Kristallstrukturen der Terpyridin-Komplexe [Cd(terpy)Cl2], [Cu(terpy)(CN)Cl] und [Cu(terpy)][Cu(CN)3] · H2O

Crystal Structures of the Terpyridine Complexes [Cd(terpy)Cl₂], [Cu(terpy)(CN)Cl], and [Cu(terpy)][Cu(CN)₃] · H₂O By reaction of cadmium chloride with 2,2′ : 6′,2″-terpyridine (“terpy”) in water/acetone crystals of [Cd(terpy)Cl₂] ( 1) were formed. The compound crystallizes monoclinic, space group P2₁/c, a = 1111.70(10), b = 823.10(7), c = 1643.00(14) pm, β = 93.913(1)°, Z = 4. Starting from mixtures of different molar ratios of copper(II) chloride, terpyridine, and KCN in water/methanole, two complexes of different composition were obtained. At the molar ratio of 1 : 1 : 2 a copper(II) coordination compound with both halide and pseudohalide ligands, [Cu(terpy)(CN)Cl] ( 2 ), was formed which also crystallizes monoclinic, P2₁/c, a = 1065.6(3), b = 824.6(2), c = 1644.5(7) pm, β = 98.214(3)°, Z = 4. At a molar ratio of 1 : 1 : 10 a partial reduction of copper(II) occured with formation of a mixed valency compound [Cu(terpy)][Cu(CN)₃] · H₂O ( 3 ) which crystallizes in the hexagonal space group P6₅22, with a = b = 800.29(1), c = 4771.05(7) pm, Z = 6. Compounds 1 and 2 are structurally similar, the coordination of the metal atoms is square pyramidal. Networks are formed by hydrogen bridges. In 3 the copper(II) ions show a distorted square planar coordination by the three N atoms of the terpy ligand and one N atom of a bridging CN^– group, the copper(I) atoms, however, show trigonal planar coordination by three CN^– ligands to which the water molecules are bonded by hydrogen bridges. Thus helical chains are formed which stretch in the direction of the screw axes. The EPR spectrum of 3 was measured.     

FeCl3 solutions in isopropanol-water

Summary This paper is devoted to the characterization of FeCl₃ solutions in isopropanol containing water. For this goal optical absorption and e.p.r. techniques have been used in conjunction with magnetization and M?ssbauer data reported very recently. It is shown that in a 10⁻² M solution of FeCl₃ containing 0.4 M of water the main iron(III) species present in the solution are [FeCl₄]⁻ (55%) and [FeCl₂(H₂O)₄]⁺ (20%) while the remainding 25% is due to dihydroxo dimers, . When the water concentration increases the [FeCl₄]⁻ anions are progressively destroyed, the main iron(III) species present in the solution being the dihydroxodimers and [FeCl₂(H₂O)₄]⁺. The variation of the concentration of the three species mentioned with the water content and FeCl₃ concentration is presented in this paper.     

Reaction of Ru3(CO)12 with 1,3-diferrocenylprop-2-ene-1-one. Crystal and molecular structures of the complexes Ru3(CO)8(FcC=CHCOFc)2 and [Ru(CO)2Cl(FcC=CHCOFc)]2

The reaction of Ru₃(CO)₁₂ with 1,3-diferrocenylprop-2-en-1-one,trans-FcCH=CHCOFc (where Fc is ferrocenyl), in boiling hexane afforded the complex (2c), which was converted into (3c) upon further heating. These complexes gave the complex (4) containing two Cl-bridged oxaruthenacycles upon dissolution in CHCl₃ or CH₂Cl₂. The structures of complexes 3 and 4 were established by X-ray diffraction analysis. According to the data of¹H NMR spectroscopy, the Cl-bridged complex exists in solutions as a mixture of isomers along with the monomeric form resulting from the cleavage of the halide bridges. All interconversions of the isomers occur with the participation of the monomeric form. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1616–1623, September, 2000.     

