The Crystal and Molecular Structure of trans-Dichloro-mer-tris(dimethylphenyl-phosphine)hydridoiridium(III) by X-Ray and Neutron Diffraction

1987 ◽  
Vol 40 (6) ◽  
pp. 1043 ◽  
Author(s):  
GB Robertson ◽  
PA Tucker

The crystal and molecular structure of mer -(PMe2Ph)3H- trans-Cl2IrIII (1) has been determined by single-crystal X-ray and neutron diffraction analyses. Crystals are monoclinic, space group P1, with a 8.91 9(4), b 9.895(4), c 12.269(6) �, α 70.33(4), β 81.75(4), γ 88.26(4)�, Z 2. The structure was solved by conventional heavy atom methods and refined by full-matrix least-squares analyses to final R values of 0.067 (X-ray data, R = ∑// Fo/-/Fc2/∑Fo/, 7516 independent reflections) and 0.086 (neutron data, R = ∑/Fo2- Fc2/∑ Fo2 2290 independent reflections). Weighted mean values for metal-ligand distances are Ir -P(trans to H) 2.365(2) �, Ir -P(trans to PMe2Ph) 2.329(2) � and Ir -Cl(trans to Cl) 2.402(2) and 2.364(2) �. The iridium-hydrogen bond [1.616(7) �] is trans-lengthened, vis-a-vis Ir -H trans to Cl, by c. 0.05 �. The difference in the mutually trans Ir -Cl bond lengths is ascribed to the inequivalence of intramolecular non-bonding interactions. The Ir -P(trans to PMe2Ph) bond length in (1) is shorter than that in mer -(PMe2Ph)Cl3IrIII. The smaller steric requirement of the hydride ligand in (1) allows the mutually trans phosphines to move away from their cis neighbour. In turn, the phosphines approach the metal more closely to compensate for the decreased phosphine substituent-phosphine substituent non-bonding interactions.

1988 ◽  
Vol 41 (5) ◽  
pp. 641 ◽  
Author(s):  
GB Robertson ◽  
PA Tucker

The structure of mer-(Pme2Ph)3Cl-cis-H2IrIII (1) has been determined by single-crystal X-ray and neutron diffraction analyses. Crystals are monoclinic, space group P21, with a 11.476(4), b 14.069(5), c 8.286(3)Ǻ, β 92.45(1)° and Z 2. Full-matrix least-squares analyses converged 0.022 for 7773 X-ray data and R(F2) = 0.062 for 1538 neutron data. Ir -H [1.557(11)Ǻ trans to Cl, 1.603(10) Ǻ trans to P] and Ir -P distances [2.292(1)Ǻ trans to P, 2.328(1)Ǻ trans to H] both exhibit trans lengthening effects. Consistent with the increased hydride content the Ir -P distances in (1) are c. 0.04 Ǻ shorter than for the corresponding bonds in its dichloro monohydrido analogues and c. 0.08 Ǻ shorter than those in the trichloride . In contrast Ir-Cl [2.505(1)Ǻ] is not significantly different to the corresponding distance (2.504 Ǻ av.) in mer -(PMe2Ph)3-cis-Cl2HIrIII.


1979 ◽  
Vol 34 (3) ◽  
pp. 434-436 ◽  
Author(s):  
A. Müller ◽  
S. Pohl ◽  
M. Dartmann ◽  
J. P. Cohen ◽  
J. M. Bennett ◽  
...  

Abstract The novel tri-nuclear metal-sulfur cluster [Mo3S(S2)6]2- can be obtained as its ammonium salt by the reaction of a Moiv containing aqueous solutions with polysulfide. Its crystal and molecular structure has been determined by a single crystal X-ray study. The crystals are monoclinic (space group Cm, with a = 11.577(6) Å, b = 16.448(7) Å, c = 5.716(2) Å, β = 117.30(3)°, V = 967.2 Å3 , Z = 2, dexptl. = 2.54(2) g/cm3 , dcal = 2.54 g/cm3). The structure consists of isolated [Mo3S(S2)6]2- units, with three Mo atoms at the vertices of a triangle. There are bridging as well as terminal S22--ligands lying above and below the Mo3-plane (bond distances: Mo-Mo = 2.722 Å, Mo-S(terminal) = 2.435, Mo-S(bridging) = 2.452, Mo3-S = 2.353(4) Å and S-S = 2.04 Å (mean values)).


1975 ◽  
Vol 53 (22) ◽  
pp. 3383-3387 ◽  
Author(s):  
Joseph Hubert ◽  
André L. Beauchamp ◽  
Roland Rivest

The crystal and molecular structure of dithiocyanato(triphenylarsine)mercury(II) has been determined from X-ray diffraction data. The crystals are monoclinic, space group P21/c, with a = 10.290(7), b = 21.199(23), c = 10.719(7) Å, β = 112.00(2)°, and Z = 4. The structure has been solved by the heavy-atom method and refined by block-diagonal least-squares calculations. The agreement factor R obtained for 2607 'observed' reflections is 0.030. The crystal consists of single molecules. The 'characteristic' coordination number of mercury is three, with two sulfur and one arsenic atoms at the apexes of a triangle. The nitrogen atoms of the thiocyanate groups are at 2.67 and 2.74 Å from the adjoining mercury atoms and therefore link the different molecules together.


