Synthesis and Characterization of Metal Complexes of two Novel Pyridine‐Derived Macrocyclic Ligands Bearing o‐ and p‐Nitrobenzyl Pendant Groups

The pendant‐armed ligands L¹ and L² were synthesized by N‐alkylation of the two secondary aminic groups of the oxaazamacrocyclic precursor L with o‐nitrobenzylbromide (L¹) or p‐nitrobenzylbromide (L²). Metal complexes of L¹ and L² have been synthesized and characterized by microanalysis, MS‐FAB, conductivity measurements, IR, UV‐Vis, ¹H and ¹³C NMR spectroscopy and magnetic studies. Crystal structures of ligands L¹ and L², as well as complexes [CdL¹(NO₃)₂]·2CH₃CN and [Ag₂Br(L²)₂](ClO₄)·2CH₃CN have been determined by single crystal X‐ray crystallography.     

Metal Complexes with a New Tetrapyridyl Pendant Armed Macrocyclic Ligand. X‐ray Crystal Structures of CuII and NiII Complexes

A new pendant‐armed macrocyclic ligand, L¹, bearing four pyridyl pendant groups has been synthesized by N‐alkylation of the tetraazamacrocyclic precursor L with 2‐picolyl chloride hydrochloride. Metal complexes of L¹ have been synthesized and characterized by microanalysis, MS‐FAB, conductivity measurements, IR, UV‐Vis, ¹H and ¹³C NMR spectroscopy and magnetic studies. Crystal structures of the ligand L¹ as well as of the complexes [Ni₂L¹](ClO₄)₄·5CH₃CN and [Cu₂L¹](ClO₄)₄·4.5CH₃CN have been determined by single crystal X‐ray crystallography. The X ray studies show the presence of two metal atoms within the macrocyclic ligand in both metal complexes showing five coordination arrangement for the metal ions.     

Structures of Nickel(II) and Copper(II) Complexes of 14-Membered Macrocyclic Quadridentate Ligands

The structures of 41 Ni(II) and 17 Cu(II) complexes of macrocyclic quadridentate ligands have been analyzed, and are discussed about bond lengths, bond angles, conformations, and configurations, upon which many conclusions are formed. The inter- or intra-molecular hydrogen bonds exist among ligands and hydrates in many compounds and play an important role in the structures. There are exhibited two distinct peaks on the histogram of the average Ni-N distances, corresponding to four coordination and six coordination; these average Ni-N distances are 1.95(4) Å and 2.10(5) Å, respectively. The most probable structures of Ni(II) macrocyclic compounds have coordination number six for the metal ion, chair forms for six-membered rings, planar structure for the metal ion and the four donor atoms of the quadridentate ligand and an inversion center at the central metal ion.     

Synthesis,Structure, and Spectroscopic Properties of Copper(II) and Nickel(II) Complexes Containing the 1, 4, 7‐Triisopropyl‐1, 4, 7‐triazacyclononane Ligand

Three new complexes [CuL(N₃)₂] ( 1 ), [CuL(SCN)₂] ( 2 ), and [NiL(SCN)₂] ( 3 ) (L = 1, 4, 7‐triisopropyl‐1, 4, 7‐triazacyclononane, [—NR—C₂H₄—NR—C₂H₄—NR—C₂H₄—], R = i‐Pr) have been synthesized and structurally characterized. The three complexes all crystallize in the monoclinic space group P2₁/n, with the unit cell parameters a = 9.100(5), b = 19.492(11), c = 11.646(6)Å, β = 94.526(9)° for 1 , a = 10.148(3), b = 13.611(5), c = 15.777(6)Å, β = 95.412(6)° for 2 and a = 9.270(7), b = 16.629(14), c = 14.886(12)Å, β = 101.217(15)° for 3 . The central copper(II) and nickel(II) ions are coordinated to five nitrogen atoms, three of which from the L and two from N₃^— or SCN^—, forming a slightly distorted square pyramidal geometry. Moreover, elemental analysis, IR, UV‐vis and ESR spectra of complexes 1 ‐ 3 were also determined.     

