Polypyridines, Picrates, Lanthanides: A Plethora of Stacks?

2020 ◽  
Vol 73 (6) ◽  
pp. 529
Author(s):  
Eric J. Chan ◽  
Simon A. Cotton ◽  
Jack M. Harrowfield ◽  
Brian W. Skelton ◽  
Alexandre N. Sobolev ◽  
...  
Keyword(s):  
Nitro Group ◽  
The Other ◽  
Molar Ratio ◽  
Lanthanide Ion ◽  
X Ray ◽  
The Third ◽  
Group Oxygen ◽  
Structure Determinations ◽  
Lighter Lanthanides ◽  
Trigonal Prismatic

Reactions of the lanthanide(iii) picrates (picrate=2,4,6-trinitrophenoxide=pic) with 1,10-phenanthroline (phen) and 2,2′:6′,2′′-terpyridine (terpy) in a 1:2 molar ratio have provided crystals suitable for X-ray structure determinations in instances predominantly involving the lighter lanthanides. In all, the aza-aromatic ligands chelate the lanthanide ion, none being found as ‘free’ ligands within the lattice. The complexes of 1,10-phenanthroline have been characterised in two forms, one unsolvated (Ln=La, Sm, Eu; monoclinic, C2/c, Z 8), one an acetonitrile monosolvate (Ln=Gd; monoclinic, P21/a, Z 4), the latter being the only previously known form (with Ln=La). In both forms, the LnIII is nine-coordinate, in an approximately tricapped trigonal-prismatic environment, with two picrate ligands chelating through phenoxide and 2-nitro group oxygen atoms, the third being bound through phenoxide-O only. The 2,2′:6′,2′′-terpyridine complexes, all acetonitrile monosolvates defined for Ln=La, Gd, Er, and Y (monoclinic, C2/c, Z 4), are ionic, one picrate having been displaced from the primary coordination sphere. For Ln=La, the two bound picrates are again chelating, making the LaIII 10-coordinate in a distorted bicapped square-antiprismatic environment but in the other species they are bound through phenoxide-O only, making the LnIII ions eight-coordinate in a distorted square-antiprismatic environment. Stacked arrays of the ligands can be found in both series of complexes, with intramolecular picrate–picrate and picrate–aza-aromatic stacks being prominent features.

Structural Studies of Alkaline Earth Metal Picrates

1995 ◽  
Vol 48 (7) ◽  
pp. 1333 ◽  
Author(s):  
JM Harrowfield ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Nitro Group ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Linear Polymer ◽  
Alkaline Earth Metal ◽  
Water Molecules ◽  
X Ray ◽  
Main Group Metal ◽  
Group Oxygen ◽  
Structure Determinations

Room-temperature, single-crystal X-ray structure determinations are recorded for alkaline earth metal picrates , M( pic )2.nH2O(M = Mg, Sr , Ba ; Hpic = 2,4,6-trinitrophenol, HOC6H2(NO2)3), all crystallized from aqueous solution. Magnesium picrate ,shown to be the nonahydrate, Mg( pic )2.9H2O, forms monoclinic crystals, space group P21/c, a 15.023(3), b 6.718(4), c 26.516(2) Ǻ, β 109.55(1)°, Z = 4 f.u .,conventional R on |F| was 0.049 for No = 4062 'observed' (I > 3σ(I)) reflections. The structure, unusually among the main group metal picrates studied so far, has no coordinative interaction between the metal and the picrate anion; the complex may be formulated as [Mg(OH2)6] ( pic )2.3H2O, with the metal present as the hexaaqua species (Mg-O 2.043(2)-2.077(2)Ǻ). The picrate ions are stacked end to end, presumably as a result of charge-transfer interactions, parallel to b, with side-by-side stacks forming a sheet along ab, and successive sheets are interleaved by layers of cations and water molecules. The strontium salt is a pentahydrate , monoclinic, C2/c, a 24.515(6), b 10.142(6), c 17.932(4) Ǻ, β 98.76(2)°, Z = 8 f.u .; R was 0.046 for No 2731. The complex is a linear polymer, [(H2O)3Sr(O,O′- pic )2(μ-OH2)](∞|∞).H2O, with eight-coordinate (SrO8) strontium. The barium salt is a hexahydrate , also a linear polymer [(H2O)5Ba(O,O′-pic )( O,O′,μ-O″-pic )]∞|∞).H2O, the ten-coordinate (BaO10) barium environment comprising the five water molecules, a pair of picrates, bidentate /chelating via the phenolic oxygen and a 2-nitro group oxygen, with one of the picrates from an adjacent metal atom offering an additional 4-nitro group oxygen, this bridging successive barium atoms. The complex is triclinic, Pī , a 15.120(5), b 11.633(3), c 6.766(3) Ǻ, α 87.24(3), β 79.16(3), γ 84.88(2)°, Z = 2 f.u .; R was 0.027 for No 3904. Repeated attempts to obtain crystals of beryllium picrate suitable for an X-ray structure determination were unsuccessful.

