Synthesis and crystal structure of an imidazolate-bridged dicopper tris(2-aminoethyl)amine complex

The [Cu(tren)(Im)Cu(tren)](ClO4)3·MeCN complex [tren=tris(2-aminoethyl)amine; Im=imidazolate anion] has been synthesized and characterized spectrally. The X-ray crystal structure analysis reveals that the imidazolate anion serves as a bridge to form a noncentrosymmetric dimeric structure in the complex. The co-ordination geometry about each copper(II) ion is a distorted trigonal bipyramid with three primary amine groups of the tren ligand forming the equatorial plane. The tertiary amine group and the imidazolate anion are in the axial positions. This revised version was published online in June 2006 with corrections to the Cover Date.     

Synthesis, characterization, and structures of copper(II)-thiosulfate complexes incorporating tripodal tetraamine ligands

The reaction of [Cu(L)(H(2)O)](2+) with an excess of thiosulfate in aqueous solution produces a blue to green color change indicative of thiosulfate coordination to Cu(II) [L = tren, Bz(3)tren, Me(6)tren, and Me(3)tren; tren = tris(2-aminoethyl)amine, Bz(3)tren = tris(2-benzylaminoethyl)amine, Me(6)tren = tris(2,2-dimethylaminoethyl)amine, and Me(3)tren = tris(2-methylaminoethyl)amine]. In excess thiosulfate, only [Cu(Me(6)tren)(H(2)O)](2+) promotes the oxidation of thiosulfate to polythionates. Products suitable for single-crystal X-ray diffraction analyses were obtained for three thiosulfate complexes, namely, [Cu(tren)(S(2)O(3))].H(2)O, [Cu(Bz(3)tren)(S(2)O(3))].MeOH, and (H(3)Me(3)tren)[Cu(Me(3)tren)(S(2)O(3))](2)(ClO(4))(3). Isolation of [Cu(Me(6)tren)(S(2)O(3))] was prevented by its reactivity. In each complex, the copper(II) center is found in a trigonal bipyramidal (TBP) geometry consisting of four amine nitrogen atoms, with the bridgehead nitrogen in an axial position and an S-bound thiosulfate in the other axial site. Each structure exhibits H bonding (involving the amine ligand, thiosulfate, and solvent molecule, if present), forming either 2D sheets or 1D chains. The structure of [Cu(Me(3)tren)(MeCN)](ClO(4))(2) was also determined for comparison since no structures of mononuclear Cu(II)-Me(3)tren complexes have been reported. The thiosulfate binding constant was determined spectrophotometrically for each Cu(II)-amine complex. Three complexes yielded the highest values reported to date [K(f) = (1.82 +/- 0.09) x 10(3) M(-1) for tren, (4.30 +/- 0.21) x 10(4) M(-1) for Bz(3)tren, and (2.13 +/- 0.05) x 10(3) M(-1) for Me(3)tren], while for Me(6)tren, the binding constant was much smaller (40 +/- 10 M(-1)).     

A pseudo‐cage complex of silver(I) with tripodal tetraamine having benzyl end groups, {tris[2‐(benzylamino)ethyl]amine‐κ4N}silver(I) perchlorate

The synthesis and crystal structure of {tris­[2‐(benzyl­amino)­ethyl]­amine‐κ⁴N}silver(I) perchlorate, [Ag(C₂₇H₃₆N₄)]ClO₄ or [Ag(bz₃tren)]ClO₄ {bz₃tren is tris­[2‐(benzyl­amino)­ethyl]­amine or N,N′,N′′‐tri­benzyl­tris(2‐amino­ethyl)­amine} are reported. The Ag atom is coordinated to four N atoms of the tren unit and is located 0.604 (3) Å out of the trigonal plane described by the three secondary amine N atoms, away from the bridgehead N atom. Edge‐to‐face π–π interactions between the aromatic end groups, and weak interactions between Ag and arene, allow the formation of a pseudo‐cage complex.     

