Synthesis, crystal structures, and properties of oxovanadium(IV)-lanthanide(III) heteronuclear complexes

A new series of oxovanadium(IV)-lanthanide(III) heteronuclear complexes [Yb(H2O)8]2[(VO)2(TTHA)](3)21 H2O (1), {[Ho(H2O)7(VO)2(TTHA)][(VO)2(TTHA)](0.5)} 8.5 H2O (2), {[Gd(H2O)7(VO)2(TTHA)][(VO)2(TTHA)](0.5)}8.5 H2O (3), {[Eu(H2O)7][(VO)2(TTHA)](1.5)} 10.5 H2O (4), and [Pr2(H2O)6(SO4)2][(VO)2(TTHA)] (5) (H6TTHA=triethylenetetraaminehexaacetic acid) were prepared by using the bulky flexible organic acid H(6)TTHA as structure-directing agent. X-ray crystallographic studies reveal that they contain the same [(VO)2(TTHA)]2- unit as building block, but the Ln3+ ion lies in different coordination environments. Although the lanthanide ions always exhibit similar chemical behavior, the structures of the complexes are not homologous. Compound 1 is composed of a [Yb(H2O)8]3+ ion and a [(VO)2(TTHA)]2- ion. Compounds 2 and 3 are isomorphous; both contain a trinuclear [Ln(H2O)7(VO)2(TTHA)]+ (Ln=Ho for 2 and Gd for 3) ion and a [(VO)2(TTHA)]2- ion. Compound 4 is an extended one-dimensional chain, in which each Eu3+ ion links two [(VO)2(TTHA)]2- ions. For 5, the structure is further assembled into a three-dimensional network with an interesting framework topology comprising V2Pr2 and V4Pr2 heterometallic lattices. Moreover, 4 and 5 are the first oxovanadium(IV)-lanthanide(III) coordination polymers and thus enlarge the realm of 3d-4f complexes. The IR, UV/Vis, and EPR spectra and the magnetic properties of the heterometallic complexes were studied. Notably, 2 shows unusual ferromagnetic interactions between the VO2+ and Ho3+ ions.     

Synthesis,structure, and ESR spectra of the new heteronuclear complex {Li4(VO)2[(OOC)2C(H)Bu]4(H2O)8}·H2O

The reaction of an aqueous solution of vanadyl sulfate VOSO₄·3H₂O, butylmalonic acid (H₂Bumal = C₄H₁₀(COOH)₂), and lithium carbonate at pH ～4–5 gave crystals of the complex Li₄(VO)₂(Bumal)₄(H₂O)₈]·H₂O (1). The structure of complex 1 was established by X-ray diffraction analysis. The molecule of complex 1 consists of two mononuclear bischelate dianionic units {VO(Bumal)₂(H₂O)} linked by four lithium ions to form the hexanuclear heterometallic {V₂Li₄} structure. The crystals and an ethanolic solution of compound 1 were studied by ESR spectroscopy.     

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.     

Asymmetrical polar modification of a bivanadium-capped Keggin POM by multiple Cu-N coordination polymeric chains

An unprecedented asymmetrically modified bivanadium-capped Keggin polyoxometalate (POM), {AsMo12O40(VO)[VO(H2O)]}.[Cu(4,4'-bipy)]5.H2O (1) (bipy = bipyridine), has been hydrothermally synthesized and structurally characterized by a routine technique. Single-crystal X-ray diffraction analysis reveals that compound 1 exhibits a unique (3,4,6)-connected 3D framework with a (6(2).8(1))2(8(3))2(6(4).8(2))2(6(1).8(14)) topology, constructed from {AsMo12O40(VO)[VO(H2O)]}5- polyoxoanions modified by six {Cu(bipy)}n coordination polymeric chains. The asymmetrical polar coordination mode has never been found in the POM chemistry hitherto. It is also the first example of the bivanadium-capped POM as an anionic template to construct a 3D framework with the highest connection number of bicapped POMs. Additionally, by just changing the length of the organic ligand, a new compound {[AsMo12O40(VO)2][Cu(bpe)]2}.[Cu(bpe)].[H2bpe].H2O (2) (bpe = bis(4-pyridyl)ethylene), has been obtained, in which the {AsMo12O40(VO)2} sections are modified by double monotrack {Cu(bpe)}n coordination polymeric chains to form a "rail-like" 1D structure.     

