Synthesis of pyrrolyldipyrrinato BF2 complexes by oxidative nucleophilic substitution of boron dipyrromethene with pyrrole

Direct oxidative nucleophilic substitution of the 3-hydrogen of BODIPY dyes by pyrrole has been developed under reflux condition under oxygen, from which a series of pyrrolyldipyrrinato BF(2) complexes 1a-h, as extended BODIPYs, have been synthesized. Most of these BODIPYs show strong fluorescence emissions at wavelengths over 600 nm in six solvents of different polarity. Removal of the BF(2) group from BODIPY 1e gave the corresponding free base pyrrolyldipyrrin 7 as an analog of the natural product prodigiosin, in high yield.     

The reactions of diphenylcarbazide and diphenylcarbazone with cations : Part III. Nature and properties of the mercury complexes

The reactions of diphenylcarbazone or diphenylcarbazide with mercury(I) or mercury(II) are studied by qualitative analysis, extraction and Job's method. Only carbazone complexes are formed. Mercury(I) and (II) both form two complexes, a 1:1 and a 1:2 complex (cation : carbazone). The complexes formed are colloids in aqueous alcoholic solutions. Decomposition of these complexes, to form diphenylcarbodiazone, is accelerated by ultraviolet and visible light.     

Spectral and thermal studies of new Co(II) and Ni(II) hexaaza and octaaza macrocyclic complexes

The macrocyclic complexes of Co(II) and Ni(II) having chloride or thiocyanate ions in the axial position have been synthesized and characterized. These complexes are synthesised by the template condensation of o-phenylenediamine or 2,3-butanedionedihydrazone with the appropriate aldehydes in NH₄OH solution in the presence of the metal ions, Co(II) and Ni(II). The complexes were characterized by spectroscopic methods (IR, UV-Vis and ESR) and magnetic measurements as well as thermal analysis (TG and DTA). The results obtained are commensurate with the proposed formulae. Spectral studies indicate that these complexes have an octahedral structure. From conductivity measurements the complexes are non-electrolytes. The kinetic of the thermal decomposition of the complexes was studied and the thermodynamic parameters are reported.     

Chelate complexes of some NNO tridentate Schiff bases with iron(II), cobalt(II), nickel(II) and copper(II)

Summary The Schiff bases a-(C₅H₄N)CMe=NNHCOR (R = Ph, 2-thienyl or Me), prepared by condensation of 2-acetylpyridine with the acylhydrazines RCONHNH₂, coordinate in the deprotonated iminol form to yield the octahedral complexes, M[NNO]₂ M = Co or Ni; [NNOH] = Schiff base and the square-planar complexes, Pd[NNO]Cl. The Schiff bases also coordinate in the neutral keto form yielding the octahedral complexes (M[NNOH]2)Z2 (M = Ni, Co or Fe; Z = C104, BF₄ or N03) and complexes of the type M[NNOH]X2 (M = Ni, Co, Fe or Cu; X = Cl, Br or NCS). Spectral and x-ray diffraction data indicate that the complexes M[NNOH]X2 (M = Ni or Fe) are polymeric octahedral, as are the corresponding cobalt complexes having R = 2-thienyl. However, the cobalt complexes Co[NNOH]X2 (X = CI or Br; R = Ph or Me) and the copper complexes Cu[NNOH]CI₂ (R = Ph, 2-thienyl or Me) are five-coordinate, while the thiocyanato complex Co[NNOH](NCS)₂ (R = 2-thienyl) is tetrahedral.     

