Synthesis,Crystal Structure,and Characterization of Two Oxamido‐bridged NiIICuIINiII Heteronuclear Complexes

Two new trinuclear complexes [Cu^II(Ni^IIX₁)₂(C₂H₅OH)₂]· (ClO₄)₂·2(CH₃OH) ( 1 ) and [Cu^II(Ni^IIX₂)₂(H₂O)]·(ClO₄)₂· 0.75(H₂O) ( 2 ) (X₁ = dianion of 5,6;13,14‐dibenzo‐7,12‐bis(ethoxycarboxyl)‐9‐methyl‐2,3‐dioxo‐1,4,8,11‐tetraazacyclotetradeca‐7,11‐diene. X₂ = dianion of 5,6;13,14‐dibenzo‐9,10‐cyclohexano‐7,12‐bis(ethoxycarboxyl)‐2,3‐dioxo‐1,4,8,11‐tetraazacyclotetradeca7,11‐diene.) have been synthesized and characterized by single crystal X‐ray analysis, elemental analysis, IR, UV and EPR spectroscopies. The complexes consist of Ni^IICu^IINi^II heteronuclear cationic entities. The central Cu^II atom of 1 lies in an octahedral coordination environment, while that of 2 resides in a square‐pyramidal coordination sphere. The adjacent trinuclear units of 1 are linked together through π‐π stacking interactions resulting in a 1D supramolecular chain, whereas the π‐π stacking interactions between the contiguous units of 2 lead to a 2D structure. The EPR spectra of the two complexes show a signal of an axially elongated octahedral Cu^II system in 1 and an axially elongated square‐pyramidal Cu^II system in 2 , respectively. The hyperfine splitting of the Cu^II atoms (I^Cu = 3/2) has also been observed in the EPR spectra.     

The unprecedented role of a Cu<Superscript>II</Superscript> cryptand in the luminescence properties of a Eu<Superscript>III</Superscript> cryptate complex

Abstract  A Eu^III cryptate complex constructed from a Cu^II cryptand with an L ^tBu ligand, [Eu^IIICu₂^II(L ^tBu)₂(NO₃)₃(MeOH)], and the corresponding Ca^II and Na^I cryptates, [Ca^IICu₂^II(L ^tBu)₂(NO₃)₂(MeOH)₂] and [Na^ICu₂^II(L ^tBu)₂(Me₂CO)](BPh₄), have been synthesized and characterized in order to shed light on the essential role of Cu^II in the luminescence of a Eu^III cryptate. The unprecedented role of a Cu^II cryptand makes it possible to produce lanthanide luminescence in a Eu^III cryptate complex and is successfully elucidated by comparison with the corresponding Ca^II and Na^I cryptates. Graphical abstract   Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Zinc(II) Complexes with 1H‐Imidazol‐4‐yl‐Containing Polyamine Ligand

The protonation and Zn^II/Cu^II complexation constants of tripodal polyamine ligand N¹‐(2‐aminoethyl)‐N¹‐(1H‐imidazol‐4‐ylmethyl)‐ethane‐1,2‐diamine (HL) were determined by potentiometric titration. Three new compounds, i.e. [H₃(HL)](ClO₄)₃ ( 5 ), [Zn(HL)Cl](ClO₄) ( 6 ) and {[Zn(L)](ClO₄)}_n ( 7 ) were obtained by reactions of HL · 4HCl with Zn(ClO₄)₂ · 6H₂O under different reaction pH, and they were compared with the corresponding Cu^II complexes reported previously. The results indicate that the reaction pH and metal ions have remarkable influence on the formation and structure of the complexes.     

