Metallkomplexe der Phosphinsäuren. XVII. Untersuchungen zur Oligomerisation von NiII- und CoII-Komplexen bifunktioneller Dithiophosphinsäuren HS(S)P(R)-R′-(R)P(S)SH [2]

Metal Complexes of Phosphinic Acids. XVII. Investigations on the Oligomerisation of Ni^II and Co^II Complexes of Bifunctional Dithiophosphinic Acids Alkali or ammonium salts of bifunctional dithiophosphinic acids react with Ni²⁺ or Co²⁺ to give complexes [S₂P(R)? (CH₂)_n? (R)PS₂M]_m or _x (R = 4-methoxyphenyl; M = Ni²⁺, Co²⁺; n = 4? 10) some of which are soluble in organic solvents and of low molecular weight (m), while others are insoluble (x). According to magnetic and spectroscopic measurements all of them contain planar NiS₄ or tetrahedral CoS₄ chromophors. While the insoluble compounds are regarded as coordination polymers, it is shown by osmometric measurements and by ³¹P{¹H} spectroscopy, that there exists the equilibrium monomers (ansa type) ? oligomers in solutions of the soluble complexes. The influence of n on the solubility and the equilibrium is discussed. The association can be explained by simple statistic considerations.     

Aminomethylierung von Thiophosphorsäuredialkylester-, Phosphon- bzw. Thiophosphonsäurealkylesteramiden,Phosphon- bzw. Thiophosphonsäurediamiden und Diphenylthiophosphinsäureamid

Aminomethylation of Phosphoro-, Phosphono-, Phosphinoamidoates and -amidothioates Dialkylphosphoroamidates, alkyl-phosphonoamidates and phosphonoamidothioates react with C₂H₅O? CH₂? NR₂ and HCOH/HNR₂, respectively, as like as a N-aminomethylation forming the corresponding derivatives of the general formula R₂P(X)? NR′? CH₂? NR″₂? R = alkoxy, alkyl, aryl; R′ = H, alkyl; X = O, S; R″ = alkyl, cycloalkyl —. Under the same conditions phosphonodiamidoates and phosphonodiamidothioates yield RP(X)-[NR′? CH₂? NR″₂]₂ or RP(X)? NHR′? (NR′? CH₂? NR″₂) only. These compounds are not formed by interactions of RP(X)(NR′? CH₂OH)₂ with sec. amines. The aminomethylation of (C₆H₅)₂P(S)NH₂ gives unexceptional [(C₆H₅)₂P(S)]₂N? CH₂? NR′₂. The i.r. and ¹H-n.m.r. data of the prepared compounds, which can't be distilled mostly, are discussed.     

Thermal decomposition of dinuclear complexes LM(μ-OOCR)<Subscript>4</Subscript>ML (L is α-substituted pyridine)

The solid-state thermal decomposition of the dinuclear pivalate complexes LM(μ-OOCR)₄ML, both those synthesized earlier (M = Mn^II, Fe^II, or Co^II; L = 2,6-(NH₂)₂C₅H₃N)) and new complexes (M = Cu^II; L = 2,6-(NH₂)₂C₅H₃N or (2-NH₂)(6-CH₃)C₅H₃N), was studied by differential scanning calorimetry and thermogravimetry. The decomposition of the Co^II complexes is accompanied by the aggregation to form the volatile octanuclear complex Co₈(μ₄-O)₂(μ_n-OOCCMe₃)₁₂ (n = 2 or 3), whereas the thermolysis of the Mn^II, Fe^II, and Cu^II complexes is destructive, the phase composition of the decomposition products being substantially dependent on the nature of metal and the α substituent R in the apical organic ligand.     

The behaviour of beryllium μ4-oxo-μ-carboxylates under electron impact

The electron impact mass spectra of eight polynuclear beryllium complexes Be₄O(RCO₂)₆ (R?H, CH₃, C₂H₅) and Be₄O(RCO₂)₅OR′ (R?CH₃, R′?H, CH₃, C₂H₅, C₃H₇; R?C₂H₅, R′?C₂H₅) are reported. The major fragmentations involve the elimination of (RCO)₂O (RCOOR′) or Be(RCO₂)₂ (Be(RCO₂)OR′) from the ions [M? L]⁺ and of {(R? H)CO}, (R′? H), H₂O and BeO from the lighter ions. The fragmentation patterns are practically independent of the organic groups present and can be rationalized by stereochemical considerations.     

