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1.
Quici S Cavazzini M Marzanni G Accorsi G Armaroli N Ventura B Barigelletti F 《Inorganic chemistry》2005,44(3):529-537
The synthesis of a new ligand (1) containing a single phenanthroline (phen) chromophore and a flexibly connected diethylenetriamine tetracarboxylic acid unit (DTTA) as a lanthanide (Ln) coordination site is reported [1 is 4-[(9-methyl-1,10-phenantrol-2-yl)methyl]-1,4,7-triazaheptane-1,1,7,7-tetraacetic acid]. From 1, an extended series of water-soluble Ln.1 complexes was obtained, where Ln is Eu(III), Tb(III), Gd(III), Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), and Er(III). The stoichiometry for the association was found 1:1, with an association constant K(A) > or = 10(7) s(-1) as determined by employing luminescence spectroscopy. The luminescence and photophysical properties of the series of lanthanide complexes were investigated in both H2O and D2O solutions. High efficiencies for the sensitized emission, phi(se), in air-equilibrated water were observed for the Ln.1 complexes of Eu(III) and Tb(III) in the visible region (phi(se) = 0.24 and 0.15, respectively) and of Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), and Er(III) in the vis and/or near-infrared region [phi(se) = 2.5 x 10(-3), 5 x 10(-4), 3 x 10(-5), 2 x 10(-5), 2 x 10(-4), 4 x 10(-5), and (in D2O) 4 x 10(-5), respectively]. For Eu.1 and Tb.1, luminescence data for water and deuterated water allowed us to estimate that no solvent molecules (q) are bound to the ion centers (q = 0). Luminescence quenching by oxygen was investigated in selected cases. 相似文献
2.
Sénéchal-David K Pope SJ Quinn S Faulkner S Gunnlaugsson T 《Inorganic chemistry》2006,45(25):10040-10042
The development of novel mixed lanthanide-transition-metal (f-d) based supramolecular self-assemblies made from neodymium- and ytterbium-based tetraamide-functionalized cyclen complexes bearing a single 1,10-phenanthroline moiety coordinating to a RuII(bipy)2 (bipy = bipyridine) unit is described. Excitation of the Ru(II) metal-to-ligand charge-transfer band in water gave rise to long-wavelength sensitized emission from the Yb(III) or Nd(III) centers, observed in the near-infrared. 相似文献
3.
S. B. Meshkova Z. M. Topilova V. S. Matiichuk N. T. Pokhodylo I. P. Kovalevskaya I. M. Rakipov P. G. Doga 《Russian Journal of Coordination Chemistry》2011,37(4):309-315
The luminescence method, mass spectrometry, and elemental analysis are used to reveal that under optimal conditions (pH 5–8) Ln3+ ions (Ln = Pr, Sm, Eu, Nd, and Yb) with 1-(2-hydroxy-4-methylphenyl)-3-(5-methyl-1-phenyl-1 H-1,2,3-triazol-4-yl)propane-1,3-dione form complexes with the mole ratio Ln: ligand = 2: 3. According to the IR spectral data, Ln3+ ions coordinate three oxygen atoms of two carbonyl groups and one hydroxyl group. In the IR spectra of the complexes, an intense band at 628.7 cm?1 is assigned to the Ln-O bond vibrations. The X-ray diffraction patterns of the complexes contain no lines corresponding to the ligand. The luminescence intensity of the complexes in the visible spectral range changes in the series Eu(III) > Sm(III) > Pr(III), whereas in the IR region the order is Yb(III) > Nd(III). In all cases, luminescence of the solid complexes is considerably more intense than that of their solutions. 相似文献
4.
5.
A. N. Gusev V. F. Shul’gin G. A. Nishchimenko S. B. Meshkova A. V. Kiriyak G. G. Aleksandrov I. L. Eremenko 《Russian Journal of Coordination Chemistry》2013,39(6):432-436
Heteroligand coordination compounds Ln(Dbm)2HL · nEtOH, where Ln is Nd(III), Yb(III), and Er(III); HDbm is dibenzoylmethane; H2L is bis(5-pyridin-2-yl-1,2,4-triazol-3-yl)methane, are synthesized and studied. The complexes are studied by elemental analysis, TGA, and IR spectroscopy. The structure of complex [Nd(Dbm)2 · HL · EtOH] · EtOH is determined by X-ray diffraction analysis. The crystals are triclinic, space group $P\bar 1$ , a = 10.2004(9), b = 11.3809(10), c = 20.9173(18) Å, α = 102.133(1)°, β = 103.568(1)°, γ = 100.306(2)°; Z = 2 (8416 reflections with I > 2σ(I), R = 0.053, Rw = 0.136). The luminescence of solid samples of the studied complexes is studied in the near-IR region. 相似文献
6.