Syntheses,Structural, and Spectroscopic Properties of Copper(II) Complexes of Constrained Macrocyclic Ligands

The complexes [Cu(L¹)(H₂O)₂](BF₄)₂ · 2H₂O ( 1 ) [L¹ = 5, 16‐dimethyl‐2, 6, 13, 17‐tetraazatricyclo(14, 4, 0^1.18,0^7.12)docosane] and 0.5[Cu(L²)(NO₃)₂][Cu(L²)](NO₃)₂ ( 2 ) [L² = dibenzyl‐5, 16‐dimethyl‐2, 6, 13, 17‐tetraazatricyclo(14, 4, 0^1.18,0^7.12)docosane] were synthesized and characterized by single crystal X‐ray analyses. In these constrained macrocycles, the central copper(II) atoms are in a tetragonally distorted octahedral environment with four nitrogen atoms of the macrocyclic ligands in equatorial positions and oxygen atoms from either water molecules or nitrato groups in axial positions. The macrocyclic ligands in both complexes adopt the most stable trans‐III conformation. The Cu–N distances [1.999(7)–2.095(7) Å] are typical for such complexes, but the axial ligands are weakly coordinating Cu–OH₂ bonds [2.693(3) Å] and Cu–ONO₂ bonds [2.873(7) Å] due to the combination of the pseudo Jahn–Teller effect and strong in‐plane ligand field. The crystals are stabilized by a three‐dimensional network by hydrogen bonds that are formed among the secondary nitrogen hydrogen atoms, oxygen atoms of water molecules, fluorine atoms of BF₄^–, and oxygen atoms of NO₃^–. The electronic absorption and IR spectroscopic properties are also discussed.     

Manganese(II), Cobalt(II), and Nickel(II) Perchlorate Complexes Containing N,O Donor Macrocyclic Ligands

Mononuclear macrocyclic complexes of manganese(II ), cobalt(II ) and nickel(II ) perchlorate using 10 different oxaazamacrocyclic ligands (L¹ — L¹⁰) have been prepared and characterized. The complexation reactions with the diiminic ligands were obtained by template condensation of the appropriate dialdehyde and diamine precursors; the reduced macrocycle complexes were synthesized using a direct route. The complexes have been characterized by elemental analyses, molar conductivity, mass spectrometry, IR, UV‐vis spectroscopy, diffuse reflectance and magnetic susceptibility measurements.     

Construction of Mononuclear Copper(II) and Trinuclear Cobalt(II) Complexes Based on Asymmetric Salamo‐Type Ligands

Mononuclear copper(II) and trinuclear cobalt(II) complexes, namely [Cu(L¹)]₂ · CH₂Cl₂ and [{Co(L²)(EtOH)}₂Co(H₂O)] · EtOH {H₂L¹ = 4,6‐dichloro‐6′‐methyoxy‐2,2′‐[1,1′‐(ethylenedioxydinitrilo)dimethylidyne]diphenol and H₃L² = 6‐ethyoxy‐6′‐hydroxy‐2,2′‐[1,1′‐(ethylenedioxydinitrilo)dimethylidyne]diphenol}, were synthesized and characterized by elemental analyses, IR and UV/Vis spectroscopy, and single‐crystal X‐ray diffraction. In the Cu^II complex, the Cu^II atom is four‐coordinate, with a N₂O₂ coordination sphere, and has a slightly distorted square‐planar arrangement. Interestingly, the obtained trinuclear Co^II complex is different from the common reported 2:3 (L:Co^II) salamo‐type Co^II complexes. Infinite 2D layer supramolecular structures are formed via abundant intermolecular hydrogen bonding and π ··· π stacking interactions in the Cu^II and Co^II complexes.     

