Unusual dodecahedral coordination in the structure of ammonium tetrakis[4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione]praseodymate(III) monohydrate, NH4Pr(C8H4F3O2S)4.H2O

Chiroptical Spectra of Tetrakis (+)‐3‐Heptafluorobutylrylcamphorate Ln(III) Complexes with an Encapsulated Alkali Metal Ion: Solution Structures as Revealed by Chiroptical Spectra

“…24 (+)-Hhfbc(0.84 mmol) was dissolved in 8 ml of EtOH and was deprotonated by NH 3 aq (28%). Eu(OAc) 3 ·4H 2 O (0.28 mmol) dissolved in EtOH (2 ml) and H 2 O (1 ml) was added.…”

“…This is confirmed by the X-ray structures of most tetrakis(β-diketonato) lanthanide(III) complexes and molecular mechanics calculations. 20 Additionally, there are some examples of configurationally chiral tetrakis(β-diketonato) Ln(III) complexes such as enantiomeric pairs of DD- D 2 -( gggg )-8-Cs[Y(hfac) 4 ], 21,22 –Cs[Eu(hfac) 4 ], 23 –NH 4 [Pr(ttf) 4 ] (ttf, thionyltrifluoroacetonate), 24 –(Hpip)[Gd(BA) 4 ]) (Hpip, piperidinium and BA, benzoylacetyacetonate), 25 and SAPR- D 2 -( ssss )-8-(Et 3 NH)[Eu(dbm) 4 ] (dbm, dibenzoylmethanate) 26 (Scheme 1). On the other hand, labile tris- or tetrakis-(chiral β-diketonato) Ln(III) complexes such as (+)-hfbc((+)-3-heptafluorobutyrylcamphorate) or (+)-tfac((+)-3-trifluoroacetylcamphorate) (Scheme 2) have been extensively utilized for chiral discrimination by nuclear magnetic resonance (NMR) 6 and chiroptical techniques consisting of CD or circularly polarized luminescence (CPL).…”

The structure of N-methylpyridinium iodide

“…A weighting scheme was then determined by an analysis of variance (Lalancette, Cefola, Hamilton & La Placa, 1967) With the hydrogen atoms held invariant and assigned isotropic temperature factors of 4.0 A 2, and all other atoms allowed anisotropic thermal motion, the refinement converged to values of R F = 0.066, R w = 0.086 {R w = l/2}; the estimated standard deviation of an observation of unit weight = 1.44, and the scale factor --2.78. The scale factor was found to be highly correlated with the I diagonal thermal parameters as evidenced by correlation coefficients of 0.614, 0.573 and 0.588 between the scale factor and fl~ ~, fl22, fl3s, respectively.…”

Structure of (±)-cis-pinonic acid

“…= 1.022, max. = 1.049; 2Oma x = 60 ° (0 _< h _< 15, 0 ___ k_ 16, -12 _< l___ 12); three standard reflections were recorded every 27 reflections (_+ 1.5%), 3204 reflections measured in 8-20 scan mode, 3065 unique, 335 rejected by profile scan (Gliek, 1975), 538 unobserved with I < 3a, 2048 with I _> 3a(/); structure solved with MULTAN80 (Main, Fiske, Hull, Lessinger, Germain, Declereq & Woolfson, 1980), all non-H atoms found from best E map (CFOM = 3.00); H positions found in difference Fourier maps; H-atom positional parameters refined, B's constant at B n + 1, where n is the atom to which the H is bound; all non-H atoms refined with anisotropic thermal parameters; (Main et al, 1980); refinement and Fourier analysis -LINUS (Andrews, 1974, from ORFLS, Busing, Martin & Levy, 1962); Fourier analysis and difference maps -FORDAP (Zalkin, 1962); analysis of variance -NANOVA (Lalancette, Cefola, Hamilton & La Placa, 1967); bond-distance and bond-angle error analysis -ORFFE (Busing, Martin & Levy, 1964); graphics -OR TEPII (Johnson, 1970).…”