Magnetic properties of cyano-bridged Ln3+-M3+ complexes. Part I: trinuclear complexes (Ln3+ = La, Ce, Pr, Nd, Sm; M3+ = FeLS, Co) with bpy as blocking ligand

The reaction of Ln(NO3)3(aq) with K3[Fe(CN)6] or K3[Co(CN)6] and 2,2'-bipyridine in water/ethanol led to eight trinuclear complexes: trans-[M(CN)4(mu-CN)2{Ln(H2O)4(bpy)2}2][M(CN)6].8H2O (M = Fe3+ or Co3+, Ln = La3+, Ce3+, Pr3+, Nd3+, and Sm3+). The structures for the eight complexes [La2Fe] (1), [Ce2Fe] (2), [Pr2Fe] (3), [Nd2Fe] (4), [Ce2Co] (5), [Pr2Co] (6), [Nd2Co] (7), and [Sm2Co] (8) have been solved; they crystallize in the triclinic space group P and are isomorphous. They exhibit a supramolecular 3D architecture through hydrogen bonding and pi-pi stacking interactions. A stereochemical study of the nine-vertex polyhedra of the lanthanide ions, based on continuous shape measures, is presented. No significant magnetic interaction was found between the lanthanide(III) and the iron(III) ions.     

Utility of Arylamido Ligands in Yttrium and Lanthanide Chemistry(1)

The reactivity of KNHAr reagents (Ar = C(6)H(5), C(6)H(3)Me(2)-2,6, C(6)H(3)(i)Pr(2)-2,6) with lanthanide and yttrium trichlorides has been investigated. With the larger metals Nd and Sm and the smaller 2,6-dimethyl-substituted ligand, the bimetallic dianionic complexes [K(THF)(6)](2)[Ln(&mgr;-NHC(6)H(3)Me(2)-2,6)(NHC(6)H(3)Me(2)-2,6)(3)](2) (Ln: Sm, 1a; Nd, 1b) are isolated as the potassium salts. Under the same reaction conditions YCl(3) forms a bimetallic anion which retains chloride: [K(DME)(2)(THF)(3)][Y(2)(&mgr;-NHC(6)H(3)Me(2)-2,6)(2)(&mgr;-Cl)(NHC(6)H(3)Me(2)-2,6)(4)(THF)(2)], 2. With the larger 2,6-diisopropyl ligands, neutral complexes are isolated in both solvated monometallic and unsolvated bimetallic forms. With Nd, a distorted octahedral trisolvate, Nd(NHC(6)H(3)(i)Pr(2)-2,6)(3)(THF)(3), 3, was obtained, whereas with Yb and Y the trigonal bipyramidal disolvates, Ln(NHC(6)H(3)(i)Pr(2)-2,6)(3)(THF)(2) (Ln: Yb, 4a; Y, 4b), were isolated. THF-free complexes of the NHC(6)H(3)(i)Pr(2)-2,6 ligand are available by reacting the amine NH(2)C(6)H(3)(i)Pr(2)-2,6 with Ln[N(SiMe(3))(2)](3) complexes. By this route, the dimers [Ln(&mgr;-NHC(6)H(3)(i)Pr(2)-2,6)(NHC(6)H(3)(i)Pr(2)-2,6)(2)](2) (Ln: Yb, 5a; Y, 5b) were isolated. The reaction of the unsubstituted arylamido salt KNHC(6)H(5) with NdCl(3) produced an insoluble material which was characterized as [Nd(NHC(6)H(5))(3)(KCl)(3)], 6. 6 reacted with Al(2)Me(6) in hexanes and produced a heteroleptic mixed-metal complex {[Me(2)Al(&mgr;-Me(2))](2)Nd(&mgr;(3)-NC(6)H(5))(&mgr;-Me)AlMe}(2), 7, and the trimeric aluminum arylamido complex [Me(2)Al(&mgr;-NHC(6)H(5))](3), 8. The solvent of crystallization and relevant crystallographic data for the compounds identified by X-ray analysis follow: 1a,THF, 156 K, P2(1)/n, a = 12.985(2) ?, b = 27.122(5) ?, c = 17.935(3) ?, beta = 100.19(1) degrees, V = 6216(1) ?(3), Z = 2, 6148 reflections (I > 3sigma(I)), R(F)() = 7.1%; 1b,THF, 156 K, P2(1)/n, a = 12.998(2) ?, b = 27.058(3) ?, c = 17.962(2) ?, beta = 99.74(1) degrees, V = 6225(1) ?(3), Z = 2; 2,DME/hexanes, P2(1)/n, a = 23.335(2) ?, b = 12.649(1) ?, c = 27.175(3) ?, beta = 96.36(1) degrees, V = 7971(1) ?(3), Z = 4, 2788 reflections (I > 3sigma(I)), R(F)() = 9.5%; 3, THF, P2(1), a = 12.898(1) ?, b = 16.945(1) ?, c = 13.290(1) ?, beta = 118.64(2) degrees, V = 2549.3(3) ?(3), Z = 2, 3414 reflections (I > 3sigma(I)), R(F)() = 4.3%; 4a, hexanes, P2(1), a = 9.718(2) ?, b = 19.119(3) ?, c = 12.640(2) ?, beta = 112.08(1) degrees, V = 2176.3(6) ?(3), Z = 2, 2933 reflections (I > 3sigma(I)), R(F)() = 4.3%; 4b, hexanes, 158 K, a = 9.729(2) ?, b = 19.095(5) ?, c = 12.744(1) ?, beta = 112.11(1) degrees, V = 2193.4(6) ?(3); 5b, hot toluene, 158 K, P2(1), a =19.218(9) ?, b = 9.375(3) ?, c = 19.820(5) ?, beta = 110.25(2) degrees, V = 3350(2)?(3), Z = 2, 1718 reflections (I > 2sigma (I)), R1 = 9.7%; 7, hexanes, 156 K, P&onemacr;, a = 9.618(3) ?, b = 12.738(4) ?, c = 9.608(3) ?, alpha = 99.32(1) degrees, beta = 108.87(1) degrees, gamma = 94.23(1) degrees, V = 1089.1(6) ?(3), Z = 2, 2976 reflections (I > 3sigma(I)), R(F)() = 3.9%; 8, hexanes, 156 K, Pcab, a = 23.510(5) ?, b = 25.462(5) ?, c = 8.668(2) ?, V = 5188(1) ?(3), Z = 8, 1386 reflections (I > 3sigma(I)), R(F)() = 5.7%.     