Synthesis and spectral characterization of macrocyclic Ni<Superscript>II</Superscript> complexes derived from various diamines,Ni<Superscript>II</Superscript> perchlorate and 1,4-bis(2-carboxyaldehydephenoxy)butane

Six new macrocyclic complexes were synthesized by reaction of 1,4-bis(2-carboxyaldehyde phenoxy)butane with various diamines. Then, their nickel(II) perchlorate complexes were synthesized by the template effect by reaction of 1,4-bis(2-carboxyaldehyde phenoxy)butane, Ni(ClO₄)₂ · 6H₂O and various diamines. The metal-to-ligand ratio of Ni^II metal complexes was found to be 1:1. The compounds are coordinated to the central metal as tetradentate O₂N₂ ligands The Ni^II complexes are proposed to exhibit tetrahedral geometry. Ni^II metal complexes are 1:2 electrolytes as shown by their molar conductivities (Λ_M) in DMF (dimethyl formamide) at 10⁻³ m. The structure of Ni^II metal complexes is proposed from elemental analysis, f.t.-i.r., u.v.-vis., magnetic susceptibility measurements, molar conductivity measurements and mass spectra.     

Heterospin complexes of fluorinated dinuclear Cu<Superscript>II</Superscript> and Mn<Superscript>II</Superscript> triketonates with nitroxides

Dinuclear heterospin complexes of Cu^II and Mn^II 1,1,1,7,7,7-hexafluoroheptane-2,4,6-trionates ([Cu₂L₂] and [Mn₂L₂], respectively) with nitronyl nitroxides 2-R-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide 1-oxyls (NIT-R, R = H, Me, Et, m-C₅H₄N, m-NCC₆H₄, p-NCC₆H₄, PzMe) and the diradical NIT-Pz-(CH₂)₄-Pz-NIT (Pz is 1,4-pyrazolylene) were synthesized and structurally characterized. In the complexes under study, the CuII atom tends to have the square-pyramidal coordination environment, and the MnII atom is in an octahedral environment. The magnetochemical investigation of the compounds in the temperature range of 2–300 K showed that the antiferromagnetic exchange coupling dominates in the [Cu₂L₂] molecules, whereas this coupling in [Mn₂L₂] is manifested in the experimental plot μ_eff(T) at T < 100 K. The magnetic properties of the heterospin complexes of [Cu₂L₂] with NIT-R are also determined by the intramatrix antiferromagnetic exchange coupling. For the complexes of [Mn₂L₂] with NIT-R, the coordination mode of the nitroxide plays a decisive role.     

Assembling of transitional metal Cu<Superscript>II</Superscript> and Mn<Superscript>II</Superscript> with 4-pyridin-2-yl-pyrimidine-2-sulfonate adjusted by anions

Reactions of sodium 4-pyridin-2-yl-pyrimidine-2-sulfonate (NaL) with Cu^II and Mn^II ions in water produced a zig-zag chain polymer, [CuL(NCS)] _n (1), and a dinuclear complex, [Mn₂L₂Cl₂(H₂O)₂] (2), respectively. It is observed that counteranions and hydrogen bonds play basic roles in the resulting structure in which 3D networks were formed through intermolecular hydrogen bonding.     

Ion exchange in bimetallic cage copper organosiloxanes and the synthesis of polynuclear metal complexes containing Li and Cu<Superscript>II</Superscript> atoms

The replacement of sodium (potassium) atoms by lithium in a series of bimetallic (“alkaline”) cage copper organosiloxanes was investigated. The reactions of cage Cu^II(Na) or Cu^II(K) derivatives of organometallosiloxanes (OMS) with LiCl afford the corresponding Cu^II(Li) derivatives. The rate and degree of replacement are mainly determined by the structure of the molecular cage of the starting OMS. In the case of globular-like bimetallic OMS of the general formula [RSiO₂]₁₂[Cu₄M₄] (R = Me, H₂C=CH-(Vin), or Ph; M = Na or K), the ion exchange occurs under mild conditions at a high rate to give the corresponding Cu^II(Li) derivatives [RSiO₂]₁₂Cu₄Li₄ with the same structure (∼80% yield). Sandwich-like bimetallic OMS of the general formula [RSiO₂]₆[Cu₄M₄][RSiO₂]₆ (R = Ph or Vin; M = Na or K) react more slowly, the reaction proceeding stepwise. In the latter case, partial substitution products, viz., heterometallic sandwich complexes, for example, {[VinSiO₂]₆}₂Cu₄K₂Li₂, were isolated. The structures and compositions of the reaction products were studied by X-ray diffraction, gel permeation chromatography, and elemental analysis. The selectivity of the replacement of alkali metal atoms allows the synthesis of the desired globular or sandwich cage Cu(Li) metallosiloxanes, which are difficult to prepare.     

