Perchlorate Ligands Research Articles

Synthesis, structural characterization, and thermal properties of octahedral diperchlorato complexes of copper(II) with the chelating 2-aminomethylpiperidine and 2-aminomethylpyridine ligands

Two distorted octahedral copper(II) coordination compounds; [Cu(AMPp)2(OClO3)2] (1) and [Cu(AMP)2(OClO3)2] (2) (2-aminomethylpiperidine and 2-aminomethylpyridine) have been synthesized on a SP Sephadex C-25 cation exchanger resin for high purity. Their structures have been determined by single-crystal X-ray diffraction, fourier transform infrared spectroscopy, and also thermal analysis. In both structures, the metal center adopts an elongated octahedral geometry in which two chelating amine ligands occupy the square plane in a trans-position, and two perchlorate ligands occupy the axial sites. The thermal stability of both complexes is relatively high. However, the thermal stability of 2 with the aromatic ring was 12 °C higher, due to intermolecular hydrogen bonds, π⋯π, and π⋯O interactions.

Structural trends in a series of bulky dialkylbiarylphosphane complexes of CuI.

CuI complexes containing the bulky dialkylbiarylphosphane 2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl (tBuXPhos, L) and an ancillary ligand (Cl-, Br-, I-, MeCN, ClO4- or SCN-) have been structurally characterized, namely, chlorido[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I), [CuCl(C29H45P)], 1, bromido[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I), [CuBr(C29H45P)], 2, [2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]iodidocopper(I), [CuI(C29H45P)], 3, (acetonitrile-κN)[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I) hexafluoridophosphate, [Cu(CH3CN)(C29H45P)]PF6, 4, [2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP](perchlorato-κO)copper(I), [Cu(ClO4)(C29H45P)], 5, and di-μ-thiocyanato-κ2S:N;κ2N:S-bis{[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I)}, [Cu2(NCS)2(C29H45P)2], 6. Iodide complex 3 shows significant CuI-arene interactions, in contrast to its chloride 1 and bromide 2 counterparts, which is attributed to the weaker interaction between the iodide ion and the CuI centre. When replacing iodide with an acetonitrile (in 4) or perchlorate (in 5) ligand, the reduced interaction between the CuI atom and the ancillary ligand results in stronger CuI-arene interactions. No CuI-arene interactions are observed in dimer 6, due to the tricoordinated CuI centre having sufficient electron density from the coordinated ligands.

Lineshape analysis of perchlorate anions on manganese(III) porphyrin and observing nanoscopic water environments

Perchlorate IR lineshapes in ionic solutions, polymeric membrane, and perchlorate coordinated onto manganese(III) porphyrin were investigated using various model systems. The lineshape of perchlorate ligand is very sensitive to the nanoscopic aqueous environment. The observed asymmetric mode of ligated perchlorate has a smaller bandwidth and faster dynamics than that of 1M perchlorate aqueous solution. When we used chemical exchange models of coherence, the IR lineshapes of 6M-concentrated anionic solutions have better fit. The IR lineshape of 6M-concentrated anionic solution in the polymer matrix was best fitted by assuming the chemical exchange of coherence with spectral diffusion.

Linear trinuclear copper(II)-alkali/alkaline earth metal compounds derived from a compartmental ligand

The work in this investigation deals with syntheses, crystal structures and ESI-MS positive of five compounds of composition [(CuIIL)2NaI](ClO4) (1), [(CuIIL)2KI](ClO4) (2), [{CuIIL(H2O)}CaII(CuIIL)](ClO4)2 (3), [(CuIIL)(µ-ClO4)SrII{CuIIL(MeOH)0.6}](ClO4)·1.2MeOH (4) and [(CuIIL)(µ-ClO4)BaII{CuIIL(MeOH)}](ClO4)·MeOH (5), where H2L = N,N′-bis(3-ethoxysalicylidene)-1,4-butanediamine. The s-block metal ion in all of these five compounds occupies an O8 (four phenoxo and four ethoxy) site provided by two L2− ligands. While NaI, KI and CaII are eight-coordinated, SrII and BaII are nine-coordinated due to additional coordination by an oxygen atom of a bridging perchlorate ligand. In all of 1–5, the two CuII and MI/II are positioned in almost linear way (CuII–MI/II–CuII angle range = 168.24–175.39°). The geometries of the coordination environments have been understood from SHAPE analyses. A disagreement has been observed for the first time between the results of SHAPE analyses and Addison geometric parameter for the pentacoordinated environment. Some interesting structural features regarding composition, metal-ligand bond lengths and twisting of the aromatic rings have been observed. UV-Vis spectra indicates two d-d absorption of copper(II) centers in each of the five compounds. ESI-MS positive reveals the appearance of some tri/di/mononuclear ions.

