Ttha Ligand Research Articles

A Flexible Hexacarboxylate-Samarium(III) Metal–Organic Framework: Synthesis, Structure and Spectroscopic Properties

A new flexible triazine-based polycarboxylate metal–organic framework, [Sm2(TTHA)(H2O)4]·9H2O (I) (TTHA = 1,3,5-triazine-2,4,6-triamine hexaacetate), has been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction, elemental analysis and FT-IR spectroscopy. Crystal data for I are monoclinic C2/c, a = 12.6974(13) A, b = 16.7309(12) A, c = 14.8076(15) A, β = 91.452(8)°, V = 3,144.7(5) A3. Each SmIII ion is 9-coordinate in a distorted tri-capped trigonal prismatic geometry; but, the principal inorganic building block is {Sm2O16}, which comprises two of these polyhedra that share an edge. The complex exhibits a three-dimensional open-framework structure of approximately 31 % void volume, which comprises two types of channels oriented in three directions; [0 0 1], [1 1 0] and [−1 1 0]. The network can be simplified into either the cooperite (pts) or anatase (ant) topologies depending on the choice of nodes. The UV–Vis spectra of the compound are dominated by the absorption of the TTHA ligand. Thermogravimetric analysis shows that the loss of channel and coordinated water upon heating occurs in two distinct steps.

Nine-coordinate dinuclear Na6[Gd 2 III (Ttha)2] · 8H2O and mononuclear (H2En)3[GdIII(Ttha)]2 · 11H2O complexes: Synthesis and structural determination

The Na6[Gd2III(Ttha)2] · 8H2O (I) (H6Ttha = triethylenetetramine-N,N,N′,N″,N‴,N‴-hexaacetic acid) and (H2En)3[GdIII(Ttha)]2 · 11H2O (II) (En = ethylenediamine) complexes were prepared with heat-refluxing and acidity-adjusting methods, respectively. Their composition and structures were determined by elemental analysis and single-crystal X-ray diffraction techniques. Complex I shapes a binuclear and nine-coordinated structure and crystallizes in the orthorhombic crystal system with space group Pccn. The central Gd3+ ion is coordinated with one Ttha ligand by three N atoms and four O atoms and with one adjacent Ttha ligand by two O atoms. The crystal data are as follows: a = 26.036(13) A, b = 21.007(10) A, c = 22.694(12) A, V = 12412(11) A3, Z = 8, c = 1.699 g/cm3, μ = 2.254 mm−1, F(000) = 6368, R = 0.0602, and wR = 0.1146 for 3434 observed reflections with I ≥ 2σ(I). The GdN3O6 part in the [Gd2III(Ttha)2]6− complex anion forms a pseudo-tricapped trigonal prismatic geometry. Complex II is also nine-coordinate, but mononuclear and crystallizes in the monoclinic crystal system with space group P21/n. While the central Gd3+ ion is coordinated by four nitrogen atoms and five oxygen atoms from the same Ttha ligand. The crystal data are as follows: a = 17.7726(17) A, b = 19.2942(17) A, c = 20.6045(19) A, β = 111.4600(10)°, V = 6575.6(10) A3, Z = 8, c = 1.693 g/cm3, μ = 2.102 mm−1, F(000) = 3428, R = 0.0333 and wR = 0.0827 for 14792 observed reflections with I ≥ 2σ(I). Otherwise, the GdN4O5 part in each [GdIII(Ttha)]3− complex anion adopts a pseudo-monocapped square antiprismatic polyhedron.