Diamond‐ and Graphite‐Like Octacyanometalate‐Based Polymers Induced by Metal Ions

By using cyclohexane‐1,2‐diamine (chxn), Ni(ClO₄)₂ ? 6H₂O and Na₃[Mo(CN)₈] ? 4H₂O, a 3D diamond‐like polymer {[Ni^II(chxn)₂]₂[Mo^IV(CN)₈] ? 8H₂O}_n ( 1 ) was synthesised, whereas the reaction of chxn and Cu(ClO₄)₂ ? 6H₂O with Na₃[M^V(CN)₈] ? 4H₂O (M=Mo, W) afforded two isomorphous graphite‐like complexes {[Cu^II(chxn)₂]₃[Mo^V(CN)₈]₂ ? 2H₂O}_n ( 2 ) and {[Cu^II(chxn)₂]₃[W^V(CN)₈]₂ ? 2H₂O}_n ( 3 ). When the same synthetic procedure was employed, but replacing Na₃[Mo(CN)₈] ? 4H₂O by (Bu₃NH)₃[Mo(CN)₈] ? 4H₂O (Bu₃N=tributylamine), {[Cu^II(chxn)₂Mo^IV(CN)₈][Cu^II(chxn)₂] ? 2H₂O}_n ( 4 ) was obtained. Single‐crystal X‐ray diffraction analyses showed that the framework of 4 is similar to 2 and 3 , except that a discrete [Cu(chxn)₂]²⁺ moiety in 4 possesses large channels of parallel adjacent layers. The experimental results showed that in this system, the diamond‐ or graphite‐like framework was strongly influenced by the inducement of metal ions. The magnetic properties illustrate that the diamagnetic [Mo^IV(CN)₈] bridges mediate very weak antiferromagnetic coupling between the Ni^II ions in 1 , but lead to the paramagnetic behaviour in 4 because [Mo^IV(CN)₈] weakly coordinates to the Cu^II ions. The magnetic investigations of 2 and 3 indicate the presence of ferromagnetic coupling between the Cu^II and W^V/Mo^V ions, and the more diffuse 5d orbitals lead to a stronger magnetic coupling interaction between the W^V and Cu^II ions than between the Mo^V and Cu^II ions.     

Heterospin complexes of polynuclear Ni<Superscript>II</Superscript> compounds containing hexafluoroacetylacetonate and pivalate ligands with nitroxides