Modifizierung von Schichtsilicaten mit sterisch anspruchsvollen Metallkomplexen. 3. Synthese und Intercalation der planar-quadratischen Komplexe [Cu(bppep)(H2O)](ClO4)2 und [Ni(bppep)(Cl)Cl] (bppep = 2,6-Bis[1-phenyl-1-(pyridin-2-yl)ethyl]pyridin) in Hectorit

Modification of Layer Silicates by Sterically Demanding Metal Complexes: Synthesis and Intercalation of the Square Planar Complexes [Cu(bppep)(H₂O)](ClO₄)₂ and [Ni(bppep)(Cl)]Cl (bppep = 2,6-Bis[1-phenyl-1-(pyridine-2-yl)ethyl]pyridine) in Hectorite Sodium-aqua hectorite reacts with [Cu(bppep)(H₂O)](ClO₄)₂ and [Ni(bppep)(Cl)]Cl with exchange of the sodium-aqua cations against the complex cations [Cu(bppep)(H₂O)]²⁺ and [Ni(bppep)(Cl)]⁺, respectively. In addition, cation-anion pairs of [Cu(bppep)(H₂O)](ClO₄)₂ and [Ni(bppep)(Cl)]Cl are also intercalated between the hectorite layers (intersalation). On the other hand, it is possible to synthesize [Cu(bppep)(H₂O)]²⁺ or [Ni(bppep)(H₂O)]²⁺ modified hectorites without additional ion-pair intercalation (intersalation) by reaction of nickel- and copper-hectorites with the bppep ligand.     

Addition of protic molecules to coordinated 2-pyridinecarboxaldehyde in gold(III), palladium(II), and platinum(II) complexes

The reactions of Au^III, Pt^II and Pd^II complexes with 2-pyridinecarboxaldehyde (2CHO-py) have been examined in protic (H₂O, MeOH, EtOH) and aprotic (DMF, CH₂Cl₂) solvents. Compounds in which the pyridine ligand is N-coordinated, either in the original aldehydic form or in a new form derived from addition of one or two protic molecules, have been isolated, namely: [Au(2CHO-py · H₂O)Cl₃], [Au(2CHO-py · MeOH)Cl₃], [Au(2CHO-py · 2EtOH)Cl₃], cis-[Pt(2CHO-py)₂Cl₂], trans-[Pd(2CHO-py)₂Cl₂], trans-[Pt(dmso)(2CHO-py)Cl₂], [Pt{C₅H₄N-(CH₂SMe)}Cl(2CHO-py)](ClO₄), [Pt(terpy)(2CHOpy)](ClO₄)₂, [Pt(terpy)(2CHO-py · H₂O)](ClO₄)₂ (terpy = 2,2′:6′,2′′-terpyridine). ¹H-n.m.r. experiments show that the addition of the protic molecule(s) to the Pt^II and Pd^II complexes is reversible. The effects of the nature of the metal ion and the ancillary ligands as well as of the total charge of the complexes on the relative stability of the addition products are discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Syntheses and Characterization of Cyanide‐Bridged Bimetallic Compounds Zn(terpy)(H2O)M(CN)4 (terpy = 2,2′:6′,2′′‐ter­pyridine; M = Ni,Pd, Pt) with Linear Chains

The self‐assembly reaction of zinc ions with tetracyanometalates in the presence of the tridentate chelated ligand 2,2′:6′,2′′‐terpyridine (terpy) yielded three cyanide‐bridged bimetallic compounds of general formula Zn(terpy)(H₂O)M(CN)₄ [M = Ni ( 1 ), Pd ( 2 ), Pt ( 3 )]. Compounds 1 – 3 were characterized by X‐ray diffraction (XRD), infrared spectroscopy (IR), and thermogravimetric (TG) analysis. Single‐crystal XRD analysis revealed that compounds 1 – 3 are isostructural and the structure consists of [Zn(terpy)(H₂O)]²⁺ moieties and [M(CN)₄]^2– units linked alternatively to generate a one‐dimensional (1D) linear chain. The chains are further connected together through hydrogen bonding and π–π stacking interactions, forming a 3D supramolecular network. IR spectroscopic analysis indicated the presence of cyanide groups and terpy ligands in the structure. TG and powder XRD results showed that compounds 1 – 3 have higher thermal stabilities and exhibited irreversible for desorption/resorption of one coordinated water molecule.     