Oxidfluoridsulfide der Lanthanoide vom Formeltyp M3OF5S (M = Nd, Sm, Gd–Ho) / Oxide Fluoride Sulfides of the Lanthanoids with the Formula M3OF5S (M = Nd, Sm, Gd–Ho)

2011 ◽  
Vol 66 (3) ◽  
pp. 213-220
Author(s):  
Hagen Grossholz ◽  
Oliver Janka ◽  
Thomas Schleid
Keyword(s):  
Crystal Structure ◽  
Electron Beam ◽  
Single Crystal ◽  
The Other ◽  
Molar Ratio ◽  
Hexagonal Crystal Structure ◽  
Hexagonal Crystal ◽  
X Ray ◽  
Phase Pure ◽  
Trigonal Prismatic

First attempts to synthesize a lanthanoid(III) oxide fluoride sulfide were successful by reacting DyF3 and Dy2O3 with dysprosium and sulfur in a 2 : 5 : 1 : 3 molar ratio at 850 ◦C in tightly sealed tantalum ampoules. In analogy to the dysprosium compound Dy3OF5S, the other representatives of the M3OF5S series with M = Nd, Sm, Gd-Ho could be prepared as well. Almost phase-pure samples were obtained under similar flux-assisted (NaCl) conditions according to 2M +5MF3 +M2O3 + 3S →3M3OF5S. In the hexagonal crystal structure (space group: P63/m; a ≈ 961 - 939 pm, c ≈ 378 - 367 pm; c/a≈0.39,Vm ≈91 - 84 cm3 mol−1, Z = 2), the M3+ cations reside in ninefold anionic coordination realized as tricapped trigonal prisms formed by seven light (O2−/F−) and two heavier S2− anions. One light-anion position exhibits the exclusive character of F− in trigonal non-planar coordination (CN = 3), while the other position with a tetrahedral cationic environment (CN = 4) is mixed occupied by F− and O2− in a 2 : 1 ratio. The S2− anions are coordinated in a trigonal prismatic way by six M3+ cations. From the data of single-crystal X-ray structure analyses, no indication of any ordering for the O2− and F− anions could be obtained, but bond-valence and MAPLE calculations confirmed the results of electron-beam microanalyses carried out earlier to reveal ordered models for Dy3OF5S.

Structural Systematics of Lanthanide(III) Picrate Solvates: Neutral, Mononuclear Ln(pic)3(dimethylsulfoxide)3 Arrays

2020 ◽  
Vol 73 (6) ◽  
pp. 447
Author(s):  
Zouhair Asfari ◽  
Eric J. Chan ◽  
Jack M. Harrowfield ◽  
Brian W. Skelton ◽  
Alexandre N. Sobolev ◽  
...  
Keyword(s):  
Single Crystal ◽  
Metal Atom ◽  
Molecular Species ◽  
The Other ◽  
Triangular Face ◽  
Hydrated Form ◽  
X Ray ◽  
Tricapped Trigonal Prism ◽  
Structure Determinations ◽  
Trigonal Prismatic