The heterospin mixed-ligand complex [Ni₆(OH)₄Piv₄(hfac)₄(NIT-Ph)₂] (1) (NIT-Ph is 4,4,5,5-tetramethyl-2-phenyl-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide, hfac is hexafluoroacetylacetonate, and Piv is pivalate) was synthesized. The method for the synthesis of complex 1 is based on the replacement of acetone molecules in the hexanuclear complex containing the hexafluoroacetylacetonate and pivalate ligands [Ni₆(OH)₄Piv₄(hfac)₄(Me₂CO)₄] by NIT-Ph molecules. Two monodentate NIT-Ph molecules replace four acetone molecules, because the coordination of the O atom of the nitroxide group results in the blocking of one of the positions in the coordination environment of Ni^II the access to which is hindered by the phenyl ring of NIT-Ph. As a result, these ions are in a square-pyramidal environment unusual of Ni^II. In the low-temperature range, the dependence of the magnetization of 1 on the magnetic field is described by the Brillouin function. The reaction of [Ni₆Piv₄(hfac)₄(OH)₄(Me₂CO)₄] with the nitronyl nitroxide radicals 4,4,5,5-tetramethyl-2-(4-pyridyl)-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide (NIT-p-Py) or 4,4,5,5-tetramethyl-2-(1-methyl-1H-imidazol-5-yl)-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide (NIT-Iz) containing the pyridine or 1-methylimidazol-5-yl substituent, respectively, in the side chain is accompanied by the decomposition of the polynuclear fragment and affords the mononuclear complexes Ni(hfac)₂(NIT-p-Py)₂ and Ni(hfac)₂(NIT-Iz)₂, respectively. The reaction of 4,4,5,5-tetramethyl-2-(1-methyl-1H-imidazol-5-yl)-4,5-dihyd-ro-1H-imidazol-1-oxyl (Im-Iz), which is the imine analog of NIT-Iz, with [Ni₆Piv₄(hfac)₄(OH)₄(Me₂CO)₄] afforded the decanuclear complex [Ni₁₀(OH)₈Piv₄(hfac)₈(Im-Iz)₂(H₂O)₆]. The molecular and crystal structures of all heterospin compounds were determined, and the magnetic properties of all compounds were investigated in the 2–300 K temperature range.     

5-[2-(Methylthio)ethyl]-3-phenyl-2-thioxoimidazolidin-4-one and its complexes with transition metals (Co<Superscript>II</Superscript>, Ni<Superscript>II</Superscript>, and Cu<Superscript>II</Superscript>). Synthesis and electrochemical investigation

The reaction of 5-[2-(methylthio)ethyl]-3-phenyl-2-thioxoimidazolidin-4-one (LH) with salts MCl₂· xH₂O (M = Co, Ni, Cu; x = 2, 6) afforded the [M(L)Cl]_n complexes of Ni^II, Co^II, and Cu^II. The electrochemical behavior of the LH ligand and its complexes was studied using the cyclic voltammetry and rotating disk electrode techniques. The structures of the synthesized compounds were determined by the data of UV—Vis and IR spectroscopy, mass spectrometry, and electrochemical characteristics. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 339–343, February, 2007.     

Syntheses,crystal structures and magnetic properties of two honeycomb-layered bimetallic assemblies,K2[NiII(cyclam)]3[FeII(CN)6]2 · 12H2O and [NiII(cyclam)]3[FeIII(CN)6]2 · 16H2O

Two bimetallic assemblies, K₂[Ni^II(cyclam)]₃[Fe^II(CN)₆]₂ · 12H₂O (1) and [Ni^II(cyclam)]₃[Fe^III(CN)₆]₂ · 16H₂O (2) (cyclam = 1,4,8,11-tetraazacyclotetradecane), were obtained by reaction of K₄[Fe(CN)₆] and [Ni(cyclam)](ClO₄)₂ in aqueous media at different temperatures. Their crystals were structurally determined and magnetic properties were studied. Both of the compounds have honeycomb-layered structures, which are formed by Fe₆Ni₆ units linked through the cyanide bridges. Structure (1) consists of polyanions containing Ni^II–NC–Fe^II linkages and K⁺ cations, while structure (2) is a two-dimensional neutral layer containing Ni^II–NC–Fe^III linkages. The magnetic properties of (1) and (2) have been investigated in the 5–300 K range. Compound (1) exhibits a weak antiferromagnetic interaction with Weiss constant = –0.35 K; compound (2) shows ferromagnetic intralayer and antiferromagnetic interlayer interactions.     