Synthesis and characterization of heterodinuclear Ln(3+)-Fe3+ and Ln(3+)-Co3+ complexes,bridged by cyanide ligand (Ln3+ = lanthanide ions). Nature of the magnetic interaction in the Ln(3+)-Fe3+ complexes

The reaction of Ln(NO3)3.aq with K3[Fe(CN)6] or K3[Co(CN)6] in N,N'-dimethylformamide (DMF) led to 25 heterodinuclear [Ln(DMF)4(H2O)3(mu-CN)Fe(CN)5].nH2O and [Ln(DMF)4(H2O)3(mu-CN)Co(CN)5].nH2O complexes (with Ln = all the lanthanide(III) ions, except promethium and lutetium). Five complexes (Pr(3+)-Fe3+), (Tm(3+)-Fe3+), (Ce(3+)-Co3+), (Sm(3+)-Co3+), and (Yb(3+)-Co3+) have been structurally characterized; they crystallize in the equivalent monoclinic space groups P21/c or P21/n. Structural studies of these two families show that they are isomorphous. This relationship in conjunction with the diamagnetism of the Co3+ allows an approximation to the nature of coupling between the iron(III) and the lanthanide(III) ions in the [Ln(DMF)4(H2O)3(mu-CN)Fe(CN)5].nH2O complexes. The Ln(3+)-Fe3+ interaction is antiferromagnetic for Ln = Ce, Nd, Gd, and Dy and ferromagnetic for Ln = Tb, Ho, and Tm. For Ln = Pr, Eu, Er, Sm, and Yb, there is no sign of any significant interaction. The isotropic nature of Gd3+ helps to evaluate the value of the exchange interaction.     

Spectroscopic and magnetic properties of a series of μ-cyano bridged bimetallic compounds of the type M(II)-NC-Fe(III) (M = Mn, Co, and Zn) using the building block [Fe(III)(CN)5imidazole]2-

