Struktur-Reaktivitäts-Beziehungen bei koordinativ ungesättigten Chelatkomplexen. VII Zum Einfluß axialer Basen auf den Spin-Grundzustand und die Charge-Transfer-Spektren von Eisenkomplexen eines farblosen,porphyrin-verwandten [N4]-Makrocyclus

Structure Reactivity Correlations in Coordinatively Unsaturated Metal Chelate Complexes. VII. Effect of Axial Bases on the Spin Ground State and the Charge Transfer Spectra of Iron Complexes with a Colorless Porphyrine-like [N₄]-Macrocycle In contrast to similar macrocycles without the carbonyl substituents R², the iron(II) complexes 3 react with several bases to form stable adducts. With imidazole, dark red diamagnetic (S = 0) sesqui- and diadducts have been isolated. They are oxidized quickly by air to give dark green polymeric low-spin (S = 1/2) iron(III) derivatives with one imidazolate anion as a bridging axial ligand. With pyridine, ammonia, methanol etc. intense red monoadducts are formed which are intermediate-spin (S = 1) complexes. Preparation of 3a in the presence of water results in a very instable yellow product which appears to be a high-spin (S = 2) diadduct. All the iron(II) complexes are extremely sensitive to air. The spectra of the iron(III) derivatives exhibit a single CT band in the visible region. The energy of the sharp maximum is strongly influenced by axial ligands and can be used to characterize the coordination properties of several bases.     

Struktur-Reaktivitäts-Beziehungen bei koordinativ ungesättigten Chelatkomplexen. IV. Zur Reaktion von Sauerstoff mit Cobalt(II)-Chelaten dreizähniger,dianionischer Schiffscher Basen

Structure Reactivity Correlations in Coordinatively Unsaturated Chelate Complexes. IV. Reaction of Dioxygen with Cobalt(II) Chelates of Tridentate Di-anionic Schiff Base Ligands The high-spin cobalt(II) chelates 3 form with pyridine isolable adducts which are also high-spin complexes. In the case 3 b a low-spin mono-adduct is indicated by ESR spectroscopy, which is changed time-dependently into a stable quadratic-pyramidal form. With 1, 10-phenanthroline 3 b forms a low-spin mono-adduct. The spectrophotometric titration of 3 d with pyridine indicates an equilibrium A + 2 Py ? APy₂ (β₂ = 0,36 M^?2) where A represents probably the tetrameric form of 3 d . In pyridine, 3 a , 3 b , and 3 d react with O₂ in an 1:1 ratio; 3 c binds O₂ in the ratio 2:1. The formation of superoxo complexes is indicated by ESR spectroscopy for the complexes 3 a , 3 b , and 3 d . 3 b reacts with O₂ in piperidine to give the free superoxide ion. In n-butylamine a species is formed which seems to be an ion pair with direct interactions between the free O₂^? ion and the coordinated amine nitrogen.     

Copper(II), Nickel(II) and Cobalt(II) Complexes of Dibasic Tridentate Schiff Bases

Complexes of Cu(II), Ni(II) and Co(II) with the Schiff bases derived from o-aminobenzoic acid with salicylaldehyde and its 5-chloro and 5-bromo derivatives have been prepared. The 1:1 (metal-ligand) stoichiometry of these complexes is shown by elemental analysis, gravimetric estimations and conductometric titrations while the structures of the complexes are proved by i.r. spectra and thermogravimetric analysis. The magnetic susceptibility and electronic spectra of Cu(II) complexes indicate the nonplanar binuclear structures while that of Ni(II) and Co(II) show their paramagnetic octahedral geometry. The molar conductance values in nitrobenzene indicate the nonelectrolytic behaviour of the complexes. The results show that the complexes of the type (Cu·L)₂, Ni·L·3H₂O and Co·L·3H₂O are formed having solvent molecule in coordination with the metal ion. The monopyridine and monoammonia adducts of Cu(II) complexes were found to be monomeric.     