Ab initio study of the complexes of first-row transition-metal ions with CH, CH2, and CH3

The geometries and bonding characteristics of the complexes of the first-row transition-metal ions with CH, CH₂ and CH₃ were investigated byab initio molecular orbital theory. MCH⁺ and MCH₂ ⁺ are linear and coplanar, respectively. Both of them are with obvious treble or double bond characteristics, but these multiple bonds are mostly “imperfect”. The calculated bond dissociation energies of , and are mostly close to the experimental values, and appear in similar periodic trends from Sc to Zn. Project supported by the National Natural Science Foundation of China (Grant No. 29170070).     

Studies on the magnetic properties of two cobalt(II) complexes bearing 1,4-phenylenediacetate ligands

One reported compound [Co(PDA)(4,4′-bipy)]_n·nH₂O and one new compound [Co(PDA)(Im)₂(H₂O)₂]_n·nH₂O were prepared by the reactions of Co(NO₃)₂·6H₂O or Co(OH)₂ with 1,4-phenylenediacetic acid (H₂PDA) in the presence of the ancillary ligands 4,4′-bipyridine (4,4′-bipy) or imidazole (Im), and their magnetic properties were investigated. The presence of 4,4′-bipy in [Co(PDA)(4,4′-bipy)]_n·nH₂O results in a μ ₃-bridging mode of the PDA²⁻ ligand with one μ ₂-carboxylato group and one chelating carboxylato group and the construction of a 2D framework as reported in the literature. The introduction of Im ligand in [Co(PDA)(Im)₂(H₂O)₂]_n·nH₂O helps to construct a one dimensional chain with the two carboxylato groups of PDA²⁻ ligand in monodentate coordination modes. The magnetic studies reveal the presence of dominant antiferromagnetic interaction in [Co(PDA)(4,4′-bipy)]_n·nH₂O with a field-induced magnetic transition due to spin-flop. Magnetically, [Co(PDA)(Im)₂(H₂O)₂]_n·nH₂O presents a mononuclear structure. This work reveals that the introduction of ancillary ligands in the Co(II)-PDA system adjusts the linking modes of PDA²⁻ and therefore the resulting frameworks and their magnetic properties.     

Reactions of [Cp*Ru(H<Subscript>2</Subscript>O)(NBD)]<Superscript>+</Superscript> with diynes