In this contribution, we describe the preparation and single-crystal X-ray diffraction of a new building block for bimetallic solid state materials. X-ray diffraction data of these complexes indicate that (PPh(4))(2)[Fe(CN)(5)imidazole]·2H(2)O crystallizes in the triclinic space group P1 with a = 9.8108(15) ?, b = 11.1655(17) ?, c = 23.848(4) ?, α = 87.219(2)°, β = 85.573(2)°, γ = 70.729(2)°, and Z = 2, while its precursor Na(3)[Fe(CN)(5)(en)]·5H(2)O crystallizes in the monoclinic space group P2(1)/n with a = 8.3607(7) ?, b = 11.1624(9) ?, c = 17.4233(14) ?, β = 90.1293(9)°, and Z = 4. Spectroscopic and magnetic properties of a series of bimetallic materials were obtained by reaction of the complex [Fe(CN)(5)imidazole](2-) with hydrated transition metal ions [M(H(2)O)(n)](2+) (M = Mn, Co, Zn; n = 4 or 6). The new bimetallic materials obtained are [Co(H(2)O)(2)][Fe(CN)(5)imidazole]·2H(2)O (1), [Mn(CH(3)OH)(2)][Fe(CN)(5)imidazole] (2), Zn[Fe(CN)(5)imidazole]·H(2)O (3), and [Mn(bpy)][Fe(CN)(5)imidazole].H(2)O (4). All of the complexes crystallize in the orthorhombic system. X-ray single-crystal analysis of the compounds identified the Imma space group with a = 7.3558(10) ?, b = 14.627(2) ?, c = 14.909(2) ?, and Z = 4 for 1; the P2(1)2(1)2(1) space group with a = 7.385(5) ?, b = 13.767(9) ?, c = 14.895(10) ?, and Z = 4 for 2; the Pnma space group with a = 13.783(2) ?, b = 7.167(11) ?, c = 12.599(2) ?, and Z = 4 for 3; and the Pnma space group with a = 13.192(3) ?, b = 7.224(16) ?, c = 22.294(5) ?, and Z = 4 for 4. The structures of 1, 2, and 4 consist of two-dimensional network layers containing, as the repeating unit, a cyclic tetramer [M(2)Fe(2)(CN)(4)] (M = Mn, Co). H bonding between the layers in the structure of 1 results in a quasi-three-dimensional network. The structure of 3 was found to be three-dimensional, where all of the cyano ligands are involved in bridging between the metal centers. The bridging character of the cyano is confirmed spectroscopically. The magnetic properties have been investigated for all of the bimetallic systems. Compound 1 shows ferromagnetic behavior with an ordering temperature at 25 K, which is higher than the corresponding Prussian Blue analogue Co(x)[Fe(CN)(6)](y)?·zH(2)O. Compound 2 shows weak ferromagnetic behavior and an interlayer antiferromagnetic character, while 3, as expected, shows paramagnetic character due to the diamagnetic character of Zn(2+). Compound 4 shows antiferromagnetic behavior.     

Lanthanide-3d cyanometalate chains Ln(III)-M(III) (Ln=Pr, Nd, Sm, Eu, Gd, Tb; M=Fe) with the tridentate ligand 2,4,6-tri(2-pyridyl)-1,3,5-triazine (tptz): evidence of ferromagnetic interactions for the Sm(III)-M(III) compounds (M=Fe, Cr)

A series of cyanide-bridged chain mixed Fe(III)/Ln(III) (Ln=Pr, Nd, Sm, Eu, Gd, Tb) complexes with the tridentate ligand 2,4,6-tri(2-pyridyl)-1,3,5-triazine (tptz) used as a capping group has been prepared. Reactions of tptz and LnCl3 with K3Fe(CN)6 yield a family of air-stable 1-D compounds {[Pr(tptz)(H2O)4Fe(CN)6].8H2O}infinity, {[Nd(tptz)(H2O)4Fe(CN)6].8H2O}infinity, {[Sm(tptz)(H2O)4Fe(CN)6].8H2O}, {[Eu(tptz)(H2O)4Fe(CN)6].6H2O}infinity, {[Gd(tptz)(H2O)4Fe(CN)6].6H2O}infinity, and {[Tb(tptz)(H2O)4Fe(CN)6].8H2O}infinity. Temperature dependent magnetic susceptibility studies of reveal that in , the Sm(III) and Fe(III) ions are ferromagnetically coupled with 3-D ordering occurring below 3.5 K. The appearance of the frequency dependent out-of-phase signal is explained in terms of an ordering with a spin glass-like behavior. To compare the magnetic behavior of with related compounds, {[Sm(tptz)(H2O)4Co(CN)6].8H2O}infinity and {[La(tptz)(DMF)(H2O)3Fe(CN)6].5H2O}infinity, {[Sm(tmphen)(DMF)3(H2O)Fe(CN)6].2H2O}infinity, {[Sm(tmphen)2(H2O)2Fe(CN)6].MeOH.13H2O}infinity and {[Sm(tmphen)2(H2O)2Cr(CN)6].MeOH.9H2O}infinity with 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen) were also prepared.     

