Lewis-Base Adducts of Group 11 Metal(I) Compounds. LVII. Crystal-Structure of Bis(2,6-diacetyl-pyridine)silver(I) Perchlorate

1989 ◽  
Vol 42 (8) ◽  
pp. 1381 ◽  
Author(s):  
SB Silong ◽  
LM Engelhardt ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Structural Characterization ◽  
Room Temperature ◽  
Bond Angle ◽  
Lewis Base ◽  
The Other ◽  
Tridentate Ligands ◽  
Coordination Spheres ◽  
Silver Atoms

The synthesis and room temperature structural characterization of the title compound [AgL2]+(C104)-, L= 2,6-diacetylpyridine, are reported. Crystals are orthorhombic, Pcan, a 19.629(7), b 14.603(4) and c 14.469(4) � , Z = 8; R was 0.050 for 1987 'observed' reflections. The structure contains two independent [AgL2]+ species, the central nitrogen atoms of the quasi-tridentate ligands being opposed in the coordination spheres of the silver atoms. Both have crystallographically imposed 2 symmetry; in one, this is normal to the N-Ag-N line [actual bond angle, 175.6(2); Ag-N, 2.316(6), Ag-O, 2.589(7) and 2.522(7) � ], relating the two ligands. In the other, it is coincident; for one ligand Ag-N and Ag-O are 2.285(8) and 2.500(8) � , while for the other the two values are 2.271(8) and 2.543(7) �. The silver-nitrogen distances are appreciably longer than the value of 2.166(4) � found for the [Ag( py )2]+ cation.

Structural Systematics of Rare Earth Complexes. VII. Crystal Structure of Bis(2,2'/6',2␛-Terpyridinium) Octaaquaterbium(III) Heptachloride Hydrate

1994 ◽  
Vol 47 (2) ◽  
pp. 391 ◽  
Author(s):  
CJ Kepert ◽  
BW Skeleton ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Single Crystal ◽  
Structural Characterization ◽  
Title Compound ◽  
Room Temperature ◽  
Chloride Ions ◽  
Full Matrix ◽  
X Ray

The room-temperature single-crystal X-ray structural characterization of the title compound (tpyH2)2[Tb(OH2)8]Cl7.~2⅓H2O is recorded. Crystals are triclinic, Pī , a 17.063(5), b 16.243(3), c 7.878(3) Ǻ, α 84.78(2), β 84.39(3), γ 87.81(2)°, Z = 2 formula units; 3167 'observed' diffractometer reflections were refined by full-matrix least-squares procedures to a residual of 0.057. Notable features of interest of the compound are the 'chelation' of chloride ions by the terpyridinium cations , and the existence of a free [Tb(OH2)8]2+ cation in the presence of an abundance of chloride ions.

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.

Synthesis and structural characterization of BaV4O9

2007 ◽  
Vol 63 (2) ◽  
pp. 270-276 ◽  
Author(s):  
Thomas Reeswinkel ◽  
Sebastian Prinz ◽  
Karine M. Sparta ◽  
Georg Roth
Keyword(s):  
Crystal Structure ◽  
Thermal Expansion ◽  
Structural Characterization ◽  
Room Temperature ◽  
Monoclinic Space Group ◽  
Temperature Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Expansion Tensor

The new spin ½ V4+ barium oxovanadate BaV4O9 was synthesized and studied by means of single-crystal X-ray diffraction. Its room-temperature structure is monoclinic, space group P2/c. We discuss the temperature evolution of the crystal structure and thermal expansion tensor of the material between 293 and 100 K.

Lewis-Base Adducts of Group 11 Metal(I) Compounds. LXVIII Synthesis and Structural Systematics of Some 1 : 3 Adducts of Silver(I) Compounds with Triphenylstibine, [(Ph3Sb)3AgX], X = Cl, I, SCN, NCS, CN, ONO2

1997 ◽  
Vol 50 (6) ◽  
pp. 587 ◽  
Author(s):  
Effendy ◽  
John D. Kildea ◽  
Allan H. White
Keyword(s):  
Single Crystal ◽  
Structural Characterization ◽  
Room Temperature ◽  
Lewis Base ◽  
Nitrate Complex ◽  
X Ray ◽  
Ethanol Solvate ◽  
New Form ◽  
Pseudo Halides