Über Chalkogenolate. 139. Untersuchungen über Dialkylester von Chalkogenokohlensäuren. 2. O,Se- und S,Se-Dialkylmonothiomonoselenocarbonate

On Chalcogenolates. 139. Studies on Dialkyl Esters of Chalcogenocarbonic Acids. 2. O,Se- and S, Se-Dialkyl Monothiomonoselenocarbonates The hitherto unknown esters RSe? CS? OR′, where R = C₂H₅, ⁿC₃H₇ and R′ = C₂H₅, ⁿC₃H₇, are formed by reaction of NaSeR with Cl? CS? OR′ and of RSe? CS? Cl with HOR′. At the first time, the esters RSe? CO? SR′ with R = R′ = C₂H₅, ⁿC₃H₇ have been prepared by reaction between NaSeR and Cl? CO? SR′. The compounds have been characterized by means of diverse spectroscopic methods.     

(Croconato‐κ2O,O′)bis­(1,10‐phenanthroline‐κ2N,N′)cobalt(II), and the nickel(II) and copper(II) analogues

The title complexes, [M(C₅O₅)(C₁₂H₈N₂)₂], with M = Co^II, Ni^II and Cu^II, all lie across twofold rotation axes, around which two 1,10‐phenanthroline ligands are arranged in a chiral propeller manner. The Co^II and Ni^II complexes are isostructural, with octa­hedral coordination geometry, while the local geometry of the Cu^II complex is severely distorted from octa­hedral.     

Über Chalkogenolate. 85. Untersuchungen über Halbester der Trithiokohlensäure 3. Schwingungsspektren von Alkylthioxanthogensäuren und Wasserstoffbrücken in den freien Säuren

On Chalcogenolates. 85. Studies on Hemiesters of Trithiocarbonic Acid 3. Vibrational Spectra of Alkyl Thioxanthic Acids and Hydrogen Bondings in the Free Acids The IR spectra of alkyl thioxanthic acids RS? CS(SH) with R = CH₃, C₂H₅, ⁿC₃H₇, ⁱC₃H₇, ⁿC₄H₉, ^sC₄H₉, ^tC₄H₉, and CH₃S? CS(SD) as well as the Raman spectrum of the Compound with R = CH₃ have been assigned. The formation of hydrogen bondings in the free acids has been studied by means of i.r. spectra, ¹H-n.m.r. spectra, and electron absorption spectra. The energies of the hydrogen bondings have been calculated.     

Magnetochemical Complexity of Hexa‐ and Heptanuclear Wheel Complexes of Late‐3d Ions Supported by N,O‐Donor Pyridyl–Methanolate Ligands

The scaffold geometries, stability and magnetic features of the (pyridine‐2‐yl)methanolate (L) supported wheel‐shaped transition‐metal complexes with compositions [M₆L₁₂] ( 1 ), [Na?(ML₂)₆]⁺ ( 2 ), and [M′?(ML₂)₆]²⁺ ( 3 ), in which M=Co^II, Ni^II, Cu^II, and Zn^II were investigated with density functional theory (DFT). The goals of this study are manifold: 1) To advance understanding of the magnetism in the synthesized compounds [Na?(ML₂)₆]⁺ and [M′?(ML₂)₆]²⁺ that were described in Angew. Chem. Int. Ed.­ 2010 , 49, 4443 ( I ‐{Na?Ni₆}, I ‐{Ni′?Ni₆}) and Dalton Trans.­ 2011 , 40, 10526 ( II ‐{Na?Co₆}, II ‐{Co′?Co₆}); 2) To disclose how the structural, electronic, and magnetic characteristics of 1 , 2 , and 3 change upon varying M^II from d⁷ (Co²⁺) to d¹⁰ (Zn²⁺); 3) To estimate the influence of the Na⁺ and M′²⁺ ions (X^Q+) occupying the central voids of 2 and 3 on the external and internal magnetic coupling interactions in these spin structures; 4) To assess the relative structural and electrochemical stabilities of 1 , 2 , and 3 . In particular, we focus here on the net spin polarization, the determination of the strength and the sign of the exchange coupling energies, the rationalization of the nature of the magnetic coupling, and the ground‐state structures of 1 , 2 , and 3 . Our study combines the broken symmetry DFT approach and the model Hamiltonian methodology implemented in the computational framework CONDON 2.0 for the modeling of molecular spin structures, to interpret magnetic susceptibility measurements of I ‐{Na?Ni₆} and I ‐{Ni′?Ni₆}. We illustrate that whereas the structures, stability and magnetism of 1 , 2 , and 3 are indeed influenced by the nature of 3d transition‐metals in the {M₆} rims, the X^Q+ ions in the inner cavities of 2 and 3 impact these properties to an even larger degree. As exemplified by I ‐{Ni′?Ni₆}, such heptanuclear complexes exhibit ground‐state multiplets that cannot be described by simplistic model of spin‐up and spin‐down metal centers. Furthermore, we assess how future low‐temperature susceptibility measurements at high magnetic fields can augment the investigation of compound 3 with M=Co, Ni.     

