Pyrrolyl complexes of the early transition metals. 3. Preparation and crystal structure of (η5-C5H5)2Zr(η1-NC4H2Me2)2 and Zr(η1-NC4H2Me2)4

1986 ◽  
Vol 64 (7) ◽  
pp. 1254-1257 ◽  
Author(s):  
R. Vann Bynum ◽  
H.-M. Zhang ◽  
William E. Hunter ◽  
Jerry L. Atwood

The title compounds were synthesized by the reactions of NaNC4H2Me2 with the appropriate complex metal chloride in THF. The crystal structures have been determined from X-ray data measured by counter methods. (η5-C5H5)2Zr(η1-NC4H2Me2)2 crystallizes in the orthorhombic space group Pbca with cell dimensions a = 15.797(6), b = 14.327(5), c = 16.417(6) Å, and ρcalcd = 1.46 g cm−3 for Z = 8. Full-matrix least-squares refinement led to a final R factor of 0.041 based on 536 observed reflections. Zr(η1-NC4H2Me2)4 belongs to the monoclinic space group P21/n with a = 14.065(5), b = 10.717(4), c = 15.733(6) Å, β = 90.61(4)°, and ρcalcd = 1.31 g cm−3 for Z = 4. A final R value of 0.029 resulted from the refinement on the basis of 2649 observed reflections. The dicyclopentadienyl derivative exhibits two features of importance. The Zr—N—centroid angles are 159 and 168°, and the Zr—N bond lengths are 2.24(2) Å. In the homoleptic complex the corresponding values are 164–169° and 2.069(3)–2.090(3) Å. In both cases the bonding parameters are indicative of a substantial amount of π overlap between the zirconium atom and the pyrrolyl nitrogen atom.


1992 ◽  
Vol 47 (3) ◽  
pp. 305-309 ◽  
Author(s):  
Anja Edelmann ◽  
Sally Brooker ◽  
Norbert Bertel ◽  
Mathias Noltemeyer ◽  
Herbert W. Roesky ◽  
...  

Abstract The Molecular Structures of [2,4,6-(CF3)3C6H2S]2 (1) [2,4,6-Me3C6H2Te]2 and [2-Me2N-4,6-(CF3)2C6H2Te]2 (3) have been determined by X-ray diffraction. Crystal data: 1: orthorhombic, space group P212121, Z = 4, a = 822.3(2), b = 1029.2(2), c = 2526.6(5) pm (2343 observed independent reflexions, R = 0.042); 2: orthorhombic, space group Iba 2, Z = 8, a = 1546.5(2), b = 1578.4(2), c = 1483.9(1) pm (2051 observed independent reflexions, R = 0.030); 3: monoclinic, space group P 21/c, Z = 4, a = 1118.7(1), b = 1536.5(2), c = 1492.6(2) pm, β = 98.97(1)° (3033 observed independent reflexions, R = 0.025).



1988 ◽  
Vol 41 (3) ◽  
pp. 283 ◽  
Author(s):  
GB Robertson ◽  
PA Tucker

The structures of two crystalline modifications of mer -(Pme2Ph)3H-cis-Cl2IrIII, (1), have been determined from single-crystal X-ray diffraction data. Modification (A) is monoclinic, space group P21/c with a 12.635(1), b 30.605(3), c 14.992(2)Ǻ, β 110.01(2)° and Z = 8. Modification (B) is orthorhombic, space group Pbca with a 27.646(3), b 11.366(1), c 17.252(2)Ǻ and Z = 8. The structures were solved by conventional heavy atom techniques and refined by full-matrix least- squares analyses to conventional R values of 0.037 [(A), 8845 independent reflections] and 0.028 [(B), 5291 independent reflections]. Important bond lengths [Ǻ] are Ir -P(trans to Cl ) 2.249(1) av. (A) and 2.234(1) (B), Ir -P(trans to PMe2Ph) 2.339(2) av. (A) and 2.344(1), 2.352(1) (B), Ir-Cl (trans to H) 2.492(2), 2.518(2) (A) and 2.503(1) (B) and Ir-Cl (trans to PMe2Ph)2.452(2) av. (A) and 2.449(1)(B). Differences in chemically equivalent metal- ligand bond lengths emphasize the importance of non-bonded contacts in determining those lengths.