Polynuclear copper(II) complexes with hexadentate Schiff base directed by the counter ion. Syntheses, crystal structures and magnetic properties

Abstract Four new complexes, [Cu 9 L 6 ( µ 3 -ClO 4 ) 2 ](ClO 4 ) 4 ·4CHCl 3 1 , [Cu 3 L 2 (H 2 O) 2 ](ClO 4 ) 2 ·3H 2 O 2 , [Cu 6 L 4 (N 3 ) 2 ](ClO 4 ) 2 3 and [Cu 2 L(CH 3 COO) 2 ] 4 , where H 2 L stands for the Schiff base N , N ′-bis[(2-hydroxybenzilideneamino)-propyl]-piperazine, were obtained and structurally characterized. Compounds 1 , 2 and 3 contain the Cu 3 L 2 2+ entities in which L 2− acts in an unsymmetrical mode with N 3 O donor set wrapped around marginal copper(II) and with the remained NO sets bound to the central copper ion. The marginal copper(II) ions are in distorted square pyramidal environment, whereas that of the central one is square planar. In 1 , the peripheral copper(II) ions (Cu1) are disposed linearly with a two-fold axis passing through the central Cu2 and with the Cu1⋯Cu2 and Cu2⋯Cu1′ distances of 6.755 A. The linear trinuclear units are bridged by a rare µ 3 -1,2,3 perchlorate ligand thus describing a 2D network. In [Cu 3 L 2 (H 2 O) 2 ](ClO 4 ) 2 ·3H 2 O, the Cu 3 L 2 2+ unit is capped by two water molecules. Here, due to the intramolecular hydrogen bonds, the metal ions are disposed in the corner of a triangle with the Cu1⋯Cu2, Cu1⋯Cu3 and Cu2⋯Cu3 distances of 5.976, 5.314 and 5.760 Ǻ, respectively. In [Cu 6 L 4 (N 3 ) 2 ](ClO 4 ) 2 , two Cu 3 L 2 2+ units are bridged by two azido groups thus forming a macrocycle of six copper(II) ions. In [Cu 2 L(CH 3 COO) 2 ], L 2− acts as a symmetrical binucleatig ligand through the two N 2 O sets disposed on each side of the piperazine ring and pointed away in opposite directions. The square pyramidal environment of copper is achieved by chelate acetato co-ligand.

Syntheses, crystal structures and ESI-MS of mononuclear–dinuclear, trinuclear and dinuclear based one-dimensional copper(II)–s block metal ion complexes derived from a 3-ethoxysalicylaldehyde–diamine ligand

This paper presents the syntheses, crystal structures and electrospray ionization mass spectra (ESI-MS) of four copper(II)–s-block metal ion compounds of composition [{CuIILNaI(H2O)2}(CuIIL)](ClO4) (1), [(CuIIL)2CaII](ClO4)2·2CH3CN·H2O (2), [CuIILSrII(ClO4)2(H2O)]n (3) and [CuIILBaII(ClO4)2(H2O)]n (4), where H2L is the compartmental acyclic Schiff base ligand, obtained on [2+1] condensation of 3-ethoxysalicylaldehyde and trans-1,2-diaminocyclohexane. Compound 1 is a [2×1+1×1] cocrystal of one dinuclear [CuIILNaI(H2O)2]+ moiety and one mononuclear [CuIIL] moiety; the reason of cocrystallization is the hydrogen bonding interaction of a coordinated water molecule of the dinuclear unit with the O(phenoxo)2O(ethoxy)2 compartment of the mononuclear unit. [(CuIIL)2CaII](ClO4)2·2CH3CN·H2O (2) is a trinuclear, non-sandwiched compound where the second metal ion (CaII) is situated in between two O(phenoxo)2O(ethoxy)2 compartments of two [CuIIL] moieties. [CuIILSrII(ClO4)2(H2O)]n (3) and [CuIILBaII(ClO4)2(H2O)]n (4) are isomorphous and dinuclear CuIIMII (M=Sr or Ba) based one-dimensional systems, where polymerization takes place through the perchlorate ligands. A number of peaks are observed in the ESI-MS and those are well assigned. Although the compositions of 1, 2 and 3/4 are different, the ESI-MS of all the four compounds reveal the appearance of trinuclear, dinuclear and mononuclear ions. The peculiar/interesting aspects of the four compounds are discussed.

