Ligand-Metal Interaction in Transition-Metal Complexes with Tripodal Polyaza Ligands

Five complexes ([Cu(tpc)] 2+ 1, [Cu(tpa)] 2+ 2, [Co(tpa)] 2+ 3, [Fe(tpa)] 2+ 4 and [Mn(tpa)] 2+ 5) (tpc = N, N', N' tris[(2 pyridyl)methyl] 1,4,7 triaza cyclononane(L1) and tpa = tris[2 ((2 pyridyl)methyl imino)ethyl]amine(L2)) were synthesized and characterized. The crystal structures of 1, 3 and 4 were determined by X ray crystallography. Electrochemical investigations over two cupric complexes reveal that 2 has a less negative redox potential than that of 1. Electronic spectra of 2, 3, 4 and 5 show that the distinction in metal ion results in a shift of the ligand based π*←π transition.

Topology and Photoluminescence Property of a Neodymium-carboxylate Coordination Polymer Based on a Tripodal Flexible Ligand

A new metal-organic coordination polymer {[Nd（tci）（H2O）2]·2H2O}n（1） has been synthesized based on the flexible tricarboxylate ligand tris（2-carboxyethyl）isocyanuric acid（H3tci） and structurally characterized by single-crystal X-ray diffraction analyses, elemental analysis, infrared spectra（IR）, powder X-ray diffraction（PXRD） and thermogravimetric analysis（TGA）. Complex 1 crystallizes in triclinic, space group P1 with a = 9.1648（11）, b = 9.3326（12）, c = 12.440（2） , C（12）H（20）N3O（13） Nd, Mr = 558.55, V = 886.9（2） 3, Z = 2, Dc = 2.092 g·cm-3, μ = 3.006 mm-1, F（000） = 554, 2.56〈θ〈25.00°, λ（Mo Kα） = 0.71073 , T = 293（2） K, the final R = 0.0662 and w R = 0.2071. X-ray diffraction analysis reveals that complex 1 is a two-dimensional layer, which is further assembled into a three-dimensional supramolecular architecture through hydrogen bonding interactions. The structure of complex 1 can be simplified as a rare 2-periodic uninodal {48·62} topology and a non-interpenetrating kgd topology. Furthermore, the thermal stability and photoluminescence property of 1 were investigated.

Synthesis and Structural Characterization of Erbium Complex with Tripodal Ligand, N, N, N′, N′, N″, N″ Hexaisopropyl-2, 2′, 2″-Nitrilotris (2,1-ethoxy) triacetamide (L)

A new tripodal ligand, N, N, N′, N′, N″, N″ hexaisopropyl 2, 2′, 2″ nitrilotris (2,1 ethoxy) triacetamide (L) and its new erbium picrate complex were prepared. The structure of the complex was determined by X ray crystal structure analysis. The result reveals that the Er 3+ is encapsulated by the three arms of the tripodal ligand, and nine coordinated by the bridged head nitrogen atom, all ether oxygen atoms and carbonyl oxygen atoms of the ligand, and two oxygen atoms of the bidentate picrate. The coordination polyhedron is a distorted mono-capped square antiprism.

A Pyridine-copper Inclusion Complex of a New Tripodal Ligand

A pyridine-copper inclusion complex with [Cu(py)4Cl]+ core was prepared in the presence of tripodal ligand tbst {tbst = 1,3,5-tris(2-benzimidazol)sulfanylmethyl-2,4,6-trimethyl- benzene}, and its structure has been determined. It crystallizes in triclinic, space group P with a = 9.0822(2), b = 17.6026(4), c = 18.7156(4) ? a = 93.40, b = 91.2980(1), g = 91.5560(1), V = 2984.81(1) 3, C58H63Cl2CuN11O4S3, Mr = 1208.81, Z = 2, F(000) = 1262, Dc = 1.345 g/cm3, m = 0.615 mm-1, R = 0.0713 and wR = 0.1307 for 7798 observed reflections (I > 2s(I)). X-ray analysis reveals that the uncoordinated tbst and pyridine as guest molecules are included in the complex with formula {[Cu(py)4Cl]Cl}(tbst)(py)4H2O. The tbst, pyridine, aqua and Cl- anion in the com- plex form extensive hydrogen-bonding interactions, building up a quasi-dinuclear structure.

