Synthesis and crystal structure of aqua(diaminobithiazole) (iminodiacetato)nickel(II) hydrate

Crystals of the title compound, [(C₆H₆N₄S₂)(C₄H₅NO₄)(H₂O)Ni]·H₂O, consist of the Ni(II) complex and lattice water. The Ni(II) complex adopts a distorted octahedral coordination geometry formed by an iminodiacetate anion (IDA), a diaminobithiazole (DABT) and a coordinated water molecule. A twisted configuration of DABT is the distinguishing feature in the complex, the dihedral angle between thiazole rings of DABT being 20.04(8)°. An aromatic stacking interaction occurs between thiazole rings from neighboring complex molecules, and is considered as the reason for the twisted configuration. The tridentate IDA dianion chelates to a Ni(II) atom in afacialconfiguration. A hydrogen bond network holds the complex molecules together to form a supramolecular structure.     

Synthesis and crystal structure of an iminodiacetatocadmium(ii) complex containing benzimidazole

The crystal structure of the complex tris(benzimidazole)iminodiacetato(2-)cadmium(II) dihydrate, (BZIM)₃(IDA)Cd·2H₂O, was determined by single-crystal X-ray methods. The Cd(II) ion assumes distorted octahedral coordination geometry formed by three benzimidazole molecules and an iminodiacetate dianion. The dianion chelates Cd(II) as a terdentate in the facial configuration. Weak intermolecular C–H···π interactions exist between neighboring benzimidazole rings. The thermal decomposition of the title complex has been studied. IR assignments based on the molecular structure have been made.     

Mixed‐ligand Copper(II) Complexes with N‐isopropyl‐iminodiacetato(2‐) and C‐phenyl‐imidazole Ligands. Crystal Structures of H2iPIDA, [Cu(iPIDA)(H2ϕim)(H2O)]·3H2O and [Cu(iPIDA)(H5ϕim)]n

The crystal of the N‐isopropyl‐iminodiacetic acid ( 1 ) consists of a 3D H‐bonded framework where the zwitterion (H₂iPIDA^±) is intra‐stabilized by one N⁺‐H···O interaction and both carboxyl are half‐protonated and involved in linear O‐H···O inter‐molecular bridges of 2.46 Å. The mixed‐ligand complexes [Cu(iPIDA)(H2?im)(H₂O)]·3H₂O ( 2 ) and [Cu(iPIDA)(H5?im)]_n ( 3 ) have also been synthesized and studied by thermal, spectral, magnetic and X‐ray diffraction methods. Both complexes exhibit a square base pyramidal coordination, type 4+1. Compound 3 is the less steric hindered 'remote' isomer, with H5?im instead of H4?im.     

Synthesis,Crystal Structure and Properties of [Cu(phen)3][Cu(pheida)2]·10H2O and [(phen)2Cu(μ‐BAAP)Cu(μ‐BAAP)Cu(phen)2][Cu(BAAP)2]·8.5H2O (H2pheida = N‐phenetyl‐iminodiacetic acid,H2BAAP = N‐benzylaminoacetic‐2‐propionic acid)

The salts [Cu(phen)₃][Cu(pheida)₂]·10H₂O ( 1 ) and [(phen)₂Cu(μ‐BAAP)Cu(μ‐BAAP)Cu(phen)₂][Cu(BAAP)₂]·8.5H₂O ( 2 ) (H₂pheida = N‐phenetyl‐iminodiacetic acid, H₂BAAP = N‐benzylaminoacetic‐2‐propionic acid, phen = 1, 10‐phenanthroline) have been prepared and studied by thermal, spectroscopic and X‐ray diffraction methods. 1 has the rather unusual [Cu(phen)₃]²⁺ cation and two non‐equivalent [Cu(pheida)₂]^2— anions with a coordination type 4+2 but quite different tetragonality (T = 0.848 and 0.703 for anions 1 and 2, respectively). The crystal consists of multi‐π, π‐stacked chains (…anion 2 — cation — cation — anion 2…) connected by hydrophobic interactions; these chains build channels which are partially filled by anions 1 and water molecules. In contrast, compound 2 has a mixed‐ligand trinuclear cation with a bridging central moiety close similar to the counter anion. The formation of such a trinuclear cation is discussed as a consequence of the most advantageous molecular recognition process between [Cu(phen)₂(H₂O)_{1 or 2}]²⁺ and [Cu(BAAP)₂]^2— in solution. In the crystal of 2, multi‐π, π‐stacked arrays of C₆‐rings from phen and (BAAP)^2— ligands of trinuclear cations generate channels where counter anions and water molecules are located.     