Experimental and theoretical study of the reactions between neutral vanadium oxide clusters and ethane, ethylene, and acetylene

Reactions of neutral vanadium oxide clusters with small hydrocarbons, namely C2H6, C2H4, and C2H2, are investigated by experiment and density functional theory (DFT) calculations. Single photon ionization through extreme ultraviolet (EUV, 46.9 nm, 26.5 eV) and vacuum ultraviolet (VUV, 118 nm, 10.5 eV) lasers is used to detect neutral cluster distributions and reaction products. The most stable vanadium oxide clusters VO2, V2O5, V3O7, V4O10, etc. tend to associate with C2H4 generating products V(m)O(n)C2H4. Oxygen-rich clusters VO3(V2O5)(n=0,1,2...), (e.g., VO3, V3O8, and V5O13) react with C2H4 molecules to cause a cleavage of the C=C bond of C2H4 to produce (V2O5)(n)VO2CH2 clusters. For the reactions of vanadium oxide clusters (V(m)O(n)) with C2H2 molecules, V(m)O(n)C2H2 are assigned as the major products of the association reactions. Additionally, a dehydration reaction for VO3 + C2H2 to produce VO2C2 is also identified. C2H6 molecules are quite stable toward reaction with neutral vanadium oxide clusters. Density functional theory calculations are employed to investigate association reactions for V2O5 + C2H(x). The observed relative reactivity of C2 hydrocarbons toward neutral vanadium oxide clusters is well interpreted by using the DFT calculated binding energies. DFT calculations of the pathways for VO3+C2H4 and VO3+C2H2 reaction systems indicate that the reactions VO3+C2H4 --> VO2CH2 + H2CO and VO3+C2H2 --> VO2C2 + H2O are thermodynamically favorable and overall barrierless at room temperature, in good agreement with the experimental observations.     

The effect of the substituents in the malonate anion and the solvent molecules on the structures of novel coordination polymers [Li2VO(R2mal)2]n

Reactions of vanadyl sulfate (VOSO₄?3H₂O) with dimethylmalonic (H₂Me₂mal = = C₃H₆(CO₂H)₂), cyclobutane-1,1-dicarboxylic (H₂cbdc = C₄H₆(CO₂H)₂), or butylmalonic acid (H₂Bumal = C₄H₁₀(CO₂H)₂) and Li₂CO₃ in a ratio of 1: 2: 2 afforded novel coordination polymers of similar compositions ([Li₂(VO)(Me₂mal)₂]_n (1), [Li₂(VO)(Me₂mal)₂(EtOH)-(H₂O)]_n (2), [Li₄(VO)₂(cbdc)₄(H₂O)₇]_n (3), and [Li₂(VO)(Bumal)₂(H₂O)_5.5]_n (4)) but different structures. The crystal structures of the compounds containing the Me₂mal^2– and Bumal^2– anions depend on the solvent nature.     

Synthesis,Crystal Structure,and Photoluminescent Properties of Two Porous Pillared-layer Metal-organic Frameworks Constructed by Benzene-1,3,5-tricarboxylic Acid and Bisimidazole Ligands

Russian Journal of Coordination Chemistry - Two pillared layer metal organic frameworks, namely {[Co3(Btc)2(Bib)3(H2O)2] · 7H2O}n(I) and {[Cd2(Btc)(Bib)2(Fma)(H2O)] · H2O}n (II), where...     

Synthesis,Crystal Structures,and Magnetic Properties of Two Manganese(II)/Cobalt(II) Coordination Polymers Constructed by Nitrogenous Carboxylic Acid

Russian Journal of General Chemistry - Two new coordination polymers, {[Mn2(L)(H2O)2]·H2O}n (1) and {[Co2(L)(H2O)2]·H2O}n (2) (H4L = 2-(2,4,6-tricarboxylphenyl)-6-carbxoylbenzimi-dazole),...     

Construction of 3d-4f mixed-metal complexes based on a binuclear oxovanadium unit: synthesis, crystal structure, EPR, and magnetic properties