Synthesis and characterization of Pr(III), Nd(III) and Er(III) complexes with 2,6-pyridinedimethanol
The reactions of Ln(NO3)3?6H2O (Ln=Pr, Nd or Er) with the potentially tridentate O,N,O chelating ligand 2,6-pyridinedimethanol (H2pydm) in a 1:2 M ratio were investigated, and complexes with the formula [Ln(H2pydm)2(NO3)2](NO3) (Ln=Pr or Nd) (1 and 2) and [Er(H2pydm)3](NO3)3 (3) were isolated. The compounds contain 10-coordinate Pr(III) and Nd(III) ions that crystallize in the triclinic space group P-1 while the 9-coordinate Er(III) complex crystallizes in the monoclinic system (P21/n). A new lanthanide complex, [Pr(H2pydm)3](Cl)3?DMF (4), has been synthesized by reaction of PrCl3?6H2O and H2pydm. The nine-coordinate Pr(III) is bound to three H2pydm ligands. X-ray crystal structures of 1–4 reveal that the ligand coordinates tridentate via the pyridyl nitrogen and the two hydroxyl oxygens. The electronic absorption spectra of 1–4 show 4f–4f transitions. 相似文献
7.
Shavaleev NM Accorsi G Virgili D Bell ZR Lazarides T Calogero G Armaroli N Ward MD 《Inorganic chemistry》2005,44(1):61-72
Mononuclear complexes [Re(bpym)(CO)(3)Cl] and [Pt(bpym)(CC-C(6)H(4)CF(3))(2)] (bpym = 2,2'-bipyrimidine), in which one of the bipyrimidine sites is vacant, have been used as "complex ligands" to prepare heterodinuclear d-f complexes in which a lanthanide tris(1,3-diketonate) unit is attached to the secondary bipyrimidine site to evaluate the ability of d-block chromophores to act as antennae for causing sensitized near-infrared (NIR) luminescence from adjacent lanthanide(III) centers. The two sets of complexes so prepared are [Re(CO)(3)Cl(mu-bpym)Ln(fod)(3)] (abbreviated as Re-Ln; where Ln = Yb, Nd, Er) and [(F(3)C-C(6)H(4)-CC)(2)Pt(mu-bpym)Ln(hfac)(3)] (abbreviated as Pt-Ln; where Ln = Nd, Gd). Members of both series have been structurally characterized; the metal-metal separation across the bipyrimidine bridge is approximately 6.3 A in each case. In these complexes, the (3)MLCT (MLCT = metal to ligand charge-transfer) luminescences of the mononuclear [Re(bpym)(CO)(3)Cl] and [Pt(bpym)(CC-C(6)H(4)CF(3))(2)] complexes are quenched by energy transfer to those lanthanides (Ln = Yb, Nd, Er) that have low-lying f-f states capable of NIR luminescence; as a result, sensitized NIR luminescence is seen from the lanthanide center following excitation of the d-block unit. In the solid state, quenching of the luminescence from the d-block chromophore is complete, indicating efficient d --> f energy transfer, as a result of the short metal-metal separation across the bipyrimidine bridge. In a CH(2)Cl(2) solution, partial dissociation of the dinuclear complexes into the mononuclear units occurs, with the result that some (3)MLCT luminescence is observed from mononuclear [Re(bpym)(CO)(3)Cl] or [Pt(bpym)(CC-C(6)H(4)CF(3))(2)] present in the equilibrium mixture. Solution UV-vis and luminescence titrations, carried out by the addition of portions of Ln(fod)(3)(H(2)O)(2) or Ln(hfac)(3)(H(2)O)(2) to the d-block complex ligands, indicate that binding of the lanthanide tris(1,3-diketonate) unit at the secondary bipyrimidine site to give the d-f dinuclear complexes occurs with an association constant of ca. 10(5) M(-)(1). 相似文献
8.
S. S. Sandhu J. N. Kumaria Prof. Ranjit S. Sandhu 《Monatshefte für Chemie / Chemical Monthly》1977,108(5):1105-1112
The stability constants of the complexes of 3-hydroxynaphthalene-2-carboxylic acid with some lanthanides have been obtained potentiometrically in aqueous dioxane (50%,V/V) at three temperatures and keeping the ionic strength at 0.1M (KNO3), usingIrving-Rossotti titration technique. The values of overall changes in G°, H°, and S° have also been evaluated. 相似文献
9.
