Ewa Gałdecka

Structure of a novel polynuclear europium compound with N-phosphonomethylglycine: heptaaquaperchloratodi-μ4-N-phosphonomethylglycine-dieuropium(III) triperchlorate monohydrate, [Eu2(HO3PCH2NH2CH2CO2)2(H2O)7(ClO4)]·3ClO4·H2O

The solid-state structure of the europium(III) complex with N-phosphonomethylglycine (PMG) has been obtained from aqueous solution, at pH ca. 1.6, where a 1:1 M:L molar ratio has been kept. The crystal structure of the [Eu2(HO3PCH2NH2CH2CO2)2(H2O)7(ClO4)]·3ClO4·H2O compound has been determined by single-crystal X-ray diffraction. In the structure of the title compound a two-dimensional polymer is formed, with an unexpected architecture. The oxygen atom of one of four perchlorate groups is engaged in the coordination besides that of the PMG groups. The glyphosate molecules are present as zwitterions. The polymeric chains are composed of two types of dimeric subunits. The first one is created by simple and chelating carboxyl bridges, and the second by phosphonate groups; in the latter type the dimeric unit coordination of metal ions is completed by two oxygen atoms of two perchlorate groups. In the first subunit four, and in the second subunit three water molecules are coordinated by each europium atom. The eighth water molecule and three of four perchlorate groups are outside the metal coordination. Therefore, two non-equivalent metal sites, eight- and nine-fold coordinated, exist in the structure. The structure is stabilized by an extended network of hydrogen bonds. The conformations of the two PMG molecules are quite different.

Crystal structure and optical properties of Ln(III) octahedral complexes with hexamethylphosphortriamide; [Ln(HMPA)6](ClO4)3

Abstract The neodymium and europium complexes with HMPA (hexamethylophosphortriamide O=P[N(CH 3 ) 2 ] 3 ) of formula Ln(HMPA) 6 (ClO 4 ) 3 were synthesized and obtained as monocrystals from non-aqueous solutions. The structure of the neodymium complex [C 36 H 108 N 18 O 18 P 6 Cl 3 Nd] has been determined by X-ray diffraction. It crystallizes in the cubic space group Fm3m , with the unit cell parameter a = 19.222(1) A. The structure was solved by direct method and refined using the anisotropic full-matrix least-squares method. The final R ( wR ) factors were 0.042 (0.049) for 468 observed reflections (3098 measured). Each metal ion is coordinated to six HMPA molecules through oxygen atoms of a PO group with Nd-O bond lengths of 2.340(8) A. Metal ions occupy symmetry centre in ideal octahedral ( O h ) symmetry. The three −N(CH 3 ) 2 groups statistically occupy four equivalent positions with an occupancy factor 3/4, which is reflected in the spectral properties of the complex. The compounds were characterized by IR, Raman, luminescence and absorption spectroscopy at 5, 77 and 293 K. Probabilities of electronic transitions for the Nd ion were analysed and compared with those for centrosymmetric single crystals with antipyrine with the formula: Nd(AP) 6 (ClO 4 ) 3 . The intensity of the hypersensitive transition of the title compound is lower, moreover a drastic decrease of intensities in the IR region is observed. Attention is focused on a vibronic transition occurring between crystal-field (electronic) levels with simultaneous excitation of phonon or vibrational modes (in the 7 F 0 → 5 D 2 excitation spectrum of Eu 3+ and 4 I 9/2 → 4 G 5/2 , 4 G 7/2 in the absorption spectrum of Nd 3+ ). Using the IR and Raman data of Ln(HMPA) 6 (ClO 4 ) 3 crystals, a preliminary assignment of vibronic lines was made.

Novel polynuclear compound of europium with N-phosphonomethylglycine : spectroscopy and structure

Abstract Phosphonic acid analogues of amino acids display interesting biological activities, the possible applications of which range from medicine to agriculture. Aminophosphonates are found in tissues as free compounds but their most frequent forms of occurrence include complex structures, such as lipids, proteins and polysaccharides [1] . For the first time, to our knowledge, lanthanide compounds with N-phosphonomethylglycine were obtained and analyzed by X-ray diffraction methods. The compound is polynuclear, with unexpected architecture, and crystallizes in the P21/c space group (cell parameters a=17.788(4) A, b=10.706(2) A, c=18.560(4) A, β=113.37(3)°, Z=4). Two nonequivalent metal sites exist in the structure. Both carboxyl and phosphonate groups of the ligand are involved in metal ion coordination forming two centrosymmetric dimers: one by the carboxyl (simple and chelating) bridges, and one by phosphonate groups. Moreover, in the latter dimer, coordination of metal ion is completed by three water molecules and one oxygen of perchlorate ion, thus the coordination number is 8. In the former dimer, additional water molecules are bonded and the coordination number of Eu becomes 9, with a little different distortion. The M–M distances are 4.012 and 5.940 A for carboxyl and phosphonic dimers, respectively. The compound was characterized by IR and electron spectroscopy methods. Absorption, excitation and emission spectra were measured down to 77 K. Electron transition probabilities and splitting of levels were analyzed and compared to the structural data. Assignment of the vibronic components in electronic transitions, which obey the selection rule ΔJ=0.2 was made on the basis of IR spectra.