The syntheses and room-temperature single-crystal X-ray structural characterization of 1 : 3 adducts formed between silver(I) (pseudo-) halides, AgX, and triphenylstibine, SbPh3, are described for X = Cl, I, SCN, NCS, CN, NO3 (1)-(6). The chloride, as its methanol solvate (1a), is isomorphous with the arsine analogue: triclinic, P-1, a 13·373(4), b 14·48(6), c 14·702(3) Å, α 83·49(3), β 87·76(2), γ 76·45(3)°; Z = 2, conventional R on F being 0·046 for No 5514 independent ‘observed’ reflections (I > 3σ(I )). A new form (1b) of the chloride has also been authenticated: monoclinic, P 21/c, a 12·832(2), b 54·24(1), c 18·519(8) Å, β 129·68(3)°; Z = 8 (R 0·065 for No 5672). No bromide has been obtained; the iodide (2) is described as monoclinic, P 21/n, a 19·611(4), b 14·473(6), c 17·74(1) Å, β 98·28(3)°; Z = 4 (R 0·036 for No 6769). The thiocyanate crystallizes from acetonitrile or pyridine as an S-bonded form (3) isomorphous with the arsine analogue: monoclinic, P 21/n, a 19·143(7), b 14·288(5), c 18·694(6) Å, β 98·81(2)°; Z = 4 (R 0·037 for No 4482). From 2-methylpyridine, remarkably, a solvate is obtained in which the thiocyanate is N-bonded (4): triclinic, P-1, a 27·261(5), b 14·767(3), c 13·319(1) Å, α 91·53(1), β 101·58(1), γ 92·29(2)°; Z = 4 (R 0·045 for No 6900). The cyanide is also monoclinic, P 21/n, a 19·442(7), b 14·267(3), c 17·741(6) Å, β 97·63(3)°, z = 4; R 0·057 for No 2487. The unsolvated 1 : 3 nitrate complex (6a) is monoclinic, P 21/n, a 19·602(5), b 14·455(1), c 17·727(2) Å, β 97·19(2)°, Z = 4; R was 0·034 for No 6522. The complex is isomorphous with the arsenic and phosphorus analogues, being mononuclear [(Ph3Sb)3Ag(O2NO)]. The ethanol solvate (6b) is triclinic, P-1, a 13·352(5), b 14·548(9), c 14·701(4) Å, α 81·64(4), β 84·45(3), γ 75·32(4)°, Z = 2; R was 0·058 for No 4702. Ag-Sb range between 2·6980(8) and 2·843(3) Å in the precise determinations; Ag-X are 2·481(4) and 2·52(1) Å (the two chlorides), 2·757(1) (I), 2·533(3) (SCN), 2·21(1) (NCS), 2· 09(3) (CN), 2·377(7) Å (unidentate ONO2)

Effects of the [OC6F5] moiety upon structural geometry: crystal structures of half-sandwich tantalum(V) aryloxide complexes from reaction of Cp*Ta(N t Bu)(CH2 R)2 with pentafluorophenol

2011 ◽  
Vol 67 (5) ◽  
pp. 416-424 ◽  
Author(s):  
Jacqueline M. Cole ◽  
Michael C. W. Chan ◽  
Vernon C. Gibson ◽  
Judith A. K. Howard
Keyword(s):  
Crystal Structure ◽  
Structural Characterization ◽  
Twist Angle ◽  
The Other ◽  
Structural Geometry ◽  
Factors Affecting ◽  
Imido Complexes ◽  
Half Sandwich ◽  
Oxide Derivative