Abstract  Formal [2 + 2 + 2] addition reaction of [Cp*Ru(H₂O)(NBD)][BF₄] (NBD = norbornadiene) with 4,4′-Diethynylbiphenyl generates [C₉H₉-η⁶-C₆H₄(RuCp*)–C₆H₄(RuCp*)-η⁶-C₉H₉][BF₄]₂. The reaction of [Cp*Ru(H₂O)(NBD)][BF₄] with 1,4-diphenylbutadiyne generates the unusual [2 + 2 + 2] additional organic compound Ph–C≡C–C₉H₈–Ph in addition to the organometallic compound [Cp*Ru(η⁶-C₆H₅–C≡C–C≡C–Ph)][BF₄]. [C₉H₉-η⁶-C₆H₄(RuCp*)–C₆H₄(RuCp*)-η⁶-C₉H₉][BPh₄]₂ is generated after the reaction of compound [C₉H₉-η⁶-C₆H₄(RuCp*)–C₆H₄(RuCp*)-η⁶-C₉H₉][BF₄]₂ with Na[BPh₄]. The structure of this compound was confirmed by X-ray diffraction. A possible approach to form Ph–C≡C–C₉H₈–Ph and [Cp*Ru(η⁶-C₆H₅–C≡C–C≡C–Ph)][BF₄] is suggested. Graphical Abstract  Formal [2 + 2 + 2] addition reaction of [Cp*Ru(H₂O)(NBD)]BF₄ (NBD = norbornadiene) with 4,4′-Diethynylbiphenyl generates [C₉H₉-η⁶-C₆H₄(RuCp*)–C₆H₄(RuCp*)-η⁶-C₉H₉][BF₄]₂. The reaction of [Cp*Ru(H₂O)(NBD)][BF₄] with 1,4-diphenylbutadiyne simply generates unusual [2 + 2 + 2] additional organic compound Ph–C≡C–C₉H₈–Ph in addition to the organometallic compound [Cp*Ru(η⁶-C₆H₅–C≡C–C≡C–Ph)][BF₄]. [C₉H₉-η⁶-C₆H₄(RuCp*)–C₆H₄(RuCp*)-η⁶-C₉H₉][BPh₄]₂ is generated after the reaction of compound [C₉H₉-η⁶-C₆H₄(RuCp*)–C₆H₄(RuCp*)-η⁶-C₉H₉][BF₄]₂ with Na[BPh₄]. The structure of this compound was confirmed by X-ray diffraction. And the possible approach to form Ph–C≡C–C₉H₈–Ph and [Cp*Ru(η⁶-C₆H₅–C≡C–C≡C–Ph)][BF₄] was suggested. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis and characterization of [Cu(Phca2en)(PPh3)X] (X=Cl, Br, I, NCS, N3) complexes: crystal structures of [Cu(Phca2en)(PPh3)Br] and [Cu(Phca2en)(PPh3)I]

New mixed-ligand copper(I) complexes, [Cu(Phca₂en)(PPh₃)X], [Phca₂en = N,N′-bis(β-phenylci-nnamaldehyde)-1,2-diiminoethane and X=Cl (1), Br (2), I (3), NCS (4), N₃ (5)] have been synthesized and characterized by various techniques. ¹H and ¹³C-NMR and IR spectral data of these copper(I) complexes are compared with the free ligand to elucidate some structural features. The structures of [Cu(Phca₂en)(PPh₃)Br] (2) and [Cu(Phca₂en)(PPh₃)I] (3) have been determined from single-crystal data showing that the coordination geometry around copper atom is a distorted tetrahedron. Furthermore, these Cu(I) complexes exhibit supramolecular motifs of the type multiple phenyl embraces resulting from attractive interactions between phenyl rings of PPh₃ moieties. The presence of the C–H…Cu weak intramolecular hydrogen bonds, due to the trapping of C–H bonds in the vicinity of the metal atoms, is also reported.     

[Ni(terpy)(H2O)]‐trans‐[Ni‐(μ‐CN)2‐(CN)2]n,a one‐dimensional linear tetra­cyano­nickelate chain

The one‐dimensional chain catena‐poly­[[aqua(2,2′:6′,2′′‐terpyridyl‐κ³N)­nickel(II)]‐μ‐cyano‐κ²N:C‐[bis­(cyano‐κC)nickelate(II)]‐μ‐cyano‐κ²C:N], [Ni(terpy)(H₂O)]‐trans‐[Ni‐μ‐(CN)₂‐(CN)₂]_n or [Ni₂­(CN)₄­(C₁₅H₁₁N₃)(H₂O)], consists of infinite linear chains along the crystallographic [10] direction. The chains are composed of two distinct types of nickel ions, paramagnetic octahedral [Ni(terpy)(H₂O)]²⁺ cations (with twofold crystallographic symmetry) and diamagnetic planar [Ni(CN)₄]^2? anions (with the Ni atom on an inversion center). The [Ni(CN)₄]^2? units act as bidentate ligands bridging through two trans cyano groups thus giving rise to a new example of a trans–trans chain among planar tetra­cyano­nickelate complexes. The coordination geometry of the planar nickel unit is typical of slightly distorted octahedral nickel(II) complexes, but for the [Ni(CN)₄]^2? units, the geometry deviates from a planar configuration due to steric interactions with the ter­pyridine ligands.     