Optically active transition metal complexes. Part 119:New rhodium(I) complexes containing two different types of optically active ligands

The synthesis of novel rhodium(I) complexes containing two different chiral ligands is described. These ligands are on the one hand (−)-diop and on the other hand various optically active pyrroleimines, which derive from 1-phenylethylamine or 1-cyclohexylethylamine with an (R)- or (S)-configuration. The resulting (−)-diop–pyrrolylimine–rhodium(I) complexes are diastereomers and are expected to give different stereoselectivities in enantioselective catalysis (double stereoselection). In addition, the synthesis of novel rhodium(I) complexes containing 1,5-cyclooctadiene and various chiral pyrroleoxazoline ligands is described. All the complexes are used in the enantioselective hydrogenation of ketopantolactone (see following paper).     

Coordination properties of tridentate (N,O,O) heterocyclic alcohol (PDC) with Cu(II). Mixed ligand complex formation reactions of Cu(II) with PDC and some bio-relevant ligands

The formation equilibria of copper(II) complexes and the ternary complexes Cu(PDC)L (PDC=2,6-bis-(hydroxymethyl)-pyridine, HL=amino acid, amides or DNA constituents) have been investigated. Ternary complexes are formed by a simultaneous mechanism. The results showed the formation of Cu(PDC)L, Cu(PDC, H(-1))(L) and Cu(PDC, H(-2))(L) complexes. The concentration distribution of the complexes in solution is evaluated as a function of pH. The effect of dioxane as a solvent on the protonation constant of PDC and the formation constants of Cu(II) complexes are discussed. The thermodynamic parameters DeltaH degrees and DeltaS degrees calculated from the temperature dependence of the equilibrium constants are investigated.     

Technetium tetrachloride as a precursor for small technetium(IV) complexes

Polymeric technetium tetrachloride reacts with monodentate donor ligands such as THF, acetonitrile, DMSO, thioxane (1-oxa-4-thiacyclohexane), PMe2Ph, PPh3, OPPh3, or OH2 via cleavage of the polymeric network and the formation of [TcCl4(L)2] complexes. The configuration of the products is dependent on the donor atoms such that trans coordination is established with "soft" donor atoms such as sulfur or phosphorus, while cis-[TcCl4(L)2] complexes are formed with the "harder" donors oxygen or nitrogen. The ambivalent thioxane binds to technetium via the sulfur atom. The trans products are air stable and resistant to hydrolysis. The cis complexes, however, undergo stepwise hydrolysis, during which complexes of the composition [Cl3(L)2TcOTc(L)2Cl3] (L = CH3CN, DMSO, or OH2) are formed. They are the first representatives of a new class of technetium(IV) complexes with a bridging oxo ligand. The Tc-O bond lengths in these bridges are between 1.803(1) and 1.823(2) A.     

Role of paramagnetic Ni(I) and Ni(III) complexes in catalytic reactions of unsaturated hydrocarbons

By analyzing experimental data collected by systematic investigation of Ni(I) complex formation conditions, it is demonstrated that, when a system simultaneously contains Ni(0) and Ni(II) complexes, whether cationic or electroneutral, stabilized by olefinic or organoelement ligands, the complexes undergo comproportionation to form Ni(I) complexes. Using individual Ni(II) complexes as examples, it is shown that the spontaneous decomposition of hydrido and organometallic Ni(II) complexes yields Ni(I) complexes. The Ni(I) and Ni(III) complexes are involved in the catalytic cycles of reactions of olefins and acetylenes.     

Constantes de formation des complexes de stoechiometrie 1:1 et 1:2 ainsi que des complexes mixtes formes entre le plutonium(III) et divers acides amino-polyacetiques

Determination of the formation constants of 1:1, 1:2 and mixed complexes between plutonium(III) and various aminopolyacetic acids The complexation of plutonium(III) with various aminopolyacetic acids is investigated by potentiometric titration at 25°C and at a constant ionic strength of 1 (KC1). The formation constants of the 1:1 complexes are reported for NTA, HEDTA, EDTA, DCTA and DTPA. The formation constants of the 1:2 complexes with NTA, HEDTA and EDTA as well as those of the mixed complexes formed between Pu(HEDTA) or Pu(EDTA) and NTA, IMDA or glycine are also reported. Several pK values of the 1:1, 1:2 and mixed complexes have been determined. These results are discussed within the framework of those obtained previously with the lanthanides.     