氮烃基化tren银配合物的合成及二维超分子结构

合成了氮烃基化三角架tren配体L·3HCl(L= [N, N′, N″ 三(4 甲氧苄基) 三(2 氨乙基)胺] ),并得到了其单核Ag(I)配合物 [AgL]NO3.晶体结构研究表明Ag(I)离子被三角架配体L四齿螯合,与罕见的笼形结构相似,NOˉ根没有参加配位,而作为氢键的受体将分子组装成二维超分子结构.     

Thermodynamic and spectroscopic studies of lanthanides(III) complexation with polyamines in dimethyl sulfoxide

The thermodynamic parameters of complexation of Ln(III) cations with tris(2-aminoethyl)amine (tren) and tetraethylenepentamine (tetren) were determined in dimethyl sulfoxide (DMSO) by potentiometry and calorimetry. The excitation and emission spectra and luminescence decay constants of Eu3+ and Tb3+ complexed by tren and tetren, as well as those of the same lanthanides(III) complexed with diethylenetriamine (dien) and triethylenetetramine (trien), were also obtained in the same solvent. The combination of thermodynamic and spectroscopic data showed that, in the 1:1 complexes, all nitrogens of the ligands are bound to the lanthanides except in the case of tren, in which the pendant N is bound. For the larger ligands (trien, tren, tetren) in the higher complexes (ML2), there was less complete binding by available donors, presumably due to steric crowding. FT-IR studies were carried out in an acetonitrile/DMSO mixture, suitably chosen to follow the changes in the primary solvation sphere of lanthanide(III) due to complexation of amine groups. Results show that the mean number of molecules of DMSO removed from the inner coordination sphere of lanthanides(III) is lower than ligand denticity and that the coordination number of the metal ions increases with amine complexation from approximately 8 to approximately 10. Independently of the number and structure of the amines, linear trends, similar for all lanthanides, were obtained by plotting the values of DeltaGj degrees, DeltaHj degrees, and TDeltaSj degrees for the complexation of ethylenediamine (en), dien, trien, tren, and tetren as a function of the number of amine metal-coordinated nitrogen atoms. The main factors on which the thermodynamic functions of lanthanide(III) complexation reactions in DMSO depend are discussed.     

Synthesis, characterization and crystal structure of a tris(2-aminoethyl)amine copper complex with a imidazole coligand

Summary The complex [Cu(tren)ImH](ClO₄)₂ [tren = tris(2-aminoethyl) amine, ImH = imidazole] has been synthesized and characterized by elemental analyses, conductivity measurements, magnetic moments, and electronic, i.r., e.s.r. and XPS spectral studies. The X-ray crystal structure reveals that there are two kinds of cation [Cu(tren)(ImH)]²⁺ in the crystal, cations A and B, in a 21 ratio, respectively; so the stoichiometric formula is [Cu(tren)(ImH)]_1.5(ClO₄)₃. Cation B is disordered. The Cu^II ions in both cations A and B are in a trigonal bipyramidal geometry with the three primary amine groups of the tren ligand forming the equatorial plane, and the tertiary amine group and the imidazole ligand in apical positions.     

Anion binding with a tripodal amine

Binding studies of the tren-based amine, L (N,N',N' '-tris(2-benzylaminoethyl)amine), with inorganic anions and two crystal structures, [H(3)L][H(2)PO(4)](3).H(3)PO(4) and [H(3)L][Br](3), are reported. NMR titration results indicate that the ligand binds H(2)PO(4)(-) and HSO(4)(-) more strongly than NO(3)(-) and halides. In the crystal structure of the phosphate complex, the ligand is triprotonated with the three arms pointing outward in a trigonal-planar-like arrangement. Four phosphate species are associated with the receptor, and have been assigned as three H(2)PO(4)(-) counterions located between each of the tren arms, and an additional H(3)PO(4) molecule above the quasi-planar tren. The structure of the bromide complex is slightly different, although again the tren receptor is triprotonated and quasi-planar, but in this case C(2v)-like symmetry is seen with two of the arms pointed in the same direction with a bromide ion in between. The other two bromides lie outside of the tren arms.     