Heterodinukleare Cobalt(II)‐, Nickel(II)‐, Kupfer(II)‐, Zink(II)und Palladium(II)‐Komplexe mit einem makrocyclischen Liganden vom Schiff‐Basen‐Typ: Synthesen und Strukturen

Complexes with Macrocyclic Ligands. IV. Heterodinuclear Cobalt(II), Nickel(II), Copper(II), Zinc(II) and Palladium(II) Complexes with a Macrocyclic Ligand of Schiff‐Base Type: Syntheses and Structures The synthesis and properties of nickel(II), copper(II), and palladium(II) complexes, [ML^Ph] ( 3 ; L^Ph = N,N′‐phenylene‐bis(3‐formyl‐5‐tert.‐butyl‐salicylaldimine)), are described. These neutral mononuclear complexes react with metal(II) perchlorate and 1,3‐propylenediamine to form heterodinuclear, macrocyclic, cationic complexes of the type [MM′(L^Ph,3)]²⁺ ( 4 ; M = Ni, Cu, Pd; M′ = Co, Cu, Zn). The structures of the five new compounds [NiCo(L^Ph,3)](ClO₄)₂, [NiCu(L^Ph,3)](ClO₄)₂, [CuCu(L^Ph,3)](ClO₄)₂, [CuZn(L^Ph,3)](ClO₄)₂, and [PdCu(L^Ph,3)](ClO₄)₂ were determined by X‐ray diffraction.     

Structural Study of Nickel(II), Copper(II), and Palladium(II) Complexes of 2‐Pyridineformamide 3‐Hexamethyleneiminylthiosemicarbazone

Reduction of 2‐cyanopyridine by sodium in the presence of 3‐hexamethyleneiminylthiosemicarbazide produces 2‐pyridineformamide 3‐hexamethyleneiminylthiosemicarbazone, HAmhexim. Complexes with nickel(II), copper(II) and palladium(II) have been prepared and the following complexes structurally characterized: [Ni(Amhexim)OAc], [{Cu(Amhexim)}₂C₄H₄O₄]·2DMSO·H₂O, [Cu(HAmhexim)Cl₂] and [Pd(Amhexim)Cl]. Coordination is via the pyridyl nitrogen, imine nitrogen and thiolato or thione sulfur atom when coordinating as the anionic or neutral ligand, respectively. [{Cu(Amhexim)}₂C₄H₄O₄] is a binuclear complex with the two copper(II) ions bridged by the succinato group in [Cu‐(HAmhexim)Cl₂] the Cu atom is 5‐coordinate and close to a square pyramid structure and in [Ni(Amhexim)OAc] and [Pd(Amhexim)Cl] the metal atoms are planar, 4‐coordinate.     

Synthesis and Characterization of a Novel Macrocyclic vic‐Dioxime and Some of its Mono and Trinuclear Complexes

The (E, E)‐dioxime containing a dithia‐dioxa‐diaza macrocyclic moiety 5,6 : 11,12 : 17,18‐tribenzo‐2,3‐bis(hydroxyimino)‐1,4‐diaza‐7,16‐dithia‐10,12‐dioxacyclooctadecane ( H₂L ) has been synthesized in high yield by a 1 + 1 addition of cyanogendi‐N‐oxide with 2,3 : 8,9 : 14,15‐tribenzo‐1,16‐diamino‐4,13‐dithia‐7,10‐dioxahexadecane ( 3 ) which was obtained from condensation reaction with 2‐amino thiophenol and 1,2‐bis(2‐bromoethoxy)benzene, in dichloromethane at –10 °C. Two vic‐Dioxime ligands coordinate with Ni(II), Cu(II) and Co(III) through its hydroxyimino nitrogen donor atoms by the loss of the oxime protons. Homo and heterotrinuclear Cu^II₃ and Co^IIIPd^II₂ complexes of this ligand have been prepared; their two ligand molecules are connected via hydroxyimino or BF₂⁺‐bridging groups and two of the metal ions are coordinated by a diaza‐dithia mixed donor macrocyclic moiety. The macrocyclic ligand and its transition metal complexes have been characterized on the basis of ¹H‐, ¹³C‐NMR, IR and MS spectroscopy and elemental analysis data.     

