Showing papers in "Inorganic Chemistry in 1989"

Electronic spectra and photophysics of platinum(II) complexes with alpha-diimine ligands - Solid-state effects. I - Monomers and ligand pi dimers

Abstract: Two types of emission behavior for Pt(II) complexes containing alpha-diimine ligands have been observed in dilute solution. If the complex also has weak field ligands such as chloride, ligand field (d-d) excited states become the lowest energy excited states. If only strong field ligands are present, a diimine 3(pi-pi/asterisk/) state becomes the lowest. In none of the cases studied did metal-to-ligand charge transfer excited state lie lowest.

Metal ion recognition in ligands with negatively charged oxygen donor groups. Complexation of iron(III), gallium(III), indium(III), aluminum(III), and other highly charged metal ions

Abstract: The existence of good linear relationships between the formation constant log values of complexes of ligands containing negative oxygen donor groups only and log K 1 (OH − ) values for the metal ions is demonstrated for a variety of ligands containing phenolate, carboxylate, and hydroxamate donor groups. The formation constants of DFB (desferriferrioxamine-B), BAMTPH (a synthetic trihydroxamate), and several dihydroxamic acids of the type HONHCO(CH 2 ) n CONHOH with several metal ions are reported and used to demonstrate the general existence of linear relationships of the above type

Luminescence study of complexation of europium and dicarboxylic acids

Abstract: Luminescence lifetime measurements of Eu(III) have been used to study the hdration of Eu(III) when complexed by alkane-dicarboxylate ligands. In its mono(malonate) complex, Eu(III) was found to have 2.3 fewer water molecules than the uncomplexed hydrated cation. In the formation of its 1:1 complexes with succinate, glutartate, and adipate, Eu(III) lost 1.5 molecules of water. When these dicarboxylate ligands reacted with the EuNTA complex to form the 1:1:1 ternary species, the malonate anion replaced 2.2, the succinate 1.5, and the glutarate and adipate 1.0 water molecules (all these values have ca. {plus minus}0.5 uncertainty). These data are discussed in terms of the effect on chelation of increased alkyl chain length. 13 refs., 4 figs., 5 tabs.

Oxoperoxo(citrato)- and dioxo(citrato)vanadates(V): synthesis, spectra, and structure of a hydroxyl oxygen bridged dimer K2[VO(O2)(C6H6O7)]2.2H2O

Abstract: Preparation de complexes du type M[VO(O 2 )(C 6 H 6 O 7 )]•H 2 O (M=K + , NH 4 + , Cs + ). Caracterisation spectrometrique IR et etude radiocristallographique du complexe dimere

Energy level tailoring in ruthenium(II) polyazine complexes based on calculated and experimental ligand properties

Abstract: The effects of experimental and calculated ligand properties on the electronic structure of ruthenium(II) polyazines have been rationalized in the complexes (L 3 Ru) 2+ , [(L)Ru(bpy) 2 ] 2+ , and {(η 4 ,μ-L)[Ru(bpy) 2 ] 2 } 4+ , where L denotes the four isomeric bidiazines 3,3'-bipyridazine, 2,2'-bipyrazine, and 4,4'-bipyrimidine and η 2 -azo-2,2'-bipyridine and where η 4 ,μ-L denotes the symmetrically bridging ligands 2,2'-bipyrimidine, 2,5-bis(2-pyridyl)pyrazine, 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, and azo-2,2'-bipyridine. Crucial factors determining the redox potentials and metal-to-ligand charge-transfer (MLCT, d →π*) absorption energies are the ground-state basicities, the π* orbital energies, and electron densities at the coordinating atoms of the ligands. Mono- and binuclear complexes with unusually long wavelength MLCT absorptions have been obtained by applying the described strategies in the design and selection of ligands

Steric effects in polypyrazolylborate ligands. Poly(3-isopropylpyrazolyl)borates: ligands of intermediate steric requirements

Abstract: The synthesis, structures, and coordination chemistry of a series of polypyrazolylborate ligands, [H n B(3-isopropylpyrazol-1-yl) 4−n ] − and [HB(3-isopropyl-4-bromopyrazol-1-yl) 3 ] − , are presented. These ligands are made by the reaction of tetrahydroborate ion with the appropriate pyrazole. A series of metal complexes was prepared and characterized by analytical and spectroscopic data. In addition, four complexes were characterized by means of X-ray diffraction techniques. The results presented here indicated that these ligands have properties that are unique and transitional from those of the previously reported, relatively unhindered ligands such as [H n B(pyrazolyl-1-yl) 4−n ] − to the sterically bulky ligands [H n B(3-R-pyrazol-1-yl) 4−n ], where R=tert-butyl and phenyl groups

Chemistry of molybdenum with hard-soft donor ligands. 2. Molybdenum(VI), -(V), and -(IV) oxo complexes with tridentate Schiff base ligands

Abstract: The synthesis and characterization of a number of oxomolybdenum(VI), -(V), and -(IV) complexes with salicylaldehyde thiosemicarbazones as the SNO-donor metal-binding substrates are described