Synthesen,spektroskopische Eigenschaften und Kristallstrukturen zweikerniger homo- und heteroleptischer μ-Carbido-Komplexe von Eisen(IV) mit Phthalocyaninat- und Tetraphenylporphyrinat-Liganden

Syntheses, Spectroscopical Properties, and Crystal Structures of Binuclear Homo- and Heteroleptic μ-Carbido Complexes of Iron(IV) with Phthalocyaninate and Tetraphenylporphyrinate ligands μ-Carbidophthalocyaninato(2–)iron(IV)tetraphenylporphyrinato(2–)iron(IV) ( 2 ) and μ-carbido-bis(tetraphenylporphyrinato(2–)iron(IV)) ( 1 ) are synthesized by the reaction of phthalocyaninato(2–)ferrate(I) with dichlorcarbenetetraphenylporphyrinato(2–)iron(II). 1 and 2 as well as μ-carbido-bis(phthalocyaninato(2–)iron(IV)) ( 3 ) are soluble in tetrahydrofuran, but only 2 and 3 form solvent adducts 2 a and 3 a by coordination of thf to each of the iron atoms in trans position to the bridging C atom. The crystal structures of the solvates 1 · thf, 2 a · thf and 3 a · thf, crystallizing from the thf solutions, are determined: 1 · thf, orthorhombic, Fddd, a = 21.966(3) Å, b = 22.300(1) Å, c = 31.220(3) Å, Z = 8; 2 a · thf, orthorhombic, P22₁2₁, a = 14.487(3) Å, b = 20.753(5) Å, c = 25.803(7) Å, Z = 4; 3 a · thf, orthorhombic, P2₁2₁2₁, a = 12.642(1) Å, b = 22.361(7) Å, c = 23.629(3) Å, Z = 4. In all three double-decker complexes both ”︁tetrapyrrol”︁”︁ ligands are held together by a linear Fe–C–Fe bridge in a staggered ( 1 · thf, 3 a · thf) or ecliptic conformation ( 2 a · thf). The Fe–C distances vary between 1.71 and 1.64 Å (average: 1.68 Å). In 2 a · thf and 3 a · thf the iron atoms are nearly in the centre (Ct) of the (N_p)₄ planes (d(Fe–Ct) ∼ 0.1 Å), but in 1 · thf these atoms are directed by 0.27 Å towards the bridging C atom. The macrocyclic ligands of 1 · thf are severely concavely, those of 2 a · thf and 3 a · thf slightly distorted. The electronic absorption spectra and vibrational spectra are discussed.     

Synthesis,characterization and cytotoxicity of Pt(II), Pd(II), Cu(II) and Zn(II) complexes with 4’‐substituted terpyridine

Eight novel Pt(II), Pd(II), Cu(II) and Zn(II) complexes with 4’‐substituted terpyridine were synthesized and characterized by elemental analysis, UV, IR, NMR, electron paramagnetic resonance, high‐resolution mass spectrometry and molar conductivity measurements. The cytotoxicity of these complexes against HL‐60, BGC‐823, KB and Bel‐7402 cell lines was evaluated by MTT assay. All the complexes displayed cytotoxicity with low IC₅₀ values (<20 μm ) and showed selectivity. Complexes 3 , 5 , 7 and 8 exerted 9‐, 5‐, 12‐ and 7‐fold higher cytotoxicity than cisplatin against Bel‐7402 cell line. The cytotoxicity of complexes 3 , 5 , 6 , 7 and 8 was higher than that of cisplatin against BGC‐823 cell line. Complexes 3 , 7 and 8 showed similar cytotoxicity to cisplatin against KB cell line. Complex 7 exhibited higher cytotoxicity than cisplatin against HL‐60 cell line. Among these complexes, complex 7 demonstrated the highest in vitro cytotoxicity, with IC₅₀ values of 1.62, 3.59, 2.28 and 0.63 μm against HL‐60, BGC‐823, Bel‐7402 and KB cells lines, respectively. The results suggest that the cytotoxicity of these complexes is related to the nature of the terminal group of the ligand, the metal center and the leaving groups. Copyright © 2013 John Wiley & Sons, Ltd.     