A series of coordination polymers constructed from flexible bis(benzimidazole)ether ligands and different carboxylates

Six new coordination polymers constructed from two structurally related ligands, 2,2′-bis(2-methylbenzimidazole) ether (L1) and 2,2′-bis(2-ethylbenzimidazole)ether (L2), have been synthesized. They are [Cu(L1)(bz)₂] (1), [Cu(L2)(bz)₂] (2), [Zn₂(L1)(m-bdc)₂] (3), [Cd₂(L2)(m-bdc)₂(H₂O)]₂·H₂O (4), [Zn(L1)(OH-bdc)-(H₂O)] (5) and [Zn₂(L₂)(btca)] (6), where Hbz = benzoic acid, m-H₂bdc = 1,3-benzenedicarboxylic acid, OH-H₂bdc = 5-hydroxyisophthalic acid, and H₄btca = 1,2,4,5-benzenetetracarboxylic acid. In 1 and 2, the bidentate N-donor ligands (L1 and L2) bridge neighboring metal centers to form 1D single chains. The bz anions are attached on both sides of the chains. In 3 and 4, the N-donor ligands (L1 and L2) in cis conformations bridge two metal centers to generate a [M₂(L1)]⁴⁺ unit (M = Zn(II) and Cd(II)). The adjacent [M₂(L1)]⁴⁺ units are further linked via the dicarboxylate anions to form 1D double chain structures. In 5, the Zn(II) cations are bridged by OH-m-bdc anions to form an infinite polymeric chain. The L1 ligands are attached on one side of the chain in a monodentate mode. In 6, two Zn(II) cations are bridged by two L2 ligands to form a [ZnL2]₂ ⁴⁺ ring, which is further linked by btca anions to generate a 2D layer. The luminescent properties of the ligands and 3–6 in the solid state at room temperature were also studied.     

Structure and magnetic properties of a novel heterospin 1-D chain complex containing both Cu(II) and nitroxide radicals as spin branches

A novel heterospin one-dimensional (1-D) chain complex containing both Cu(II) and nitroxide radical ligands, {[Cu(tcph)(H₂O)₄][Cu(tcph)(NIT3Py)₂]·2H₂O} _n (1) (H₂tcph = tetrachloro-phthalic acid, NIT3Py = 2-(3′-pyridyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide), has been synthesized and structurally characterized. The structure consists of neutral chains of copper(II) ions bridged by tcph and coordinated alternatively by nitroxide radicals as spin branches and solvated water as co-ligand. The magnetic data were fitted using an approximate theoretical model based on population analysis to obtain the coupling parameter values of J _Cu2-Rad = 22.4 cm⁻¹ and J′_Cu1-Cu2 = −2.4 cm⁻¹, indicating the intramolecular ferromagnetic interaction between Cu(II) and NIT3Py and weak antiferromagnetic interaction between Cu1 and Cu2 linked by tcph.     

Two new 2-D frameworks based on tetra-copper(II)-substituted sandwich-type polyoxotungstate anions and [Cu2(dien)2(OH)]3+ cations