Reactivity of triangular oxalate cluster complexes [M<Subscript>3</Subscript>Q<Subscript>7</Subscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>3</Subscript>]<Superscript>2−</Superscript> (M = Mo or W; Q = S or Se)

The reactions of the oxalate complexes [M₃Q₇(C₂O₄)₃]²⁻ (M = Mo or W; Q = S or Se) with Mn^II, Co^II, Ni^II, and Cu^II aqua and ethylenediamine complexes in aqueous and aqueous ethanolic solutions were studied. The previously unknown heterometallic complexes [Mo₃Se₇(C₂O₄)₃Ni(H₂O)₅]·3.5H₂O (1) and K₃{[Cu(en)₂H₂O]([Mo₃S₇(ox)₃]₂Br)}·5.5H₂O (2) were synthesized. In these complexes, the oxalate clusters serve as monodentate ligands. The K(H₂en)₂[W₃S₇(C₂O₄)₃]₂Br·4H₂O salt (3) was isolated from solutions containing Co^II, Ni^II, or Cu^II aqua complexes and ethylenediamine. The reaction of [Mo₃Se₇(C₂O₄)₃]²⁻ with HBr produced the bromide complex [Mo₃Se₇Br₆]²⁻, which was isolated as (Bu₄N)₂[Mo₃Se₇Br₆] (4). Complexes 1–3 were characterized by X-ray diffraction, IR spectra, and elemental analysis. The formation of 4 was detected by electrospray mass spectrometry. 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. 1645–1649, September, 2007.     

Über Chalkogenolate. 140. Untersuchungen über Dialkylester von Chalkogenokohlensäuren. 3. S,Se-Dialkyldithiomonoselenocarbonate Existenzbeweis von Alkylselenoxanthaten [S2C?SeR]−

On Chalcogenolates. 140. Studies on Dialkyl Esters of Chalcogenocarbonic Acids. 3. S,Se-Dialkyl Dithiomonoselenocarbonates. Evidence for the Existence of Alkyl Selenoxanthates [S₂C? SeR]^? The esters RSe? CS? SR′ with R = R′ = C₂H₅, ⁿC₃H₇ as well as with R = ⁿC₃H₇ and R′ = C₂H₅ have been produced by three different methods. The compounds have been characterized by means of electron absorption, infrared, nuclear magnetic resonance (¹H, ¹³C, and ⁷⁷Se), and mass spectra. The unstable alkyl selenoxanthates M[S₂C? SeR], where M = Na, K and R = C₂H₅, ⁿC₃H₇, are formed by reaction of carbon disulfide with the corresponding alkane selenolate. Freshly prepared they react with alkyl iodides R′I to yield RSe? CS? SR′.     

Synthesis and study of N-(1-phenylethylidene)-N-(4H-1,2,4-triazol-4-yl)amine, N′-(4H-1,2,4-triazol-4-yl)benzamidine, and cobalt(ii), nickel(ii), and copper(ii) complexes based on these ligands

Methods were developed for the synthesis of complexes of Co^II, Ni^II, and Cu^II nitrates and chlorides with N-(1-phenylethylidene)-N-(4H-1,2,4-triazol-4-yl)amine (L¹) and N′-(4H-1,2,4-triazol-4-yl)benzamidine (L²). The Co^II and Ni^II complexes have a linear trinuclear structure. The Cu^II complexes are polynuclear. Both ligands are coordinated to the metal ions in a bidentate-bridging mode through the N(1) and N(2) atoms of the heterocycle. In all compounds, the coordination polyhedron can be described as a distorted octahedron. The molecular and crystal structure of the [Ni₃(L¹)₆(EtOH)₂(H₂O)₄](NO₃)₆·2EtOH·4H₂O complex was established.     