1997 ◽  
Vol 50 (9) ◽  
pp. 903 ◽  
Author(s):  
Trevor W. Hambley ◽  
Walter C. Taylor ◽  
Stephen Toth

Four novel norditerpenoids were isolated from a new encrusting sponge, conveniently labelled Aplysilla pallida. The structures of aplypallidenone (1), aplypallidoxone (2), aplypallidione (3) and aplypallidioxone (4) were elucidated by spectroscopic studies and the crystal structures of aplypallidenone and aplypallidoxone have been determined by X-ray diffraction methods. The structure of (1) was refined to a residual of 0·040 for 1665 independent observed reflections and the structure of (2) was refined to a residual of 0·031 for 1699 independent observed reflections. The crystals of (1) are orthorhombic, space group P212121, a 7·728(2), b 10·838(4), c 24·880(5) Å, Z 4. Those of (2) are monoclinic, space group C 2, a 23·927(7), b 6·674(2), c 14·033(3) Å, Z 4.



1992 ◽  
Vol 70 (3) ◽  
pp. 792-801 ◽  
Author(s):  
Jagadese J. Vittal ◽  
Philip A. W. Dean ◽  
Nicholas C. Payne

The structures of three tetramethylammonium salts containing anions of formula [(μ-SePh)6(MSePh)4]2− (M = Zn and Cd) were determined by single crystal X-ray diffraction techniques. The Zn salt crystallizes in different space groups depending upon the solvent combination used in the synthesis. Thus crystals of (Me4N)2[Zn4(SePh)10], 1, grown from a mixture of methanol, acetonitrile, and acetone are triclinic, space group [Formula: see text] with cell dimensions a = 13.214(2), b = 23.859(2), c = 13.072(1) Å, α = 91.134(8), β = 113.350(8), γ = 79.865(9)°, and Z = 2. In the absence of acetone, a solvated crystal (Me4N)2[Zn4(SePh)10]•CH3CN, 2, is formed, which belongs to the monoclinic space group P21/n with a = 14.248(1), b = 39.722(2), c = 13.408(1) Å, β = 97.132(5)°, and Z = 4. The Cd salt (Me4N)2[Cd4(SePh)10], 3, crystallizes in the monoclinic space group P21/c, with a = 20.830(2), b = 14.282(1), c = 25.872(1) Å, β = 99.626(6)°, and Z = 4. These three salts are the first examples of homoleptic, tetranuclear selenolatometal(II) anions with (μ-Se)6M4 cages of adamantane-type stereochemistry. In each case the phenyl substituents of the bridging ligands adopt the configuration [aae, aae, aee, aee], which has the minimum number of two 1,3-axial–axial non-bonding substituent interactions. Keywords: selenolate complexes, synthesis, X-ray crystallography, isomerism, adamantane stereochemistry.



1995 ◽  
Vol 73 (9) ◽  
pp. 1520-1525
Author(s):  
Luciano Antolini ◽  
Ugo Folli ◽  
Dario Iarossi ◽  
Adele Mucci ◽  
Silvia Sbardellati ◽  
...  

The crystal structures of the title compounds were determined by single crystal X-ray diffraction techniques. The molecule of the Z isomer, which crystallizes in the monoclinic space group C2/c with Z = 4 in a cell of dimensions a = 14.891 (2), b = 10.780(2), c = 8.769(1) Å, β = 97.47(2)°, V = 1395.7(7) Å3 has crystallographic twofold symmetry. The E form crystallizes in the orthorhombic space group Pbca with a = 11.730(1), b = 6.932(1), c = 16.841(1) Å, V = 1369.4(2) Å3 and Z = 4. Its molecules have crystallographically dictated [Formula: see text] symmetry. In both isomers the phenyl rings are roughly perpendicular to the average ethylene plane. The atoms characterizing this plane show significant deviations from planarity in the Z isomer. Marked bond-angle distortions at the ethene carbons of both structures are observed. The 1H and 13C NMR spectra of the compounds were measured and, particularly in the case of the 1H chemical shifts, fall into two quite separate spectral regions. At low temperature, two conformational isomers, those with different relative orientation of the C—Cl bonds of the phenyl rings, are observed in the spectrum of each compound. Keywords: chlorostilbenes, overcrowded molecules. X-ray structure, conformations, NMR spectroscopy.