The oxovanadium(IV)-lanthanide(III) heteronuclear complexes, [[Ce(H2O)7(VO)(TTHA)0.5][(VO)2(TTHA)]].8H2O (2), [Pr(H2O)7(VO)3(TTHA)1.5].10H2O (3), and [Nd(H2O)7(VO)3(TTHA)(1.5)].10H2O (4) (H6TTHA = triethylenetetraaminehexaacetic acid), were prepared based on a binuclear building block of [(VO)2(TTHA)]2- in [VO(H2O)5][(VO)2TTHA].4H2O (1). The X-ray crystallographic studies show that 1 is an ion-pair complex, containing the [(VO)2(TTHA)]2- unit as a useful building block. Adding the light Ln3+ ions to this synthesis system, three new 3d-4f mixed-metal-based complexes were obtained. Although the light lanthanide ions always exhibit similar chemical behavior, the structures of 2-4 are not homologous. 2 is exhibited as a one-dimensional coordination polymer, comprising an unusual Ce2V2 heterometallic lattice in the chain structure, which is the second report of a oxovanadium(IV)-lanthanide(III) coordination polymer. 3 and 4 are isomorphic, every two of the Ln3+ cations linked three [(VO)2(TTHA)]2- anions, forming an interesting linear octanuclear structure. This kind of heteronuclear linear complex is rather rare, which expands the realm of 3d-4f complexes. Further investigations such as IR spectra, UV-vis spectra, magnetic properties, and EPR spectra were studied, and a detailed discussion is given for this system.     

Structures and magnetic properties of ferromagnetic coupling 2D Ln-M heterometallic coordination polymers (Ln = Ho, Er; M = Mn, Zn)

Four new heterometallic coordination polymers have been successfully synthesized, namely, {[Ho(2)(HCAM)(6)Mn(3)(H(2)O)(12)].17.5H(2)O}(n) (1), {[Er(2)(HCAM)(6)Mn(3)(H(2)O)(12)].17.5H(2)O}(n) (2), {[Ho(2)(HCAM)(6)Zn(3)(H(2)O)(12)].26H(2)O}(n) (3), and {[Er(2)(HCAM)(6)Zn(3)(H(2)O)(12)].26H(2)O}(n) (4) (H(3)CAM = chelidamic acid). X-ray crystallographic studies reveal that coordination polymers 1-4 are isostructural and crystallized in the rhombohedral crystal system, space group R3. These compounds comprise a 2D honeycomb-type framework. A 2D water sheet is first found in 3 and 4, which exhibits a novel topological motif. The magnetic results for 1-4 show that ferromagnetic interactions take place between the Ho(3+)/Er(3+) and Mn(2+) ions within 1 and 2.     

Interaction of vanadyl (VO2+) with ligands containing serine, tyrosine, and threonine

Reaction of vanadyl sulfate with an aldehyde (2-hydroxy-1-naphthaldehyde (nap); 3-methoxysalicylaldehyde = o-vanillin (van)) and an amino acid carrying an OH group (L-tyrosine (L-tyr); L-serine (L-ser), L-threonine (L-thr)) yielded the complexes [VO(nap-D-Tyr)(H2O)] 1a, [VO(van-D,L-Tyr)(H2O)] 1c, [VO(nap-Ser)(H2O)] 2a, [VO(van-D,L-Ser)(H2O)] 2b, [VO(nap-Thr)(H2O)] 3a, and [VO(van-Thr)(H2O)] 3b. [VO(nap-L-tyr(H2O)], 1b, was obtained from the reaction between [VO(nap)(2)] and l-TyrOMe. The crystal and molecular structures of 1a.CH3OH, 1b.CH3OH, 1c.H2O, 2b.2H2O, and the Schiff base nap-D,L-TyrOMe (4) are reported. The ligands coordinate in a tridentate manner through the phenolate component of nap or van, the imine nitrogen, and the carboxylate of the amino acid. Direct coordination of the (deprotonated) OH amino acid functionality is not observed in these complexes. Instead, the OH groups are involved in hydrogen bonding, leading, along with pi-pi stacking, to extended one- and three-dimensional supramolecular networks. The relevance for the interaction between oxovanadium(IV,V) and proteins having serine, threonine, or tyrosine at their reactive sites is addressed.     

A series of vanadogermanates from 1D chain to 3D framework built by Ge-V-O clusters and transition-metal-complex bridges