Chasing the Evasive Fe═O Stretch and the Spin State of the Iron(IV)-Oxo Complexes by Photodissociation Spectroscopy.

We demonstrate the application of infrared photodissocation spectroscopy for determination of the Fe═O stretching frequencies of high-valent iron(IV)-oxo complexes [(L)Fe(O)(X)]2+/+ (L = TMC, N4Py, PyTACN, and X = CH3CN, CF3SO3, ClO4, CF3COO, NO3, N3). We show that the values determined by resonance Raman spectroscopy in acetonitrile solutions are on average 9 cm-1 red-shifted with respect to unbiased gas-phase values. Furthermore, we show the assignment of the spin state of the complexes based on the vibrational modes of a coordinated anion and compare reactivities of various iron(IV)-oxo complexes generated as dications or monocations (bearing an anionic ligand). The coordinated anions can drastically affect the reactivity of the complex and should be taken into account when comparing reactivities of complexes bearing different ligands. Comparison of reactivities of [(PyTACN)Fe(O)(X)]+ generated in different spin states and bearing different anionic ligands X revealed that the nature of anion influences the reactivity more than the spin state. The triflate and perchlorate ligands tend to stabilize the quintet state of [(PyTACN)Fe(O)(X)]+, whereas trifluoroacetate and nitrate stabilize the triplet state of the complex.

Crystal structure of trans-(1,8-dibutyl-1,3,6,8,10,13-hexa-aza-cyclo-tetra-decane-κ(4) N (3),N (6),N (10),N (13))bis-(perchlorato-κO)copper(II) from synchrotron data.

The structure of the title compound, [Cu(ClO4)2(C16H38N6)] has been determined from synchrotron data, λ = 0.62988 Å. The asymmetric unit comprises one half of the Cu(II) complex as the Cu(II) cation lies on an inversion center. It is coordinated by the four secondary N atoms of the macrocyclic ligand and the mutually trans O atoms of the two perchlorate ions in a tetra-gonally distorted octa-hedral geometry. The average equatorial Cu-N bond length is significantly shorter than the average axial Cu-O bond length [2.010 (4) and 2.569 (1) Å, respectively]. Intra-molecular N-H⋯O hydrogen bonds between the macrocyclic ligand and uncoordinating O atoms of the perchlorate ligand stabilize the mol-ecular structure. In the crystal structure, an extensive series of inter-molecular N-H⋯O and C-H⋯O hydrogen bonds generate a three-dimensional network.

Di-μ-hydroxido-κ4O:O-di-μ-perchlorato-κ4O:O′-bis[(2,2′-bipyridine-κ2N,N′)copper(II)

In the title binuclear copper(II) complex, [Cu2(ClO4)2(OH)2(C10H8N2)2], the CuII ion is coordinated in the form of a Jahn–Teller distorted octahedron by two bi­pyridine N atoms, two perchlorate O atoms and two hydroxide O atoms, and displays a distorted octa­hedral geometry. The mol­ecule belongs to the symmetry point group C 2h. The CuII ion is located on a twofold rotation axis and the hydroxide and perchlorate ligands are located on a mirror plane. Within the dinuclear mol­ecule, the Cu⋯Cu separation is 2.8614 (7) Å. The crystal structure exhibits O—H⋯O, C—H⋯O and π–π [centroid–centroid distance = 3.5374 (13) Å] inter­actions.

Technetium and rhenium pentacarbonyl perchlorates: Structure and reactivity

Carbonyl perchlorates [M(ClO4)(CO)5] (M = Tc, Re) were prepared by treatment of [TcI(CO)5] and [ReCl(CO)5], respectively, with AgClO4 in dichloromethane. The complexes were isolated in the form of yellowish and colorless crystals, respectively, and characterized by IR spectroscopy and single crystal X-ray diffraction (XRD). Perchlorate ion is coordinated to the central atom in the monodentate fashion. Perchlorate ligand in the coordination sphere of [M(ClO4)(CO)5] (M = Tc, Re) can be readily substituted by a molecule of a coordinating solvent (acetonitrile). [Re(CO)5(CH3CN)]ClO4 is stable with respect to thermal decarbonylation and was isolated and characterized by single crystal XRD. The coordination polyhedron of rhenium in [Re(CO)5(CH3CN)]ClO4 is less distorted than that in [M(ClO4)(CO)5]. [Tc(CO)5(CH3CN)]ClO4, contrary to its rhenium analog, is unstable in acetonitrile solution and undergoes rapid decarbonylation to form [Tc(CO)3(CH3CN)3]ClO4.