Synthesis,Characterization and Structure of Bis‐ and Tetrakis‐Aziridine‐Nickel(II) and Copper(II) Complexes

The synthesis and characterization of mononuclear tetrakis‐aziridine nickel(II ) and copper(II ) complexes as well as of a dinuclear bis‐aziridine copper(II ) complex are described. The reactions of anhydrous MCl₂ (M = Ni^II, Cu^II) with aziridine (= az = C₂H₄NH, C₂H₃MeNH, CH₂CMe₂NH) in CH₂Cl₂ at room temperature in a 1:5 and 1:2 molar ratio, respectively, afforded the tetrakis‐aziridine complexes [M(az)₄Cl₂] (M = Ni, Cu) or the dimeric bis‐aziridine complex [Cu(az)₂Cl₂]₂. After purification, all of the complexes were fully characterized. The single crystal structure analysis revealed two different coordination modes. Whereas both nickel(II ) complexes can be classified as showing an elongated octahedral structure, copper(II ) complexes show either an elongated octahedral or a square pyramidal arrangement forming dimers with chlorido bridges in axial positions. Furthermore, the results of magnetic measurements of the nickel(II ) and copper(II ) compounds are presented.     

3‐(Arylhydrazono)pentane‐2, 4‐diones and their Complexes with Copper(II) and Nickel(II) — Synthesis and Crystal Structures

A series of new 3‐(arylhydrazono)pentane‐2, 4‐diones ( 1 ‐ 6 ) synthesized from pentane‐2, 4‐dione and diazonium salts of respective anilines using the procedure of Japp‐Klingemann are described. Complexes with Cu^II and Ni^II salts are prepared ( 7 ‐ 10 , respectively). Spectroscopic properties of these compounds have been studied and X‐ray crystal structures of selected hydrazones ( 3 , 4 , 6 ) and of the hydrazone complexes ( 7 ‐ 10 ) are reported. The structures of the uncomplexed hydrazones feature an intramolecular N‐H···O interaction to yield a six‐membered H‐bond ring reflecting preference of the hydrazone tautomeric structure. All the complexes are mononuclear 2:1 (L:M) structures of six‐membered chelate type involving N₂O₂ binding sites that are quadratic arranged but differ in the entire coordination environment dependent on the metal and the ligand substitution including distorted octahedral and quadratic pyramidal coordination geometries in the Cu^II complexes 7 and 8 or nearly regular square planar coordination geometry in the Ni^II complexes 9 and 10 , respectively. In the crystal packings, strong and weak H‐bond interactions cause supramolecular network structures.     

Complexes of N‐Thiophosphorylthiourea tBuNHC(S)NHP(S)(OiPr)2 with Zinc(II), Cadmium(II), Nickel(II), and Cobalt(II) Cations

Reaction of the potassium salt of N‐thiophosphorylthiourea tBuNHC(S)NHP(S)(OiPr)₂ ( HL ) with Zn^II, Cd^II, Ni^II and Co^II in aqueous EtOH leads to complexes of common formula M(L‐S,S′)₂ ( ML₂ ). Complexes were investigated by IR, UV‐Vis, ¹H and ³¹P{¹H} NMR spectroscopy and microanalysis The structure of complex NiL₂ was investigated by single crystal X‐ray diffraction analysis. The nickel(II) ion has a squre‐planar environment, S₄, with two anionic ligands involving 1,5‐S,S′‐coordination mode. The ligands are bound in a trans configuration.     