Syntheses and crystal structures of nine-coordinate K2[EuIII(dtpa)(H2O)]·5H2O and Na2[TbIII(Httha)]·6H2O complexes

The title complexes, K2[EuIII(dtpa)(H2O)]·5H2O (H5dtpa = diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid), Na2[TbIII(Httha)]·6H2O (H6ttha = triethylenetetramine-N,N,N′,N′,N″,N″-hexaacetic acid), were prepared, and their compositions and structures were determined by elemental analyses and single-crystal X-ray diffraction techniques. The crystal of K2[EuIII(dtpa)(H2O)]·5H2O belongs to triclinic crystal system and \( P\bar 1 \) space group. The crystal data are as follows: a = 8.3540(17), b = 10.147(2), c = 15.059(3) α = 84.63(3)A, β = 82.02(3)°, γ = 83.96(3)°, V = 1253.1(4)A3, Z = 2, R = 0.0325 and wR = 0.1013 for 4407 observed reflections with I ≥ 2σ(I). The [EuIII(dtpa)(H2O)]2− has a nine-coordinate pseudo-monocapped square antiprismatic structure, in which the nine coordinate atoms, three N and six O are from one dtpa ligand and one water molecule. The crystal of the Na2[TbIII(Httha)]·6H2O belongs to monoclinic system and P21/c space group. The crystal data are as follows: a = 10.3976(10), b = 12.7908(13), c = 23.199(2) A = 90.914(2)°, V = 3084.9(5)A3, Z = 4, R = 0.0309 and wR = 0.0704 for 5429 observed reflections with I ≥ 2σ(I). In the [TbIII(Httha)]2−, the Tb3+ ion is nine-coordinated yielding a pseudo-monocapped square antiprismatic conformation, in which the ttha ligand coordinates to the central Tb3+ ion with four N atoms and five O atoms. There is a free non-coordinate carboxyl group (−CH2COOH) that can be modified by some biological molecules having target function.

Synthesis and structures of nine-coordinate K[Dy(Edta)(H2O)3] · 3.5H2O, (NH4)3 [Dy(Ttha)] · 5H2O, and eight-coordinate NH4[Dy(Cydta)(H2O)2] · 4.5H2O complexes

The title complexes, K[Dy(Edta)(H2O)3] · 3.5 H2O (I) (H4Edta = ethylenediamine-N,N,N′,N′-tetraacetic acid), (NH4)3[Dy(Ttha)] · 5H2O (II) (H6Ttha = triethylenetetramine-N, N,N′,N″,N‴,N‴-hexaacetic acid), and NH4[Dy(Cydta)(H2O)2] · 4.5H2O (III) (H4Cydta = trans-1,2-cyclohexanediamine-N,N,N′,N′-tetraacetic acid), were prepared, and their compositions and structures were determined by elemental analyses and single-crystal X-ray diffraction techniques, respectively. In complex I, the Dy3+ ion is nine-coordinated by an Edta ligand and three water molecules, yielding a pseudo-monocapped square antiprismatic conformation, and the complex crystallizes in the orthorhombic crystal system with space group Fdd2. The crystal data are as follows: a = 19.751(7), b = 35.573(12), c = 12.227(4) A, V = 8591(5) A3, Z = 16, space group Fdd2 ρc = 1.877 g/cm3, μ = 3.742 mm−1, F(000) = 4800, R = 0.0259, and wR = 0.0616 for 3218 observed reflections with I ≥ 2σ(I). For complex II, the Dy3+ ion is nine-coordinated by a Ttha ligand, yielding a pseudo-monocapped square antiprismatic conformation, and the complex crystallizes in the monoclinic crystal system with space group P21/c. In addition, there is a free non-coordinate carboxyl group (-CH2COO−) in the [Dy(Ttha)]3− complex anion. The crystal data are as follows: a = 10.353(3), b = 12.746(4), c = 23.141(7) A, β = 91.005(5)°, V = 3053.2(15) A3, Z = 4, space group P21/c ρc = 1.730 g/cm3, μ = 2.532 mm−1, F(000) = 1620, R = 0.0332 and wR = 0.0924 for 5390 observed reflections with I ≥ 2σ(I). For complex III, the Dy3+ ion is eight-coordinated by a ligand Cydta and two water molecules, yielding a distorted square antiprismatic conformation, and the complex crystallizes in the triclinic system with space group P $$ \bar 1 $$ . The crystal data are as follows: a = 8.604(3), b = 10.012(4), c = 14.369(6) A, α = 88.330(6)°, β = 75.363(6)°, γ = 88.285(6)°, space group P $$ \bar 1 $$ V = 1196.9(8) A3, Z = 2, ρc = 1.776 g/cm3, μ = 3.194 mm−1, F(000) = 644, R = 0.0445 and wR = 0.1041 for 3931 observed reflections with I ≥ 2σ(I).