Three-dimensional 3d-4f heterometallic coordination polymers: synthesis, structures, and magnetic properties

Three new 3d-4f heterometallic coordination polymers, [Ln(2)(H(2)O)(4)M(2)(H(2)O)(2)(QA)(5)].nH(2)O (H(2)QA = quinolinic acid; Ln = Gd, M = Ni, n = 7 (1); Ln = Gd, M = Co, n = 6.5 (2); Ln = Dy, M = Co, n = 6.5 (3)), have been synthesized through hydrothermal pretreatment and cooling-down crystallization. These compounds possess the isostructural 3D frameworks with 1D chairlike channels along the c axis, which are occupied by noncoordinating water molecules. Crystal data: for 1, C(35)H(41)Gd(2)Ni(2)N(5)O(33), orthorhombic, space group Pna2(1), with a = 28.567(6) A, b = 14.498(3) A, c = 12.250(2) A, and Z = 4; for 2, C(35)H(40)Gd(2)Co(2)N(5)O(32.5), orthorhombic, space group Pna2(1), with a = 28.843(3) A, b = 14.4325(13) A, c = 12.2275(9) A, and Z = 4; for 3, C(35)H(40)Dy(2)Co(2)N(5)O(32.5), orthorhombic, space group Pna2(1), with a = 28.8471(14) A, b = 14.4534(10) A, c = 12.2520(7) A, and Z = 4. The magnetic behaviors for the three compounds have been investigated.     

Structural and photophysical properties of coordination networks combining [Ru(bipy)(CN)4]2- anions and lanthanide(III) cations: rates of photoinduced Ru-to-lanthanide energy transfer and sensitized near-infrared luminescence

Co-crystallization of K2[Ru(bipy)(CN)4] with lanthanide(III) salts (Ln = Pr, Nd, Gd, Er, Yb) from aqueous solution affords coordination oligomers and networks in which the [Ru(bipy)(CN)4]2- unit is connected to the lanthanide cation via Ru-CN-Ln bridges. The complexes fall into two structural types: [{Ru(bipy)(CN)4}2{Ln(H2O)m}{K(H2O)n}] x xH2O (Ln = Pr, Er, Yb; m = 7, 6, 6, respectively), in which two [Ru(bipy)(CN)4]2- units are connected to a single lanthanide ion by single cyanide bridges to give discrete trinuclear fragments, and [{Ru(bipy)(CN)4}3{Ln(H2O)4}2] x xH2O (Ln = Nd, Gd), which contain two-dimensional sheets of interconnected, cyanide-bridged Ru2Ln2 squares. In the Ru-Gd system, the [Ru(bipy)(CN)4]2- unit shows the characteristic intense (3)metal-to-ligand charge transfer luminescence at 580 nm with tau = 550 ns; with the other lanthanides, the intensity and lifetime of this luminescence are diminished because of a Ru --> Ln photoinduced energy transfer to low-lying emissive states of the lanthanide ions, resulting in sensitized near-infrared luminescence in every case. From the degree of quenching of the Ru-based emission, Ru --> Ln energy-transfer rates can be estimated, which are in the order Yb (k(EnT) approximately 3 x 10(6) sec(-1), the slowest energy transfer) < Er < Pr < Nd (k(EnT) approximately 2 x 10(8) sec(-1), the fastest energy transfer). This order may be rationalized on the basis of the availability of excited f-f levels on the lanthanide ions at energies that overlap with the Ru-based emission spectrum. In every case, the lifetime of the lanthanide-based luminescence is short (tens/hundreds of nanoseconds, instead of the more usual microseconds), even when the water ligands on the lanthanide ions are replaced by D2O to eliminate the quenching effects of OH oscillators; we tentatively ascribe this quenching effect to the cyanide ligands.     