The synthesis, chemical and structural characterization of a series of pentamethylcyclopentadienyl (Cp*) tantalum imido complexes and aryloxide derivatives are presented. Specifically, the imido complexes Cp*Ta(N t Bu)(CH2 R)2, where R = Ph [dibenzyl(tert-butylamido) (η5-pentamethylcyclopentadienyl)tantalum(IV) (1)], Me2Ph [tert-butylamido)bis(2-methyl-2-phenylpropyl) (η5-pentamethylcyclopentadienyl)tantalum(IV) (2)], CMe3 [(tert-butylamido)bis(2,2-dimethylpropyl) (η5-pentamethylcyclopentadienyl)tantalum(IV) (3)], are reported. The crystal structure of (3) reveals α-agostic interactions with the Ta atom. The resulting increase in the tantalum core coordination improves electronic stability. As such it does not react with pentafluorophenol, in contrast to the other two reported imido complexes [(1) and (2)]. Addition of C6F5OH to (1) yields a dimeric aryl-oxide derivative, [Cp*Ta(CH2Ph)(OC6H5)(μ-O)]2 [di-μ-oxido-bis[benzyl(pentafluorophenolato) (η5-pentamethylcyclopentadienyl)tantalum(V)] (4)]. Its crystal structure reveals long Ta—O(C6H5) bonds but short oxo-bridging Ta—O bonds. This is explained by accounting for the fierce electronic competition for the vacant d π orbitals of the electrophilic TaV centre. Steric congestion around each metal is alleviated by a large twist angle (77.1°) between the benzyl and pentafluorophenyl ligands and the ordering of each of these groups into stacked pairs. The imido complex (2) reacts with C6F5OH to produce a mixture of Cp*Ta(OC6F5)4 [tetrakis(pentafluorophenolato)(η5-pentamethylcyclopentadienyl)tantalum(V) (5)] and [Cp*Ta(OC6F5)2(μ-O)]2 [di-μ-oxido-bis[bis(pentafluorophenolato)(η5-pentamethylcyclopentadienyl)tantalum(V)] (6)]. Steric congestion is offset in both cases by the twisting of its pentafluorophenyl ligands. Particularly strong electronic competition for the empty d π metal orbitals in (6) is reflected in its bond geometry, and owes itself to the more numerous electron-withdrawing pentafluorophenyl ligands. The balance of steric and electronic factors affecting the reactivity of Cp* tantalum imido based complexes with pentafluorophenol is therefore addressed.

scholarly journals Analysis of isothermal sintering of zinc-titanate doped with MgO

2007 ◽  
Vol 39 (3) ◽  
pp. 241-248 ◽  
Author(s):  
N. Obradovic ◽  
S. Stevanovic ◽  
M. Mitric ◽  
M.V. Nikolic ◽  
M.M. Ristic
Keyword(s):  
Crystal Structure ◽  
Mechanical Activation ◽  
Structural Characterization ◽  
Ball Mill ◽  
Room Temperature ◽  
Zinc Titanate ◽  
Different Temperatures ◽  
Doped Zno ◽  
Titanate Ceramics

The aim of this work was analysis of isothermal sintering of zinc titanate ceramics doped with MgO obtained by mechanical activation. Mixtures of ZnO, TiO2 and MgO (0, 1.25 and 2.5%) were mechanically activated 15 minutes in a planetary ball mill. The powders obtained were pressed under different pressures and the results were fitted with a phenomenological compacting equation. Isothermal sintering was performed in air for 120 minutes at four different temperatures. Structural characterization of ZnO-TiO2-MgO system after milling was performed at room temperature using XRPD measurements. DTA measurements showed different activation energies for pure and doped ZnO-TiO2 systems. Thus addition of MgO stabilizes the crystal structure of zinc titanate.

Lewis-Base Adducts of Group 11 Metal(I) Compounds. LXXI Synthesis, Spectroscopy and Structural Systematics of Some 1 : 2 Binuclear Adducts of Silver(I) Compounds with Triphenylarsine, [(Ph3As)2Ag(µ-X)2Ag(AsPh3)2], X = Cl, Br, I, SCN

1997 ◽  
Vol 50 (6) ◽  
pp. 627 ◽  
Author(s):  
Graham A. Bowmaker ◽  
Effendy ◽  
John D. Kildea ◽  
Eban N. de Silva ◽  
Allan H. White
Keyword(s):  
Infrared Spectra ◽  
Structural Characterization ◽  
Room Temperature ◽  
Far Infrared ◽  
Lewis Base ◽  
X Ray ◽  
C 23 ◽  
Pseudo Halides ◽  
Far Infrared Spectra

