40]nonaphyrin(1.1.1.1.1.1.1.1.1) and its heterometallic complexes with palladium-carbon bonds

meso-Pentafluorophenyl- substituted [40]nonaphyrin(1.1.1.1.1.1.1.1.1) 3 has been prepared by using a stepwise ring-size-selective synthesis, and has been reduced with NaBH(4) to [42]nonaphyrin(1.1.1.1.1.1.1.1.1) 5. Structurally, 3 is characterized by a figure-of-eight shape, consisting of a porphyrin-like tetrapyrrolic segment and a hexaphyrin-like hexapyrrolic segment, whereas 5 has been found to adopt a distorted nonplanar butterfly-like shape. In the mono-metal complexes 6 and 7, a Zn(II) or Cu(II) ion is bound by the porphyrin-like tetrapyrrolic segment, maintaining the overall structure of 3. Similarly to 3, complexes 6 and 7 are interconvertible with the corresponding complexes 9 and 10 through two-electron reduction with NaBH(4) and oxidation with DDQ. The metal-free hexaphyrin-like segments of 6 and 7 have been shown to serve as a suitable platform for the complexation of two palladium ions, providing hetero-trinuclear metal complexes 11 (Zn(II)-Pd(II)-Pd(II)) and 13 (Cu(II)-Pd(II)-Pd(II)) in high yields, in which the Zn or Cu ion resides at the same porphyrin-like segment, and one Pd ion is bound in an NNCC fashion through double C--H bond activation while the other is bound in an NNC fashion with single C--H bond activation. Multi-metal complexes 11, 12, and 13 exhibit small electrochemical HOMO-LUMO gaps (<0.6 eV), despite their nonplanar conformations.     

New heterometallic coordination polymers based on zinc(II) complexes with Schiff-base ligands and dicyanometallates: synthesis,crystal structures,and luminescent properties

Four new d¹⁰ heterometallic coordination polymers have been obtained using three Schiff-base ligands, zinc(II) nitrate, and dicyanometallates: ₁^∞[{Zn₃(Salen)₂}{μ-Au(CN)₂}₂] (1); ₁^∞[Zn(Saldmen){μ-Ag(CN)₂}]·2H₂O (2); ₁^∞[Zn(Salampy){μ-Ag(CN)₂}] (3); ₁^∞[Zn(Salampy){μ-Au(CN)₂}] (4). The Schiff bases are obtained from condensation of salicylaldehyde with ethylenediamine (H₂Salen); N,N-dimethyl-ethylenediamine (HSaldmen) and, respectively, 2-aminomethyl-pyridine (HSalampy). The dicyanometallates are K[Ag(CN)₂] and K[Au(CN)₂]. The compounds were characterized by X-ray single-crystal diffraction, infrared spectroscopy, UV–vis spectroscopy, and elemental analysis. In compound 1, the homotrimetallic units, {Zn₃(salen)₂}²⁺, are connected by two [Au(CN)₂]^? bridges, forming a 1-D double chain. In compounds 2–4, the crystal structures show polymeric zigzag chains generated by the mononuclear zinc(II) nodes and [M(CN)₂]^? spacers. The luminescence properties of the new heterometallic polymers have also been investigated.     

Synthesis and characterization of Li(I)-M(II) (M = Co, Ni) heterometallic complexes as molecular precursors for LiMO2

Lithium-containing heterometallic complexes with cobalt (Li₂Co₂(Piv)₆(2,4-Lut)₂ (2, Piv is the pivalate anion) and Li₂Co₂(O₂CCH₂Bu^t)₆(2,4-Lut)₂ (3)) and with nickel (Li₂Ni₂(Piv)₆(DME)₂ (4) and Li₂Ni₂(Piv)₆(2,2′-bpy)₂ (5)) were synthesized. The structures of the complexes were established by X-ray diffraction. The magnetic properties of complexes 2 and 4 were studied. The thermal behavior of compounds 2, 3, and 5 was investigated. It was shown that the compounds under study can be used as molecular precursors for the synthesis of lithium cobaltate and nickelate.     

Synthesis and structures of new heteronuclear cluster complexes [PPh4][Fe4Rh3Se2(CO)16] and [PPh4]2[Fe3Rh4Te2(CO)15]

The reaction of the K₂[Fe₃Q(CO)₉] clusters (Q = Se or Te) with Rh₂(CO)₄Cl₂ under mild conditions is accompanied by complicated fragmentation of cores of the starting clusters to form large heteronuclear cluster anions. The [PPh₄][Fe₄Rh₃Se₂(CO)₁₆] and [PPh₄]₂[Fe₃Rh₄Te₂(CO)₁₅] compounds were isolated by treatment of the reaction products with tetraphenylphosphonium bromide. The structures of the products were established by X-ray diffraction. In both compounds, the core of the heteronuclear cluster consists of two octahedra fused via a common Rh₃ face. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 775–778, May, 2006.     