Synthesis and solid- and liquid-state characterization of a hexameric cluster of titanium(IV): Ti6(.mu.2-O)2(.mu.3-O)2(.mu.2-OC4H9)2(OC4H9)6(OCOCH3)8

Abstract: Cristallisation dans P21/c avec a=18,508, b=10,818, c=17,831 A, β=104,00˚, Z=2; affinement jusqu'a R=0,055. La molecule centrosymetrique contient six atomes Ti, coordines octaedriquement. Les liaisons Ti-O(butoxy longueur moyenne ou longue (2,061 A) La longueur de cette derniere s'explique par un transfert π depuis l'oxygene de la liaison Ti-O(N 2 -oxo) vers cet oxygene. Ce compose joue un role cle en chimie sol-gel

Non-metal redox kinetics : hypochlorite and hypochlorous acid reactions with cyanide

Abstract: Determination spectrophotometrique des constantes cinetique de reactions d'un exces de SO 3 2− vis-a-vis de HOCl et ClO − en presence du tampon carbonate Mecanisme faisant intervenir la formation d'especes intermediaires HOClSO 3 2− , ClSO 3 − via un transfert de Cl + ou d'O 2−

Manganese(II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate). Synthesis and characterization of a paramagnetic chelate for magnetic resonance imaging enhancement

Abstract: Preparation et caracterisation spectrometrique RMN du coordinat du titre. Etude potentiometrique de la complexation avec des ions de metaux de transition et de la protonation. Etude radiocristallographique du complexe de Mn (II)

Complexes of rhenium carbonyl containing ferrocenyl-derived ligands: tunable electron density at rhenium by control of the redox state of the ferrocenyl ligand

Abstract: The new complexes (Fe(C 5 H 4 PPh 2 ) 2 )Re(CO) 3 Cl, cis-(FcPPh 2 )Re(CO) 4 Cl, fac-(FcPPh 2 ) 2 Re(CO) 3 Cl, fac-(FcPy) 2 Re(CO) 3 Cl, and FcRe(CO) 5 (Fc = ferrocenyl; Py = 4-pyridyl) have been synthesized and characterized for the purpose of investigating the tunability of the electron density on Re by changes in the redox state of the ferrocene center(s). The structures of (Fe-(C 5 H 4 PPh 2 ) 2 )Re(CO) 3 Cl and fac-(FcPPh 2 ) 2 Re(CO) 3 Cl were solved by X-ray crystallography

Intervalence transfer in pentammineruthenium complexes of .alpha.,.omega.-dipyridyl polyenes

Abstract: Preparation de complexes dinucleaires, du ruthenium (II) pontes par des ω,ω-dipyridylpolyenes. Spectrometrie UV visible et proprietes electrochimiques: obtention d'un compose a valence mixte par oxydation progressive du ruthenium (II)

Efficient reduction of dioxygen with ferrocene derivatives, catalyzed by metalloporphyrins in the presence of perchloric acid

Abstract: Reduction of dioxygen with ferrocene derivatives (Fc) is catalyzed by metalloporphyrins (MTPP + : M = Co, Fe, Mn; TPP = tetraphenylporphyrin) or Co(TIM) 3+ (TIM: a tetraaza macrocyclic ligand) in the presence of HClO 4 in acetonitrile (MeCN)

(. mu. -1,1 prime -Bis(diphenylphosphine)ferrocene)bis(chlorogold): Synthesis, iron-57 and gold-197 Moessbauer spectroscopy, x-ray crystal structure, and antitumor activity

Abstract: The title compound 2, Fdpp(AuCl){sub 2}, synthesized via the addition of Fdpp (1) to an aqueous solution of ((HOCH{sub 2}CH{sub 2}){sub 2}S)AuCl generated in situ by the thiodiglycol reduction of HAuCl{sub 4} showed a {sup 31}P({sup 1}H) NMR chemical shift at {delta} 27.39, which was downfield from that of 1 at {delta} -17.34 relative to (CH{sub 3}O)PO. The {sup 57}Fe Moessbauer spectrum of 2 is a doublet with parameters (IS = 0.50 mm/s relative to Fe, QS = 2.33 mm/s) similar to those of ferrocene. The {sup 197}Au Moessbauer spectrum of 2 is an asymmetric doublet (QS = 6.93 mm/s) with an IS of 3.81 mm/s relative to Au metal. Fdpp(AuCl){sub 2} crystallized in space group P{bar 1} with lattice constants a = 16.192 (4) {angstrom}, b = 16.921 (4) {angstrom}, and c = 10.878 (5) {angstrom} with Z = 3. Two crystallographically independent molecules, A and B, were observed in the structure of 2 with a chloroform solvate molecule per 1.5 formula units of the gold complex. For A, the P atoms are 180{degree} opposed and the rings exactly staggered, while in B the P atoms are 150{degree} apart and the rings are partially staggered. The P-Au-Cl linkage ismore » nearly linear, and the bond distances fall within normal ranges. Evaluation in an ip P388 leukemia mouse model showed 1 and 2 to have only marginal activity with an increased life span (ILS) relative to untreated controls of 30% at a maximally tolerated dose (MTD) of 231 {mu}mol/kg and 40% ILS at 4 {mu}mol/kg, respectively. 27 refs., 4 figs., 3 tabs.« less