Synthesis and Crystal Structure of a New Mn_8 Compound with Tripodal Ligand

A new manganese compound [Mn8（tmp）2（Htmp）4（（CH3）3CCO2）4（py）2Cl2]·2py （1·2py, H3tmp = 1,1,1-tri（hydroxymethyl）propane, py = pyramid） has been synthesized and its structure was characterized by IR, elemental analysis and X-ray diffraction. Compound 1 belongs to the triclinic system, space group P1 with a = 13.378（5）, b = 14.334（5）, c = 15.012（6） , α = 107.637（5）, β = 95.635（3）, γ = 92.825（4）°, V = 2720.7（17） 3, Z = 1, C76H124N4O26Cl2Mn8, Mr = 2022.23, Dc = 1.234 Mg/m3, μ = 1.007 mm-1, F（000） = 1052, T = 293（2） K, the final R = 0.0755 and wR = 0.2163 for all 6463 observed reflections （I 〉 2σ（I））. X-ray analysis shows that the core of 1 contains a [Mn8] mixed-valence rod-like unit consisting of six edge-sharing triangles （Mn3）, each of which is bridged by a μ3-oxygen atom.

A Mn(Ⅱ) Coordination Polymer with the Flexible Tripodal Ligand 1,3,5-Tris-(imidazol-1-ylmethyl)benzene

A new Mn（Ⅱ） coordination polymer {[Mn（timb）2（H2O）2]·（Cl）2·（H2O）2}n（1,timb = 1,3,5-tris-（imidazol-1-ylmethyl）benzene） has been synthesized and characterized by elemental analysis,IR,TG and single-crystal X-ray diffraction.The title compound crystallizes in the triclinic system,space group P1 with a=9.0774（13）,b=9.8720（15）,c=11.4898（16）A,α=93.378（3）,β= 95.471（3）,γ=101.101（3）°,V=1002.6（3）A^3,Mr=834.67,Dc=1.382 g/cm^3,μ（MoKα）=0.517mm^-1,F（000）=435,GOF=0.986,Z=1,the final R=0.0506 and wR=0.1139 for 3517 observed reflections I〉2σ（I）.It consists of one-dimensional double stranded chains formed through bridging bidentate timb ligands,and these chains are further connected to yield a 3D supramolecular framework by hydrogen bonding interactions and π…π stacking interactions.

Synthesis,Characterization and Luminescent Properties of Complexes of Rare Earth Nitrates with Tris{2-[N-(pyridine-methanoyl)amino]ethyl} amine

A tripodal ligand, tris{2 [N (pyridine methanoyl)amino]ethyl}amine(L), and its complexes with rare earth nitrates were synthesized. These new complexes with the general formula of Ln(NO 3) 3·L·6H 2O(where Ln=La, Nd, Eu, Tb, Y) were characterized by elemental analysis, IR spectra, thermal analysis, 1 H NMR spectra, molar conductivity and luminescent spectra. All the complexes are stable in air and their conductances in acetonitrile solution lie in the range of 142～150 S·cm 2·mol -1 , indicating 1∶1 type electrolytes. The IR and 1H NMR spectra of the ligand and its complexes show that all the C=O groups take part in coordination to the metal ions. The thermal behaviour of Eu complex shows that the weight losses at 75～120 ℃ and 120～210 ℃ correspond to the loss of four lattice water molecules and that of two coordinated water molecules, respectively. The luminescent spectra of the complexes of Eu(Ⅲ) and Tb(Ⅲ) were investigated in methanol.

Synthesis of a Novel Chiral Trihydroxamic Acid Containing L-Pro-L-Ala-L-Ala-β-(HO)Ala-OMe Unit

An N-hydroxyl peptide unit of H-L-Pro-L-Ala-L-Ala-β-（BnO）Ala-OMe was synthesized by stepwise chain building method in solution. Then, based on nitrilotriacetic acid backbone and this N-hydroxyl peptide unit, a novel chiral tripodal ligand P as an analogue of desferrichrome, has been synthesized. In neutral pH, ligand P formed stable tri（hydroxamato）- iron（Ⅲ） complexes which showed a maximum absorptiota （∑max=2750 M^-lcm^-1） at 422 nm in UV-Vis spectra. The characteristic absorption spectra are similar to those of natural trihydroxamate-type siderophores.

Crystal Structures of Cu(Ⅰ)and Cu(Ⅱ)Complexes of Tris(N-n-propylbenzimidazol-2-ylmethyl)amine

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｃｏｎｔｒｏｌｅｄｄｅｓｉｇｎｏｆｓｏｌｉｄ－ｓｔａｔｅａｒｃｈｉｔｅｃｔｕｒｅｓａｎｄｃｒｙｓｔａｌｅｎｇｉｎｅｅｒｉｎｇｈａｓｃｕｒｒｅｎｔｌｙｂｅｅｎｒｅｃｏｇｎｉｚｅｄａｓｏｎｅｏｆｔｈｅｍｏｓｔｉｍｐｏｒｔａｎ...