Synthese und Charakterisierung von Cobalt(II)‐ und Kupfer(I)‐Komplexen mit Guanidin‐Pyridin‐Hybridliganden

Syntheses and Structures of Cobalt(II) and Copper(I) Complexes with Guanidine‐Pyridine Hybridligands The guanidine‐pyridine hybridligands N‐(1,3‐dimethylimidazolidin‐2‐ylidene)‐2‐(pyridine‐2‐yl)ethanamine (DMEGepy, L1 ) and 1,1,3,3‐tetramethyl‐2‐(2‐(pyridine‐2‐yl)ethyl)guanidine (TMGepy, L2 ) have been synthesized and characterized. The reaction of DMEGepy with CoCl₂ and TMGepy with CuI lead to the mononuclear complexes {N‐(1,3‐dimethylimidazolidin‐2‐ylidene)‐2‐(pyridine‐2‐yl)ethanamine}cobalt(II) dichloride ( 1 ) and {1,1,3,3‐tetramethyl‐2‐(2‐(pyridine‐2‐yl)ethyl)guanidine}copper(I) iodide ( 2 ). By the characterization of these complexes we are able to compare the complexation chemistry of the hybridguanidine and bisguanidine ligands with regard to the various N donor functions systematically.     

Synthesis and Crystal Structures of Dinuclear Palladium and Mononuclear Nickel Complexes of Macrocyclic N8S4 Ligands

The N₈S₄ donor ligand L¹ has been investigated regarding its capability to support the formation of coordinatively unsaturated Pd₂ complexes and its use as a starting material for functionalized N₈S₄ systems. L¹ represents a macrotricyclic ligand comprising four 4‐tert‐butyl‐2,6‐bis(aminomethyl)thiophenolate units, whose N and S atoms are linked by ethylene units. Treatment of L₁ with [Pd(NCMe)₂Cl₂] produced the dinuclear complex [Pd₂Cl₂(H₂L¹)]⁴⁺, which was isolated as its pale‐yellow perchlorate salt [Pd₂Cl₂(H₂L¹)](ClO₄)₄ (H₂ 1 ) and characterized by elemental analysis, IR, NMR and MS spectroscopy and X‐ray crystallography. The structure shows two planar PdN₂SCl units which are located in the central 24‐membered ring of L¹. Reaction of L¹ with CH₂O/HCO₂H under Eschweiler‐Clarke conditions followed by deprotection with sodium in liquid ammonia furnished the permethylated octaamine‐tetrathiophenol H₄L⁴. The identity of H₄L⁴ was ascertained by an X‐ray crystal structure determination of one of its metal complexes.     

Synthesis and Characterization of some Unsymmetrical Schiff Base Ligands and their Nickel(II) Complexes Incorporating o‐Phenylenediimine Units

Six new nickel(II) complexes of the unsymmetrical Schiff base ligands derived from o‐phenylenediamine were synthesized. These complexes were prepared by template and non‐template reactions of the precursor 3‐acetyl‐4‐[N‐(2'‐aminophenyl)‐amino]‐3‐buten‐2‐one ( HL °) with appropriate o‐hydroxycarbonyl aromatic compounds, aromatic 1, 3‐oxo aldehydes and 1, 3‐diketones. The nickel(II) compounds were characterized by analytical and spectroscopic methods. Crystal structure of complex [3‐acetyl‐(6, 7)‐benzo‐8‐salicylidene‐5, 8‐diazahepta‐3‐ene‐2‐onato(2‐)]nickel(II) ( NiL ¹) has been determined by X‐ray powder diffraction method, revealed that the molecules are almost flat, and there are no forces other than van der Waals interactions between molecules. The structure was solved by global optimisation technique and refined by the Rietveld method, obtained R_F and R_wp are 11.6 and 17.4%, respectively. The synthesis of a new unsymmetrical nickel(II) tetraazamacrocyclic complex is also described.     