New water-soluble rhodium(I) complexes containing 1-methyl-1-azonia-3,5-diaza-7-phosphaadamantane iodide

Reaction of [Rh2Cl2(CO)4] with stoichiometric quantities of 1-methyl-1-azonia-3,5-diaza-7-phosphaadamantane iodide (mtpa+I-) in MeOH and H2O yields square-planar [RhI(CO)(mtpa+I-)2] 1 and trigonal-bipyramidal [RhI(CO)(mtpa+I-)3]·4H2O 2, respectively. The complexes are stable in aqueous solution under inert atmosphere and catalyse the hydroformylation and the hydrocarboxylation of alkenes and the hydrogenation of aldehydes and alkenes. An X-ray crystallography study revealed that 2 has a TBPY-5 structure. The coordination around the Rh atom forms a nearly ideal trigonal bipyramid [a=15.705(3) A, b=13.219(3) A, c=20.894(4) A, monoclinic, space group P21/c, Z=4, β=110.72(3)°].

Structural, spectroscopic and catalytic properties of water-soluble hydride rhodium complexes [RhH(Rtpa+I−)4]H2O (R=Me, Et)

Abstract New rhodium(I) hydrido complexes [RhH(mtpa+I−)4]·H2O (1) and [RhH(etpa+I−)4]·H2O (2) (where mtpa+I−=1-methyl-1-azonia-3,5-diaza-7-phosphatricyclo[3.3.1.13,7]decane iodide, etpa+I−=1-ethyl-1-azonia-3,5-diaza-7-phosphatricyclo[3.3.1.13,7]decane iodide) have been synthesized and characterized using 1H, 31P NMR and IR spectra and X-ray crystallography. Both complexes have the trigonal-bipyramidal structure. The 1H NMR spectra indicate that in solutions the complexes have fluxional properties. The compounds are very stable in water under neutral atmosphere. They are efficient catalysts of hydrogenation of CC bonds in two-phase catalytic systems.

CARBONYL RUTHENIUM(III) COMPLEXES WITH 1,10-PHENANTHROLINE AND 2,2'-BIPYRIDINE

Abstract The reaction of ruthenium trichloride with 1,10-phenanthroline or 2,2′-bipyridine in formic acid leads to the formation of ruthenium(III) carbonyl complexes: [RuCl3(CO)(phen)], 1, and [RuCl3(CO)(bpy)], 2. The crystal structures of the complexes have been determined by single-crystal X-ray analysis. Both complexes have distorted octahedral structures with CO ligands in the trans coordination site relative to the nitrogen atom. The EPR spectra of complexes 1 and 2 dissolved in DMF have been investigated. For both compounds a hyperfine structure has been observed for g3 in the spectra.

Synthesis, reactivity and structure of [Ir4(μ-CO)3(CO)5(μ-PPh2pyl)(PPh2pyl)2]

Abstract Ir( 4 (CO) 12 reacts with P(Ph 2 pyl) 3 giving [Ir 4 (μ-CO) 3 (CO) 5 (μ-PPh 2 pyl)(PPh 2 pyl) 2 ] containing one phosphine bridging ligand coordinating via P and N atoms and [Ir 4 (μ-CO) 3 (CO) 6 (PPh 2 pyl) 3 ] which in solution is at equilibrium with the former cluster.

The Pr–Fe–Sn ternary system: phase diagram and crystal structure of PrFe0.4Sn2

Abstract The isothermal section of Pr–Fe–Sn system at 670 K has been investigated by EDAX and X-ray phase analysis. Two ternary compounds, Pr 6 Fe 13 Sn and PrFe 0.4 Sn 2 have been found. Crystal structure of the PrFe 0.4 Sn 2 compound was refined to be isotypic with CeNiSi 2 ( a =4.545(1) A, b =16.833(3) A, c =4.448(1) A).

Phase equilibria in the ternary systems Pr–Fe–Bi and Sm–Fe–Bi

Abstract Phase equilibria in the systems Pr–Fe–Bi and Sm–Fe–Bi were investigated by X-ray powder diffraction and the isothermal cross-sections at 400°C were obtained. The R 5 FeBi 2 compounds (R=Pr, Sm) of unknown crystal structure, stable within the temperature range from the melting temperature to 400°C have been found. The existence of the Pr 6 Fe 13 Bi and Sm 6 Fe 13 Bi compounds (Nd 6 Fe 13 Si structure type) in cast alloys has been confirmed, but they are not stable at the temperature of the heat treatment.

Structure and properties of di-μ-acetato-dichlorobis(2,2′-bipyridine)dirhodium(II)-trihydrate

Reduction of [Rh2(μ-OAc)2(bpy)2(H2O)2](OAc)2 and [Rh2Cl2(μ-OAc)2(bpy)2] · 3H2O complexes with ethanol and [Cr2(OAc)4(H2O)2] has been investigated using e.p.r. and u.v.–vis. spectra. The results indicate that stable complexes containing the [Rh23+] entity are not formed. The X-ray structure of [Rh2Cl2(μ-OAc)2(bpy)2] · 3H2O has been determined. Coordination around the Rh atom is in the form of a distorted octahedron. The complex shows an almost ideal eclipsed conformation. The equatorial coordination sites are occupied by bridging carboxylato ligands and 2,2′-bipyridine and axial positions by the Cl ligand and the rhodium atom. The Rh–Rh distance is 2.574 Å.