic route that avoided high temperature reaction conditions. New complexes 2, 3a’,b, and 4a’,b,d were characterised by elemental analysis, infrared, XRPD methods and single-crystal X-ray for 2a. This complex is also a two-dimensional coordination polymer in which the [(S) LMe]- anion acts as µ4N,2O,2O’ bridging ligand. Compounds 1-4a’ are the first examples of homochiral coordination polymers with imidazole-monocarboxylate ligands based on non-natural amino acids. Preliminary studies in the metal-catalysed preparation of chiral α aminophosphonates were carried out but, unfortunately, no enantioselectivity was observed.