The syntheses and structures of ten-coordinate K6[PrIII(ttha)]2 · 10H2O and nine-coordinate K4[(Httha)2] · 14H2O complexes

The title complexes, K6[PrIII(ttha)]2 · 10H2O and K4[(Httha)2] · 14H2O (H6ttha = triethylenetetraaminehexaacetic acid), have been prepared and characterized using IR, elemental analyses and single-crystal X-ray diffraction techniques. The crystal of K6[PrIII(ttha)]2 · 10H2O has a ten-coordinate mononuclear structure with a distorted bicapped square antiprismatic prism, belonging to the triclinic crystal system and P space group. The crystal data are as follows: a = 9.697(4) Å, b = 16.183(6) Å, c = 20.957(8) Å, V = 2963.0(19) Å3, Z = 2. The crystal of K4[(Httha)2] · 14H2O belongs to the monoclinic crystal system and P21/n space group, with a = 11.2787(10) Å, b = 25.706(2) Å, c = 22.058(2) Å, V = 6231.5(10) Å3, Z = 4, and is a binuclear nine-coordinate pseudo-monocapped square antiprism. The results provide the dividing point of nine-coordinate and ten-coordinate rare earth complexes with ttha ligand.

Ten‐Coordinate Neodymium(III) Complexes with Triethylenetetraaminehexaacetic Acid

AbstractThe crystal structures and spectroscopic (IR, Raman, UV/Vis) data for the complexes [C(NH2)3]2[Nd(HTTHA)]·3H2O (I) and [C(NH2)3]3[Nd(TTHA)]·6H2O (II) are presented. Crystals of I are triclinic, P$\bar {1}$, a = 9.998(2), b = 10.730(2), c = 15.557(3) Å, α = 106.89(3)°, β = 90.27(3)°, γ = 93.24(3)°, V = 1594.0(5) Å3, Z = 2, while the chiral crystals of II are monoclinic, P21, a = 10.157(2), b = 15.958(3), c = 12.788(3) Å, β = 112.68(3)°, V = 1912.5(7) Å3, Z = 2. Both structures consist of the complex monomeric anions, guanidinium cations and water of hydration. The NdIII ions are ten‐coordinate. The TTHA ligand coordinates to the NdIII ions with six of its carboxyl oxygen atoms and four nitrogen atoms. Although the coordination environments of both NdIII cations are essentially the same, the spectral results of both crystals reveal the influence of the degree of protonation of the ligand on the NdIII ion. The IR and Raman spectra allowed us to assign some important frequencies. A comparison of the electronic absorption spectra of NdIII–TTHA complexes in solution and in single crystals of I and II allows the detection of a small elongation of the Nd–O and Nd–N bonds in these complexes as compared to the [Nd(TTHA)]3– moiety in the previously reported complex Na3[Nd(TTHA)]·2.5NaClO4·7.617H2O and indicates that the coordination geometry of the ten‐coordinate neodymium complex in solution is the same as in the chiral crystal II. The intensities of the f–f transitions in NdIII–TTHA solutions and of crystals I and II were analysed on the basis of the Judd–Ofelt theory. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Rare earth metal complexes with triethylenetetraminehexaacetic acid