Three novel extended vanadogermanates, {[(en)(2)Cd(2)Ge(8)V(12)O(40)(OH)(8)(H(2)O)][Cd(en)(2)](2)}·6H(2)O (1), {[Zn(2)(dap)(3)][Zn(dap)](2)Ge(6)V(15)O(48)(H(2)O)}[Zn(dap)(2)(H(2)O)](2)·3H(2)O (2), and {[Cd(3)(μ-dien)(2)(Hdien)(2)(H(2)O)(2)]Ge(4)V(16)O(42)(OH)(4)(H(2)O)}·2H(2)O (3; en=ethylenediamine, dap=1,2-diaminopropane, dien=diethylenetriamine), have been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, powder XRD, thermogravimetric analysis, and single-crystal XRD. Their Ge-V-O cluster anions are derived from the V(18)O(42) cluster shell by replacing VO(5) square pyramids with Ge(2)O(7) groups. Compound 1 exhibits a 1D sinusoidal chain built up from rare inorganic-organic hybrid dicadmium-substituted vanadogermanate {[Cd(en)](2)V(12)O(40)(GeOH)(8)(H(2)O)} clusters and [Cd(en)(2)] complexes. Compound 2 is the first example of a 2D network based on linkage of the unusual {Ge(6)V(15)O(48)(H(2)O)} clusters and two types of Zn complex fragments. Compound 3 is an unprecedented 3D framework built by {Ge(4)V(16)O(42)(OH)(4)(H(2)O)} clusters and rare trinuclear bridging complex cations [Cd(3)(μ-dien)(2)(Hdien)(2)(H(2)O)(2)](8+). Magnetic measurements illustrate that both 1 and 2 have antiferromagnetic exchange interactions between metal centers, whereas 3 exhibits ferrimagnetic behavior, which is rare in polyoxovanadate complexes.     

Syntheses,structures and magnetic properties of three cobalt(II) coordination polymers based on flexible itaconic acid ligands

Transition Metal Chemistry - Three Co(II) coordination polymers, namely [Co(ia)(bpe)0.5(H2O)]n (1), {[Co(ia)(bib)(H2O)]·H2O}n (2) and {[Co(ia)(btmb)(H2O)]·H2O}n (3)...     

Synthesis, structure, and characterization of novel two- and three-dimensional vanadates: Ba2.5(VO2)3(SeO3)4.H2O and La(VO2)3(TeO6).3H2O

Two new vanadates, Ba(2.5)(VO2)3(SeO3)4.H2O and La(VO2)3(TeO6).3H2O, have been synthesized by hydrothermal methods using BaCO3, Ba(OH)2.H2O, La(NO3)3.6H2O, V2O5, TeO2, and H2SeO3 as reagents. The structures were determined by single-crystal X-ray diffraction. Ba(2.5)(VO2)3(SeO3)4.H2O exhibits a two-dimensional layered structure consisting of VO(5) square pyramids and SeO3 polyhedra, whereas La(VO2)3(TeO6).3H2O has a three-dimensional framework structure composed of VO(4) tetrahedra and TeO6 octahedra. Infrared and Raman spectroscopy, UV-vis diffuse reflectance spectroscopy, and thermogravimetric analysis are also presented. Crystal data: Ba(2.5)(VO2)3(SeO3)4.H2O, trigonal, space group P (No. 147) with a = b = 12.8279(15) A, c = 7.2631(9) A, V = 1035.1(2) A(3), and Z = 2; La(VO2)3(TeO6).3H2O, trigonal, space group R3c (No. 161) with a = b = 9.4577(16) A, c = 23.455(7) A, V = 1816.9(7) A3, and Z = 6.     

Syntheses,crystal structures and properties of four metal coordination complexes constructed from aromatic carboxylate and benzimidazole-based ligands

Transition Metal Chemistry - Four metal–organic coordination complexes, namely {[Zn(SIP)(mbi)2]·(Hmbi)·(H2O)2}n (1), {[Cd3(SIP)2(bbhb)3(H2O)4]·(H2O)2}n (2),...     

Tuning of inter- versus intrachain magnetic interactions in cyano-bridged Ni(II)/M(III) (M = Cr, Fe, Co) chain complexes

The reaction of [M(CN)6]3- (M = Cr3+, Fe3+, Co3+) with the nickel(II) complex of 2,4-diamino-1,3,5-triazin-6-yl-{3-(1,3,5,8,12-pentaazacyclotetradecane)} ([NiL]2+) in excess of ANO3 or ACl (A = Li+, Na+, K+, Rb+, Cs+, NH4+) leads to the cyano-bridged dinuclear assemblies A{[NiL][M(CN)6]}.xH2O (x = 2-5). X-ray structures of Li{[NiL][Cr(CN)6]}.5H2O, NH4{[NiL][Cr(CN)6]}.3.5H2O, K{[NiL][Cr(CN)6]}.4H2O, K{[NiL][Fe(CN)6]}.4H2O, Rb{[NiL][Fe(CN)6]}.3.5H2O, and Cs{[NiL][Fe(CN)6]}.3.5H2O, as well as the powder diffractometry of the entire Fe(III) series, are reported. The magnetic properties of the assemblies are dependent on the monocation A and discussed in detail. New efficient pathways for ferromagnetic exchange between Ni(II) and Fe(III) or Cr(III) are demonstrated. Field dependencies of the magnetization for the Fe(III) samples at low temperature and low magnetic field indicate a weak interchain antiferromagnetic coupling, which is switched to ferromagnetic coupling at increasing magnetic field (metamagnetic behavior). The interchain magnetic coupling can be tuned by the size of the A cations.     