Heterospin mixed-ligand heterotrinuclear Co<Superscript>II</Superscript>, Gd<Superscript>III</Superscript>, Co<Superscript>II</Superscript> complex with nitronyl nitroxide

A method was developed for the synthesis of mixed-metal heterospin compounds with the direct coordination of the nitroxide fragment based on the replacement of acetonitrile molecules in the heterotrinuclear complex [Co₂Gd(NO₃)Piv₆(CH₃CN)₂] with nitroxide molecules. The molecular and crystal structure of the heterospin mixed-ligand heterotrinuclear Co^II, Gd^III, Co^II complex [Co₂Gd(NO₃)Piv₆(NIT-Me)₂], where NIT-Me is stable nitronyl nitroxide, was established. The magnetic properties of this complex were investigated in the temperature range of 2–300 K. The coordination of nitroxide groups to Co^II ions is responsible for strong exchange interactions between the unpaired electrons in the exchange clusters {>-·O-Co^II}, resulting in the virtually complete spin coupling between each coordinated >N-·O group and one of the unpaired electrons of each Co^II ion at temperatures below 200 K. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1742–1745, September, 2007.     

Dodecanuclear Ni<Superscript>II</Superscript> complex containing pivalate and hexafluoroacetylacetonate ligands

A dodecanuclear complex [Ni₁₂Piv₁₀(hfac)₆(OH)₈(EtOH)₆]·C₆H₁₄ was isolated from various synthetic systems simultaneously containing Ni^II and the pivalate and hexafluoro-acetylacetonate anions. The structure of this complex was determined and the magnetic properties were investigated. The use of EtOH as the solvent or the presence of EtOH in the reagents is the decisive factor for the formation of this complex.     

Synthesis,characterization and biological studies of Co<Superscript>II</Superscript>, Ni<Superscript>II</Superscript>, Cu<Superscript>II</Superscript> and Zn<Superscript>II</Superscript> complexes of Schiff bases derived from 4-substituted carbostyrils[quinolin2(1H)-ones]

Schiff bases derived from 4-aminomethylcarbostyril and their transition metal complexes with Co^II, Ni^II, Cu^II and Zn^II have been synthesized and characterized by elemental analysis, molar conductance, magnetic susceptibilities electronic, IR, PMR, ESR, FAB-Mass and thermal studies. From the above spectral studies it is concluded that the ligands of 4-substituted carbostyril Schiff bases, viz, salicylidene 4-aminomethylcarbostyril (SAMC); o-vanillinsalicylidene 4-aminomethylcarbostyril (VAMC) and 5′ chlorosalicylidene 4-aminomethylcarbostyril (CSAMC) act as bidenate molecules coordinating through azomethine nitrogen and phenolic oxygen. The ligands and their metal complexes have been screened in vitro for antibacterial, antifungal and antitumor activity. The results indicate that the biological activity increases on complexation. The Cu^II complexes of the above ligands show greater inhibitory action towards the P388/s tumor cells at lower concentrations.     

Synthesis and Crystal Structure of Two Succinato‐Bridged Macrocyclic Nickel(II) Complexes

Two dinuclear succinato‐bridged nickel(II) complexes [Ni(RR‐L)]₂(μ‐SA)(ClO₄)₂ ( 1 ) and [Ni(SS‐L)]₂(μ‐SA)(ClO₄)₂ ( 2 ) (L = 5, 5, 7, 12, 12, 14‐hexamethyl‐1, 4, 8, 11‐tetraazacyclotetradecane, SA = succinic acid) were synthesized and characterized by EA, Circular dichroism (CD), as well as IR and UV/Vis spectroscopy. Single crystal X‐ray diffraction analyses revealed that the Ni^II atoms display a distorted octahedral coordination arrangement, and the succinato ligand bridges two central Ni^II atoms in a bis bidentate fashion to form dimers in 1 and 2 . The monomers of {[Ni(RR‐L)]₂(μ‐SA)}²⁺ and {[Ni(SS‐L)]₂(μ‐SA)}²⁺ are connected by O–H ··· O and N–H ··· O hydrogen bonds into a 1D right‐handed and left‐handed helical chain along the b axis, respectively. The homochiral natures of 1 and 2 are confirmed by the results of CD spectroscopy.     