Reversible binding of dioxygen by the copper(I) complex with tris(2-dimethylaminoethyl)amine (Me6tren) ligand

At low temperatures, the mononuclear copper(I) complex of the tetradentate tripodal aliphatic amine Me(6)tren (Me(6)tren = tris(2-dimethylaminoethyl)amine) [Cu(I)(Me(6)tren)(RCN)](+) first reversibly binds dioxygen to form a 1:1 Cu-O(2) species which further reacts reversibly with a second [Cu(I)(Me(6)tren)(RCN)](+) ion to form the dinuclear 2:1 Cu(2)O(2) adduct. The reaction can be observed using low temperature stopped-flow techniques. The copper superoxo complex as well as the peroxo complex were characterized by resonance Raman spectroscopy. The spectral characteristics and full kinetic and thermodynamic results for the reaction of [Cu(I)(Me(6)tren)(RCN)](+) with dioxygen are reported.     

Synthesis, Characterization, and Crystal Structure of a Novel Copper(II) Complex with an Asymmetric Coordinated 2,2'-Bipyridine Derivative: A Model for the Associative Complex in the Ligand-Substitution Reactions of [Cu(tren)L](2+)?

The titled compound, (tris(2-aminoethyl)amine)(4,5-diazafluoren-9-one) copper(II) perchlorate, [Cu(C(6)H(18)N(4))(C(11)H(6)N(2)O)(ClO(4))(2)], 1, has been designed, synthesized, and characterized. The electronic and ESR spectra are very different from those of [Cu(tren)L](2+) complexes where L is monodentate ligand. The X-ray analysis revealed that the complex crystallizes in the monoclinic space group P2(1)/c, with a = 10.726(6) ?, b = 14.921(7) ?, c = 14.649(4) ?, beta = 95.13(3) degrees, and Z = 4. The copper(II) ion is coordinated by four nitrogen atoms from tris(2-aminoethyl)amine (tren) and two nitrogen atoms from 4,5-diazafluoren-9-one (dzf) to form an unusual six-coordinate (4 + 1 + 1') geometry. The structure is very rare, and to our knowledge, it is the first example of an asymmetric bidentate phenanthroline derivative metal complex. The structure could be used as a model of the associative complex in the ligand-exchange and ligand-substitution reactions of [Cu(tren)L](2+) and the catalytic mechanisms of enzymes involving copper sites. From the electronic and variable-temperature ESR spectra in solution, the possible mechanism of these reactions has also been proposed. As a comparison, the complex [Cu(tren)(ImH)(ClO(4))(2)], 2, was also synthesized and characterized, where ImH is imidazole.     

Two new [Ni(tren)2]2+ complexes: [Ni(tren)2]Cl2 and [Ni(tren)2]WS4

Both title compounds, bis­[tris(2‐amino­ethyl)­amine]­nickel(II) dichloride, [Ni(tren)₂]Cl₂, (I), and bis­[tris(2‐amino­ethyl)­amine]­nickel(II) tetra­thio­tungstate, [Ni(tren)₂]WS₄, (II), contain the [Ni(tren)₂]²⁺ cation [tren is tris(2‐amino­ethyl)­amine, C₆H₁₈N₄]. The tren mol­ecule acts as a tridentate ligand around the central Ni atom, with the remaining primary amine group not bound to the central atom. In (I), Ni²⁺ is located on a centre of inversion surrounded by one crystallographically independent tren mol­ecule. In the [Ni(tren)₂]²⁺ cation of (II), the Ni atom is bound to two crystallographically independent tren mol­ecules. The Ni atoms in the [Ni(tren)₂]²⁺ complexes are in a distorted octahedral environment consisting of six N atoms from the chelating tren mol­ecules. The counter‐ions are chloride anions in (I) and the tetrahedral [WS₄]^2? anion in (II). Hydro­gen bonding is observed in both compounds.     

E.s.r., magnetic, optical and biological (SOD and antimicrobial) studies of imidazolate bridged Cu(II)-Zn(II) and Cu(II)-Ni(II) complexes with tris(2-amino ethyl)amine as capping ligand: a plausible model for superoxide dismutase

X-band e.s.r. and optical absorption spectra of the imidazolate bridged heterobimetallic complexes [(tren)Cu-E-Im-Zn-(tren)](ClO(4))(3) and [(tren)Cu-E-Im-Ni-(tren)](ClO(4))(3), where trentris(2-aminoethyl)amine, E-Im=2-ethylimidazolate ion and the related mononuclear complexes [Cu(tren)](ClO(4))(2) and [(tren)Cu-E-ImH)](ClO(4))(2) have been described. Biological activities (superoxide dismutase and antimicrobial) have also been measured and compared with reported complexes.     