Adducts of dimethylsulfoxide, dmso=Me2SO, with lanthanide(iii) picrates (picrate=2,4,6-trinitrophenoxide, pic) of stoichiometry Ln(pic)3·3dmso have been prepared and characterised by single-crystal X-ray structure determinations as discrete, neutral, mononuclear molecular species. Such complexes have been obtained across the gamut of Ln, specifically for Ln=La, Pr, Nd, Sm, Gd, Dy, Yb, Lu, and Y, presumably also accessible for other intermediate members, the series being isomorphous (monoclinic, C2/c, Z=8); a second triclinic P form has also been identified for Ln=La, Pr. In both forms, the metal atom coordination environments are nine-coordinate, tricapped trigonal prismatic, [Ln(dmso-O)3(pic-O,O′)3], two of the three unidentate ligands lying in one of the trigonal planes and one in the other (an isomer we have termed meridional, mer). A hydrated form of Ln(pic)3·2dmso·H2O stoichiometry has also been defined for Ln=Sm, Gd, Lu, the metal atom environment again nine-coordinate, [Ln(dmso-O)2(H2O)(pic-O,O′)3], but now fac, with the three unidentate ligands occupying one triangular face of the tricapped trigonal prism and involved in a centrosymmetric H-bonding array with the three similar ligands of an adjacent complex; the three capping atoms are nitro-oxygen atoms, the phenoxy-O triad occupying the other face.

Structural Systematics of 2/4-Nitrophenoxide Complexes of Closed-Shell Metal Ions. VII Acid Salts of the 4-Nitrophenoxides of Group 2

1998 ◽  
Vol 51 (8) ◽  
pp. 785 ◽  
Author(s):  
Jack M. Harrowfield ◽  
Raj Pal Sharma ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Room Temperature ◽  
Calcium Salt ◽  
Three Dimensional ◽  
Closed Shell ◽  
The Other ◽  
X Ray ◽  
C 23 ◽  
Structure Determinations ◽  
Group 2 ◽  
Acid Salts

Room-temperature single-crystal X-ray structure determinations are recorded for a number of Group 2 4-nitrophenoxide acid salts, variously hydrated M(4-np)2.x(4-npH).yH2O. Ca(4-np)2.2(4-npH).8H2O is monoclinic, P 21/n, a 30·52(1), b 10·027(1), c 23·65(2) Å, β 116·3(5)°, Z = 8, conventional R on |F| being 0·058 for No 5092 independent ‘observed’ (I > 3s(I)) reflections. Sr(4-np)2.2(4-npH).8H2O, based on a subcell of the former, is monoclinic, P 21/c, a 15·576(5), b10·081(6), c 24·20(2) Å, β 117·99(5)° , Z = 4, R 0·054 for No 2908. Ba(4-np)2.2(4-npH).4H2O is orthorhombic, Fdd2, a 28·01(1), b 19·90(1), c 10·692(7)Å, Z = 8, R 0·028 for No 1967. The strontium array (and that of the calcium salt developed from it) may be represented as [(H2O)6Sr(4-npH.4-np)] (4-npH.4-np), a neutral ligand being unsymmetrically chelated to the strontium through the nitro group, with a quasi-parallel counter ion hydrogen-bonded to it by phenoxide confrontation. The other two 4-np residues make up a similar phenoxide-confronting pair (4-npH.4-np), the hydrogen being more intimately associated with one moiety. The barium salt is also an interesting array: the 10-coordinate barium lies on a crystallographic 2 axis, in an environment of two pairs of symmetry-related nitro-chelating ligand anions, and a pair of nitro-O coordinating neutral 4-npH ligands; the whole [(H2O)4Ba(4-np)2(4-npH)2] array may be envisaged as a single neutral (super)molecule. Hydrogen bonds between confronting phenoxides of the neutral 4-npH components of the parent and the 4-np- components of neighbouring molecules link the whole into a three-dimensional array.

Structure and Stereochemistry of Adducts of Tris(dipivaloylmethanato)europium(III), Eu(dpm)3, with Some Dipolar Aprotic Unidentate O-Donors

2020 ◽  
Vol 73 (6) ◽  
pp. 455
Author(s):  
Eric J. Chan ◽  
Jack M. Harrowfield ◽  
Brian W. Skelton ◽  
Alexandre N. Sobolev ◽  
Allan H. White
Keyword(s):  
Single Crystal ◽  
Dimethyl Sulfoxide ◽  
The Other ◽  
Asymmetric Unit ◽  
X Ray ◽  
Metal Atoms ◽  
Oxygen Donor ◽  
Trigonal Prismatic