Synthesis,spectroscopic characterization,crystal and molecular structure of [ReOBr(hmquin-7-COOH)2] and [ReOCl(hmquin-7-COOH)2] · MeCN complexes. DFT and TD-DFT calculations for [ReOBr(hmquin-7-COOH)2]

Novel [ReOBr(hmquin-7-COOH)₂] (1) and [ReOCl(hmquin-7-COOH)₂] · MeCN (2 · MeCN) complexes have been prepared by treatment of [ReOX₃(AsPh₃)₂] with an excess of 8-hydroxy-2-methylquinoline-7-carboxylic acid in acetonitrile. The compounds were characterized structurally and spectroscopically. The electronic structure of 1 has been calculated with the density functional theory (DFT) method, and additional information about binding has been obtained by NBO analysis. The UV–Vis spectrum of 1 has been discussed on the basis of TDDFT calculations.     

Kinetic Analysis of Thermogravimetric Data XXXII. DSC Study of Some [Co(Diox·H)2(amine)2]X and H[Co(Diox·H)2(N3)2] Type Complexes with Alicyclic α-dioximes

14 mixed Co(III) dioximine chelates of the types [Co(Diox·H)₂(amine)₂]X (X = Br, I, NO₃, ClO₄) and H[Co(Diox·H)₂(N₃)₂], respectively (Diox·H₂-1,2-cyclohexane dione dioxime (nyoxime), 1,2-cycloheptane dione dioxime (heptoxime) 1,2-cyclooctane dione dioxime (octoxime) were obtained and their thermal decompositions were studied in an argon atmosphere. After the dehydration of the crystallohydrates, both types of complexes exhibit 3 decomposition stages. For the [Co(Diox·H)₂(amine)₂]X type complexes (X = Br, I) the first endothermal stage is the substitution of an amine molecule for the external sphere anion and this process is followed by two exothermal decomposition stages. With H[Co(Diox·H)₂(N₃)₂] type complexes the first and third processes are relatively slow, but the second process is very fast, corresponding to a vertical portion of the TG curves. From the TG curves kinetic parameters were derived for 11 processes and the validity of a non-linear compensation law was observed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effect of the rigidity and flexibility features of 2-pyridinyl or 8-quinolinyl based N-N chiral ligands on the stereochemical properties of [Pd(N-N)Cl2] complexes

The [Pd(N-N^∗)Cl₂] complexes have been obtained, as yellow solids, in almost quantitative yields; N-N^∗ indicate bidentate chiral ligands (S_a)-1, (S_a)-2, (S,S)-3, (R,R)-4, containing the rigid 2-pyridinyl or 8-quinolinyl building block skeleton and the C₂-symmetric chiral framework trans-2,5-dimethylpyrrolidinyl or (S)-(+)-2,2′-(2-azapropane-1,3-diyl)-1,1′-binaphthalene. The ligands pairs have the same C₂-symmetric chiral framework but different building block skeleton, beyond that for the basicity in the N-donor atoms, for rigidity and flexibility features. The N-N^∗ ligands act as chelating ligands leading a square planar geometry. The compounds [Pd(S,S-3)Cl₂] and [Pd(R,R-4)Cl₂] have been also characterised by X-ray diffraction. The rigidity and flexibility features of (S,S)-3 and (R,R)-4 ligands induce a different orientation of the trans-2,5-dimethylpyrrolidinyl moiety with respect to the pyridinyl and quinolinyl plane. This work shows that intrinsic rigidity and flexibility are not enough to define the ligand properties and to preview the effects that they induce on the reactivity of the metal complex.     

Transition-Metal-Substituted Gallanes: Synthesis and Spectroscopic Studies of Highly Polar σ(M—Ga) Bonds,Structures of trans-(Ph3P)(CO)3Co—Ga[(CH2)3N(C 2H5)2]R (R = Cl,CH3) and (n5-C5H5)(CO)2Fe—GaCl2 [N(CH3)3]