A Structural Study of the Iminodiacetate Moiety Conformation in N‐(1‐adamantyl)‐iminodiacetate(2‐) Copper(II) Complexes

N,N‐bis(carboxymethyl)‐1‐adamantylamine acid (H₂BCAA) or N‐(1‐adamantyl)‐iminodiacetic acid forms zwitterions that are intra‐stabilized by a ‘bifurcated’ N⁺‐H···O(carboxyl)₂ interaction. In the crystal, both half‐protonated carboxyl groups of H₂BCAA^± are involved in linear O‐H···O inter‐molecular bridges of 2.46Å. In the studied BCAA‐Cu^II derivatives, the iminodiacetate‐moiety of the BCAA chelating ligand exhibits a mer‐NO₂ conformation in [Cu(BCAA)(H₂O)₂] ( 1 ) and [Cu(BCAA)(Him)]₂ ( 2 ), but a fac‐O₂+N(apical) conformation in [Cu(BCAA)(bpy)(H₂O)]·3.5H₂O ( 3 ) [Him = imidazole, bpy =2,2′‐bipyridine]. In clear contrast, dipyridylamine (dpya), as auxiliary ligand, seems to be unable to promote the fac‐O₂+N(apical) conformation in BCAA, as reveal the structures of two new salts with the trinuclear cation [(dpya)₂Cu‐μ₂‐Cu(BCAA)₂‐Cu(dpya)₂]²⁺ and the anions [Cu(BCAA)₂]^2? ( 4 ) or NO₃^? ( 5 ), respectively.     

pH- and mol-ratio dependent formation of zinc(II) coordination polymers with iminodiacetic acid: Synthesis, spectroscopic, crystal structure and thermal studies

Three novel zinc coordination polymers (NH₄)_n[Zn(Hida)Cl₂]_n (1), [Zn(ida)(H₂O)₂]_n (2), [Zn(Hida)₂]_n·4nH₂O (3) (H₂ida=iminodiacetic acid) and a monomeric complex [Zn(ida)(phen)(H₂O)]·2H₂O (4) (phen=1,10-phenanthroline) have been synthesized and characterized by X-ray diffraction methods. 1 and 2 form one-dimensional (1-D) chain structures, whereas 3 exhibits a three-dimensional (3-D) diamondoid framework with an open channel. The mononuclear complex 4 is extended into a 3-D supramolecular architecture through hydrogen bonds and π-π stacking. Interestingly, cyclic nonplanar tetrameric water clusters are observed that encapsulated in the 3-D lattice of 4. Based on ¹H and ¹³C NMR observations, there is obvious coordination of complex 2 in solution, while 1 and 3 decompose into free iminodiacetate ligand. Monomer [Zn(ida)(H₂O)₃] (5) is considered as a possible discrete species from 2. These coordination polymers can serve as good molecular precursors for zinc oxide.     

Determination of alkali and alkaline earth elements along with nitrogen in uranium based nuclear fuel materials by ion chromatography (IC)

An accurate and sensitive ion chromatographic (IC) method with suppressed conductivity detection is described for determination of traces of Na, K, Mg and Ca along with nitrogen in uranium based materials. The method involves matrix separation after sample dissolution by hydrolyzing and filtering off the polyvalent cations. Transition elements interfering in the determination of Ca were removed by cation exchange cartridge containing iminodiacetate resin. Detection limits were between 2 and 6 μg L⁻¹ and overall precision were better than ±5%. Recovery of spiked cations was in range from 96% to 104%. Results obtained were in good agreement with other methods.     