Transition Metal Complexes of p-Sulfonatocalix[5]arene

The X-ray crystal structure of the p-sulfonatocalix[5]arene(5)(-) anion (1b) in the form of the dimeric hydrate Na(10)[p-sulfonatocalix[5]arene](2).33.5H(2)O (2) is reported. The reactions of 1b with a number of transition metal salts to form transition metal bridged bis(calixarene) inclusion complexes have also been investigated. The X-ray crystal structure of the "Co(H(2)O)(4)(2+)" bridged species Na(8)[Co(H(2)O)(4)(p-sulfonatocalix[5]arene)(2)].2CH(3)C(O)N(CH(3))(2).37H(2)O (3) which incorporates a "supercavity" large enough to encompass 2 N,N-dimethylacetamide (dma) guest molecules as well as ca. 15 water molecules and Na(+) ions is reported. Crystal data are as follows: for 2, monoclinic space group P2(1)/c, Z = 4, a = 22.0644(4), b = 19.1180(3), c = 27.7834(4) ?, beta = 91.780(1), V = 11714.1(5) ?(3); complex 3, orthorhombic space group Pnma, Z = 4, a = 22.2271(5), b = 30.1693(6), c = 18.8503(4) ?, V = 12640.6(5) ?(3).     

Synthesis, crystal structure, and photochromism of novel two-dimensional supramolecular networks based on Keggin-type polyoxoanion and lanthanide coordination cations

Three new compounds [Ln(NMP)(4)(H(2)O)(4)][H(x)()GeMo(12)O(40)].2NMP.3H(2)O (Ln = Ce(IV) (1), Pr(IV) (2), x = 0; Ln = Nd(III) (3), x = 1; NMP = N-methyl-2-pyrrolidone) have been prepared in aqueous solution and characterized by elemental analyses, IR, UV-vis, and TG analyses. The single crystal X-ray diffraction shows that all three compounds are isostructural. In their structures, an interesting two-dimensional supramolecular network is constructed by the [GeMo(12)O(40)](4)(-) anion and [Ln(NMP)(4)(H(2)O)(4)](3+/4+) cation building blocks via hydrogen-bonding interactions, exhibiting the porous structure. Upon irradiation with UV light, the crystals of 1-3 show photochromic behavior.     

Interconvertable modular framework and layered lanthanide(III)-etidronic acid coordination polymers

Isostructural modular microporous Na2[Y(hedp)(H2O)0.67] and Na4[Ln2(hedp)2(H2O)2].nH2O (Ln = La, Ce, Nd, Eu, Gd, Tb, Er) framework-type, and layered orthorhombic [Eu(H2hedp)(H2O)2].H2O and Na0.9[Nd0.9Ge0.10(Hhedp)(H2O)2], monoclinic [Ln(H2hedp)(H2O)].3H2O (Ln = Y, Tb), and triclinic [Yb(H2hedp)].H2O coordination polymers based on etidronic acid (H5hedp) have been prepared by hydrothermal synthesis and characterized structurally by (among others) single-crystal and powder X-ray diffraction and solid-state NMR. The structure of the framework materials comprises eight-membered ring channels filled with Na+ and both free and lanthanide-coordinated water molecules, which are removed reversibly by calcination at 300 degrees C (structural integrity is preserved up to ca. 475 degrees C), denoting a clear zeolite-type behavior. Interesting photoluminescence properties, sensitive to the hydration degree, are reported for Na4[Eu2(hedp)2(H2O)2].H2O and its fully dehydrated form. The 3D framework and layered materials are, to a certain extent, interconvertable during the hydrothermal synthesis stage via the addition of HCl or NaCl: of the 3D framework Na4[Tb2(hedp)2(H2O)2].nH2O, affords layered [Tb(H2hedp) (H2O)].3H2O, whereas layered [Tb(H2hedp)(H2O)2].H2O reacts with sodium chloride yielding a material similar to Na4[Tb2(hedp)2(H2O)2].nH2O. In layered [Y(H2hedp)(H2O)].3H2O, noncoordinated water molecules are engaged in cooperative water-to-water hydrogen-bonding interactions, leading to the formation of a (H2O)13 cluster, which is the basis of an unprecedented two-dimensional water network present in the interlayer space.     

Syntheses, structure, and luminescent properties of novel hydrated rare earth borates Ln2B6O10OH4•H2O (Ln = Pr, Nd, Sm, Eu, Gd, Dy, Ho, and Y)