Struktur-Reaktivitäts-Beziehungen bei koordinativ-ungesättigten Chelatkomplexen. VI. Synthese,Adduktbildung, Redoxpotentiale und photochrome lodderivate von Eisen(II)-Komplexen Schiffscher Basen mit elektronenziehenden Substituenten

Structure Reactivity Correlations in Coordinatively Unsaturated Chelate Complexes. VI. Synthesis, Adduct Formation, Redox Potentials, and Photochromic Iodine Derivatives of Iron(II) Complexes with Schiff Base Ligands Possessing Electron-Withdrawing Substituents Iron(II) complexes of the type 1 have been prepared by different synthetic methods. In contrast to similar chelates of the “saloph” and “salen” types, the high-spin complexes 1 form stable high-spin diadducts ( 1a – 1d ) and an unusual triadduct ( 1e ) with pyridine. The oxidation potentials of the Fe^II/Fe^III couple as measured by cyclic voltammetry are dependent on the solvent as well as the equatorial ligand substituents. The potentials are more positive in pyridine than in DMF, indicating a stabilization of Fe^II by pyridine. The redox potentials are discussed with respect to those of other metals in the same ligand environment. The complexes form iodine derivatives which show photochromic behaviour in THF solution. The rate of the reaction with dioxygen in the solid state as well as in pyridine solution decreases in the order 1f > 1a ≈ 1b > 1c ≈ 1d > 1e and correlates with the increasing oxidation potentials.     

Neue wasserlösliche Osmiumkomplexe des 5,10,15,20‐Tetrakis(4‐sulfonatophenyl)‐porphyrin‐Anions

Metal Complexes with Tetrapyrrole Ligands. LXXVI. New Water‐soluble Osmium Complexes of 5,10,15,20‐Tetrakis(4‐sulfonatophenyl)porphyrin‐Anion The new symmetrical osmium(II) porphyrinates [Os(tpps₄)L₂]^4– ( 1 b – g ) are formed from [OsO₂(tpps₄)]^4– ( 1 a ) by reduction in presence of the ligands L. 1 e – g react with 1‐methylimidazole to yield the unsymmetrical complexes [Os(tpps₄)LL′]^4– ( 1 h – j ). Except for 1 g – h the osmium(II) porphyrinates are not inert in presence of air and are oxidized to the osmium(III) porphyrinates [Os(tpps₄)L₂]^3– ( 2 b – f ) and [Os(tpps₄)LL′]^3– ( 2 i – j ). These anions are deposited as sodium salts.     

Struktur-Reaktivitäts-Beziehungen bei koordinativ ungesättigten Chelatkomplexen. III. Vergleich des Akzeptorverhaltens der Nickel- und Cobalt(II)-Chelate von dreizähnigen,dianionischen Schiffschen Basen

Structure Reactivity Relations of Coordinatively Unsaturated Chelate Complexes. III. Acceptor Tendency of Nickel and Cobalt Chelates with Tridentate Di-anionic Schiff Base Ligands The reactivity of nickel and cobalt chelate complexes of the type 3 with several donors is compared by isolation of stable adducts. In the case of nickel the reactivity is vigorously influenced by the substituents R¹ and R². The equatorial and the axial unoccupied coordination centers of the nickel chelates exhibit a markedly different behaviour. The cobalt(II) chelates – all of them are high spin complexes – favour O-donors. The complicate composition of the adducts point to a polynuclear structure. With pyridine, high spin diadducts have been isolated probably with coordination number 5 for the metal.     