Synthesis of α-substituted iminodiacetate ligands: α-hexadienyl derivatives for the selection of lipoxygenase mimics

Derivatives of iminodiacetic acid (IDA) are important as ligands for metal ions, having numerous applications in separations, sensing, catalysis and medicine. This report describes the preparation of two types of IDA derivatives (1, 2) that could be covalently attached to a polymer or protein surface via a variable length spacer chain. The parent compounds 1 (R′=H) were easily prepared via N-alkylation of dimethyl iminodiacetate with esters of 6-bromo-hexanoic acid and subsequent selective ester hydrolysis. Metal complexes of IDA derivatives having an α-dienyl side chain are required for the selection of histidine-rich proteins with potential lipoxygenase activity. The α-hexadienyl side chain of IDA derivative 2 was selectively introduced in the reaction of (2,4-hexadienyl acetate)Fe(CO)₃ with a glycine-derived TMS-enol ester. Subsequent demetallation, followed by N-carboxymethylation, N-deacylation, N-alkylation with a trichloroethyl 6-halohexanoate, and TCE-ester cleavage provided the desired α-hexadienyl IDA derivative 2. Amide formation with IDA acid 1b demonstrates the feasibility of conjugating the IDA ligands to polymers and proteins while Ni(II)-complexation with the derived IDA triacid 1e shows the complexing ability of the tethered IDA ligand.     

Nickel(II) derivatives of N-benzyliminodiacetate(2−) ligands,with and without imidazole: Synthesis,crystal structure and properties

In an attempt to prepare binary and ternary compounds, we have obtained two molecular complexes [Ni(MEBIDA or MOBIDA)(H₂O)₃]·nH₂O (n = 0 or 1) and two iso-type salts [Ni(Him)₆][Ni(MEBIDA or MOBIDA)₂]·4H₂O [MEBIDA = N-(p-methylbenzyl)iminodiacetate(2−) and MOBIDA = N-(p-methoxybenzyl)iminodiacetate(2−) ligands, Him = imidazole]. Our results are discussed with regard to related copper(II) and nickel(II) compounds. The reasons for which these chelating ligands produce nickel(II) salts instead of ternary compounds remain unclear since other iminodiacetate-like ligands give true ternary Ni(II) compounds with imidazole and other N-heterocyclic ligands.     

Restricting the versatile metal-binding behaviour of adenine by using deaza-purine ligands in mixed-ligand copper(II) complexes

In order to deepen our understanding of the versatile behaviour of adenine (Hade) as ligand, we have synthesized four novel ternary copper(II) complexes having two deazaadenine ligands, namely 4-azabenzimidazole (H4abim) or 7-azaindole (H7azain) as N1,N6-dideazaadenine or N1,N6,N7-trideazaadenine, respectively. The related compounds were studied by thermal, spectral and single crystal X-ray diffraction methods. In [Cu(NBzIDA)(H4abim)]_n (1) the recognition between H4abim and the (N-benzyliminodiacetate)-copper(II) chelate only displays the formation of the Cu–N7(purine-like) bond, in contrast to Hade behaviour in [Cu(NBzIDA-like)(Hade)(H₂O)]·H₂O (Cu–N3(Hade) bond reinforced by N9–H···O(IDA-like) interaction). In [Cu(EIDA)(H7azain)(H₂O)] (2, EIDA = N-ethyliminodiacetate ligand), [Cu(NBzIDA)(H7azain)(H₂O)] (3) and [Cu(μ₂-SO₄)(H7azain)₂(H₂O)₂]_n (4), H7azain binds Cu(II) centre by the Cu–N3(purine-like) bond, reinforced by a N9–H···O(IDA-like or sulfate) intra-molecular interligand interaction.