The syntheses and photophysical attributes of a range of dual-emissive lanthanide complexes are described. The simple ligand architecture is based upon a diethylenetriaminepentaacetic acid (DTPA) core and appended with two aminopyrenyl chromophores to yield the fluorescent free ligand Lpyr. Reaction of the ligand with Ln(tris-trifluoromethanosulfate) gave the mononuclear complexes Ln · Lpyr (Ln = Nd, Er, Yb). Luminescence studies revealed that the complexes were emissive in both the near-IR and UV–Vis, the latter resulting from pyrene localised emission (λem = 390 nm), the former from pyrene-sensitised emission of the lanthanide ion (λex = 337 nm). Time-resolved measurements in the near-IR indicated that the number of coordinated solvent molecules for Nd and Yb was <1, confirming the proposed coordination mode of the octadentate Lpyr. The suitability of pyrene as a sensitiser for near-IR emitting lanthanides was further demonstrated in the rare observation of ErIII emission in a non-deuteriated protic medium. 相似文献
10.
In Ir(III)/Tb(III) dyads in which the excited state energy of the Ir(III) unit lies above 22,000 cm(-1), visible-light excitation of the Ir(III) chromophore results in sensitised emission from Tb(III) following Ir → Tb energy-transfer. 相似文献
11.
M. G. Abd El-Wahed S. M. El-Megharbel M. Y. El-Sayed Y. M. Zahran M. S. Refat M. A. Al-Omar A. M. Naglah 《Russian Journal of General Chemistry》2016,86(2):391-399
The complexation between the lanthanide metal ions Ce(III), Gd(III), Nd(III), Tb(III), and Er(III) and gliclazide produced 1 : 1 molar ratio metal: gliclazide (Glz) complexes coordinated in a monodentate fashion via the OH group and having the general formulas [M(Glz)Cl3(H2O)]·xH2O (M = Ce, Gd, Nd and x = 1, 3, 4, respectively) and [M(Glz)(H2O)4]Cl3·yH2O (M = Tb, Er and y = 1, 2, respectively). The structure of the synthesized lanthanide gliclazide complexes was assigned by IR, 1HNMR, and UV-Vis spectroscopy. Thermal analysis and kinetic and thermodynamic parameters gave evidence for the thermal stability of the Glz complexes. The latter showed a significant antimicrobial effect against some bacteria and fungi. 相似文献
12.
Reaction of the cyanoruthenate anions [Ru(bpym)(CN)4]2- and [[Ru(CN)4]2(mu-bpym)]4- (bpym = 2,2'-bipyrimidine) with lanthanide(III) salts resulted in the crystallization of coordination networks based on Ru-CN-Ln bridges. Four types of structure were obtained: [Ru(bpym)(CN)4][Ln(NO3)(H2O)5] (Ru-Ln; Ln = Sm, Nd, and Gd) are one-dimensional helical chains; [Ru(bpym)(CN)4]2[Ln(NO3)(H2O)2][Ln(NO3)(0.5)(H2O)(5.5)](NO3)(0.5).5.5H2O (Ru-Ln; Ln = Er and Yb) are two-dimensional sheets containing cross-linked chains based on Ru2Ln2(mu-CN)4 diamond units, which are linked into one-dimensional chains via shared Ru atoms; [[Ru(CN)4]2(mu-bpym)][Ln(NO3)(H2O)5]2.3H2O (Ru2-Ln; Ln = Nd and Sm) are one-dimensional ladders with parallel Ln-NC-Ru-CN-Ln-NC strands connected by the bipyrimidine "cross pieces" acting as rungs on the ladder; and [[Ru(CN)4]2(mu-bpym)][Ln(H2O)6](0.5)[Ln(H2O)4](NO3)(0.5).nH2O (Ru2-Ln; Ln = Eu, Gd, and Yb; n = 8.5, 8.5, and 8, respectively) are three-dimensional networks in which two-dimensional sheets of Ru2Ln2(mu-CN)4 diamonds are connected via cyanide bridges to Ln(III) ions between the layers. Whereas Ru-Gd shows weak triplet metal-to-ligand charge-transfer (3MLCT) luminescence in the solid state from the Ru-bipyrimidine chromophore, in Ru-Nd, Ru-Er, and Ru-Yb, the Ru-based emission is quenched, and all of these show, instead, sensitized lanthanide-based near-IR luminescence following a Ru --> Ln energy transfer. Similarly, Ru2-Nd and Ru2-Yb show lanthanide-based near-IR emission following excitation of the Ru-bipyrimidine chromophore. Time-resolved luminescence measurements suggest that the Ru --> Ln energy-transfer rate is faster (when Ln = Yb and Er) than in related complexes based on the [Ru(bipy)(CN)4]2- chromophore, because the lower energy of the Ru-bpym 3MLCT provides better spectroscopic overlap with the low-energy f-f states of Yb(III) and Er(III). In every case, the lanthanide-based luminescence is relatively short-lived as a result of the CN oscillations in the lattice. 相似文献
13.