Heterotrimetallic Coordination Polymers: {CuIILnIIIFeIII} Chains and {NiIILnIIIFeIII} Layers: Synthesis,Crystal Structures,and Magnetic Properties

The use of the [Fe^III(AA)(CN)₄]^? complex anion as metalloligand towards the preformed [Cu^II(valpn)Ln^III]³⁺ or [Ni^II(valpn)Ln^III]³⁺ heterometallic complex cations (AA=2,2′‐bipyridine (bipy) and 1,10‐phenathroline (phen); H₂valpn=1,3‐propanediyl‐bis(2‐iminomethylene‐6‐methoxyphenol)) allowed the preparation of two families of heterotrimetallic complexes: three isostructural 1D coordination polymers of general formula {[Cu^II(valpn)Ln^III(H₂O)₃(μ‐NC)₂Fe^III(phen)(CN)₂ {(μ‐NC)Fe^III(phen)(CN)₃}]NO₃ ? 7 H₂O}_n (Ln=Gd ( 1 ), Tb ( 2 ), and Dy ( 3 )) and the trinuclear complex [Cu^II(valpn)La^III(OH₂)₃(O₂NO)(μ‐NC)Fe^III(phen)(CN)₃] ? NO₃ ? H₂O ? CH₃CN ( 4 ) were obtained with the [Cu^II(valpn)Ln^III]³⁺ assembling unit, whereas three isostructural heterotrimetallic 2D networks, {[Ni^II(valpn)Ln^III(ONO₂)₂(H₂O)(μ‐NC)₃Fe^III(bipy)(CN)] ? 2 H₂O ? 2 CH₃CN}_n (Ln=Gd ( 5 ), Tb ( 6 ), and Dy ( 7 )) resulted with the related [Ni^II(valpn)Ln^III]³⁺ precursor. The crystal structure of compound 4 consists of discrete heterotrimetallic complex cations, [Cu^II(valpn)La^III(OH₂)₃(O₂NO)(μ‐NC)Fe^III(phen)(CN)₃]⁺, nitrate counterions, and non‐coordinate water and acetonitrile molecules. The heteroleptic {Fe^III(bipy)(CN)₄} moiety in 5 – 7 acts as a tris‐monodentate ligand towards three {Ni^II(valpn)Ln^III} binuclear nodes leading to heterotrimetallic 2D networks. The ferromagnetic interaction through the diphenoxo bridge in the Cu^II?Ln^III ( 1 – 3 ) and Ni^II?Ln^III ( 5 – 7 ) units, as well as through the single cyanide bridge between the Fe^III and either Ni^II ( 5 – 7 ) or Cu^II ( 4 ) account for the overall ferromagnetic behavior observed in 1 – 7 . DFT‐type calculations were performed to substantiate the magnetic interactions in 1 , 4 , and 5 . Interestingly, compound 6 exhibits slow relaxation of the magnetization with maxima of the out‐of‐phase ac signals below 4.0 K in the lack of a dc field, the values of the pre‐exponential factor (τ_o) and energy barrier (E_a) through the Arrhenius equation being 2.0×10^?12 s and 29.1 cm^?1, respectively. In the case of 7 , the ferromagnetic interactions through the double phenoxo (Ni^II–Dy^III) and single cyanide (Fe^III–Ni^II) pathways are masked by the depopulation of the Stark levels of the Dy^III ion, this feature most likely accounting for the continuous decrease of χ_M T upon cooling observed for this last compound.     