X-ray Crystal Structure of a Mononuclear Copper (Ⅱ) Complex with Unusual Monodentate O-coordination of Carboxylate Group of Isonicotinate

Reaction of Cu(ClO4)2'6H2O with tripodal ligand tri s (2-benzi nd dazol yl methyl ) aInine(ntb) and sodium isonicotinate (Iso) yielded a mononuclear complex lCu(ntb)(lso)]ClO4.3.5H2O. Thestructure has been established by X-ray crystallography The Cu (Ⅱ) atom is in a distorted trigonalbipyranddal environment with three benzimindazole N atoms of ntb defining the equatorial plane, oneandne N atom of ntb, and one O atom of the carboxylate group of isonicotinate occupying the axialpositions.

Synthesis, Characterization and Crystal Structure of Bis[1 -meth oxy-2,2,2-tris-（pyrazol-1 -yl-KN2）ethane]-coppe r（Ⅱ） Bis-perchlorate

Bis[1-methoxy-2,2,2-tris-（pyrazol-l-yl-KN2）ethane]-copper（Ⅱ） bis-perchlorate （2） was synthesized by reacting of pyrazole based tripodal scorpionate ligand 1-methoxy-2,2,2-tris（pyrazol-1-yl）ethane （1） with copper（Ⅱ） perchlorate hexahydrate in methanol, acetonitrile and water mixture as solvent. Slow evaporation of the filtered reaction mixture in air produced blue color block crystals suitable for single crystal X-ray diffraction study of the title complex. Compound 2 crystallizes in the monoclinic space group P21/n with unit cell parameters, α = 8.1269（1） ,A, b = 21.8348（2）A, c = 9.1522（1） A, a = γ= 90° , β = 99.7611 （4）°. The structure of the compound was characterized by IR Spectroscopy, elemental analysis and single crystal X-ray diffraction analysis.

Synthesis and Crystal Structure of N,N',N''-Tris-(2-aminophenyltriphenylphosphium)-benzene-1,3,5-tricarboxamide

A new tripodal P,N ligand （C63H48N3O3P3） was prepared and characterized by elemental analysis, IR and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 13.013（3）, b = 28.406（6）, c = 14.911（3） A^°, β= 111.04（3）°, V= 5144.6（18） A^°^3 Z = 4, Dc = 1.276 g/cm^3, Mr = 987.95, λ（MoKa） = 0.71073 A^°,μ = 0.17 mm^-1, F（000） = 2064, R = 0.0786 and wR = 0.1545. A total of 43260 unique reflections were collected, of which 5112 with I 〉 2σ（I） were observed. The title compound has a central benzene ring, which is linked by -NH-CO- bonds to three 2-aminophenyltriphenylphosphium moieties, of which two with P（1） and P（2） centers are pointing to the same face of the central aryl ring, while the third one directs oppositely, forming a pseudo-propeller. In the crystal structure, there exist face-to-face π-π stacking interactions which increase the stability of the crystal structure.

One pot synthesis, crystal structures and properties of two new MOFs with imidazole-containing tripodal ligand

Two new different Cu(Ⅱ) MOFs with the same 1,3,5-tris(1-imidazolyl) benzene(tib) ligand {[Cu(tib)2]·(H2O)2·Br2}n(1) and {[Cu2(tib)·Br·Cl]·2Br}n(2) were obtained by one pot synthesized of tib with CuBr in the presences of HCl and water. X-ray single crystal diffraction analyses indicate that both complexes 1 and 2 have two dimensional frameworks containing different building blocks. Each Cu(Ⅱ) atom in complex 1 is coordinated by four N atoms from different tib ligands. However, there are two different cryptographic Cu(Ⅱ) atoms in complex 2, one is four coordinated by two bromine atoms and two N atoms from different tib ligands, the other is six coordinated by two chloride atoms and four N atoms from different tib ligands. The thermal gravimetric analysis of complexes 1 and 2 are depicted in the paper.

Synthesis and Crystal Structure of a New 2D Honeycomb-like Cadmium(II) Complex with Tripodal Ligand

A new cadmium(Ⅱ) coordination polymer, [Cd(TITMB)_2]-(SO_4 )·21H_2O, whereTITMB = 1, 3, 5-tris (imidazol-1-yl-methyl) -2, 4, 6-trimethylbenzene, was obtained by self-assemblyof tripodal ligand TITMB with CdSO_4·2.7H_2O in acetonitrile, and characterized by X-raycrystallography. The crystal data belongs to monoclinic space group C_c with cell parameters a =1.16891(4) nm, b= 2.06671(6) nm, c = 2.48185(7) nm, β= 97.8560(10)°, R = 0.0487, wR =0.1211. Theresults of structure analysis indicate that each TITMB ligand coordinates three metal atoms and inturn each Cd(Ⅱ) atom with octahedral coordination geometry connects six nitrogen atoms of imidazolegroup from six different TITMB ligands to produce a 2D honeycomb network structure. There are a lotof water molecules linked by hydrogen bonds and occupied the channels formed intra- andinter-sheets.