The crystal and molecular structures of K4[(Httha)2]·13.5H2O (ttha = triethylenetetraminehexaacetic acid), K4[(Httha)2]·14H2O, K3[DyIII (ttha)]·5H2O, K3[HoIII(ttha)]·5H2O and K3[ErIII(ttha)]·5H2O have been determined by single-crystal X-ray structure analyses. The crystal data of these five complexes are as follows: (1) K4[(Httha)2]·13.5H2O, monoclinic crystal system, P2(1)/n space group, Z = 4, μ = 2.339 mm−1 and F(000) = 3404. The final R and wR are 0.0514 and 0.0906 for 11,144 [I > 2.0 σ(I)] unique reflections, and 0.0976 and 0.1068 for all 26,048 reflections, respectively. (2) K4[(Httha)2]·14H2O, monoclinic crystal system, P2(1)/n space group, Z = 4, μ = 2.611 mm−1 and F(000) = 3424. The final R and wR are 0.0339 and 0.0667 for 10,699 [I > 2.0 σ(I)] unique reflections, and 0.0543 and 0.0741 for all 22,190 reflections, respectively. (3) K3[DyIII(ttha)]·5H2O, monoclinic crystal system, P2(1)/c space group, Z = 4, μ = 3.096 mm−1 and F(000) = 1716. The final R and wR are 0.0252 and 0.0600 for 5905 [I > 2.0 σ(I)] unique reflections, and 0.0336 and 0.0629 for all 16,415 reflections, respectively. (4) K3[HoIII(ttha)]·5H2O, monoclinic crystal system, P2(1)/c space group, Z = 4, μ = 3.217 mm−1 and F(000) = 1720. The final R and wR are 0.0395 and 0.0796 for 5145 [I > 2.0 σ(I)] unique reflections, and 0.0546 and 0.0833 for all 11,567 reflections, respectively. 5. K3[ErIII(ttha)]·5H2O, monoclinic crystal system, P2(1)/c space group, Z = 4, μ = 3.398 mm−1 and F(000) = 1724. The final R and wR are 0.0212 and 0.0463 for 5130 [I > 2.0 σ(I)] unique reflections, and 0.0258 and 0.0477 for all 11,796 reflections, respectively. The structure of K4[(Httha)2]·13.5H2O is composed of two parts, each has a binuclear nine-coordinate structure with distorted monocapped square antiprismatic prisms, in which the ttha ligand coordinates to one central EuIII ion with three N atoms and four O atoms and to the other EuIII ion with two O atoms. The K4[(Httha)2]·14H2O complex molecule is also composed of two parts in structure, each part has a binuclear nine-coordinate structure with distorted tri-capped trigonal prism. The [DyIII(ttha)]3− complex anion has a mononuclear nine-coordinate structure with distorted monocapped square antiprismatic geometry, in which the ttha ligand coordinates to the central DyIII ion with four N atoms and five O atoms. The [HoIII(ttha)]3− and [ErIII(ttha)]3− complex anions also have nine-coordinate structures, but the geometric conformation is close to a distorted tricapped trigonal prism. In addition, there is a free non-coordinated carboxyl group (–CH2COO−) in the [HoIII(ttha)]3− and [ErIII(ttha)]3− complex anions. The free carboxyl group could be embellished by biological molecules which have selectivity and affinity to focus positions.

Researches on crystal and molecular structures of nine-coordination mononuclear K[EuIII(Edta)(H2O)3]?3.5H2O and binuclear K4[Eu2III(HTtha)2]?13.5H2O