Polynuclear Ni<Superscript>II</Superscript> and Co<Superscript>II</Superscript> hexafluoroacetylacetonates

Hydrolysis of [M₄(hfac)₄(MeO)₄(MeOH)₄] (М = Сo, Ni and hfac is hexafluoroacetylaceton ate) is a convenient way of obtaining polynuclear complexes [Ni₇(hfac)₆(OH)₈(H₂O)₆]?2H₂O, [Co₁₂(hfac)₁₀(OH)₁₄(H₂O)₈]?2H₂O?2MePh, [Co₁₂(hfac)₁₀(OH)₁₄(H₂O)₄(Me₂CO)₄]?3PhMe, and [Co₁₂(hfac)₁₀(OH)₁₄(H₂O)₆(Me₂CO)₂]?2H₂O?2Me₂CO, whose structures were confirmed by X-ray analysis.     

trans‐Bis(cyano‐κC)(1,4,8,11‐tetraazacyclotetradecane‐κ4N)manganese(III) perchlorate,a low‐spin manganese(III) complex

The crystal structure of the low‐spin (S = 1) Mn^III complex [Mn(CN)₂(C₁₀H₂₄N₄)]ClO₄, or trans‐[Mn(CN)₂(cyclam)](ClO₄) (cyclam is the tetradentate amine ligand 1,4,8,11‐tetra­aza­cyclo­tetra­decane), is reported. The structural parameters in the Mn(cyclam) moiety are found to be insensitive to both the spin and the oxidation state of the Mn ion. The difference between high‐ and low‐spin Mn^III complexes is that a pronounced tetragonal elongation of the coordination octahedron occurs in high‐spin complexes and a slight tetragonal compression is seen in low‐spin complexes, as in the title complex.     

Inclusion of nickel(<Emphasis Type="SmallCaps">II</Emphasis>) and copper(<Emphasis Type="SmallCaps">II</Emphasis>) complexes with aliphatic polyamines in cucurbit[8]uril

The inclusion compound of macrocyclic cavitand cucurbit[8]uril (CB[8]) with the nickel(II) complex containing the tetraazamacrocyclic ligand cyclam, {[Ni(cyclam)]@CB[8]}Cl₂··16H₂O (1), and the inclusion compounds of CB[8] with the copper(II) bis-ethylene-diamine complex, {trans-[Cu(en)₂(H₂O)₂]@CB[8]}Cl₂·{CB[8]}·42H₂O (2a) and {trans-[Cu(en)₂(H₂O)₂]@CB[8]}Cl₂·17H₂O (2b), were synthesized and characterized by X-ray diffraction analysis, IR and ESR spectroscopy, and electrospray mass spectrometry. Guest—host inclusion compounds can be directly synthesized starting from a metal complex and cucurbit[8]uril, as was exemplified by the preparation of compounds 2a and 2b.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2414–2419, November, 2004.     

Complexes derived from the general copper(II)/maleamic acid/N,N′,N′′-chelate reaction systems: Synthetic,reactivity, structural and spectroscopic studies

The synthetic investigation of the Cu^II/maleamate(−1) ion (HL⁻)/N,N′,N′′-chelate general reaction system has allowed access to compounds [Cu₂(HL)₂(bppy)₂](ClO₄)₂·H₂O (1·H₂O), [Cu(HL)(bppy)(ClO₄)] (2) and [Cu(HL)(terpy)(H₂O)](ClO₄) (4) (bppy = 2,6-bis(pyrazol-1-yl)pyridine, terpy = 2,2′;6′,2′′-terpyridine). In the absence of externally added hydroxides, compound [Cu₂(L′)₂(bppy)₂](ClO₄)₂ (3) was obtained from MeOH solutions; L′⁻ is the monomethyl maleate(−1) ligand which is formed in situ via the Cu^II-assisted HL⁻ → L′⁻ transformation. In the case of tptz-containing (tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine) reaction systems, the Cu^II-assisted hydrolysis of tptz to pyridine-2-carboxamide (L1) afforded complex [Cu(L1)₂(NO₃)₂] (5). The crystal structures of 1–5 are stabilized by intermolecular hydrogen bonding and π–π stacking interactions. Characteristic IR bands of the complexes are discussed in terms of the known structures and the coordination modes of the ligands.