Two solvatomorphic forms of a copper complex formulated as Cu(L1)(ClO4)2·1.2H2O and Cu(L1)(ClO4)2, whereL1is 3,10-C-meso-3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecane

Two copper complex solvatomorphs, namely (3,10-C-meso-3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecane)bis(perchlorato-κO)copper(II) 1.2-hydrate, [Cu(ClO4)2(C18H40N4)]·1.2H2O, (I), and (3,10-C-meso-3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecane)bis(perchlorato-κO)copper(II), [Cu(ClO4)2(C18H40N4)], (II), are described and compared with each other and with a third, already reported, anhydrous diastereomer, denoted (III). Both compounds present very similar centrosymmetic coordination environments, with the Cu(II) cation lying on an inversion centre in a distorted 4+2 octahedral environment, defined by the macrocyclic N4 group in the equatorial sites and two perchlorate groups in trans-axial positions [one of the perchlorate ligands in (I) is partially disordered]. The most significant difference in molecular shape is seen in the orientation of the perchlorate anions, and the influence of this on the intramolecular hydrogen bonding is discussed. The (partially) hydrated state of (I) favours the formation of chains along [011], while the anhydrous character of (II) and (III) promotes loosely bound structures with low packing indices.

Perchlorate anion on manganese(III) porphyrin as an ATR-IR probe for nanoscopic water environments

The effects of aqueous environments on the perchlorate infrared lineshape were investigated in various ionic solutions, including a polymeric polyvinyl chloride membrane and perchlorate coordinated to manganese(III) porphyrin, using the model frequency–frequency correlation function (FFCF). The perchlorate ligand moiety is considered a useful infrared probe in aqueous nanoscopic environments. We observed an asymmetric mode of the ligated perchlorate, in which the lineshape had a smaller bandwidth and faster dynamics than that of a 1 M perchlorate aqueous solution. In the 6 M solutions, we observed at least two conformations with faster dynamics than that of the 1 M solution, regardless of whether it was in the heterogeneous polymer matrix.

The molecular and supramolecular structures of three new lead(II) complexes with the pincer-type ligand 4′-chloro-2,2′:6′,2″-terpyridine (TpyCl)

Three new 1:1 complexes of lead(II) with the pincer-type ligand 4′-chloro-2,2′:6′,2″-terpyridine (TpyCl), [Pb(TpyCl)(NO 3) 2] n (1), [Pb(TpyCl)(ClO 4) 2] n (2) and [Pb(TpyCl)Br 2] 2 (3), have been synthesized and characterized by X-ray crystal structure determination as well as spectroscopy and thermal analysis. 1 and 2 are coordination polymers in which the coordination polyhedra are linked via nitrate and perchlorate ligands, respectively, to chains. 3 exhibits a dimeric molecular structure with Pb(μ-Br) 2Pb type bridging. In all three compounds the chains and the oligomers are connected to networks via supramolecular interactions which include O···O, C–H···O, C–H···Cl and C–H···Br hydrogen bonding and π– π stacking as well.

Di-μ-perchlorato-bis{μ-2-[(2-pyridyl)methylaminomethyl]phenolato)dicopper(II) acetonitrile disolvate

In the crystal of the dinuclear title compound, [Cu2(C13H13N2O)2(ClO4)2]·2CH3CN, the two bridging perchlorate ions chelate to the two CuII atoms in a μ-O:O′ fashion on opposite sides of the equatorial plane. The CuII ions display a distorted octa­hedral coordination geometry (in the usual 4 + 2 Jahn–Teller arrangement), each being coordinated by two O atoms from the two perchlorate ligands, and two N and O atoms from the reduced Schiff base ligand. The asymmetric unit contains two acetonitrile solvent mol­ecules. In the crystal structure, in addition to N—H⋯O hydrogen bonds, there are weak C—H⋯O inter­actions between the perchlorate O atoms and the reduced Schiff base ligand. C—H⋯N inter­actions are also present.

Bis(perchlorato-κO)tetrakis[1-(2-pyridyl)-4-(4-pyridylmethyl-κN)piperazine]cadmium(II)

In the title compound, [Cd(ClO4)2(C15H18N4)4], the CdII ion is coordinated in a slightly distorted octa­hedral environment by two trans monodentate perchlorate ligands and four 1-(2-pyrid­yl)-4-(4-pyridylmeth­yl)piperazine (pmpp) ligands. In the crystal structure, mol­ecules are organized into layers parallel to the ab plane by C—H⋯O inter­actions. Similar inter­actions promote the stacking of these layers into the three-dimensional crystal structure.