The crystal and molecular structures of the K[EuIII(Edta)(H2O)3] ⋅ 3.5H2O (I) (H4Edta = ethylenediaminetetraacetic acid) and K4[Eu2III(HTtha)2] ⋅ 13.5H2O (II) (H6Ttha = triethylenetetraminehexaacetic acid) complexes have been determined by single-crystal X-ray diffraction analyses. The crystal of I belongs to orthorhombic crystal system and Fdd2 space group. The crystal data are as follows: a = 1.9849(6)nm, b = 3.5598(11)nm, c = 1.2222(4)nm, V = 8.636(5)nm3, Z = 16, M = 596.37, ρ(calcd) = 1.835g/cm3, µ= 3.166mm−1, and F (000) = 4752. The final R and wR values are 0.0269 and 0.0692 for 2936 (I > 2.0 σ(I)) reflections and 0.0317 and 0.0708 for all 7284 unique reflections, respectively. The [EuIII(Edta)(H2O)3]− complex anion has a nine-coordination pseudo-monocapped square antiprismatic structure in which the nine coordinated atom are two N and seven O atoms (four from one Edta ligand and three water molecules). The crystal of II belongs to monoclinic system and P21/n space group. The crystal data are as follows: a = 1.1337(3)nm, b = 2.5753(6)nm, c = 2.2138(6) nm, β= 102.871(5)°, V = 6.301(3) nm3, Z = 4, M = 1682.33, ρ(calcd) = 1.773g/cm3, e = 2.339mm−1, and F(000) = 3404. The final R and wR are 0.0514 and 0.0906 for 11144 (I> 2.0σ(I)) reflections and 0.0976 and 0.1068 for all 26 048 unique reflections, respectively. The whole complex molecule is composed of two close parts in which every one has a nine-coordination structure as a distorted monocapped square antiprism. The Ttha ligand in the [Eu2III(HTtha)2]4− complex anion coordinates to one central Eu 3+ ion with three N atoms and four O atoms and to the other Eu3+ ion with two O atoms.

Syntheses and structural researches of nine-coordinate (NH 4) 2[Er III(Httha)]·6H 2O and ten-coordinate (CH 3NH 3) 3[Nd III(ttha)]·CH 3NH 2·4H 2O

The crystal and molecular structures of the (NH 4) 2[Er III(Httha)]·6H 2O (ttha=triethylenetetraminehexaacetic acid) and (CH 3NH 3) 3[Nd III(ttha)]·CH 3NH 2·4H 2O complexes have been determined by single-crystal X-ray structure analyses. The crystal of the (NH 4) 2[Er III(Httha)]·6H 2O complex belongs to monoclinic crystal system and P2(1)/ c space group. The crystal data are as follows: a=1.0324(4) nm, b=1.2745(4) nm, c=2.3170(8) nm, β=91.014°, V=3.0482(18) nm 3, Z=4, M=800.84, D c =1.743 g cm −3, μ=2.839 mm −1 and F(000)=1624. The final R and wR values are 0.0261 and 0.0696 for 5384 [ I>2.0 σ( I)] unique reflections, and 0.0329 and 0.0719 for all 12442 reflections, respectively. The complex [Er III(Httha)] 2− anion has a nine-coordinate pseudo-monocapped square antiprismatic structure in which the nine coordinate atoms, four N and five O are from one ttha ligand. The crystal of the (CH 3NH 3) 3[Nd III(ttha)]·CH 3NH 2·4H 2O complex belongs to triclinic system and P 1 ̄ space group. The crystal data are as follows: a=1.0772(3) nm, b=1.2194(4) nm, c=1.4505(4) nm, α=105.502(4)°, β=98.225(5)°, γ=99.906(5)°, V=1.7723(9) nm 3, Z=2, M=831.98, D c =1.559 g cm −3, μ=1.542 mm −1 and F(000)=862. The final R and wR are 0.0291 and 0.0786 for 6224 [ I>2.0 σ( I)] unique reflections, and 0.0348 and 0.0823 for all 7398 reflections, respectively. The complex [Nd III(ttha)] 3− anion has a ten-coordination structure with distorted bicapped square antiprismatic prism in which the ttha acts as a decadentate ligand with four N atoms of amino groups and six O atoms of carboxylic groups.