Ligand design for complexation in aqueous solution. 1. Neutral oxygen donor bearing groups as a means of controlling size-based selectivity for metal ions

Abstract: Complexation d'ions de metaux alcalino-terreux, de Cd 2+ , Ni 2+ , Cu 2+ , Pb 2+ et K + avec une serie d'ethers couronnes substitues. Determination des constantes de formation et de protonation. Etude radiocristallographique d'un complexe de K +

Oxomolybdenum(IV,V,VI) Complexes: Structures, Reactivities, and Criteria of Detection of Binuclear (μ-oxo)molybdenum(V) Products in Oxygen Atom Transfer Systems

Abstract: A series of dioxo-Mo(VI) Schiff base complexes of the type MoO 2 (R-L)(solv) has been prepared: L=2-(salicylideneamino)-phenolate(2-) (sap) or 2-(salicylideneamino)benzenethiolato(2-) (ssp); solv=solvent. Salicylidene ring substituents R were selected to promote solubility and crystallinity. The unsubstituted complexes MoO 2 (sap)(solv) and MoO 2 (ssp)(solv) have been previously reported. The structures of two members of the series were determined

Oxidation chemistry of ruthenium-salen complexes

Abstract: The synthesis of [Ru III (salen)(X)(Y)] n [n=1, (X)(Y)=(CN) 2 ; n=0, (X)(Y)=(PPh 3 )(PBu 3 ), (PPh 3 )(py); n=1, (X)(Y)=(PPh 3 )(N 3 ), (PPh 3 )(TsO) (TsO=tosylate anion) from [Ru III (salen)(PPh 3 )(Cl)] is described. These ruthenium(III) complexes are dark green air-stable solids. Their cyclic voltammograms display reversible Ru(IV)/Ru(III) and Ru(III)/Ru(II) couples. At room temperature, they catalyze oxidation of alkenes by PhIO. With norbornene and cyclooctene, epoides are formed. The mechanism of the catalytic oxidation is discussed

New synthetic cobalt Schiff base complexes as oxygen carriers

Abstract: The synthesis and dioxygen affinities of ten new cobalt Schiff base complexes and two new cobalt complexes obtained by reduction of Schiff bases are reported and compared in a common solvent with two well-known parent Schiff base complexes and six Schiff base complexes recently reported

Ferromagnetic phase transitions of two one-dimensional ferrimagnets formed by manganese(II) and nitronyl nitroxides cis octahedrally coordinated

Abstract: The antiferromagnetic coupling constant has been estimated to be on the order of 260 cm −1 for both compounds. Low-field magnetic measurements reveal that both compounds undergo a magnetic phase transition at 8.1 and 8.6 K for I and II, respectively. The magnetization curves indicate that the transition is ferromagnetic. The magnetic anisotropy, which is of the Ising type, is originated mainly by the dipolar interaction between manganese and radical. The EPR spectra at room temperature do not show the typical behavior of one-dimensional systems due to the fact that the chains are not linear but zigzag; however, effects due to short-range order are visible in the EPR resonance fields on lowering the temperature

Acid-base behavior in the ground and excited states of ruthenium(II) complexes containing tetraimines or dicarboxybipyridines as protonatable ligands

Abstract: Reference LPI-ARTICLE-1989-024doi:10.1021/ic00322a015View record in Web of Science Record created on 2006-02-21, modified on 2016-08-08

NMR Study of the reactions of the cis-diamminediaquaplatinum(II) cation with glutathione and amino acids containing a thiol group

Abstract: 195Pt, 15N, 1H, and 13C NMR spectra have been used to study the reactions between cis-Pt(NH 3) 2(H 2O) 22+ (1) and amino acids containing a thiol group. N-Acetyl-L-cysteine, DL-homocysteine, and glutathione each form a dinuclear complex containing a Pt 2S 2 four-membered ring. Ammonia is slowly lost from these complexes. L-Cysteine (cysH 2) gives a similar complex, together with smaller quantities of cis-Pt(NH 3) 2(SCH 2CH(NH 3)(CO 2H)) 2 2+ and Pt(NH 3) 2(cysH-N,S) +. Penicillamine (penH 2) with 1 in strongly acidic solution gives initially the complex [{Pt(NH 3) 2} 2(penH)] 3+, in which the two Pt atoms are bridged by sulfur and carboxylate. After standing, this complex isomerizes to one in which sulfur still bridges the two Pt atoms, but with one also coordinated by ammine nitrogen and the other by carboxylate oxygen.

Pillaring of layered titanates by polyoxo cations of aluminum

Abstract: Preparation d'un compose d'intercalation du tetratitanate avec [Al 13 O 4 (OH) 24 (H 2 O) 12 ] 7+ par echange cationique, a partir de titanates d'ammonium quaternaires. Analyse par diffraction RX, spectrometrie IR et thermogravimetrie