Formation and Structural Characterization of Metal Complexes derived from Thiosalicylic Acid

The formation and structural aspects of some metal complexes of thiosalicylic acid (TSA) were studied. The μ‐bridging tetra‐coordinated Ru complex, [Ru(C₆H₄(CO₂)(μ‐S)(H₂O)]₂ ( 1 ) was formed by hydrothermal reaction of TSA with RuCl₃. The complexes [M(dtdb)(phen)(H₂O)]_n ( 2 – 4 ) (M = Zn^II, Co^II, Ni^II, dtdb = 2,2′‐dithiodibenzoate anion, phen = 1,10‐phenanthroline) were obtained by the slow diffusion technique and the in situ S–S bond formation was confirmed by elemental, spectral and X‐ray analysis. Reaction of TSA with CuCl₂ and 2,2′‐bipyridine (bipy) under the slow diffusion technique yielded the dimer [Cu(tdb)(bipy)] ( 5 ) (tdb = thiodibenzoic acid), where the in situ generation of 2,2′‐thiodibenzoic acid was observed.     

Über die Umsetzung von P4E3I2 (E = S,Se) mit einigen Carbonsäuren und Dithiocarbonsäuren

On the Reaction of P₄E₃I₂ (E = S, Se) with some Carboxylic Acids and Dithiocarbamic Acids By the reaction of α-P₄E₃I₂ (E = S, Se) with carboxylic acids, dithiobenzoic acid or dithiocarbamic acids in the presence of triethylamin or with (C₆H₅)₃SnR, or of β-P₄E₃I₂ with tin-organic compounds α-P₄E₃(I)R, α(β)-P₄E₃R₂ [R = ? OC(O)C₆H₅, ? OC(O)CH₃, ? SC(S)NC₅H₁₀, ? SC(S)N(C₂H₅)₂], α-P₄S₃(I)SC(S)C₆H₅, α-P₄S₃(SC(S)C₆H₅)₂ and β-P₄E₃(I)R (R = ? OC(O)C₆H₅, ? OC(O)CH₃) were prepared in solution and identified by ³¹P NMR spectroscopy. In addition α-P₄S₃(NC₅H₁₀)(SC(S)NC₅H₁₀) was detected. The β-isomers could be obtained also with lesser yields by the reaction with the dithiocarbamic acids, too. The substitution of the second iodine ligand in β-P₄E₃I₂ resulted mainly in β-P₄S₃(R_exo)₂ and by inversion of the configuration at a phosphorus atom, in β-P₄E₃R_exoR_endo. α-P₄S₃I₂ reacted with methanol in CS₂ to α-P₄S₃(OCH₃)(SC(S)OCH₃) and α-P₄S₃(SC(S)OCH₃)₂. The ³¹P NMR data of the compounds are discussed. The ³¹P NMR spectra of the α(β)-P₄E₃ dithiocarbamates indicate dynamic processes in the solution, e. g. α-P₄S₃(I)(SC(S)NR₂) showed an intramolecular conversion, due to the anisobidentate dithiocarbamate ligand. This behaviour had not previously been noticed for compounds with a P₄S₃-skeleton.     

Cobalt(II) and cobalt(III) complexes with 4′‐(4‐cyanophenyl)‐2,2′:6′,2′′‐terpyridine

4′‐Cyanophenyl‐2,2′:6′,2′′‐terpyridine (cptpy) was employed as an N,N′,N′′‐tridentate ligand to synthesize the compounds bis[4′‐(4‐cyanophenyl)‐2,2′:6′,2′′‐terpyridine]cobalt(II) bis(tetrafluoridoborate) nitromethane solvate, [Co^II(C₂₂H₁₄N₄)₂](BF₄)₂·CH₃NO₂, (I), and bis[4′‐(4‐cyanophenyl)‐2,2′:6′,2′′‐terpyridine]cobalt(III) tris(tetrafluoridoborate) nitromethane sesquisolvate, [Co^III(C₂₂H₁₄N₄)₂](BF₄)₃·1.5CH₃NO₂, (II). In both complexes, the cobalt ions occupy a distorted octahedral geometry with two cptpy ligands in a meridional configuration. A greater distortion from octahedral geometry is observed in (I), which indicates a different steric consequence of the constrained ligand bite on the Co^II and Co^III ions. The crystal structure of (I) features an interlocked sheet motif, which differs from the one‐dimensional chain packing style present in (II). The lower dimensionality in (II) can be explained by the disturbance caused by the larger number of anions and solvent molecules involved in the crystal structure of (II). All atoms in (I) are on general positions, and the F atoms of one BF₄⁻ anion are disordered. In (II), one B atom is on an inversion center, necessitating disorder of the four attached F atoms, another B atom is on a twofold axis with ordered F atoms, and the C and N atoms of one nitromethane solvent molecule are on a twofold axis, causing disorder of the methyl H atoms. This relatively uncommon study of analogous Co^II and Co^III complexes provides a better understanding of the effects of different oxidation states on coordination geometry and crystal packing.     