The salt elimination reaction of the transition carbonyl metal-lates [L(CO)_nM](Na/K) (M = Cr, Mo, W, Mn, Re, Fe, Co, Ni; L= CO, n⁵-C₅R₅, PR₃; n= 1-4; R= alkyl, aryl) with the base-stabilized galliumhalides Cl_aGaR₃ -a(Do) (R = H, alkyl, halide; Do = THF, N(CH₃)₃, NC₇H₁₃) or Cl_aGa[(CH₂)₃N-R₂](R)₂ - _a yielded almost quantitatively the transition metal-substituted, gallanes [L(CO)_nM]_aGaR₃ - _a(Do) and [L(CO)_n-M]_aGa[(CH₂)₃NR₂](R)₂ - _a, respectively. Residual halide functionalities in these complexes were selectively replaced by various other groups. The new compounds were characterized by means of elemental analysis, ¹H-, ¹³C-, ³¹P-NMR, MS, and lR v(CO) data. The single-crystal X-ray structure analysis of trans-(Ph₃P)(CO)₃Co-Ga[(CH₂) ₃N(C₂H₅)₂](R)( 6s : R = Cl, 6t : R= CH₃) showed s̀(Co-Ga) lengths of 237.78(4) and 249.5(1) pm, respectively. A short s̀(Fe-Ga) contact of 236.18(3) pm was found for (n⁵-C₅H₅)(CO)₂Fe-Ga-Cl₂[N(CH ₃)₃] ( 5a ). Low-pressure MOCVD experiments were performed to give thin films of analytically pure CoGa alloy.     

Fullerene complexes with bis(η6-hexamethylbenzene)chromium, hexamethylbenzene, and hexaethylbenzene

The [60]fulleride of bis(η-hexamethylbenzene)chromium(I) [(η⁶-C₆Me₆)₂Cr]^⋅+[C₆₀]^⋅−, and the complexes C₆₀·C₆Me₆ and C₆₀·C₆Et₆ were synthesized. Thermal decomposition of [(η⁶-C₆Me₆)₂Cr]^⋅+[C₆₀]^⋅− was studied. The molecular structures of C₆₀·C₆Me₆ and C₆₀·C₆Et₆ were determined. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 220—224, February, 2006.     

New N-pyrazole, P-phosphinite hybrid ligands and corresponding Rh(I) complexes: X-ray crystal structures of complexes with [Rh, N, P-phosphinite, Cl, (CO)] core

Two new N-pyrazole, P-phosphinite hybrid ligands 3-(3,5-dimethyl-1H-pyrazol-1-yl)propyldiphenylphosphinite (L³) and 2-(3,5-diphenyl-1H-pyrazol-1-yl)ethyldiphenylphosphinite (L⁴) are presented. The reactivity of these ligands and two other ligands reported in the literature (3,5-dimethyl-1H-pyrazol-1-yl)methyldiphenylphosphinite (L¹) and 2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyldiphenylphosphinite (L²) towards [RhCl(CO)₂]₂ (1) have been studied and complexes [RhCl(CO)L] (L = L² (2), L³ (3) and L⁴ (4)) have been obtained. For L¹ only decomposition products have been achieved. All complexes were fully characterised by analytical and spectroscopic methods and the resolution of the crystalline structure of complexes 2 and 3 by single-crystal X-ray diffraction are also presented. In these complexes, the ligands are coordinated via κ²(N,P) to Rh(I), forming metallocycles of seven (2 and 4) or eight (3) members and finish its coordination with a carbonyl monoxide and a trans-chlorine to phosphorus atom. In both complexes, weak intermolecular interactions are present. NMR studies of complexes 2-4 show the chain N-(CH₂)_x-O becomes rigid and the protons diastereotopic.     

Electrochemical insights into the mechanisms of proton reduction by [Fe2(CO)6{micro-SCH2N(R)CH2S}] complexes related to the [2Fe](H) subsite of [FeFe]hydrogenase

Electrochemical investigations on a structural analogue of the [2Fe](H) subsite of [FeFe]H(2)ases, namely, [Fe(2)(CO)(6){micro-SCH(2)N(CH(2)CH(2)- OCH(3))CH(2)S}] (1), were conducted in MeCN/NBu(4)PF(6) in the presence of HBF(4)/Et(2)O or HOTs. Two different catalytic proton reduction processes operate, depending on the strength and the concentration of the acid used. The first process, which takes place around -1.2 V for both HBF(4)/Et(2)O and HOTs, is limited by the slow release of H(2) from the product of the {2 H(+)/2 e} pathway, 1-2H. The second catalytic process, which occurs at higher acid concentrations, takes place at different potentials depending on the acid present. We propose that this second mechanism is initiated by protonation of 1-2H when HBF(4)/Et(2)O is used, whereas the reduction of 1-2H is the initial step in the presence of the weaker acid HOTs. The potential of the second process, which occurs around -1.4 V (reduction potential of 1-3H(+)) or around -1.6 V (the reduction potential of 1-2H) is thus dependent on the strength of the available proton source.     

Thermal deamination of some complexes of the type [CO(Diox·H)2 (Amine)2]X

The thermal deamination of [Co(diox·H)₂(amine)₂]X type complexes were studied in dynamic temperature conditions (diox·H₂ stands for 1,2-cycloheptanedione dioxime (heptoxime, heptox·H₂) and 1,2-cyclo-octanedione dioxime (octoxime, octox·H₂), amine for aniline and pyridine,X for Br, I and NCS). Kinetic parametersn, E and logZ have been derived for some derivatives by means of two computerized integral methods. The influence of the sample weight, heating rate and chemical constitution upon the kinetic parameters, as well as the kinetic compensation effect are discussed.