Single crystal X-ray structural characterisations are reported for adducts of the form [(L-O)Eu(O,O′-dpm)3] obtained by the crystallisation of tris(dipivaloylmethanato)europium(iii) (dpm=[HC(C(tBu).CO)2]−) from an array of dipolar aprotic oxygen-donor solvents L (L=N-methylpyrrolidinone (nmp), trimethylphosphate, (MeO)3PO, (tmp), hexamethylphosphoramide (hmpa), dimethylacetamide (dma), dimethyl sulfoxide (dmso), and the bidentate octamethylpyrophosphoramide (ompa). In all adducts, the resulting arrays contain seven-coordinate metal atoms, which adopt two different isomeric forms of the mono-capped trigonal prismatic stereochemistry, the L=dma and dmso adducts corresponding to one type, nmp and tmp the other. The adduct formed with ompa behaves as a pair of discrete metal environments bridged by the O-ompa-O′ ligand, thus; [(dpm-O,O′)3Eu(O-ompa-O′)Eu(O,O′-dpm)3], and is found in two forms, one in which both Eu environments is of the tmp type, the other of the dmso/dma type. In the hmpa adduct, the asymmetric unit of the structure is a disordered composite of both types. In none of the adducts is there any further solvation beyond coordination of a single L.

One-dimensional ribbons of solvated Ag sulfonates

1999 ◽  
Vol 77 (3) ◽  
pp. 313-318 ◽  
Author(s):  
George KH Shimizu ◽  
Gary D Enright ◽  
Gabriela S Rego ◽  
John A Ripmeester
Keyword(s):  
Coordination Polymer ◽  
Single Crystal ◽  
The Other ◽  
Monoclinic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
One Dimensional ◽  
X Ray ◽  
Structure Determinations

Single crystal X-ray structure determinations of two solvated silver sulfonates have been obtained and these compounds have been shown to adopt infinite one-dimensional motifs. {AgOTs(MeCN)}[Formula: see text] (OTs = p-toluenesulfonate) crystallizes in the monoclinic space group, P21, a = 8.4278(5) Å, b = 5.7413(3) Å, c = 12.1057(7) Å, β = 109.24(1)°. {Ag(NDSA)(MeCN)2(H3O)(H2O)2}[Formula: see text] (NDSA = 1,5-naphthalenedisulfonate) crystallizes in the triclinic space group, P[Formula: see text], a = 8.3407(4) Å, b = 10.4374(5) Å, c = 12.3399(6) Å, α = 101.941(8)°, β = 109.24(1)°, γ = 102.190(8)°. Despite one compound containing a monosulfonate and the other a disulfonate, both complexes form infinite one-dimensional arrays.Key words: silver, sulfonates, coordination polymer.

Transmetalation reactions with nitrogen-containing "pincer"-class ligands on platinum(II) centers

2001 ◽  
Vol 79 (5-6) ◽  
pp. 709-718 ◽  
Author(s):  
Martin Albrecht ◽  
Stuart L James ◽  
Nora Veldman ◽  
Anthony L Spek ◽  
Gerard van Koten
Keyword(s):  
Ligand Binding ◽  
Platinum Complexes ◽  
Binding Mode ◽  
Unit Cell ◽  
The Other ◽  
Pincer Ligand ◽  
X Ray ◽  
Spectroscopic Analyses ◽  
Structure Determinations ◽  
Independent Molecules

The transmetalation reaction of the aryllithium compound [Li(NCN)]2 (NCN is the monoanionic "pincer" ligand [C6H3(CH2NMe2)2-2,6]-) with the cyclometalated arylplatinum complex [PtCl(NCN)] afforded the bisaryl platinum(II) complex [Pt(NCN)2] (3) containing one η3-N,C,N-terdentate and the other η1-C-monodentate-bonded pincer ligand. Spectroscopic analyses on 3 suggest that η3 to η1 interconversion of the ligand binding mode (or vice versa) is inhibited. Two independent X-ray structure determinations on crystals of 3 revealed the existence of a rare polymorph containing one and three crystallographically independent molecules, respectively, in the unit cell. A similar transmetalation reaction with lithium and platinum complexes containing heteroleptic NCNRR' ligands (NCNRR' is [C6H3(CH2NRR')-2,6]- with R = R' = Me or R = Me, R' = Et) pointed to the formation of a heterodinuclear cationic bisaryl platinum lithium species as an intermediate of a preequilibrium to the final transmetalation products, involving, rapid transcyclometalation (TCM) reactions. These TCM reactions comprise the exchange of the monoanionic NCNRR' ligands between the platinum(II) and lithium centers. A consequence of the latter properties is that the strong Pt—N bonds in [PtX(NCN)] complexes are considerably weakened by the presence of Li+ cations.Key words: transmetalation, transcyclometalation (TCM), platinum, bisaryl complex, polymorphism.