2-Aminoacetophenone-2-thenoylhydrazone complexes of bivalent 3d metal ions

Summary 2-Aminoacetophenone-2-thenoylhydrazone, Haath, C₄H₃SC(O)NHN=C(Me)C₆H₄NH₂-o, forms complexes with metal(II) salts of empirical compositions [VO(Haath)₂SO₄], [M(Haath)₂Cl₂] [M=Co^II, Ni^II, Cu^II or Zn^II] and [M(aath)₂] [M=V^IVO, Co^II, Ni^II, Cu^II or Zn^II] which have been characterized by elemental analyses, molar conductance, magnetic susceptibility, electronic, e.s.r., i.r. and n.m.r. (¹H and¹³C) spectral studies. X-ray and electron diffraction patterns have been obtained in order to elucidate the structure of the Cu^II complexes. Photoacoustic spectra of powder Ni^II complexes have been recorded and interpreted in the light of u.v./vis. spectra.     

Zur Kenntnis der Organophosphorverbindungen. XV. Darstellung und Reaktionen von Trimethylsilylestern der Phosphinsäuren

On Organophosphorus Compounds. XV. Preparation and Reactions of Trimethylsilyl Esters of Phosphinic Acids Trimethylsilylesters of Phosphinic acids R₂P(X)YSi(CH₃)₃ (R ? CH₃, C₂H₅, C₃H₇, t?C₄H₉, C₆H₅; X, Y ? O, S) were prepared by 7 different methods as in some cases easily hydrolysable but thermally remarkably stable compounds. The properties and some reactions of these substances are reported, their structures confirmed by IR? as well as ¹H- and ³¹P-NMR-spectroscopy. Dimethylsilylen-bis(phosphinic acid esters) were obtained according to \documentclass{article}\pagestyle{empty}\begin{document}$ 2{\rm R}_{2} {\rm P(\rm X)\rm ONH}_{4} + {\rm R}_{\rm 2} {\rm SiCl}_{2} \to 2{\rm E NH}_{4} {\rm Cl + R}_{2} {\rm P(X) - O - SiR}_{2} - {\rm O - P(X)R}_{2} ({\rm R = CH}_{3};{\rm X = O,S}) $\end{document}.     

The relationship between ligand structures and their CoII and NiII complexes: Synthesis and characterization of novel dimeric CoII/CoIII complexes of bis(thiosemicarbazone)

4,6-Diacetylresorcinol serves as a starting point for the generation of multidentate S/N/O or O/N/O symmetrical chelating agents by condensation with thiosemicarbazide or semicarbazide to yield the corresponding bis(thiosemicarbazone) H₄L¹ or bis(semicarbazone) H₄L², respectively. Reaction of H₄L¹ and H₄L² with M(NO₃)₂·6H₂O (M?=?Co or Ni) afforded dimeric complexes for H₄L¹ and binuclear complexes for H₄L², revealing the tendency of S to form bridges. The dimeric cobalt complexes of H₄L¹ are very interesting in that they contain Co^II/Co^III, side/side, low-spin octahedral coordinated Co^III-ions and high-spin square-planar coordinated Co^II-ions. These complexes have the general formula [(H₂L¹)₂Co₂(H₂O) (NO₃)]·nEtOH. Arguments supporting these anomalous Co^II/Co^III structures are based on a pronounced decrease in their magnetic moments, elemental and thermal analyses, visible and IR spectra, as well as their unreactivity towards organic bases such as 1,10-phenanthroline (phen), 2,2′-bipyridine (Bpy), N,N,N′,N′-tetramethylethylenediamine (Tmen) and 8-hydroxyquinoline (oxine, Ox). The dimeric octahedral Ni^II complex [(H₂L¹)₂Ni₂(H₂O)₄]·3H₂O showed higher reactivity towards phen and Bpy and formed adducts; [(HL¹)Ni₂(B)(H₂O)₅] NO₃ (B?=?phen or Bpy). In the presence of oxine, the dimeric brown paramagnetic octahedral complex [(H₂L¹)₂Ni₂(H₂O)₄]·3H₂O was transformed to the dimeric brick-red diamagnetic square-planar complex [(H₃L¹)₂Ni₂](NO₃)₂. The latter showed dramatic behavior in its ¹H NMR spectrum in DMSO-d ₆, which was explained on the basis of H⁺-transfer. By contrast, the binuclear Ni^II–H₄L² complex (11) showed higher reactivity towards phen, Bpy and oxine. These reactions afforded mixed dimeric complexes having the molar ratio 2?:?2?:?1 (Ni^II?:?H₄L²?:?base). The binuclear Co^II–H₄L² complex afforded an adduct with phen and trinuclear complexes with Bpy and oxine. All complexes were found to be unreactive towards Tmen. Structural characterization was achieved by elemental and thermal analyses, spectral data (electronic, IR, mass and ¹H NMR spectra) and conductivity and magnetic susceptibility measurements.     