Formation of Nanosized Catalysts Based on Palladium Phosphine Complexes and the Nature of Their Activity

Findings on the formation and features of nanosized particles based on palladium complexes, which are active in hydrogenation catalysis, are summarized. Depending on the nature of a reducing agent, nanosized particles formed by the reduction of palladium(II) phosphine complexes are either metallic nuclei stabilized by organophosphorus ligands or associates of polynuclear phosphido or phosphinideno palladium complexes whose surface contains immobilized Pd(0) clusters. The ensembles of the Pd(0) atoms are active in hydrogenation.     

铂(Ⅱ)类抗肿瘤药物

自顺铂临床用于抗肿瘤药物以来,在铂配合物中寻找新的药物已成为研究的热点,现在已有顺铂、卡铂和奥沙利铂在广泛应用于临床。根据经典的构效关系,上千个新的铂类化合物被设计与合成出来。我们综述了铂（Ⅱ）类抗肿瘤药物近五年的研究状况,介绍了包括含有生物活性基团的铂（Ⅱ）配合物,具有空间位阻的铂（Ⅱ）配合物,反式铂（Ⅱ）配合物,含S、P配位原子铂（Ⅱ）配合物和多核铂（Ⅱ）配合物,总结了这些化合物的抗肿瘤机理、活性。     

New Transition and Actinide Metal Complexes of 2‐Carboxy‐phenylhydrazo‐Benzoylacetone Ligand: Synthesis,Characterization and Biological Study

A new series of binary mononuclear complexes were prepared from the reaction of the hydrazone ligand, 2-carboxyphenylhydrazo-benzoylacetone (H2L), with the metal ions, Cd(II), Cu(II), Ni(II), Co(II), Th(IV) and UO2(VI). The binary Cu(II) complex of H2L was reacted with the ligands 1,10-phenanthroline or 2-aminopyridine to form mixed-ligand complexes. The binary complexes of Cu(II) and Ni(II) are suggested to have octahedral configurations. The Cd(II) and Co(II) complexes are suggested to have tetrahedral and/or square-planar geometries, respectively. The Th(IV) and UO2(VI) complexes are suggested to have octahedral and dodecahedral geometries, respectively. The mixed-ligand complexes have octahedral configurations. The structures of all complexes and the corresponding thermal products were elucidated by elemental analyses, conductance, IR and electronic absorption spectra, magnetic moments, 1H NMR and TG-DSC measurements as well as by mass spectroscopy. The ligand and some of the metal complexes were found to activate the enzyme pectinlyase.     

Cationic Gold(II) Complexes: Experimental and Theoretical Study**

Gold(II) complexes are rare, and their application to the catalysis of chemical transformations is underexplored. The reason is their easy oxidation or reduction to more stable gold(III) or gold(I) complexes, respectively. We explored the thermodynamics of the formation of [Au^II(L)(X)]⁺ complexes (L=ligand, X=halogen) from the corresponding gold(III) precursors and investigated their stability and spectral properties in the IR and visible range in the gas phase. The results show that the best ancillary ligands L for stabilizing gaseous [Au^II(L)(X)]⁺ complexes are bidentate and tridentate ligands with nitrogen donor atoms. The electronic structure and spectral properties of the investigated gold(II) complexes were correlated with quantum chemical calculations. The results show that the molecular and electronic structure of the gold(II) complexes as well as their spectroscopic properties are very similar to those of analogous stable copper(II) complexes.     