Stabilization of copper(II) thiosulfonate coordination complexes through cooperative hydrogen bonding interactions

A series of copper(II) thiosulfonate complexes have been prepared via the reaction of [Cu(Me 3tren)(OH 2)](ClO 4) 2 (Me 3tren = tris(2-methylaminoethyl)amine) with three thiosulfonate ligands (RSO 2S (-), where R = Me, Ph, and MePh) and characterized by microanalysis, FTIR spectroscopy, and X-ray crystallography. In these complexes, the distorted trigonal bipyramidal copper(II) coordination sphere is occupied by four amine nitrogen atoms from the tripodal tetramine ligand and an apically bound sulfur atom from the thiosulfonate ligand. By using the tripodal tetramine ligand the oxidation of the thiosulfonate has been restricted, allowing the isolation of the complexes. The Cu-S distances were found to be similar to those in related thiosulfate complexes, indicating coordinative interactions of similar strength. Two types of intramolecular hydrogen bonding interactions were evident which enhance the binding of the thiosulfonate to the copper(II) center. These interactions, which involve two amine N-H groups and either one or two thiosulfonate oxygens, were found to be weaker than in the corresponding thiosulfate complexes. The complex formation constants for the thiosulfonate complexes (log K f = 0.3-0.7) were found to be two orders of magnitude lower than compared to the thiosulfate analogues. This correlates well with a lower strength of intramolecular hydrogen bonding.     

The encapsulation of ferrocyanide by copper(II) complexes of tripodal tetradentate ligands. Novel H-bonding networks incorporating heptanuclear and pentanuclear heterometallic assemblies

Substitution of the weakly binding aqua ligand in [Cu(tren)OH2](2+) and [Cu(tpa)OH2](2+) (tren = tris(2-aminoethyl)amine; tpa = tris(2-pyridylmethyl)amine) by a cyano ligand on ferricyanide results in the assembly of heteropolynuclear cations around the cyanometalate core. In water, the reduction of the Fe(III) core to Fe(II) generates complexes that feature heteropolycations in which ferrocyanide is encapsulated by the Cu(II) moieties: [(Cu(tpa)CN)6Fe][ClO4]8-3H2O 1, [(Cu(tren)CN)6Fe][ClO4]8-10H2O 2, [(Cu(tren)CN)6Fe][Fe(CN)6]2[ClO4]2-15.8H2O 3, and [(Cu(tren)CN)6Fe][(Cu(tren)CN)4Fe(CN)2][Fe(CN)6)]4-6DMSO-21H2O 4. The formation of discrete molecules, in preference to extended networks or polymeric structures, has been encouraged through the use of branched tetradentate ligands in conjunction with copper(II), a metal center with the propensity to form five-coordinate complexes. Complex 3 crystallizes in the monoclinic space group P2(1)/c (#14) with a = 14.8674(10), b = 25.9587(10), c = 27.5617(10) A, beta = 100.8300(10) degrees, and Z = 4, and it is comprised of almost spherical heptanuclear cations, [(Cu(tren)CN)6Fe](8+), whose charge is balanced by two ferricyanide and two perchlorate counteranions. Complex 4 crystallizes in the triclinic space group P1 (# 1) with a = 14.8094(8), b = 17.3901(7), c = 21.1565(11) A, alpha = 110.750(3), beta = 90.206(2), gamma = 112.754(3) degrees, and Z = 1, and it is comprised of the heptanuclear [(Cu(tren)CN)6Fe](8+) cation and pentanuclear [(Cu(tren)CN)4Fe(CN)2](4+) cation, whose terminal cyano ligands are oriented trans to each other. The charge is balanced exclusively by ferricyanide counteranions. In both complexes, H-bonding interactions between hydrogens on primary amines of the tren ligand, terminal cyano groups of the ferricyanide counterions, and the solvent of crystallization generate intricate 3D H-bonding networks.     