Bis[μ-3-(1H-pyrazol-1-yl)benzonitrile-κ2N:N′]bis[perchloratosilver(I)

In the title centrosymmetric complex, [Ag2(ClO4)2(C10H7N3)2], the unique AgI ion is coordinated by an N atom from a carbonitrile group, an N atom from a symmetry-related pyrazole group and an O atom of a perchlorate ligand to form a distorted T-shaped environment. Two 3-(1H-pyrazol-1-yl)benzonitrile ligands each bridge two AgI ions to form a dinuclear complex. In the crystal structure, there are weak Ag⋯O inter­actions within the range 2.70–3.01 Å linking dimeric units into layers approximately parallel to (100). The O atoms of the perchlorate ligand are disordered over two sites with occupancies of 0.570 (11) and 0.430 (11), respectively.

Time-Resolved Laser Fluorescence Spectroscopy and Extended X-Ray Absorption Spectroscopy Investigations of the N3− Complexation of Eu(III), Cm(III), and Am(III) in an Ionic Liquid: Differences and Similarities

The complexation of the lanthanide Eu(III) and the actinides Cm(III) and Am(III) by N3- was investigated by application of time-resolved laser fluorescence spectroscopy (TRLFS) and X-ray absorption spectroscopy (XAFS) in the ionic liquid solution of C4mimTf2N (1-butyl-3-methylimidazolium-bis(trifluoromethylsulfonyl)imide). TRLFS measurements show that the interaction of azide with Eu(CF3SO3)3 and Eu(ClO4)3 results in both dynamic luminescence quenching by collisional encounters of N3- with Eu(III) and static luminescence quenching by inner-sphere complexation of Eu(III) by N3-. Hereby, the complexation of Eu-triflate by azide starts at a lower N3- concentration as compared to the perchlorate salt. The authors ascribe this phenomenon to a stronger bonding of ClO4- toward the metal ion than triflate, as well as to a stronger electrostatic repulsion of N3- by the perchlorate ligand. In both actinide samples (Cm(ClO4)3, Am(ClO4)3), the complexation with azide exhibits a clear kinetic hindrance. Nevertheless, mixed actinide-perchlorate-azide complexes are formed after several days in C4mimTf2N. The different reaction kinetics for the Ln- and An-complexation by azide may provide the opportunity for an effective separation of lanthanides from actinides in the nuclear fuel cycle by the use of N-based extractants in ionic liquid solution.

A novel [CuII4] cluster from the assembly of two [CuII2L]+units by a central µ4-1,1,2,2 perchlorate ligand

A perchlorate ligand in the rare mu4-1,1,2,2 binding mode is seen for the first time as the sole support for the assembly of two cationic [Cu II 2L]+ fragments (H3L = a dinucleating ligand) in the formation of a magnetically-exchanged tetranuclear cluster.

Unusual bridging modes for percholorate in a 2D polymeric lead(II) complex, {[Pb(bpy)(µ-OAc)]2(µ-O2ClO2)(µ-OClO2O)}n

A lead(II) complex containing 2,2′-bipyridine (bpy), acetate and perchlorate ligands, [Pb(bpy)(CH3COO)(ClO4)] has been synthesized and characterized by elemental analysis, IR-, 1H NMR-, 13C NMR spectroscopy. Single crystal X-ray data show the complex is two dimensional polymeric as a result of an unusual perchlorate bi- and unidentate bridging with repeating dimeric {[Pb(bpy)(µ-OAc)]2(µ-O2ClO2)(µ-OClO2O)}n units. The Pb atom has an unsymmetrical eight-coordinate geometry with a coordination gap around the Pb(II) ion, possibly occupied possibly by a stereo-active lone pair of electrons on lead(II).

One‐Dimensional Holodirected Lead(II) Coordination Polymer, [Pb(μ2‐TPPZ)(NO3)(ClO4)]n (TPPZ = 2, 3, 5, 6–tetra(2‐pyridyl)pyrazine)

AbstractA lead(II) complex with 2,3,5,6‐tetra(2‐pyridyl)pyrazine (TPPZ), nitrate, and perchlorate ligands has been synthesized and characterized by CHN elemental analysis and IR and 207Pb NMR spectroscopy. The single crystal X‐ray data of the [Pb2(μ‐TPPZ)2(NO3)2(ClO4)2] compound show that the complex is a one‐dimensional coordination polymer and that the Lead atom has a less‐common, ten‐coordinate holodirected geometry.