Metal chelates of salicyl-4-aminoantipyrine

The formation constants of salicyl-4-amino-2,3-dimethyl-1-phenyl-3-pyrazoline-5-one (SAAP) complexes with 3d transition metal ions [Cu(II), Ni(II), Co(II), Zn(II) and Mn(II)] have been determined in 60% ethanol-water medium ofμ = 0.1M (NaCl) at 25°C. It is observed that the formation constants for chelates with 3d transition metals follow the order Mn(II) < Co(II) < Ni(II) < Zn(II) < Cu(II). The effects of metal ions, ionic radii, electronegativities and ionization potentials on chelate formation constants are discussed. Complexes of UO₂(II) and Pd(II) have been synthesized and characterised by elemental analysis, electrolytic conductance, IR spectra and magnetic measurements. The ligand forms the complexes PdLCl and UO₂L₂,2H₂O, where L is a uninegatively charged tridentate ligand (ONO donor sets).     

Chlorthionitrenkomplexe des Molybdäns

Chlorothionitrene Complexes of Molybdenum Molybdenum pentachloride reacts with trimer thiazylchloride, (NSCl)₃, forming the chlorothionitrene complex \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm Cl}_4 {\rm Mo} = \mathop {\rm N}\limits^ \oplus = \mathop {{\rm SCl}}\limits^ \ominus $\end{document}, in which the chlorothionitrene ligand is to be understood as (NSCl)^2? group. I reacts with phosphorylchloride forming the solvate Cl₃PO? Mo(Cl₄)(NSCl) ( II ) that can also be obtained directly from MoCl₅ · OPCl₃ and trithiazylchloride. II reacts with chloride ions giving the anionic chlorothionitrene complex [Cl₅Mo(NSCl)]? ( III ). Thermal decomposition of I leads to MoNCl₃ under SCl₂ cleavage, while reaction of I with chloride ions gives [MoNCl₄]?. Both reactions prove chlorothionitrene complexes to be excellent precursors for the syntheses of nitrido complexes. The complexes I—III have been characterized by IR spectroscopy.     

Phosphinsubstituierte Chelatliganden. XVIII. Penta- und Tetracarbonylmetall-Komplexe des Chroms,Molybdäns und Wolframs mit sekundären und tertiären Phosphinothioformamid-Liganden

Phosphine Substituted Chelate Ligands. XVIII. Penta- and Tetracarbonylmetal Complexes of Chromium, Molybdenum, and Tungsten with Secondary and Tertiary Phosphinothioformamide Ligands Mono- and bidentately coordinated phosphinothioformamide complexes are obtained by photochemical substitution of the metal hexacarbonyls M(CO)₆ (M ? Cr ( a ), Mo ( b ), W ( c )). The M(CO)₅ · THF adducts react with secondary thioamides under exclusion of light to give the P-coordinate pentacarbonyl complexes [(CO)₅MPPh₂C(S)NHR¹] (R¹ ? Ph ( 1a – c ), Me ( 2a )). The photoreaction of M(CO)₅ · THF with secondary and tertiary thioamides at low temperatures leads to the formation of the P, S-chelate complexes . The corresponding N-silylated complexes 6a – c (R¹ ? Me₃Si, R² ? Ph) are obtained by direct photosubstitution of M(CO)₆ in cyclohexane solution. The labile bis(thioformamide) complexes [(CO)₄M(PPh₂C(S)NHMe)₂] ( 7a – c , cis-trans isomers) are synthesized in low yields according to the same procedure. The attempted alkylation of the chelate complexes 3a – c remains unsuccessful, whereas the secondary thioformamides react with n-BuLi/CH₂Br₂ to give the methylene bis(thioformirnidoesters) [Ph₂PC(NR¹)S]₂CH₂ (R¹ ? Ph (8), Me ( 9 )) in quantitative yields.     