1998 ◽  
Vol 53 (2) ◽  
pp. 206-210 ◽  
Author(s):  
D. Sonnak ◽  
W. Preetz

Abstract X-ray structure determinations have been performed on single crystals of trans-(Ph4P)2-[B6H4I2] (1) (triclinic, space group P1̄, a = 9.9680(12), b = 10.9690(11), c = 11.0470(14) Å,α = 88.167(9), β = 80.466(12), γ = 68.839(11)°, Z = 1), mer-(Ph4P)2[B6H3I3] · 2 CH2Cl2 (2)(triclinic, space group P1̄, a = 11.8694(11), b = 15.1699(13), c = 17.051(2) Å, α = 75.118(9), β = 71.953(10), γ = 69.331(8)°, Z = 2), trans-(Ph4P )2[B6H2I4] · 2 CH3CN (3) (monoclinic, space group P21/n, a = 14.9665(10), b = 7.6783(10), c = 23.385(3) Å, β = 95.78(9)°, Z = 2), and (CH2Py2)[B6HI5] (4) (orthorhombic, space group Pnma, a = 13.660(2), b = 11.8711(13), c = 13.839(2) Å, Z = 4). The B6 octahedra are compressed in the direction of the B-I bonds, resulting in shortened diagonal B ··· B distances with average values of the groups I-B ··· B-I = 2.37 and I-B ··· B-H = 2.43 Å as compared with H-B ··· B-H = 2.49 Å.



1991 ◽  
Vol 46 (4) ◽  
pp. 337-343 ◽  
Author(s):  
Da Zhang ◽  
Shi-Qi Dou ◽  
Alarich Weiss

Abstract The molecular motion in (CH3)3XCl, X = Sn and Pb has been investigated by measurement of the second moment M2(1H) as function of temperature in the range 95 < T,/K<345. The methyl groups in both compounds rotate freely over the whole temperature range studied. In (CH3)3SnCl the C'3-rotation of (CH3)3Sn-group about the Sn CI axis sets in above 273 K. To explain the NMR and INS results, the crystal structures of (CH3)3PbCl and CH3SnBr3 were determined by single X-ray diffraction. (CH3)3PbCl crystallizes in a monoclinic space group C32-C2, a = 1276.7(3) pm, b = 982.3(3) pm, c = 547.0(2) pm, ß = 91.12(1)°; Z = 4, R = 0.035. CH3SnBr3 crystallizes in an orthorhombic space group D162h-Pnma, a = 643.0(3) pm, b= 1005.3(4) pm, c= 1148.0(4) pm; Z = 4, R =0.057



1998 ◽  
Vol 51 (3) ◽  
pp. 219 ◽  
Author(s):  
Ian R. Whittall ◽  
Mark G. Humphrey ◽  
David C. R. Hockless

The structures of Ni(C≡CR)(PPh3)(η-C5H5) (R = Ph (1), C6H4-4-NO2 (2), 4-C6H4C6H4-4′-NO2 (3), (E)-4-C6H4CH=CHC6H4-4′-NO2 (4), 4-C6H4C≡CC6H4-4′-NO2 (5), 4-C6H4N=CHC6H4-4′-NO2 (6)) have been determined by single-crystal X-ray diffraction studies, refining by full-matrix least-squares analysis. For (1), crystals are triclinic, space group P-1, with a 10·094(2), b13·429(3), c 18·835(5) Å,α 103·24(2), β 91·50(2), γ 90·10(2)°, Z 4, 5844 unique reflections (595 parameters), converging at R 0·033 and Rw 0·024. For (2), crystals are orthorhombic, space group Pna21, with a 16·799(2), b 8·681(2), c 17·485(2) Å, Z 4, 1774 unique reflections (325 parameters), converging at R 0·031 and Rw 0·029. For (3), crystals are monoclinic, space group P 21/c, with a 11·140(3), b 18·282(4), c 15·296(2) Å, β 105·18(2)°, Z 4, 3132 unique reflections (397 parameters), converging at R 0·039 and Rw 0·024. For (4), crystals are monoclinic, space group P 21/n, with a 12·929(7), b 16·953(8), c 15·601(7) Å, β 112·55(3), Z 4, 3023 unique reflections (397 parameters), converging at R 0·039 and Rw 0·025. For (5), crystals are monoclinic, space group P 21/n, with a 12·710(5), b 16·882(3), c 15·693(4) Å, β 111·37(3)°, Z 4, 3216 unique reflections (397 parameters), converging at R 0·035 and Rw 0·030. For (6), crystals are monoclinic, space group P 21/n, with a 12·594(1), b 16·936(2), c 15·611(1) Å, β 112·476(5)°, Z 4, 3564 unique reflections (397 parameters), converging at R 0·038 and Rw 0·041. For structurally characterized 18-electron (cyclopentadienyl)nickel(II) acetylide complexes, statistically insignificant decreases in the average Ni-C(1) distance and trans influence and an increase in the average C(1)-C(2) parameter are observed on introduction of an acceptor substituent at the alkynyl ligand.