1983 ◽  
Vol 61 (12) ◽  
pp. 2809-2812 ◽  
Author(s):  
P. Michael Boorman ◽  
Joanne M. Ball ◽  
Kelly J. Moynihan ◽  
Vikram D. Patel ◽  
John F. Richardson

The complex (Me2S)Cl3W(μ-SPh)2WCl3(SMe2), 1, has been isolated as one product of the 1:1 reaction between WCl4(Me2S)2 and SiMe3(SPh) in CH2Cl2 solution. A single crystal X-ray diffraction study shows that the molecule has the relatively unusual edge-shared bioctahedral structure, with a W—W bond length of 2.759(1) Å. The dimethyl sulfide ligands occupy positions trans to one another in the equatorial mean plane of the molecule, which has two-fold symmetry imposed on it. The structure was solved by the heavy atom method and refined to R = 0.044 and Rw = 0.058 for 2001 reflections. Crystals of 1 are monoclinic, space group C2/c, with a = 17.445(4), b = 12.594(2), c = 11.509(3) Å, β = 91.22(1)°, and Z = 4.


1990 ◽  
Vol 55 (4) ◽  
pp. 1010-1014 ◽  
Author(s):  
Jiří Kameníček ◽  
Richard Pastorek ◽  
František Březina ◽  
Bohumil Kratochvíl ◽  
Zdeněk Trávníček

The crystal and molecular structure of the title compound (C8H16N2NiS4) was solved by the heavy atom method and the structure was refined anisotropically to a final R factor of R = 0.029 (wR = 0.037) for 715 observed reflections. The crystal is monoclinic, space group P21/c with a = 948.3(2), b = 776.9(2), c = 1 167.4(2) pm, β = 125.14(2)°, Z = 2. The molecule contains two four-membered NiSCS rings of approximately planar configuration with the Ni atom situated at a centre of symmetry. The molecules are arranged in chains along the c-axis of the unit cell.


1986 ◽  
Vol 51 (11) ◽  
pp. 2521-2527 ◽  
Author(s):  
Jan Lokaj ◽  
Eleonóra Kellö ◽  
Viktor Kettmann ◽  
Viktor Vrábel ◽  
Vladimír Rattay

The crystal and molecular structure of SnBu2(pmdtc)2 has been solved by X-ray diffraction methods and refined by a block-diagonal least-squares procedure to R = 0.083 for 895 observed reflections. Monoclinic, space group C2, a = 19.893(6), b = 7.773(8), c = 12.947(8) . 10-10 m, β = 129.07(5)°, Z = 2, C20H38N2S4Sn. Measured and calculated densities are Dm = 1.38(2), Dc = 1.36 Mg m-3. Sn atom, placed on the twofold axes, is coordinated with four S atoms in the distances Sn-S 2.966(6) and 2.476(3) . 10-10 m. Coordination polyhedron is a strongly distorted octahedron. Ligand S2CN is planar.


1979 ◽  
Vol 57 (2) ◽  
pp. 174-179 ◽  
Author(s):  
A. Wallace Cordes ◽  
Paul F. Schubert ◽  
Richard T. Oakley

The crystal structure of 1,4-diphenyl-2,2′,3,3′,5,5′,6,6′-octamethylcyclo-1,4-diphospha-2,3,5,6-tetrasilahexane, (PhPSi2Me4)2, has been determined by single crystal X-ray diffraction. The crystals are monoclinic, space group P21/c, with a = 9.866(1), b = 11.921(1), and c = 11.324(2) Å, β = 104.31(1)°, Z = 2, and ρcalcd = 1.15 g/cm3. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.060 and Rw of 0.078, for 1173 reflections with intensities greater than 3σ. The (PhPSi2Me4)2 molecule lies on a crystallographic centre of symmetry, and the six-membered P2Si4 ring has a chair conformation with equatorial phenyl groups. The endocyclic angles at P (104.4(1)°) and Si (104.9(2)°) are intermediate between those found in cyclic hexaphosphine and hexasilane molecules, and the Si—Si and P—Si distances of 2.345(3) and 2.252(4) Å, respectively, correspond to single bond lengths, with no appreciable evidence for secondary pπ → dπ bonding between phosphorus and silicon. The Si—C (1.867(8) Å) and P—C (1.828(7) Å) bond lengths are also normal. The variations in the Si—P—C (101.6(2)°, 108.6(2)°), P—Si—C (range 106.2(3)–120.0(3)°), and Si—Si—C (range 105.8(3)–113.7(3)°) angles indicate that the positions of the exocyclic methyl and phenyl groups are influenced by both intra- and intermolecular steric forces.


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