The syntheses and room-temperature single-crystal X-ray structural characterization of binuclear 1 : 2 adducts formed between silver(I) (pseudo-)halides, AgX, and triphenylarsine, AsPh3, for X = Cl, Br, I, SCN (1)–(4), are described. The chloride (1), obtained from 2-methylpyridine, is triclinic, P-1, a 10·410(2), b 12·716(2), c 14·196(6) Å, α 113·38(2), β 109·41(2), γ 75·08(1)°, Z = 1 (dimer); conventional R on F was 0·037 for No 3979 independent ‘observed’ (I > 3σ(I)) reflections. The bromide (2a), obtained from 2,6-dimethylpyridine, and iodide (3), obtained from a mixture of AgI/saturated KI in MeOH solutions, are isomorphous, monoclinic, P 21/c a≈ 24·2, b ≈ 13·9, c ≈ 20·2 Å, β ≈ 109·5°, Z = 4 dimers; R was 0·046 and 0·044 for No 5670 and 6039 respectively. The thiocyanate (4) has a similar cell, a 24·12(1), b 12·558(8), c 23·244(4) Å, β 110·11(3)°, Z = 4 dimers, R being 0·044 for No 7956; one of the thiocyanate ligands (which bridge in Ag-SCN-Ag mode) is disordered. A second polymorph of the bromide (2b) (from a mixture of AgBr/saturated KBr in H2O) is also monoclinic, P 21/c, a 14·121(8), b 25·577(3), c 21·968(2) Å, β 125·54(3)°, Z = 4 dimers (R was 0·047 for No 5715). Ag–As range between 2·568(1) and 2·633(1) Å throughout the series; in the isomorphous bromide and iodide, values increase slightly: 2·578(1)–2·611(1), cf. 2·601(2)-2·633(1) Å respectively. Ag–X are 2·568(2)-2·670(2) (Cl); 2·688(2)–2·715(2) (Br); 2·828(2)–2·856(1) Å (I); Ag-S, N for the ordered SCN group are 2·646(3), 2·255(6) Å. A redetermination of improved precision (R 0·035, No 6030) is reported for the triphenylphosphine/thiocyanate analogue. The far-infrared spectra of [(Ph3As)2Ag(µ-X)2Ag (AsPh3)2] show v(AgX) bands at 185, 145 (X = Cl), 145, 130, 106 (X = Br) and 121 cm-1 (X = I). The splittings and band widths reflect a decrease in the degree of distortion of the Ag(µ-X)2Ag units from a symmetrically bridged structure from X = Cl to I.

Structural Characterization of a [Cl3CuL]- (L=Nitrogen Base) Species. A Novel Coordination Environment for Copper(II)

1985 ◽  
Vol 38 (5) ◽  
pp. 669 ◽  
Author(s):  
PC Healy ◽  
C Pakawatchai ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Structural Characterization ◽  
The Other ◽  
X Ray Diffraction ◽  
Nitrogen Base ◽  
Coordination Environment ◽  
X Ray

The crystal structure of [C13H10N] [CuCl3(C13H9N)].H2O(C13H9N ≡ acridine ) has been determined by single-crystal X-ray diffraction methods at 295 K, being refined by least squares to a residual of 0.037 for 1942 independent 'observed' reflections. Crystals are triclinic, Pī , a 16.27(2), b 10.080(8), c 7.236(5) Ǻ, α 88.85(6), β 82.68(8), γ 81.12(9)°, Z 2. The metal atom stereochemistry is unusual, being of pseudo-m symmetry; one of the chlorine atoms is coplanar with the copper and the acridine [Cu- Cl 2.237(2) Ǻ, N-Cu- Cl 143.5(1)°], with the other two disposed to either side of that plane [Cu- Cl 2.252(3), 2.243(2) Ǻ; Cl-Cu-Cl 145.62(7)°]. Cu-N is 2.018(5) Ǻ.