A Two-dimensional Lanthanide Coordination Framework with a New Amide-type Tripodal Ligand, 2,2',2"-Nitrilotris{[(2'-benzylaminoformyl)phenoxy]ethyl}amine

The La(III) complex with a new amide-type tripodal ligand, 2,2,2-nitrilotris{[(2-benzylaminoformyl)- phenoxy]ethyl}amine (L), was synthesized and characterized by X-ray crystallographic analysis. Crystal data: C48H55.50LaN7O18.75, Mr=1169.40, monoclinic, space group, P21/n, a=1.0644(3) nm, b=2.3889(5) nm, c=2.1917(5) nm, b=90.65, V=5.573(2) nm3, Z=1, Dc=1.394 gcm-3, R1=0.0487, wR [I>2s(I)]=0.1266. The results reveal that each La(III) ion binds to 9 oxygen atoms, three of which belong to carbonyl groups from three tripodal ligands and six to three bidentate nitrate groups and a two-dimensional sheet of 4.82 networks is assembled by metal-ligand coordination interaction. L, a heptadentate compound, merely acts as a tridentate bridging spacer due to its steric hindrance and links the La(III) ions as three-connected nodes.

Structure and Properties of a Cd(Ⅱ)Metal-organic Framework Based on a Newly Designed Heterotopic Tripodal N-Donor Ligand

In this paper,a Cd(Ⅱ)metal-organic framework(MOF),Cd-DIBT(HDIBT=5-(3?,5?-di(1 Himidazol-1-yl)-[1,1?-biphenyl]-4-yl)-1 H-tetrazole),has been constructed based on a newly designed heterotopic tripodal ligand containing both imidazolyl and pyrazolyl groups.The Cd-DIBT exhibits a new three-dimensional(3,3,9)-connected trinodal network topology with point symbol of(42·6)(43)2(48·615·812·10)(namely scnu)based on binuclear secondary building blocks(SBUs).Staggered 1 D channels were observed in such framework and was estimated to have 5487?^(3)potential solvent area(56%).The stability study reveals that the framework is unstable and easily transforms into amorphous MOF after the removal of guest molecules.In addition,the Cd-DIBT shows a ligand-centered luminescence.

Facile Access to Uranium and Thorium Phosphaethynolate Complexes Supported by Tren: Experimental and Theoretical Study

The issue of covale nee of acti nide complexes remai ns con troversial to date.The in troducti on of 2-phosphaethy nolate anion into acti・nide complexes is expected to in vestigate the reaction mode and the bon ding property.Herei n,we describe the function alizatio n of An(Tren^(TIPS))CI(1:An=U;2:An=Th)precursors with NaOCP(dioxane)_(2.5) through salt-elimination method leading to the formation of the corresponding uranium and thorium phosphaethynolate species:[U(Tren^(TIPS))(OCP)]⑶and[Th(Tren^(TIPS))(OCP)](4).

Synthesis,crystal structures and spectral properties of cobalt (Ⅱ) complexes:[ CoL (N_3) ] ·ClO_4 and CoL (N_3)_2 [L=tris ((3,5-dimethylpyrazol-1-yl) methyl) amine

Two monomeric cobalt(Ⅱ)complexes,[CoL(N3)] ClO4(1)and CoL(N3)2(2),where L is tris((3,5-dimethylpyrazol-1-yl)methyl)amine,were synthesized and their crystal structures were determined by X-ray diffraction technique.Complex 1 is five coordinated with one azide nitrogen atom and four nitrogen atoms of the tris((3,5-dimethylpyrazol-l-yl)-methyl)amine ligand,and the metal center is in distorted trigonal bipyramidal environment.Complex 2 is six coordinated distorted octahedron with the two azide nitrogen atoms and four nitrogen donors of the tris((3,5-dimethylpyrazol-1-yl)-methyl)amine ligand.The solution behaviors of the title complexes have been further investigated by UV-Vis,and 1H NMR analysis.It is found that the formation of 1 and 2 depends on the molar ratio of the azide ion to metal salt and ligand Complex 1 attached with one azide group is more stable and easy to generate than complex 2 incorporated with two azide groups,and the reasons were well discussed.