Novel Octahedral Bis[2‐(1‐aziridinyl)ethanol‐κ2N,O] Complexes of Cobalt(II)

The synthesis and molecular structure of trans‐{bis[(acetato‐κO)‐(2‐(1‐aziridinyl)ethanol‐κ²N,O)]}cobalt(II) ( 4 ) and cis‐{bis[chlorido‐(2‐(1‐aziridinyl)ethanol‐κ²N,O)]}cobalt(II) ( 5 ) is reported. Both neutral chelate complexes are prepared from the corresponding Co^II salt [CoX₂; X = OAc ( 1 ), Cl ( 2 )] and 2‐(1‐aziridinyl)ethanol (azolH, 3 ) in dry dichloromethane. A third, ionic complex, cis‐{bis[aqua‐(2‐(1‐aziridinyl)ethanol‐κ²N,O)]}cobalt(II) diacetate ( 6 ) is formed from 4 in the presence of water and could be crystallized from aqueous dichloromethane. In all cases, 2‐(1‐aziridinyl)ethanol is coordinating as bidentate chelate ligand by the nitrogen and oxygen atom of the aziridinyl and hydroxy moiety. After purification, the compounds have been fully characterized using IR spectroscopy and FAB⁺‐MS. The single‐crystal X‐ray structure analysis revealed a distorted octahedral geometry for all complexes with either trans ( 4 ) or cis ( 5 , 6 ) configuration.     

Structural characterization of five-coordinate copper(II), nickel(II), and cobalt(II) thiocyanato complexes derived from bis(2-(3,5-dimethyl-1-pyrazolyl)ethyl)amine

The reaction of M(ClO₄)₂·6H₂O with NH₄NCS in presence of the organic sterically hindered bis(2-(di-3,5-dimethyl-1-pyrazolyl)ethyl)amine (bedmpza) afforded the five-coordinate mononuclear dithiocyanato-M(II) complexes [M(bedmpza)(NCS)₂]·xMeOH (1: M = Cu²⁺, x = 0; 2: M = Ni²⁺, x = 0; 3: M = Co²⁺, x = 0.84). The compounds which proved to be non-electrolytes were characterized by IR and UV-Vis spectroscopy and their molecular structures were determined by single-crystal X-ray crystallography. In these complexes, the five-coordinate geometry was achieved by the three N-donors of the ligand bedmpza and two N atoms of the terminal thiocyanato ligands. The Cu(II) complex exists in two polymorphs 1-I and 1-II: an intermediate five-coordinate geometry with the two thiocyanato ligands are arranged as cisoid in 1-I and distorted square pyramidal geometry with the thiocyanato ligands are in transoid orientation in 1-II. Although the later geometry was also observed in the nickel complex 2, distorted trigonal bipyramidal geometry was found in 3. Each complex forms hydrogen bonds of type N-H?S from the secondary amine N(3) donor atoms to the adjacent terminal S(1) acceptor atoms of the thiocyanate group. The thermal behavior of the two polymorphs 1-I and 1-II were similar and no significant differences were observed between the two complexes.     

Structural Studies of a Copper(II) Complex with Inequivalent 2‐Acetylpyridine 3‐Piperidylthiosemicarbazonato Ligands and a Nickel(II) Complex with Different Modes of Coordination by the Two Thiosemicarbazonato Moieties of 1‐Phenylglyoxal Bis{N(4)‐diethylthiosemicarbazone}

The crystal structure of a copper(II) complex of 2‐acetylpyridine 3‐piperidylthiosemicarbazone, [Cu(Acpip)₂], indicates a tridentate, monoanionic ligand (i. e., pyridine nitrogen, imine nitrogen and thiolato sulfur atoms) and a bidentate, monanionic ligand (i. e., imine nitrogen and thiolato sulfur atoms). The stereochemistry approaches square pyramidal with the bidentate ligand occupying an apical (imine nitrogen atom) and basal (thiolato sulfur atom) position. The structure of a nickel(II) complex of 1‐phenylglyoxal N(4)‐diethylthiosemicarbazone, [Ni(Pg4DE)], has a 4‐6‐5 trichelate system rather than the 5‐5‐5 system common to bis(thiosemicarbazones). Coordination of the hydrazinic nitrogen atom of the “phenyl arm” along with the thiolato sulfur atom provides the 4‐membered chelate ring.