Ln(2)B(6)O(10)(OH)(4)?H(2)O (Ln = Pr, Nd, Sm-Gd, Dy, Ho, and Y), a new series of hydrated rare earth borates, have been synthesized under hydrothermal conditions. A single crystal of Nd analogue was used for the structure determination by X-ray diffraction. It crystallizes in the monoclinic space group C2/c with lattice constants a = 21.756(4), b = 4.3671(9), c = 12.192(2) ?, and β = 108.29(3)°. The other compounds are isostructural to Nd(2)B(6)O(10)(OH)(4)?H(2)O. The fundamental building block (FBB) of the polyborate anion in this structure is a three-membered ring [B(3)O(6)(OH)(2)](5-). The FBBs are connected by sharing oxygen atoms forming an infinite [B(3)O(5)(OH)(2)](3-) chain, and the chains are linked by hydrogen bonds, establishing a two-dimensional (2-D) [B(6)O(10)(OH)(4)?H(2)O](6-) layer. The 2-D borate layers are thus interconnected by Ln(3+) ions to form the complex three-dimensional structure. Ln(2)B(6)O(10)(OH)(4)?H(2)O dehydrates stepwise, giving rise to two new intermediate compounds Ln(2)B(6)O(10)(OH)(4) and Ln(2)B(6)O(11)(OH)(2). The investigation on the luminescent properties of Gd(2-2x)Eu(2x)B(6)O(10)(OH)(4)?H(2)O (x = 0.01-1.00) shows a high efficiency of Eu(3+) f-f transitions and the existence of the energy transfer process from Gd(3+) to Eu(3+). Eu(2)B(6)O(10)(OH)(4)?H(2)O and its two dehydrated products, Eu(2)B(6)O(10)(OH)(4) and Eu(2)B(6)O(11)(OH)(2), present the strongest emission peak at 620 nm ((5)D(0) → (7)F(2) transition), which may be potential red phosphors.     

Tuning of magnetic properties of polynuclear lanthanide(III)-octacyanotungstate(V) systems: determination of ligand-field parameters and exchange interaction

The self-assembly reaction between trivalent lanthanide ions, 2,2':6',2' '-terpyridine (terpy) ligand, and octacyanotungstate(V) leads to the formation of two series of isomorphous cyano-bridged compounds: (i) one-dimensional (1-D) chains [Ln(terpy)(DMF)(4)][W(CN)(8)].6H(2)O.C(2)H(5)OH (Ln = Ce-Dy) and (ii) dinuclear molecules [Ln(terpy)(DMF)(2)(H(2)O)(2)][W(CN)(8)].3H(2)O (Ln = Ho, Er, Yb) and the ionic [Tm(III)(terpy)(DMF)(2)(H(2)O)(3)][WV(CN)(8)].4H(2)O.DMF (DMF = N,N-dimethylformamide) system. The crystal structures of 1-D chains consist of alternating {[W(CN)(8)]} and {[Ln(terpy)]} building blocks. The neighboring chains are weakly linked through the pi-pi stacking interactions of the aromatic rings, leading to two-dimensional supramolecular layers. The dinuclear species are weakly linked through the hydrogen bonds between H2O molecules and terminal cyano ligands resulting in a columnlike arrangement of dimers. Taking into account the ligand-field splitting and the exchange interaction, we have estimated the magnetic couplings between the Ln(III) and WV centers in a series of polycrystalline 1-D chains and in dimeric systems. The corresponding exchange constants have been shown to change the sign along the series of chains. The coupling is antiferromagnetic for 1 (J = -0.24 cm(-1)) and 2 (J = -0.07 cm(-1)), whereas 3 (J = +0.47 cm(-1)), 7 (J = +0.28 cm(-1)), and 8 (J = +0.23 cm(-1)) have ferromagnetic character. In the case of dimeric systems, the coupling constants seem to be independent of the lanthanide center. The splitting structures of the ground-state multiplets of the Ln(III) centers have been shown to explain the temperature dependences of the magnetic susceptibilities.     

Two series of novel rare earth complexes with dicyanamide [Ln(dca)2(phen)2(H2O)3][dca].(phen), (Ln = Pr, Gd, and Sm) and [Ln(dca)3(2,2'-bipy)2(H2O)]n, (Ln = Gd, Sm, and La): syntheses, crystal structures, and magnetic properties

Two series of novel complexes, [Ln(dca)(2)(Phen)(2)(H(2)O)(3)](dca).(phen) (Ln = Pr (1), Gd (2), and Sm (3), dca = N(CN)(-), phen = 1,10-phenanthroline) and [Ln(dca)(3)(2,2'-bipy)(2)(H(2)O)](n), (Ln = Gd (4), Sm (5), and La (6), 2,2'-bipy = 2,2'-bipydine), have been synthesized and structurally characterized by X-ray crystallography. The crystal structures of the first series (1-3) are isomorphous and consist of discrete [Ln(dca)(2)(Phen)(2)(H(2)O)(3)]+ cations, dca anions, and lattice phen molecules; whereas the structures of the second series (4-6) are characterized by infinite chains [Ln(dca)(3)(2,2'-bipy)(2)(H(2)O)](n). The Ln(III) atoms in all complexes are nine-coordinated and form a distorted tricapped trigonal prism environment. The three-dimensional frameworks of 1-6 are constructed by intermolecular hydrogen bond interactions. Variable-temperature magnetic susceptibility measurements for complexes 1, 2, 4, and 5 indicate a Curie-Weiss paramagnetic behavior over 5-300 K.     