Zaki Nadia G. Mahmoud Walaa H. El Kerdawy Ahmed M. Abdallah Abanoub Mosaad Mohamed Gehad G. 《Research on Chemical Intermediates》2020,46(6):3193-3216
Research on Chemical Intermediates - Reaction of cocaine (Cn) with Ln(III) chloride salts [where Ln?=?La(III), Er(III), and Yb(III)] afforded complexes of the [Ln(Cn)Cl(OH2)3].2Cl type... 相似文献
14.
Lo WK Wong WK Wong WY Guo J Yeung KT Cheng YK Yang X Jones RA 《Inorganic chemistry》2006,45(23):9315-9325
A series of 3d-4f heterobimetallic phenylene-bridged Schiff base complexes of the general formula [Zn(mu-L1)Ln(NO3)3(S)n] [Ln = La (1), Nd (2), Gd (3), Er (4), Yb (5); S = H(2)O, EtOH; n = 1, 2; H2L1 = N,N'-bis(3-methoxysalicylidene)phenylene-1,2-diamine] and [Zn(mu-L2)Ln(NO3)3(H2O)n] [Ln = La (6), Nd (7), Gd (8), Er (9), Yb (10); n = 1, 2; H(2)L(2) = N,N'-bis(3-methoxy-5-p-tolylsalicylidene)phenylene-1,2-diamine] were synthesized and characterized. Complexes 1, 2, 4, and 7 were structurally characterized by X-ray crystallography. At room temperature in CH(3)CN, both neodymium(III) (2 and 7) and ytterbium(III) (5 and 10) complexes also exhibited, in addition to the ligand-centered emission in the UV-vis region, their lanthanide(III) ion emission in the near-infrared (NIR) region. The photophysical properties of the zinc(II) phenylene-bridged complexes (ZnL1 and ZnL2) were measured and compared with those of the corresponding zinc(II) ethylene-bridged complexes (ZnL3 and ZnL4). Our results revealed that, at 77 K, both ligand-centered triplet (3LC) and singlet (1LC) states existed for the ethylene-bridged complexes (ZnL3 and ZnL4), whereas only the (1)LC state was detected for the phenylene-bridged complexes (ZnL1 and ZnL2). NIR sensitization studies of [Zn(mu-L')Nd(NO3)3(H2O)n] (L' = L1-L4) complexes further showed that Nd3+ sensitization took place via the 3LC and 1LC states when the spacer between the imine groups of the Schiff base ligand was an ethylene and a phenylene unit, respectively. Ab initio calculations show that the observed differences can be attributed to the difference in the molecular vibrational properties and electron densities of the electronic states between the ethylene- and phenylene-bridged complexes. 相似文献
15.
T. V. Balashova A. P. Pushkarev V. A. Il’ichev I. D. Grishin D. V. Govorova M. N. Bochkarev 《Russian Chemical Bulletin》2016,65(7):1739-1742
Heterometallic complexes Ln(L1)5Zn (Ln = Sc, Sm, Gd) were obtained by the reactions of silylamides Ln[N(SiMe)2]3 with 2-(benzoxazol-2-yl)phenol (HL1) in the presence of diethylzinc. Similar reactions with 3-(benzothiazol-2-yl)-2-naphthol (HL2) led to the formation of complexes Ln(L2)5Zn (Ln = Nd, Er, Gd, Yb). The introduction of the zinc-containing fragments provided a considerable increase of photo- and electroluminescence intensity of the scandium complex. 相似文献
16.