Two new organic–inorganic polyoxometalates [Cu(dien)(H₂O)]₂{[Cu₂(dien)₂(OH)]₂[Cu₄(B-α-XW₉O₃₃)₂]}·4H₂O (X?=?Sb, 1; X?=?As, 2) (dien?=?diethylenetriamine) were hydrothermally synthesized and characterized by elemental analysis, IR spectra, thermogravimetric (TG) analyses, and single-crystal X-ray diffraction. Both compounds are constructed from one four-coordinate [Cu(dien)(H₂O)]²⁺, one {[Cu₂(dien)₂(OH)]₂[Cu₄(B-α-XW₉O₃₃)₂]} building unit, and four water molecules of crystallization. Structural analysis shows that the sandwich-like polyoxotungstate cluster anions [Cu₄(B-α-XW₉O₃₃)₂]^10? are linked by six adjacent dimeric cations [Cu₂(dien)₂(OH)]³⁺ into a 2-D architecture with a (6,3)-connected topology. Magnetic measurements of 1 and 2 exhibit the presence of antiferromagnetic interactions within the tetranuclear-Cu^II cluster.     

Synthesis and Reactivity of [PdCl(terpy)]Cl

 [PdCl(terpy)]Clċ3H₂O has been synthesized both by interaction of [PdCl₄]²⁻ and cis-[Pd(DMSO)₂Cl₂] with terpy (2,2^′:6^′,2^′′-terpyridine). Complex formation of [PdCl(terpy)]⁺ with L-cysteine, S-methyl-L-cysteine, and L-methionine was studied as a function of temperature (298–308 K) using of stopped-flow spectrophotometry in methanol-water (95:5 (v/v)). The ionic strength and acidity of the solutions were adjusted to 0.10 molċdm⁻³ with CH₃SO₃H. The second-order rate constant for the reaction of [PdCl (terpy)]⁺ with L-cysteine amounts to 9.60±0.5 M ⁻¹s⁻¹. L-Methionine and S-methyl-L-cysteine are unreactive under the same experimental conditions. The entropy of activation is strongly negative, which is compatible with an associative mechanism.     

Crystal structures of [Ru(terpy)(HPB)(H2O)](PF6)2 and [Ru(terpy)(HPB)(2-picoline)](PF6) and the kinetics studies of the aqua ligand substitution by pyridine and substituted pyridines

The crystal structures of [Ru(terpy)(HPB)(H₂O)](PF₆)₂, 1, and [Ru(terpy)(HPB)(2-picoline)](PF₆), 2, (where terpy = 2,2′:6′,2′′-terpyridine and HPB = 2-(2′-hydroxyphenyl)-benzoxazole) have been determined. Both structures show slightly distorted octahedral coordination around the ruthenium center. In complex 1, the imine nitrogen of the HPB ligand occupies an axial position and is trans to the aqua ligand whereas in complex 2, the imine nitrogen is trans to the nitrogen of the 2-picoline ligand. The Ru-N(2-picoline) bond distance is much longer than the other Ru-N bonds in the complex due to steric effects from the methyl group of 2-picoline. In both complexes, the phenolate oxygen of the HPB ligand is in the equatorial position and trans to the center nitrogen of the terpyridine. The reaction of [Ru(terpy)(HPB)(H₂O)](PF₆)2 with pyridine and its analogs, 2-picoline and 4-picoline in dichloromethane was monitored spectrophotometrically. There is an initial reduction of the [Ru(III)-H₂O] complex to [Ru(II)-H₂O] complex prior to the substitution of the aqua ligand. The values of the activation parameters indicate that the substitution of the aqua ligand by pyridine, 2-picoline and 4-picoline follow an associative mechanism.     

Synthesis,structures and magnetic properties of three metal-organic frameworks containing manganese(II)

Two new Mn(II) coordination polymers formed with molecular formula [Mn(H₂O)₂(HBTC)·(H₂O)] 1 and [Mn(H₂O)₂(4,4′bipy)(HBTC)₂]·(H4,4′bipy)₂ 2, where BTC = 1,2,4-benzenetricarboxylate and 4,4′bipy = 4,4′bipydine, have been synthesized via hydrothermal approach and characterized by single crystal X-ray diffraction techniques. 1 is composed of Mn–H₂O–Mn 1D chains and further the chains are linked by HBTC ligands to form a 2D network in the ab plane; 2 is constructed by Mn–4,4′bipy–Mn 1D chains along the b direction with Mn²⁺ ions coordinated to H₂BTC and water as terminal ligands to form a 2D network. We also prepared a third compound with the molecular formula of [Mn(H₂O)(HBTC)·(H₂O)] which has been recently structurally reported elsewhere. The magnetic properties of the three compounds have been studied in detail under variable temperatures.     