Lewis-Base Adducts of Group 11 Metal(I) Compounds. LIII. Synthesis and Structural Characterization of Binuclear μ,μ'-Dichloro-, Dibromo and Diiodo-bis[(pyridine)(triphenylphosphine)copper(I)] Complexes, and Their Pyridine-4-carbonitrile Analogues

1989 ◽  
Vol 42 (6) ◽  
pp. 913 ◽  
Author(s):  
LM Engelhardt ◽  
PC Healy ◽  
JD Kildea ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Structural Characterization ◽  
Lewis Base ◽  
The Other ◽  
X Ray ◽  
Structure Determinations ◽  
M Phase ◽  
And Inversion ◽  
Iodide Single Crystal

Mixed base pyridine (py)/triphenylphosphine adducts of the copper(1) halides, CuX, have been synthesized for 1 : 1 : 1 stoichiometry for X = chloride and iodide; single-crystal X-ray structure determinations of these show them to be isomorphous and isostructural with that of the bromide recorded elsewhere, being �,�′- dihalo-bridged dimers , [(PPh3)( py )CuX2Cu( py )(PPh3)], monoclinic, C2/c, a ≈ 26.2, b ≈ 14.3, c ≈ 11 .2 � , β ≈ 95, Z = 4 dimers. The bromide has been isolated as a new monoclinic C 2/m polymorph, a 11 .279(8), b 14.268(6), c 13.858(4) �, β 109.33(6)�, Z=4 dimers, and details of its structure are also recorded. The structures of their pyridine-4-carbonitrile (pycn) analogues have also been determined and found to be also binuclear, with no cyano-copper interactions; these also are an isomorphous, isostructural series, monoclinic P21/n, a ≈ 15.4, b ≈ 8.1, c ≈ 17.9 � , β ≈ 101 �, Z = 2 dimers. In each series of dimers, one half of the dimer is crystallographically independent, the generators of the other half being twofold rotor (C2/c phase), mirror (C2/m phase) and inversion centre (P21/n phase) respectively.

A re-examination of the fine structure of the walls of vesicles of the green alga Valonia

1958 ◽  
Vol 148 (931) ◽  
pp. 137-148 ◽  
Keyword(s):  
Fine Structure ◽  
Green Alga ◽  
The Other ◽  
Cellulose Microfibrils ◽  
X Ray ◽  
The Third ◽  
Right Hand ◽  
Valonia Ventricosa

The structure of the walls of vesicles of Valonia ventricosa and, to a less extent of other species, has been re-examined by the methods of X-ray analysis and electronmicroscopy, with particular reference to the criticism by Steward & Muhlethaler of the earlier statements of Preston & Astbury. It is shown that the cellulose microfibrils are present in three orientations, in separate lamellae. The third orientation, noted occasionally by Preston & Astbury but not recorded in their model, corresponds to microfibrils which are much less abundant than are those of the other two orientations both because the lamellae with this orientation are less frequent and because the microfibrils are more loosely packed in each lamella. The two ‘major’ directions ( A and B ) lie on an average at rather less than at right-angles to each other; the third direction ( x ) forms a bisector of this angle. The repeat from one lamella to the next can be . . . ABAB . . . or . . . AxB . . ., i.e. an interrupted two-lamella repeat, and not a three-lamella repeat as proposed by Steward & Muhlethaler. The structures of the walls of two whole vesicles have been worked out and give identical models. These are strictly equivalent to the model proposed by Preston & Astbury except that the third microfibril direction is present, making a rather steep right-hand spiral around the vesicle.

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