Pope SJ Coe BJ Faulkner S Laye RH 《Dalton transactions (Cambridge, England : 2003)》2005,(8):1482-1490
The new pro-ligand 4-methyl-4'-(carbonylamino(2-(tert-butoxycarbonylamino)ethyl))-2,2'-bipyridyl (L1) has been prepared and used to synthesise the complex fac-Re(I)Cl(CO)3(L1) 1 and the complex salts [M(II)(bipy)2(L1)](PF6)2 (M=RuII 8 or OsII 15). Deprotection with trifluoroacetic acid affords the amine-functionalised derivatives fac-Re(I)Cl(CO)3(L2) 2, [M(II)(bipy)2(L2)](PF6)2 (M=RuII 9 or OsII 16) which react with the dianhydride of diethylenetriamine pentaacetic acid (DTPA) to give the binuclear complex {fac-Re(I)Cl(CO)3}2(L3) 3 and the complex salts [{M(II)(bipy)2}2(L3)](PF6)4 (M = RuII 10 or OsII 17). The latter react with salts Ln(OTf)3 to afford a series of 12 heterotrimetallic compounds that contain a lanthanide (Ln) ion in the DTPA binding site; {fac-Re(I)Cl(CO)3}2(L3)LnIII (Ln=Nd 4, Er 5, Yb 6 or Y 7) and [{M(II)(bipy)2}2(L3)LnIII](PF6)(OTf)3 (M=RuII, Ln=Nd 11, Er 12, Yb 13 or Y 14; M=OsII, Ln=Nd 18, Er 19, Yb 20 or Y 21). All of these trimetallic species display absorption bands ascribed to metal-to-ligand charge-transfer (MLCT) excitations, and luminescence measurements show that these excited states can be used to sensitise near-infrared emission from LnIII (Ln=Nd, Er or Yb) ions. Single crystal X-ray structures of L1 and [RuII(bipy)2(L2H)](H2PO4)3.(CH3)2CO.0.8H2O were obtained, the latter revealing the presence of H2PO4- counter anions, the source of which is presumed to be hydrolysis of PF6- ions. 相似文献
17.
Heterogeneous self-assembly of thiacalix[4]arene-p-tetrasulfonate (TCAS), Ag(I), and Ln(III) (= Nd(III), Yb(III)) in aqueous solutions conveniently afforded ternary complexes emitting Ln(III)-centered luminescence in the near-infrared (NIR) region. A solution-state study revealed that the Ag(I)-Nd(III)-TCAS system gave a complex Ag(I)(4)·Nd(III)·TCAS(2) in a wide pH range of 6-12. In contrast, the Ag(I)-Yb(III)-TCAS system gave Ag(I)(2)·Yb(III)(2)·TCAS(2) at a pH of around 6 and Ag(I)(2)·Yb(III)·TCAS(2) at a pH of approximately 9.5. The structures of the Yb(III) complexes were proposed based on comparison with known Ag(I)-Tb(III)-TCAS complexes that show the same self-assembly behavior. In Ag(I)(2)·Yb(III)(2)·TCAS(2), two TCAS ligands sandwiched a cyclic array of a Ag(I)-Ag(I)-Yb(III)-Yb(III) core. In Ag(I)(2)·Yb(III)·TCAS(2), Yb(III) was accommodated in an O(8) cube consisting of eight phenolate O(-) groups from two TCAS ligands linked by two S-Ag-S linkages. Crystallographic analysis of Ag(I)(4)·Nd(III)·TCAS(2) revealed that the structure was similar to Ag(I)(2)·Yb(III)·TCAS(2) but that it had four instead of two S-Ag-S linkages. The number of water molecules coordinating to Ln(III) (q) estimated on the basis of the luminescent lifetimes was as follows: Ag(I)(4)·Nd(III)·TCAS(2), 0; Ag(I)(2)·Yb(III)(2)·TCAS(2), 2.4; and Ag(I)(2)·Yb(III)·TCAS(2), 0. These findings were compatible with the solution-state structures. The luminescent quantum yield (Φ) for Ag(I)(4)·Nd(III)·TCAS(2) was 4.9 × 10(-4), which is the second largest value ever reported in H(2)O. These findings suggest that the O(8) cube is an ideal environment to circumvent deactivation via O-H oscillation of coordinating water. The Φ values for Ag(I)(2)·Yb(III)(2)·TCAS(2) and Ag(I)(2)·Yb(III)·TCAS(2) were found to be 3.8 × 10(-4) and 3.3 × 10(-3), respectively, reflecting the q value. Overall, these results indicate that the ternary systems have the potential for a noncovalent strategy via self-assembly of the multidentate ligand, Ln(III), and an auxiliary metal ion to obtain a highly efficient NIR-emissive Ln(III) complex that usually relies on elaborate covalent linkage of a chromophore and multidentate ligands to expel coordinating water. 相似文献
18.