New luminescent solids in the Ln-W(Mo)-Te-O-(Cl) systems

Solid-state reactions of lanthanide(III) oxide (and/or lanthanide(III) oxychloride), MoO3 (or WO3), and TeO2 at high temperature lead to eight new luminescent compounds with four different types of structures, namely, Ln2(MoO4)(Te4O10) (Ln = Pr, Nd), La2(WO4)(Te3O7)2, Nd2W2Te2O13, and Ln5(MO4)(Te5O13)(TeO3)2Cl3 (Ln = Pr, Nd; M = Mo, W). The structures of Ln2(MoO4)(Te4O10) (Ln = Pr, Nd) feature a 3D network in which the MoO4 tetrahedra serve as bridges between two lanthanide(III) tellurite layers. La2(WO4)(Te3O7)2 features a triple-layer structure built of a [La2WO4]4+ layer sandwiched between two Te3O72- anionic layers. The structure of Nd2W2Te2O13 is a 3D network in which the W2O108- dimers were inserted in the large tunnels of the neodymium(III) tellurites. The structures of Ln5(MO4)(Te5O13)(TeO3)2Cl3 (Ln = Pr, Nd; M = Mo, W) feature a 3D network structure built of lanthanide(III) ions interconnected by bridging TeO32-, Te5O136-, and Cl- anions with the MO4 (M = Mo, W) tetrahedra capping on both sides of the Ln4 (Ln = Pr, Nd) clusters and the isolated Cl- anions occupying the large apertures of the structure. Luminescent studies indicate that Pr2(MoO4)(Te4O10) and Pr5(MO4)(Te5O13)(TeO3)2Cl3 (M = Mo, W) are able to emit blue, green, and red light, whereas Nd2(MoO4)(Te4O10), Nd2W2Te2O13, and Nd5(MO4)(Te5O13)(TeO3)2Cl3 (M = Mo, W) exhibit strong emission bands in the near-IR region.     

Synthesis, crystal structure, and magnetic studies of one-dimensional cyano-bridged Ln3+-Cr3+ complexes with bpy as a blocking ligand

The reaction of Ln(NO3)3.aq with K3[Cr(CN)6] and 2,2'-bipyridine (bpy) in a water/ethanol solution led to two families of complexes: 4 one-dimensional (1D) complexes of the formula trans-[Cr(CN)4(mu-CN)2Ln(H2O)3(bpy)2]n.4nH2O.3.5nbpy (Ln3+ = La, Ce, Pr, and Nd) and 10 1D complexes of the formula trans-[Cr(CN)4(mu-CN)2Ln(H2O)4(bpy)]n.3.5nH2O.1.5nbpy (Ln3+ = Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu). The structures for the fourteen complexes [LaCr]n (1), [CeCr]n (2), [PrCr]n (3), [NdCr]n (4), [NdCr]n (4'), [SmCr]n (5), [EuCr]n (6), [TbCr]n (7), [DyCr]n (8), [HoCr]n (9), [ErCr]n (10), [TmCr]n (11), [YbCr]n (12), and [LuCr]n (13) have been solved. Complexes 1-4 crystallize in the orthorhombic space group Pbam and are isomorphous; complexes 4'-13 crystallize in the triclinic space group PI and are isomorphous. The X-ray structural characterization of complexes 1-4 shows the presence of a discrete decameric water cluster built around a cyclic hexameric core stabilized by the solid-state structure, which represents another new mode of association of water molecules. The Ln3+-Cr3+ magnetic interaction is negligible in 6 and 12, antiferromagnetic in 2, 4', 7, 8, 9, 10, and 11, and unresolved for 3. The complex 5 is a ferrimagnet because its magnetic studies suggest the onset of a very weak ferromagnetic three-dimensional ordering.     