Solvothermal syntheses,crystal structure,and photoluminescent properties of two Cu(I) coordination polymers constructed by bisimidazole ligands

Journal of Structural Chemistry - Two Cu(I) coordination polymers {[Cu2(bibp)2]·bdc·3H2O} n (1) and {[Cu3(bib)3]·btc·5H2O} n (2), where bibp =...     

Molecular and supramolecular features of oxo-peroxovanadium complexes containing O3N, O2N2 and ON3 donor sets

The complexes [VO(O2)Hbpa]+ (1a), [VO(O2)bpa] (1b, Hbpa = bis(picolyl)-beta-alanine), [VO(O2)heida]- (2, H2heida =N-(2-hydroxyethyl)iminodiacetic acid), [VO(O2)(3OH-pic)2]- (3a), [VO(O2)(3OH-pic)2]-/[V(O2)2(3OH-pic)2]- (3b, 3OH-pic = 3-hydroxypicolinic acid), [VO(O2)(3OH-pa)2] (6, 3OH-pa = 3-hydroxypicolylamide), [VO2(3OH-pic)2]- (4), [VO(tBuO2)(3OH-pic)2] (5) and [VO(tBuO2)(3OH-pa)2]2+ (7) have been characterised. The structures of 21a[ClO4].1b.2.25H2O, K.2H2O, [NH4].H2O and [nBu4]3b are reported. Supramolecular patterns arise from intermolecular hydrogen bonds, the relevance of which for the peroxo/hydroperoxo intermediates in oxo transfer reactions catalysed by vanadate-dependent haloperoxidases is addressed. Specific solution patterns have been analysed by 51V and 17O NMR.     

Structure and properties of the thorium vanadyl tellurate, Th(VO2)2(TeO6)(H2O)2

The hydrothermal reaction of Th(NO3)4.xH2O with V2O5 and H6TeO6 at 200 degrees C under autogenously generated pressure results in the formation of Th(VO2)2(TeO6)(H2O)2 as a pure phase. The single-crystal X-ray data indicate that Th(VO2)2(TeO6)(H2O)2 possesses a three-dimensional structure constructed from ThO9 tricapped trigonal prisms, VO5 distorted square pyramids, VO4 distorted tetrahedra, and TeO6 distorted octahedra. Both of the vanadium polyhedra contain VO2+ vanadyl units with two short V=O bond distances. The tellurate octahedron is tetragonally distorted and utilizes all of its oxygen atoms to bond to adjacent metal centers, sharing edges with ThO9 and VO5 units, and corners with two ThO9, one VO5, and two VO4 polyhedra. Crystallographic data: Th(VO2)2(TeO6)(H2O)2, orthorhombic, space group Pbca, a = 12.6921(7), b = 11.5593(7), c = 13.0950(8) A, Z = 8 (T = 193 K). The UV-vis diffuse reflectance spectrum of Th(VO2)2(TeO6)(H2O)2 shows vanadyl-based charge-transfer absorption features. Th(VO2)2(TeO6)(H2O)2 decomposes primarily to Th(VO3)4 when heated at 600 degrees C in air.     

Novel 3D, 2D, and 0D first-row coordination compounds with 4,4'-bipyridine-N,N'-dioxide incorporating sulfur-containing anions

The reaction of M(S2O6) (M = Cu(II), Ni(II), and Co(II)) with 4,4'-bipyridine-N,N'-dioxide (bpdo) results in the formation of novel 3D, 2D, and mononuclear complexes. Complex 1, {[Cu(H2O)(bpdo)2](S2O6)(H2O)}n, is a 2-D wavelike polymer with the Cu(II) ion located on a 2-fold axis and having a distorted square-pyramidal coordination sphere. With Co(II) and Ni(II), 3-D complexes, {[M(bpdo)3](S2O6)(C2H5OH)7}n [M = Co(II) (2), Ni(II) (3)], were obtained. The metal atoms are situated on centers of symmetry and have octahedral environments coordinated to six bpdo molecules. The same reaction in aqueous solution with a metal/ligand ratio of 1:1 results in the formation of mononuclear complexes, {[M(bpdo)(H2O)5](SO4)(H2O)2} [M = Co(II) (4), Ni(II) (5)], accompanied by the decomposition of the dithionate anions S2O6(2-) to sulfate anions SO4(2-).