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Thermische Desaminierung einiger Komplexe des Typs [Co(Diox·H) ₂ (Amin₂]X. Über -Dioximinkomplexe der Übergangsmetalle, LXIV.

Zusammenfassung Die thermische Desaminierung einiger Komplexe des Typs [Co (Diox·H)₂(Amin)₂]X wurde bei dynamischen Temperaturbedingungen untersucht [Diox·H₂ bedeutet 1,2-Cycloheptandiondioxim, (Heptoxim, Heptox·H₂) und 1,2-Cyclooctandiondioxim (Octoxim, Octox·H₂), Amin bedeutet Anilin und Pyridin,X bedeutet Br, I, bzw. NCS]. Die kinetische Parametern, E und logZ wurden mit Hilfe von zwei computergeeigneten Integralmethoden bestimmt. Der Einfluß des Gewichtes der Proben, der Heizungsgeschwindigkeit und der chemischen Zusammensetzung auf die kinetischen Parameter, bzw. der kinetische Kompensationseffekt werden diskutiert.

     

Reaction of Ru3(CO)12 with 1,3-diferrocenylprop-2-ene-1-one. Crystal and molecular structures of the complexes Ru3(CO)8(FcC=CHCOFc)2 and [Ru(CO)2Cl(FcC=CHCOFc)]2

The reaction of Ru₃(CO)₁₂ with 1,3-diferrocenylprop-2-en-1-one,trans-FcCH=CHCOFc (where Fc is ferrocenyl), in boiling hexane afforded the complex (2c), which was converted into (3c) upon further heating. These complexes gave the complex (4) containing two Cl-bridged oxaruthenacycles upon dissolution in CHCl₃ or CH₂Cl₂. The structures of complexes 3 and 4 were established by X-ray diffraction analysis. According to the data of¹H NMR spectroscopy, the Cl-bridged complex exists in solutions as a mixture of isomers along with the monomeric form resulting from the cleavage of the halide bridges. All interconversions of the isomers occur with the participation of the monomeric form. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1616–1623, September, 2000.     

Influence of the cation on the properties of binuclear iron nitrosyl complexes. Synthesis and crystal structure of [Pr4 nN]2[Fe2S2(NO)4]

The binuclear nitrosyl complexes Q₂[Fe₂S₂(NO)₄], where Q=Me, Et, Prⁿ, and Buⁿ, were synthesized. The crystals of [Pr₄ ⁿN]₂Fe₂S₂(NO)₄ were studied by X-ray analysis. The influence of the cation size on the electronic structure and symmetry of its local environment in the synthesized complexes was examined. The decrease in the isomeric shifts in the⁵⁷Fe Mössbauer spectra is related to the increase in the length of the alkyl substituent chain of the quaternary tetraammonium cation and is consistent with changing the structural parameters: a decrease in the bond angle of the Fe?NO bond and stretching vibrations of the NO groups due to changes in intermolecular contacts.     

Synthesis,structures and magnetic properties of nickel bis (dithiolene) complexes with [Fe(qsal)2]+

Two new compounds containing the possible Fe(III) spin-crossover cation, [Fe(qsal)₂]⁺ (qsalH = N-(8-quinolyl)salicylaldimine), and nickel bis(dithiolene) anions have been synthesized. Both are 1 : 1 salts [Fe(qsal)₂][Ni(dddt)₂] · CH₃CN · CH₃OH (1) and [Fe(qsal)₂][Ni(pddt)₂] (2) (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate; pddt = 6,7-dihydro-5H-1,4-dithiepin-2,3-dithiolate). They have been characterized by X-ray crystal structure determination, elemental analysis, UV-Vis spectra and magnetic susceptibility measurements. The UV–Vis spectra are dominated by [Ni(L)₂]^? (1, L = dddt; 2, L = pddt). Magnetic studies show antiferromagnetic interaction in 1 from intermolecular S···S contacts and π–π stacking interactions, while the antiferromagnetic interaction in 2 is very weak.     

Synthesis,molecular and electronic structure of [ReCl2(N2COPh)(C4N2H4)(PPh3)2]

A new organodiazenido rhenium complex, [ReCl₂(N₂COPh)(C₄N₂H₄)(PPh₃)₂] has been obtained from the direct reaction of [ReCl₂(η²–N₂COPh–N′,O)(PPh₃)₂] with pyrazine in acetone. The complex has been characterized by spectroscopic methods and its structure determined using single-crystal X-ray diffraction techniques.