Metallkomplexe mit biologisch wichtigen Liganden. CLXVI Metallkomplexe mit Ferrocenylmethyl‐L‐cysteinat und 1,1′‐Ferrocenylbis‐(methyl‐L‐cysteinat) als Liganden

Metal Complexes of Biologically Important Ligands. CLXVI Metal Complexes with Ferrocenylmethylcysteinate and 1,1′‐Ferrocenylbis‐(methylcysteinate) as Ligands A series of complexes of transition metal ions ( Cr³⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺ ) and of lanthanide ions ( La³⁺, Nd³⁺, Gd³⁺, Dy³⁺, Lu³⁺ ) with the anions of ferrocenylmethyl‐L‐cysteine [(C₅H₅)Fe(C₅H₄CH(R)SCH₂CH(NH₃⁺)CO₂^?] (L¹) and with the dianions of 1,1′‐ferrocenylbis(methyl‐L‐cysteine) [Fe(C₅H₄CH(R)SCH₂CH(NH₃⁺) CO₂^?)₂] (R = H, Me, Ph) (L²) as N,O,S‐donors were prepared. With the monocysteine ferrocene derivative L¹ as ligands complexes [M^IIL¹₂] or [Cr^IIIL¹₂]Cl type complexes are formed whereas the bis(cysteine) ligand L² yields insoluble complexes of type [ML²]_n, presumably as coordination polymers. The magnetic moments of [Mn^IIL²]_n, [Pr^IIIL²]_n(OH)_n and [Dy^IIIL²]_n(OH)_n exhibit “normal” paramagnetism.     

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.     

Thermodynamische Untersuchungen zur Chelatbildung zwischen Aminoterephthalsäure-N,N-diessigsäure und 3 d- bzw. Erdalkalimetallionen. Eine Betrachtung zum Einfluß einer koordinativ inaktiven Carboxylgruppe auf die komplexe Bindung von Metallionen durch Aminopolycarbonsäuren

N-(2-Carboxyphenyl)iminodiacetic acid (H₃A) and N-(2,5-dicarboxyphenyl)iminodiacetic acid (H₄B) are tetradentate ligands and form complexes of the composition MA- and MB^2? with M^II ions. These compounds differ by the additional charge of the second carboxylic group only, which is fixed to the benzene nucleus and which is unable for coordination for steric reasons. Using an anisothermal calorimeter ΔH values for the formation of the complexes MA- and MB^2? in aqueous solution have been measured at an ionic strength 0.1 m KNO₃. From these data, and from the stability constants of the complexes, entropy changes ΔS have been calculated. In all cases investigated (M^m+ = H⁺, Mg²⁺, Ca²⁺, Sr²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺) the ΔH values are more negative for the complexes MA^m-3 than for complexes MB^m-4, whereas the ΔS values are greater for complexes MB^m-4. Using a simple model for the molecules of the complexes MB^m-4 and empirically determined dielectric constants of the medium between the central ions and the noncoordinated ionized carboxylic group, the electrostatic attraction between these charges was calculated. Basing on these results the influence of the noncoordinated carboxylic group on the central atom by the mesomeric and inductive effect is discussed.