INTELLIGENT METATAL COMPLEXES CONTAINING N-GLYCOSIDES FORMED FROM TRIS (2-AMINOETHYL) AMINE AND ALDOSES, HAVING MOLECULAR RECOGNITION ABILITY

Assembly of carbohydrates on nickel (Ⅱ) center by utilizing N-glycosidicbond formation with a branched amine: tris(2-aminoethyl)amine (tren), an unprecedentedchiral inversion around the metal center (Co or Mn) induced by an interaction betweensugars and sulfate anions, peroxo-bridged dinuclear cobalt (Ⅲ) complex containing N-glycoside ligands from tren and D-glucose and its reversible dioxygen binding property,and novel trimanganese complexes with a linear Mn_3 (Ⅱ, Ⅲ, Ⅱ) assemblage bridged bycarbohydrates are described.     

A rapid electrochemical method for determining rate coefficients for copper-catalyzed polymerizations

Copper(I) polyamine complexes have emerged as excellent atom-transfer radical polymerization catalysts. The rate of their reaction with organic halide initiators (the so-called activation step) varies across a broad range, depending on both the structure of the copper complex and the initiator. Herein, we report a new technique for determining the rate of copper-catalyzed activation (k(act)) using cyclic voltammetry coupled with electrochemical simulation. This method is applied to measuring k(act) for one of the most active catalysts, [Cu(I)(Me(6)tren)](+) (Me(6)tren = N,N,N-tris-(2-(dimethylamino)ethyl)amine), in reaction with ethyl bromoisobutyrate.     

Expansion of Germanato‐Polyoxovanadate Cluster Cores: Solvothermal Syntheses and Selected Properties of (trenH2)2[{M(tren)}4V15Ge6O48(H2O)] (M = Co and Zn)

Two germanato‐polyoxovanadates with the {V₁₅Ge₆O₄₈} cluster core are extended by covalent bonds to four transition metal amine complexes [M(tren)]²⁺ (M = Co and Zn, tren = tris(2‐aminoethyl)amine). The complexes have bonds to terminal atoms of the Ge₂O₇ units and such expansion of a germanato‐polyxovanadate was never observed before. The characterization of these compounds revealed the presence of two protonated tren molecules charge balancing the negative charges of the [{M(tren)}₄V₁₅Ge₆O₄₈(H₂O)]^4– anion.     

Synthesis,Crystal Structure and Properties of a 4,4′-Bipyridine Bridged Trigonal-Bipyramidal Copper Homobinuclear Complex with Tris(2-Aminoethyl)amine

The synthesis of the binuclear complex [(tren)Cu(4,4'-bipy)Cu(tren)] (ClO₄)₄ where tren = tris(2-aminoethyl) amine and 4,4'-bipy = 4,4'-bipyridine, is described. Single-crystal X-ray diffraction study of the homobinuclear complex shows that two copper(II) ions are bridged by 4,4'-bipyridine and each copper(II) ion is trigonal-bipyramidally coordinated, with tren occupying four sites [Cu-N = 2.030(2), 2.047(2), 2.078(2), and 2.119(2) Å respectively] and a bridging 4,4'-bipyridine in the apical position. The Cu-Cu distance is 11.11 Å. In variable-temperature ESR spectra, the presence of hyperfine structure suggest that some interaction exists between the two copper(II) ions. Temperature-dependent susceptibility studies indicate that it is a weak ferromagnetic interaction with 2J = 1.23 cm^-1.     