Interaction of copper(II) halides with 4-azafluorene derivatives in neutral and acid media. Crystal and molecular structure of 4-aza-9-oxofluorenium tetrabromocuprate hydrate (HL<Superscript>4</Superscript>)<Subscript>2</Subscript>CuB<Subscript>4</Subscript> · H<Subscript>2</Subscript>O

Complexes of copper(II) halides (chlorides and bromides) with some 4-azafluorene derivatives have been synthesized and studied by X-ray crystallography and IR and UV spectroscopy. In neutral media, Cu(L)₂X₂ (X = Cl, Br) complexes are formed in which the ligands are coordinated to the metal atoms though the lone pair of the endocyclic nitrogen atom and through the oxygen atoms of substituents. In acid media at pH 2, (HL²)₂CuX₄ complexes are formed in which the 4-azafluorene molecules protonated at the endocyclic nitrogen atom act as an outer-sphere cation. The molecule and crystal structure of 4-aza-9-oxofluorenium tetrabromocuprate hydrate (HL⁴)₂CuBr₄·H₂O has been determined.     

Spectroscopic studies of manganese(II) and zinc(II) complexes of 1-phenyl-3-methyl-4-acylpyrazolone-5

Mn(II) and Zn(II) complexes of a series of 4-acyl derivatives of 1-phenyl-3-methylpyrazolone-5 have been synthesized. Characterization was by elemental analyses, UV, IR and ¹H NMR analyses. The chelates were found to conform to a general molecular formula ML₂·xCH₃CH₂OH·yH₂O where M = Mn, Zn; L is the acylpyrazolone-5 anion; x = 0, 1 or 2; and y = 0, 1 or 2. Spectral analyses showed that the adducts associated with the complexes have no effect on the bathochromic shifts observed in the UV and IR spectral properties of the complexes. The stability of the C

O and COM bonds does not follow any regular pattern with respect to the carbon chain of the 4-acyl substituent. The Mn(II) complexes have μ_eff values within the range of 5.3–5.6 B.M.     

Ternäre Komplexe von Eisen(III) mit Ethylendiamintetraessigsäure und Monophenolderivaten

Ternary Complexes of Iron(III) with Ethylene Diamine Tetraacetic Acid and Derivatives of Monophenols Ternary complexes of iron(III) are investigated with ethylenediamine tetraacetic acid and some monophenols in solution as well as their reactions of formation have been controlled by spectrophotometric and elektrophoretic methods. The ratio of components in the compounds Fe: Y: L is 1: 1: 1 without any exception. The measured optical properties (λ_max' ?_max) of the complexes are discussed.     

[2+2] Cycloaddition reactions of cationic iron vinylidene complexes

Complexes (Ph₃P)(Cp)(OC)Fe⁺CCR¹₂BF⁻₄ underwent [2+2] cycloaddition reactions witn the imines MeNCHR² to give the corresponding cationic iron (II) 2-azetinylidene adducts.     

Spin crossover in homo- and heteroligand iron(II) complexes with tris(pyrazol-1-yl)methane derivatives

The studies concerning coordination compounds of various salts of iron(II) with tris(pyrazol-1-yl)methane derivatives (HC(pz)₃) are discussed. The results of a number of studies on the synthesis and investigation of the homo- and heteroligand iron(II) complexes with tris(3,5- dimethylpyrazol-1-yl)methane (HC(3,5-Me₂pz)₃) are considered. The study of the temperature dependence μ_eff (T) showed that the spin crossover (SCO) ¹A₁?⁵T₂ observed in a series of the compounds discussed is accompanied by thermochromism (color change pink (purple) ? colorless). Specific features of the SCO and their dependence on the outer-sphere anion in the iron(II) complexes are discussed. The data of the recently published work devoted to the synthesis of the iron(II) complexes with three N-substituted HC(pz)₃ derivatives (general formula ^xL, where x = H, CH₂C₆H₅ (Bn) and p-SO₃C₆H₄CH₃ (Ts)) are considered.     

Pseudohalogenmetallverbindungen. LXXIV. Darstellung von Alkylisocyanid-Eisenkomplexen aus Isoblausäure-Eisenkomplexen und primären Alkoholen mittels Redox-Kondensation

Pseudohalogeno Metal Compounds. LXXIV. Preparation of Alkyl Isocyanide Iron Complexes from Isocyano Acid Iron Complexes and primary Alcohols via Redox Condensation Isocyano acid iron complexes Fe(CN)₂(CNH)₄ · 4Et₂O and Fe(bpy)(CN)₂(CNH)₂ · 2H₂O are esterificated with methanol and ethanol in the presence of triphenylphosphine and diethyl azodicarboxylate (Mitsunobu conditions) to give the isocyanide complexes Fe(CN)₂(CNR)₄ and Fe(bpy)(CN)₂(CNR)₂ · 2H₂O (R = Me, Et) which are characterized by their spectroscopic data.     