New compounds from tellurocyanide rhenium cluster anions and 3d-transition metal cations coordinated with ethylenediamine

The compounds [Ni(en)(3)](2)[Re(6)Te(8)(CN)(6)].10H(2)O (1), [Ni(NH(3))(4)(en)](2)[Re(6)Te(8)(CN)(6)].2H(2)O (2), [Ni(NH(3))(2)(en)(2)][(Ni(en)(2))(3)(Re(4)Te(4)(CN)(12))(2)].38H(2)O (3), [Co(NH(3))(2)(en)(2)](2)[(Co(en)(2))Re(6)Te(8)(CN)(6)]Cl(2).H(2)O (4),and [(Zn(H(2)O)(en)(2))(Zn(en)(2))Re(6)Te(8)(CN)(6)].3H(2)O (5) (en = ethylenediamine) have been synthesized and characterized. Compounds 1, 4, and 5 have been synthesized by the diffusion of an aqueous (for 1 and 5) or an ammonia (for 4) solution of Cs(4)[Re(6)Te(8)(CN)(6)].2H(2)O into a glycerol solution of NiCl(2).6H(2)O (for 1), CoCl(2).6H(2)O (for 4), or ZnCl(2) (for 5). Compounds 2 and 3 have been synthesized by the reaction of an aqueous solution of Cs(4)[Re(6)Te(8)(CN)(6)].2H(2)O (for 2) or K(4)[Re(4)Te(4)(CN)(12)].5H(2)O (for 3) with an ammonia solution of Ni(en)(2)Cl(2). Compounds 1 and 2 are ionic whereas compounds 4 and 5 are one-dimensional polymers. Compound 3, a two-dimensional polymer, possesses hexagonal shaped channels of approximate diameter 10-12 A. Because the framework of compound 3 is robust, it is an attractive host for guest molecules of appropriate size and shape. The potential "guest" volume is about 37% of the unit cell volume.     

Trinuclear lanthanide complexes of a compartmental ligand N,N'-bis(2-pyridinyl)-2,6-pyridinedicarboxamide: a spectroscopic investigation

Trinuclear lanthanide complexes of the formula [Ln(3)(PPDA)(NO(3))(6)(H(2)O)(2)].NO(3).2H(2)O where Ln=La(III), Pr(III), Sm(III), Nd(III), Eu(III) Gd(III) Tb(III), Dy(III) and Y(III); H(2)PPDA=N,N'-bis(2-pyridinyl)-2,6-pyridinedicarboxamide, have been isolated. The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibility measurements and spectral (IR, NMR, UV-vis, fluorescence, FAB and EPR) and thermal studies.     

Bifunctional Mixed-Lanthanide Cyano-Bridged Coordination Polymers Ln(0.5)Ln'(0.5)(H(2)O)(5)[W(CN)(8)] (Ln/Ln' = Eu(3+)/Tb(3+), Eu(3+)/Gd(3+), Tb(3+)/Sm(3+))

A new family of mixed-lanthanide cyano-bridged coordination polymers Ln(0.5)Ln'(0.5)(H(2)O)(5)[W(CN)(8)] (where Ln/Ln' = Eu(3+)/Tb(3+), Eu(3+)/Gd(3+), and Tb(3+)/Sm(3+)) containing two lanthanide and one transition metal ions were obtained and characterized by X-ray diffraction, photoluminescence spectroscopy, magnetic analyses, and theoretical computation. These compounds are isotypical and crystallize in the tetragonal system P4/nmm forming two-dimensional grid-like networks. They present a magnetic ordering at low temperature and display the red Eu(3+) ((5)D(0) → (7)F(0-4)) and green Tb(3+) ((5)D(4) → (7)F(6-2)) characteristic photoluminescence. The Tb(0.5)Eu(0.5)(H(2)O)(5)[W(CN)(8)] compound presents therefore green and red emission and shows Tb(3+)-to-Eu(3+) energy transfer.     

Structural and photophysical properties of coordination networks combining [Ru(Bpym)(CN)4]2- or [[Ru(CN)4]2(mu-bpym)]4- anions (bpym = 2,2'-bipyrimidine) with lanthanide(III) cations: sensitized near-infrared luminescence from Yb(III), Nd(III), and Er(III) following Ru-to-lanthanide energy transfer

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.     

稀土冠醚配合物的研究 XI: 稀土(III)硝酸盐与戊二酰双(苯并-15-冠-5)配合物的合成和性质研究

本工作合成了十五个新的镧系、钇的硝酸盐和戊二酰双(苯并-15-冠-5)的配合物,并进行了元素分析、紫外光谱、红外光谱、激光拉曼光谱、差热和热重等性质研究, 对这一系列稀土配合物的性质作了比较。