New Bismuth(III), Lanthanum(III), Praseodymium (III), and Heterodinuclear Bi–La and Bi–Pr Complexes with Polyaminocarboxylate Ligands

New Bi(III), La(III) and Pr(III) complexes with a variety of high-denticity polyaminocarboxylic acids (H 4edta, H 5dtpa, H 6ttha, H 4Cydta, H 5hpdta, H 4egta) have been synthesized and characterized spectroscopically by FTIR. In the case of the decadentate ttha ligand, homodinuclear M 2(ttha) ( M=Bi, La, Pr) and heterodinuclear MM′(ttha) complexes were isolated. Detailed investigations of their thermal degradation scheme were carried out in relationship with the possible use of these complexes as molecular precursors for the formation of mixed Bi–La and Bi–Pr oxides in which the crystal structure of the fluorite-like δ-Bi 2O 3 phase can be stabilized at room temperature. Decomposition proceeds in three successive stages, consisting of dehydration, ligand pyrolysis leading to monoxo-, dioxo- or simple carbonates, depending on the metal nature, and finally decarbonatation producing the corresponding oxide: α-Bi 2O 3, La 2O 3, Pr 6O 11, BiLaO 3 or BiPrO 3.

Bis(guanidinium) (Hydrogen triethylenetetraminehexaacetato)bismuthate(III) Tetrahydrate

The Bi atom in the title compound, (CH6N3)(2)[Bi-(C18H25N4O12)].4H(2)O, is nine-coordinated through four N and five O atoms of the ttha ligand, where ttha denotes triethylenetetraminehexaacetate. The noncoordinated COOH group is involved in a strong hydrogen bond with an O atom of a neighbouring complex, thereby forming dimeric units.

Crystal structure and absorption spectroscopy of a dimeric neodymium(III) complex with triethylenetetraaminehexaacetic acid (H6ttha), Na0.5H5.5[Nd2(ttha)2]·7.5NaClO4·16.83H2O

The crystal structure and absorption spectra (IR, UV/VIS) have been determined for Na0.5H5.5[Nd2(ttha)2]· 7.5NaClO4·16.83H2O (H6ttha = triethylenetetraaminehexaacetic acid). The structure consists of the complex dimer, perchlorate anions, sodium cations and water of hydration. Both neodymium(III) ions are nine-co-ordinate. Each ttha ligand is bonded to one NdIII through four of its carboxyl oxygen atoms and three of its nitrogen atoms. Two carboxyl oxygen atoms are bonded to the other NdIII, and the fourth nitrogen atom remains unco-ordinated. The co-ordination spheres of both NdIII are essentially the same and may be defined as distorted tricapped trigonal prisms. Absorption spectra of a single crystal were measured at room and liquid-helium temperatures. The intensities of the f–f transitions were analysed on the basis of Judd–Ofelt theory. Comparison of the absorption spectra of [Nd(ttha)]3– in solution to those of single crystals of Na3[Nd(ttha)]· 2.5NaClO4·7.617H2O and Na0.5H5.5[Nd2(ttha)2]·7.5NaClO4·16.83H2O compounds allowed us to estimate the ratio of mono- to di-meric species in solution.

Solvate structures in water‐methanol solutions of MRI contrast agents: Electron spin echo envelope modulation in gadolinium chelates

Electron Spin Echo Envelope Modulation (ESEEM) data are reported for three gadolinium (III) chelates, Gd-EDTA, Gd-DTPA, and Gd-TTHA, in frozen D2O/CH3OD glasses. This series includes Gd-DTPA, an MRI contrast agent that is in clinical use. Three-pulse electron spin echo modulation patterns can be modeled to yield geometrical information; e.g., distances and numbers of Gd+3-OD interactions. Interpreted by a spherical shell model, the data for Gd-TTHA are accounted for by Gd+3 surrounded by seven deuterons at an effective distance of 3.9 A. We attribute these deuterons to second-coordination sphere solvent molecules, since it is likely that Gd+3 is fully coordinated by a TTHA ligand. For analysis of ESEEM from Gd-EDTA and Gd-DTPA, the second-sphere structures of Gd-EDTA, Gd-DTPA, and Gd-TTHA are assumed equivalent. 2H-ESEEM from inner-sphere solvent molecules gives the effective distance between deuterons and Gd+3 to be approximately 2.7 A for the inner-sphere water in both EDTA and DTPA complexes. The results of simulations also give the isotropic hyperfine and quadrupole coupling constants for solvent deuterium in these systems. Possible sources of error in the determination of r and q by this method are discussed.