1996 ◽  
Vol 49 (7) ◽  
pp. 775 ◽  
Author(s):  
TW Hambley ◽  
TW Hambley ◽  
KG Lewis ◽  
KG Lewis ◽  
DJ Tucker ◽  
...  

Reaction of olean-12-ene-3β,16β,22α,28-tetrol ( chichipegenin ) (1) with methyl orthoformate gives the 16β,22α,28-orthoformate (2). Acetylation of the ortho ester followed by hydrolysis gives the tetrol 3β-monoacetate (5). It is shown that intramolecular hydrogen bonding occurs in the tetrol (1) and the 3β-monoacetate (5) in non-polar solvents. X-Ray crystallographic data on the tetrol and its tetraacetate (4) are reported. The tetrol,C30H50O4, M 474.72, crystallized in the orthorhombic space group P 212121 with a 12.363(6), b 31.888(3), c 6.962(3) Ǻ, V 2745(1) Ǻ3, Dc(Z = 4) 1.149 g cm-3, N = N(unique) 2394, No 1878 [I > 1.5σ(I)], Nvar 500; R 0.038, Rw 0.040. The tetraacetate , C38H58O8, M 642.87, crystallized in the monoclinic space group P 21, with a 10.603(2), b 16.569(1), c 10.814(1) Ǻ, β 98.72(1)°, V 1877.9(4) Ǻ3, Dc(Z = 2) 1.137g cm-3 N 3090, Rmerge 4.67% for N(unique) 2917, No 2663 [I > 2.5σ(I)], Nvar 414; R 0.053, Rw 0.050.



1995 ◽  
Vol 48 (6) ◽  
pp. 1183 ◽  
Author(s):  
EJ Ditzel ◽  
GB Robertson

The syntheses and subsequent characterization of the complexes mer -trans-(PPri3)2(Pme2Ph)-Cl-cis-H2IrIII(1) and mer-trans-(PPri3)2(PMe2Ph)H3IrIII (2) by n.m.r. and by low temperature (153�5 K) X-ray diffraction analyses are reported. Crystals of (1) are monoclinic, space group P21/c with a 19.277(2), b 9.020(1), c 17.657(2) Ǻ, β 101.40(1)° and Z 4. Crystals of (2) are orthorhombic, space group P212121, with a 19.373(3), b 18.724(2), c 8.113(1) Ǻ and Z 4. Full-matrix least-squares analyses converged with R = 0.027 and wR = 0.031 for (1) (3243 reflections), and R = 0.030 and wR = 0.038 for (2) (2892 reflections). Consistent with previous observation, the unit increase in chloride content (in place of hydride) in (1) is accompanied by a global lengthening of 0.036 Ǻ (av.) in the Ir -P bond lengths cf. those in (2). Also, because of increased steric crowding (two PPri3 ligands in place of two Pme2Ph), the Ir-PMe2Ph bond in (1) is 0.019(2) Ǻ longer than the chemically equivalent bond in mer-(PMe2Ph)3Cl-cis-H2IrIII. In previously reported complexes in this series metrically similar increases in Ir-PMe2Ph distances result from the replacement of just one Pme2Ph ligand by PPri3.



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