Transition metal chemistry of oxime-containing ligands,part XI. Copper(II) complexes of syn-phenyl-2-pyridylketoxime and syn-methyl-2-pyridylketoxime

Summary Some copper(II) complexes of the types: Cu(HPPK)-(PPK)X, Cu(HMPK)(MPK)X (where HPPK = syn-phenyl-2-pyridylketoxime, HMPK = syn-methyl-2-pyridylketoxime and X = Cl^–, Br^–, I^–, NO₃ ^–, SCN^– or SeCN^–) Cu(HPPK)₂SO₄ 3 H₂O and Cu(HMPK)₂SO₄ · 3 H₂O were synthesized and characterized by analysis, magnetic susceptibility, e.s.r., reflectance and i.r. spectral measurements. The spectral data suggest that Cu(HPPK)(PPK)X and Cu(HMPK)(MPK)X containcis square-coplanar [Cu(HPPK)(PPK)]⁺ and [Cu(HMPK)(MPK)]⁺ units respectively, linked by weakly coordinated anions, giving infinite polymeric highly distorted octahedral chain structures, whereas Cu(HPPK)₂SO₄ · 3H₂O and Cu(HMPK)₂SO₄ · 3 H₂O have acis distorted octahedral structure containing two ligand molecules of ketoxime and a bidentate sulphate group. The polycrystalline e.s.r. spectra suggest a distorted octahedral stereochemistry for the Cu^II ion involving a ground-state. By using e.s.r. and reflectance spectral data, the orbital reduction parameters, k₁₁ and k₁ were calculated and interpreted in terms of molecular orbital coefficients.     

Metal complexes with N-(trifluoromethylbenzyl)iminodiacetate chelators (x-3F ligands). Part I. Copper(II) chelates of p-3F,m-3F,and o-3F with or without imidazole-like ligands

Eight Cu(II) complexes with N-(p-, m- or o-trifluoromethylbenzyl)iminodiacetate chelators (x-3F ligands) have been synthesized to promote C–F/H interligand interactions involving the F₃C-group: {[Cu(μ₂-p-3F)(H₂O)]·3H₂O]}_n (1), [Cu(m-3F)(H₂O)₂] (2), [Cu(p-3F)(Him)(H₂O)] (3), [Cu(m-3F)(Him)(H₂O)] (4), [Cu(o-3F)(Him)(H₂O)] (5), [Cu₂(p-3F)₂(H5Meim)₂(H₂O)₂] (6), [Cu(m-3F)(H5Meim)(H₂O)] (7), and [Cu(o-3F)(H5Meim)(H₂O)] (8) [Him and H5Meim = imidazole and the “remote” tautomer 5-methylimidazole, respectively]. The compounds were studied by single-crystal X-ray diffraction, FT-IR, electronic spectra and coupled thermogravimetric + FT-IR methods. The conformation of the iminodiacetate chelating moiety (IDA group) is fac-NO + O(apical) in 1 and mer-NO₂ in 2–8. The fac-IDA conformation observed in 1 is related to its polymeric structure and the coordination of a O’-carboxylate donor, from an adjacent complex unit, trans to the Cu–N(IDA) bond. The mer-IDA conformation in 2 is in agreement with similar compounds with an aqua ligand trans to the corresponding Cu–N(IDA) bond. As expected, the ternary complexes 3–8 feature a mer-IDA conformation. Some of the studied complexes exhibit disorder in the –CF₃ group and C–H?F interligand interactions along with conventional N–H?O and O–H?O interactions. The thermal decomposition of all studied compounds under air flow produces variable amounts of trifluorotoluene.