Cyclometalated iridium and platinum complexes as singlet oxygen photosensitizers: quantum yields, quenching rates and correlation with electronic structures

Photophysical properties are reported for a series of cyclometalated platinum and iridium complexes that can serve as photosensitizers for singlet oxygen. The complexes have the formula (C;N)(2)Ir(O;O) or (C;N)Pt(O;O) where C;N is a monoanionic cyclometalating ligand such as 2-(phenyl)pyridyl and 2-(phenyl)quinolyl, and O;O is the ancillary ligand acetylacetonate (acac) or dipivaloylmethane (dpm). Also examined were a series of (N;N)PtMe(2) complexes where N;N is a diimine such as 2,2'-bipyridyl. In general, the cyclometalated complexes are excellent photosensitizers for the production of singlet oxygen, while the (N;N)PtMe(2) complexes were ineffective at this reaction. Quantum yields of singlet oxygen production range from 0.9-1.0 for the cyclometalated Pt complexes and 0.5-0.9 for Ir complexes. Luminescence quenching and singlet oxygen formation of the Ir complexes occurs from a combination of electron and energy transfer processes, whereas the Pt complexes only react by energy transfer. For Ir complexes with low emission energy, physical deactivation of the triplet excited state becomes competitive with energy transfer to ground state dioxygen. The rates of singlet oxygen quenching for the complexes presented here are in the range 6 x 10(6)-2 x 10(7) M(-1) s(-1) for Pt complexes and 2 x 10(5)-2 x 10(7) M(-1) s(-1) for Ir complexes, respectively. Differences in the efficiency of both forming and quenching singlet oxygen between the Ir and Pt cyclometalates are believed to come about from the more exposed coordination geometry in the latter species.     

Catalytic Activity of Cationic and Neutral Silver(I)–XPhos Complexes with Nitrogen Ligands or Tolylsulfonate for Mannich and Aza‐Diels–Alder Coupling Reactions

Cationic and neutral silver(I)–L complexes (L=Buchwald‐type biaryl phosphanes) with nitrogen co‐ligands or organosulfonate counter ions have been synthesised and characterised through their structural and spectroscopic properties. At room temperature, both cationic and neutral silver(I)–L complexes are extremely active catalysts in the promotion of the single and double A³ coupling of terminal (di)alkynes, pyrrolidine and formaldehyde. In addition, the aza‐Diels–Alder two‐ and three‐component coupling reactions of Danishefsky’s diene with an imine or amine and aldehyde are efficiently catalysed by these cationic or neutral silver(I)–L complexes. The solvent influences the catalytic performance due to limited complex solubility or solvent decomposition and reactivity. The isolation of new silver(I)–L complexes with reagents as ligands lends support to mechanistic proposals for such catalytic processes. The activity, stability and metal–distal arene interaction of these silver(I)–L catalysts have been compared with those of analogous cationic gold(I) and copper(I) complexes.     

Spectroscopic studies on chromotropic mixed-ligand copper(II) complexes containing o-hydroxy benzoyl derivatives and dinitrogen bases

Synthesis of chromotropic copper(II) mixed ligand complexes of o-hydroxy benzoyl derivatives (L1) and dinitrogen bases (L2), general formula Cun(L1)(L2)nXn; where n=1 or 2, L1=4,6-diacetyl-resorcinol (H2DACR), o-hydroxy benzaldhyde (HOHBZ) or o-hydroxy acetophenone (HOHAP), L2=N,N,N',N'-tetramethylethylenediamine (Me4en), 1,10-phenanthroline (phen) or bipyridine (bipy) and X=ClO4-, NO3- or Br- have been reported. Spectral, magnetic and molar conductance measurements as well as analytical data of these complexes show either mononuclear structure for OHBZ and OHAP or binuclear structure for DACR complexes. The IR stretching vibration frequencies of Cu-N and Cu-O are linearly correlated with the d-d absorption frequencies. The d-d absorption bands of Me4en-complexes in weak donor solvents suggest square-planar, distorted octahedral and distorted trigonal bipyramid geometries for the perchlorate, nitrate and bromide complexes, respectively. However, an octahedral structure is identified for the complexes in strong donor solvents. Perchlorate complexes show a remarkable color change from violet to green as the donor ability of the axial ligand increases, whereas bromide complexes are mainly affected by the Lewis acidity of the axial ligand. Specific and non-specific interactions of solvent molecules with the complexes are investigated using the unified solvation model. Calculations of the electronic transition probability (f) of the d-d band along with molecular orbital calculations of ligands have been carried out and correlated with the experimental data.     