Lewis-Base Adducts of Group 11 Metal(I) Compounds. LXXII Synthesis, Spectroscopy and Structural Systematics of Some 1 : 2 Binuclear Complexes of Silver(I) Halides with Triphenylstibine, [(Ph3Sb)2Ag(μ-X)2Ag(SbPh3)2], X = Cl, Br, I

1997 ◽  
Vol 50 (6) ◽  
pp. 641 ◽  
Author(s):  
Graham A. Bowmaker ◽  
Effendy ◽  
Eban N. de Silva ◽  
Allan H. White
Keyword(s):  
Infrared Spectra ◽  
Structural Characterization ◽  
Room Temperature ◽  
Far Infrared ◽  
Lewis Base ◽  
Binuclear Complexes ◽  
X Ray ◽  
Centrosymmetric Dimers ◽  
Far Infrared Spectra

Syntheses and room-temperature single-crystal X-ray structural characterization of binuclear 1 : 2 adducts formed between silver(I) halides, AgX (X = Cl, Br, I), and triphenylstibine, SbPh3, are described. The three complexes are isomorphous, being triclinic, P-1, a ≈ 18·5, b ≈ 14·6, c ≈ 14·5 Å, α ≈ 62·5, β ≈ 74, γ ≈ 77°, Z = 2 centrosymmetric dimers. Conventional R on F were 0·043, 0·038 and 0·046 for 4984, 8479 and 4166 independent, ‘observed’ (I > 3σ(I)) reflections respectively. In [(Ph3b)2Ag(µ-X)2Ag(SbPh3)2], Ag–Sb range between 2·702(1) and 2·744(2) Å, lengthening slightly from chloride to iodide; Ag–X are 2·567(5)–2·628(4) (Cl), 2·684(1)–2·737(1) (Br) and 2·826(3)–2·869(3) Å (I). The far-infrared spectra of [(Ph3Sb)2Ag(µ-X)2Ag(SbPh3)2] show v(AgX) bands at 178, 158 (X = Cl), 121 (X = Br) and 110 cm-1 (X = I). The splittings and band widths reflect a decrease in the degree of distortion of the Ag(µ-X)2Ag units from a symmetrically bridged structure from X = Cl to I.

Lewis-Base Adducts of Group 11 Metal(I) Compounds. Synthesis and Structural Characterization of Some Halopyridin/triphenylphosphinesilver(I) Complexes: Some Space Group Revisions for Parts LII-LIV

1991 ◽  
Vol 44 (11) ◽  
pp. 1585 ◽  
Author(s):  
y Effend ◽  
LM Engelhardt ◽  
PC Healy ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Crystal Structures ◽  
Structural Characterization ◽  
Silver Iodide ◽  
Room Temperature ◽  
Lewis Base ◽  
Space Group ◽  
Space Groups ◽  
Phenyl Rings

Redetermination of the room-temperature crystal structures of mononuclear chloro- and bromo-pyridinebis ( triphenylphosphine )silver(I) (previously described in space group P21/m) and di-μ-iodo-bis [(pyridine)( triphenylphosphine )silver(I)](previously described in space group C2/m), consequent upon the availability of crystals of improved quality, has permitted the reassignment of space groups as P21/a (with doubled a axis) and C2/c respectively, by virtue of the facilitated detection of weak superlattice reflections. Crystals of [ Cl,BrAg ( py )(PPh3)2] are monoclinic, P21/a, a ≈ 19.6, b ≈ 20.0, c ≈ 9.1Ǻ, β ≈ 97.5°, Z = 4; the structures were refined to residuals of 0.034 and 0.040 for 2965 and 2315 'observed' reflections respectively. [(PPh3)( py )AgI2Ag( py )(PPh3)] is monoclinic, C2/c, a 27.145(6), b 14.548(3), c 11.316(4)Ǻ, β 94.83(2)°, Z 4, refining to R 0.035 for 1892 'observed' reflections, and isomorphous with the [(PPh3)( py )CuX2Cu( py )(PPh3)] family. In spite of this reassignment, the previous descriptions of the AgX /N/P cores of the species are essentially unchanged, the previous residuals of the misassigned space group determinations being comparable with the present; the only non- trivial change lies in the fact that the disordered phenyl rings of the earlier work are now fully ordered. It now seems certain that the 'second polymorph' of [(PPh3)( py )CuBr2Cu( py )(PPh3)], recorded as being isomorphous with its C2/m silver iodide counterpart, is spurious and a consequence of the use of an inferior specimen.

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