Metallkomplexe mit biologisch wichtigen Liganden. CLXV N,O‐Chelat‐Komplexe von α‐Aminosäureanionen mit cyclopalladiertem N,N‐Dimethylferrocencarbothiamid

Metal Complexes of Biologically Important Ligands. CLXV N,O‐Chelate Complexes of α‐Amino Acid Anions with Cyclopalladated N,N‐Dimethylferrocenecarbothioamide A short literature review on the reactions of various chlorobridged complexes with α‐aminoacidates, α‐amino acid esters, peptide ester or derivatives of amino acids is given. The chloro bridged o‐palladated N,N‐dimethylferrocenecarbothioamide [(fct)Pd(μ‐Cl)₂Pd(fct)] reacts with the anions of glycine, L‐alanine, L‐proline, L‐valine, L‐phenylalanine, L‐leucine, L‐isoleucine to give the N,O‐chelates [(fct)Pd(N,O‐α‐aminocarboxylate)] ( 1 – 7 ). Due to the planary chirality of the unsymmetrically disubstituted cyclopentadienyl iron moiety of fct the complexes 2 – 7 with optically active amino acidate ligands are formed as a mixture of two diastereoisomers, which can be detected by their NMR spectra.     

Koordination und Reaktivität von Sulfinylimiden RNSO in Cyclopentadienyldicarbonylmangan‐Komplexen

Coordination and Reactivity of Sulfinylimides RNSO in Cyclopentadienyldicarbonylmanganese Complexes The coordination behaviour of sulfinylimides RNSO (R = SiMe₃, Ph) towards CpMn(CO)₃ (Cp = C₅H₅, C₅H₄CH₃) has been studied. Under total exclusion of water the substitution products CpMn(CO)₂{S(O)NR} ( 2 a , b , 2 ′ a , b ) with μ¹‐S‐linkage are formed. In the presence of water, however, the SO₂ complexes 3 , 3 ′ as iminofree hydrolysis products are obtained. There are only spectroscopic indications for the directed hydrolytic conversion of the silyl derivatives 2 a , 2 ′ a into the unstable HNSO complexes 4 , 4 ′ by cleavage of the Si–N‐bond and retention of the cumulene moiety. The molecular structures of π‐C₅H₅Mn(CO)₂{S(O)NSiMe₃} ( 2 a ) and π‐C₅H₄CH₃Mn(CO)₂SO₂ ( 3 ′) were elucidated by single crystal X‐ray analyses.     

New metal chelates of 5-amino-4-azopyrazoles: The crystal and molecular structure of bis{1-phenyl-3-methyl-4-(<Emphasis Type="Italic">p</Emphasis>-tolyl)azo-5-(<Emphasis Type="Italic">p</Emphasis>-carboxymethoxyphenyl)pyrazolamidato}copper(II)

The reactions of 1,3-alkyl(aryl) derivatives of 5-amino-4-azopyrazoles (HL) with copper(2+) acetate afford metal chelates CuL₂. Complexes with the CuN₄ chromophore containing a substituted amino group (X = NR) as a donor, like their azomethine analogues, have a pseudotetrahedral structure. Copper chelates with X = NH are planar. The X-ray diffraction data and an additional hyperfine structure (ahfs) from ¹⁵N atoms of the azo group in the labeled complexes provide evidence for the formation of six-membered metallocycles. The coordination polyhedron in bis{1-phenyl-3-methyl-4-(p-tolyl)azo-5-(p-carboxymethoxyphenyl)pyrazolamidato}Cu(II) can be described as a pseudotetrahedron.