Spectral,electrochemical and molecular orbital studies on solvatochromic mixed ligand copper(II) complexes of malonate and diamine derivatives

Solvatochromic mixed ligand complexes of copper(II) with malonate and diamine derivatives, Cu(n)(RMal)(diam)(n)X(m) (where n=1 or 2, m=1-4, RMal, malonic acid (H(2)Mal), diethylmalonate (HDEtMal) or diethylethoxyethylenemalonate (DEtEMal), and diam, ethylenediamine (en), 1,3-propylenediamine (1,3-pn), N,N,N'-trimethylethylenediamine (Me(3)en), N,N,N'-triethylethylenediamine (Et(3)en), N,N,N',N'-tetramethylethylenediamine (Me(4)en), N,N,N',N'-tetramethylpropylenediamine (Me(4)pn), or N-methyl-1,4-diazacycloheptane (medach); and X=ClO(4)(-) or Cl(-)), has been synthesized and characterized by spectroscopic, magnetic, molar conductance and electrochemical measurements. The mass spectra along with the analytical data of the complexes show peaks with m/e corresponding to a bridged binuclear structure for the chloride complexes, while perchlorate complexes showed either mononuclear structure for DEtMal and DEtEMal or bridged binuclear structure for Mal complexes. These results correspond to IR spectral data, which indicated that the modes of ester and carboxylato coordination sites are mono- and/or bidentate. The d-d absorption bands in weak donor solvents suggest square-planar and distorted square pyramidal-trigonal bipyramid geometries for the perchlorate and chloride complexes; respectively. On the other hand, an octahedral structure is identified for complexes in strong donor solvents. Perchlorate complexes show a drastic color change from violet to green as the donation ability of solvent increases, whereas chloride complexes are highly affected by the acceptor properties of the solvent. Cyclic voltammetric measurements on the complexes, proposed a quasi-reversible or irreversible and mainly diffusion controlled reduction process. Such behavior has been explained according to the ECE mechanism. A linear correlation has been found between the Cu(II) reduction potential and the spectral data. Molecular orbital calculations were performed for the ligands on the bases of PM3 level and the results corresponded to the experimental data. The data are discussed in terms of chromotropic concept and its applications as a Lewis acid-base color indicator.     

N-heterocyclic carbene complexes of palladium and rhodium: cis/trans-isomers

Stable carbene complexes of palladium or rhodium are readily accessible by (i) reaction of imidazolium or triazolium salts with palladium complexes bearing basic ligands or rhodium alkoxide complexes, (ii) adduct formation of the free carbene, e.g. 1,3-dimethylimidazoline-2-ylidene, with metal compounds. In the case of palladium(II) and rhodium(I), the resulting complexes show cis/trans-isomerization and can be compared to analogous phosphine complexes.     

Efficient red-emitting cyclometalated Iridium(III) complexes containing lepidine-based ligands

Heteroleptic cyclometalated iridium(III) complexes featuring lepidine-based ligands and acetyl acetone auxiliary ligand are synthesized. Multiple lowest energy absorption bands are observed for these complexes indicating substantial mixing of the singlet and triplet levels. All the complexes emit orange or red color in dichloromethane solutions with lifetimes in the range 1.6-3.7 micros. The emission in the complexes probably originates from the (3)MLCT state. The complexes are applied as emitting guests in LED devices of the structure ITO/HTL(BPAPF or NPB)/6% Ir in CBP/BCP/Alq(3)/LiF/Al. They exhibit excellent device characteristics with an orange to red EL profile.