Kennedy F Shavaleev NM Koullourou T Bell ZR Jeffery JC Faulkner S Ward MD 《Dalton transactions (Cambridge, England : 2003)》2007,(15):1492-1499
The luminescent transition metal complexes [Re(CO)(3)Cl(bppz)] and [Pt(CC-C(6)H(4)CF(3))(2)(bppz)] [bppz = 2,3-bis(2-pyridyl)pyrazine], in which one of the diimine binding sites of the potentially bridging ligand bppz is vacant, have been used as 'complex ligands' to make heterodinuclear d-f complexes by attachment of a {Ln(dik)(3)} fragment (dik = a 1,3-diketonate) at the vacant site. When Ln = Pr, Nd, Er or Yb the lanthanide centre has low-energy f-f excited states capable of accepting energy from the (3)MLCT excited state of the Pt(II) or Re(I) centre, quenching the (3)MLCT luminescence and affording sensitised lanthanide(III)-based luminescence in the near-IR region. UV/Vis and luminescence spectroscopic titrations allowed measurement of (i) the association constants for binding of the {Ln(dik)(3)} fragment at the vacant diimine site of [Re(CO)(3)Cl(bppz)] or [Pt(CC-C(6)H(4)CF(3))(2)(bppz)], and (ii) the degree of quenching of the (3)MLCT luminescence according to the nature of the Ln(III) centre. In all cases Nd(III) was found to be the most effective of the series at quenching the (3)MLCT luminescence of the d-block component because the high density of f-f excited states of the appropriate energy make it a particularly effective energy-acceptor. 相似文献
19.
Edder C Piguet C Bünzli JC Hopfgartner G 《Chemistry (Weinheim an der Bergstrasse, Germany)》2001,7(14):3014-3024
The segmental ligand 2-[6-(N,N-diethylcarbamoyl)pyridin-2-yl]-1,1'-dimethyl-5,5'-methylene-2'-(6-methylpyridine-2-yl)bis[1H-benzimidazole] (L3) reacts with a stoichiometric mixture of LnIII (Ln = La, Eu, Gd) and M(II) (M = Zn, Fe) in acetonitrile to produce selectively the heterodimetallic triple-stranded helicates (HHH)-[LnM(L3)3]5+. In these complexes, M(II) is pseudooctahedrally coordinated by the three wrapped bidentate binding units, thus forming a noncovalent tripod which organizes the three unsymmetrical tridentate segments to give ninefold coordination to LnIII. The introduction of a methyl group at the 6 position of the terminal pyridine in L3 sterically reduces the complexing ability of the bidentate segment for M(II). Spectroscopic (ESI-MS, UV/Vis/NIR, NMR), magnetic and electrochemical measurements show that 1) the head-to-head-to-head triple helical complexes (HHH)-[LnM(L3)3]5+ are quantitatively formed in solution only for ligand concentrations larger than 0.01 M, 2) FeII adopts a pure high-spin electronic configuration in (HHH)-[LnFe(L3)3]5+ and 3) the FeII/FeIII oxidation process is prevented by steric constraints. Detailed photophysical studies of (HHH)-[Eu-Zn(L3)3]5+ confirm that the pseudotricapped trigonal-prismatic lanthanide coordination site is not affected by the methyl groups bound to the terminal pyridine, thus leading to significant Eu-centered emission upon UV irradiation. In (HHH)-[EuFe(L3)3]5+, a resonant intramolecular Eu-->Fe(II)hs energy transfer partially quenches the Eu-centered luminescence; however, the residual red emission demonstrates that high-spin iron(II) is compatible with the sensitization of Eu(III) in heterodimetallic d-f complexes. The influence of the electronic configuration of Fe(II) on the efficiency of Eu(III)-->Fe(II) energy-transfer processes is discussed together with its consequence for the design of optically active spin-crossover supramolecular devices. 相似文献
20.
Van Deun R Nockemann P Fias P Van Hecke K Van Meervelt L Binnemans K 《Chemical communications (Cambridge, England)》2005,(5):590-592
The 9-hydroxyphenal-1-one ligand forms stable 3:1 complexes with trivalent lanthanides, in which it acts as an antenna suitable for the visible light excitation (up to 475 nm) of the trivalent europium ion. 相似文献