Assembly of novel organic-decorated quaternary TM-Hg-Sb-Q compounds (TM = Mn, Fe, Co; Q = S, Se) by the combination of three types of metal coordination geometries

Four organic-decorated quaternary TM-Hg-Sb-Q compounds, namely, [Mn(phen)](2)HgSb(2)S(6) (phen = 1,10-phenanthroline) (1) and isomorphic [TM(tren)]HgSb(2)Se(5) (TM = Mn (2), Fe (3), Co (4); tren = tris(2-aminoethyl)amine) have been solvothermally prepared, and structurally characterized by single crystal X-ray diffraction analyses. 1 and 2 (3, 4) feature distinct one-dimensional neutral infinite ribbon-like structures constructed by the combination of Sb(3+), Hg(2+) and TM(2+), the latter two of which adopt different coordination modes. In compound 1, organic-decorated {[Mn(phen)](2)Sb(2)S(6)} clusters assembled by {MnS(4)N(2)} octhedra and {SbS(3)} pyramids are bridged by the {HgS(2)} groups in a linear fashion. Differently, the {SbSe(3)} pyramids, {HgSe(4)} tetrahedra and {TMSeN(4)} trigonal-bipyramids in 2 (3, 4) are combined to form novel {[TM(tren)](2)Hg(2)Sb(4)Se(12)} clusters, which are interconnected to form {[TM(tren)]HgSb(2)Se(5)}(n) ribbons. The results of optical diffuse-reflectance measurements and band structure calculations based on DFT methods indicate that 1 and 2 (3, 4) are indirect and direct semiconductors, respectively. Photocatalytic experiments have shown the ability of 2 in photodegradation of Rhodamine B (RhB).     

Order-disorder in the super-sodalite Zn3Al6(PO4)12, 4tren, 17H2O (MIL-74): a combined XRD-NMR assessment

A new mixed zinc-aluminum phosphate Zn(3)Al(6)(PO(4))(12), 4tren, 17H(2)O (MIL-74) has been hydrothermally synthesized with the tris(2-aminoethyl)amine (tren) as a structure-directing agent (453 K, 36 h, autogenous pressure). The solid was characterized by a nonclassical method combining single-crystal X-ray diffraction and several solid-state NMR experiments, RFDR, C7 double quantum ((31)P), and 3QMAS ((27)Al). Its crystal structure is cubic, a = 16.7942(1) A, but the choice of the space group does not follow usual routes of structure determination, due to some "disorder" between Zn and Al. It can be assigned as well to I-43m or to P-43n. The open-framework is built up from an enneameric unit (T = Zn, Al) containing five TO(4) and four PO(4) tetrahedra (one of the P-O bonds is terminal). A central TO(4) tetrahedral unit shares all of the corners with four phosphates groups. Two phosphate groups are connected to two other peripheral TO(4) units. It results in the formation of a "pseudo" planar building block T(5)P(4) consisting of four square 4-rings. The connection of the T(5)P(4) units generates a three-dimensional framework, which defines a super-sodalite topology. The resulting cavities (diameter of 10 A) are bound by 12-ring windows in which are located the tren species in interaction with the phosphate groups (mainly terminal P-O bonds) through hydrogen bonds. A cluster of 17 water molecules occupies the center of the super-sodalite cage. The cationic (Zn, Al) occupancy is discussed for this specific topology.     

Solvothermal Synthesis and Structures of Lamellar [Mn(tren)2]Cl2 and the Dimeric and Polymeric Hexaselenidomanganese(II) Complexes [{Mn(Se6)(tren)}2] and $^{2}_{\infty}\rm [\{Mn(Se_{6})(tren)\}]$

Reaction of [MnCl₂(tren)] with tren (tris‐(2‐aminoethyl)amine) affords the coordination polymer ( 1 ), in which the primary amino groups of tridentate tren ligands connect [(tren)Mn]²⁺ fragments into a pseudo 6³ network. The Mn atoms exhibit a capped octahedral environment with the tertiary N atom of the second tetradentate tren ligand in the capping position. Treatment of MnCl₂ with Se at 1:2 molar ratio in H₂O/tren (10:1) at 150 °C leads to formation of the dinuclear complex [{Mn(μ‐Se₆)(tren)}₂] ( 2 ), which contains tetradentate tren ligands and two bridging hexaselenide ligands in the 1κSe¹ : 2κSe⁶ mode. In contrast, reaction of [MnCl₂(tren)] with Se at a 1:6 molar ratio under similar sovothermal conditions affords the isomeric coordination polymer ( 3 ). In this complex, Se₆^2? anions now bridge [(tren)Mn]²⁺ fragments into chains, that themselves are linked into polymeric sheets through one of the primary amino groups of the tetradentate tren ligands.