Tungsten-phosphorus spin-spin coupling in tungsten carbonyl derivatives

Grim, Samuel O.; Wheatland, David A.

doi:10.1016/0020-1650(68)80058-3

Cited by 16 publications

(6 citation statements)

References 4 publications

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“…These show, like the parent hydroxo complexes, − singlets flanked by 195 Pt satellites. Smaller P−Pt coupling constants are observed for the diamido complexes, consistent with the greater donor strength of the amido ligand over the hydroxo ligand . Shifts for the bidentate phosphine complexes indicate chelation .…”

Section: Resultsmentioning

confidence: 74%

“…The upfield doublet shows larger P−Pt coupling than the downfield doublet, and the coupling constant is similar to that of the starting hydroxo complex. Since coupling constants depend on the donor strength of the ligand trans to the phosphine, we assign this signal to the phosphorus atom trans to the OH group. 1 H NMR spectra show, in addition to signals for the phosphine ligand, a pair of singlets for the OH and NH groups in the range 5.90 to −1.10 ppm.…”

Section: Resultsmentioning

confidence: 99%

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Phosphine-Based Dinuclear Platinum(II) Diamido, Amido−Hydroxo, Oxo−Amido, Oxo−Imido, Diimido, and Dihydrazido Complexes¹

James

et al. 1999

Inorg. Chem.

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The platinum(II) amido-hydroxo and diamido complexes [(L 2 Pt) 2 (µ-NHR)(µ-OH)](BF 4 ) 2 (1) (L ) PPh 3 , R ) Ph, p-tol, p-Bu t C 6 H 4 , p-NO 2 C 6 H 4 ; L 2 ) dppp, R ) Ph, p-tol) and [L 2 Pt(µ-NHR)] 2 (BF 4 ) 2 ( 2 6) Å, β ) 99.01(1)°, and Z ) 4. The cationic portion consists of two edge-shared square-planar Pt centers folded at the edge with cis-phosphines and bridging hydroxo and amido groups. LiN(SiMe 3 ) 2 , LiNPr i 2 , LiPh, or LiMe addition to 1 (L ) PPh 3 , R ) Ph, p-tol, p-Bu t C 6 H 4 ) or 1a deprotonates the hydroxo group, forming the amido-oxo complexes 5). Crystals of 4 (R ) Ph) from CH 2 Cl 2 /ether are (183 K) orthorhombic (Pna2 1 ) with a ) 38.272(2) Å, b ) 9.2841(5) Å, c ) 15.0099(7) Å, and Z ) 4. The structure consists of two edge-shared square-planar Pt centers folded at the edge with syn-bridging amido groups and chelating dppm-H ligands. Crystals of 5‚5THF from THF are (183 K) monoclinic (P2 1 /n) with a ) 17.669(5) Å, b ) 31.884(3) Å, c ) 14.686(4) Å, β ) 105.03(1)°, and Z ) 4. The structure of the cationic portion shows two edge-shared square-planar Pt centers folded at the edge with syn-bridging NHNH 2 groups and chelating dppm-H ligands. The NHNH 2 groups bridge the Pt centers through the NH portion. The NH 2 portions coordinate to a Li(THF) 2 + group in a "tweezers" fashion resulting in tetrahedral coordination about the Li atom. Further deprotonation of 4 with LiMe yields the anionic diimido complexes [(dppm-H)Pt(µ-NR)] 2 (Li) 2 (6) (R ) H, Ph, p-tol).

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Section: Resultsmentioning

confidence: 74%

Section: Resultsmentioning

confidence: 99%

Phosphine-Based Dinuclear Platinum(II) Diamido, Amido−Hydroxo, Oxo−Amido, Oxo−Imido, Diimido, and Dihydrazido Complexes¹

James

et al. 1999

Inorg. Chem.

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“…Both of these factors should enhance repulsive interactions between the two Pt centers, the small P−Pt−P angle leading to rehybridization and the more basic phosphine putting more electron density on the Pt center. The dppm hydroxo complex does have the lowest J PPt values (3023 versus 3380 (dppp) to 3857 Hz (dppf)), indicating that this complex has the smallest amount of Pt s-character in the P−Pt bond 5 Comparative Distances (Å) and Angles (deg) for [L 2 Pt(μ-OH)] 2 2+ (L = a Phosphine) ligandPt−OO···OPt···PtO−Pt−OPt−O−PtP1−Pt−P2 L 2 = dppm 2.06 2.49 3.270 74.6 105.4 73.6 L = PMe 3 a 2.07 2.54 3.261 75.9 104.1 95.4 L 2 = dppb 2.08 2.64 3.215 78.8 101.2 101.2 L 2 = dppf b 2.10 2.68 3.227 79.4 100.6 98.1 L = PPh 3 2.06 2.66 3.153 80.3 99.7 99.1 L = PEt 3 c 2.13 2.72 3.121 79.4 94 97.7 a Reference 10. b Reference 16. c Reference 15. 6 Comparative Distances (Å) and Angles (deg) for Oxo and Hydroxo Complexes ligandPt−OO···OPt···PtO−Pt−OPt−O−PtP1−Pt−P2 L 2 = dppm hydroxo 2.06 2.49 3.270 74.6 105.4 73.6 L 2 = dppm-H oxo 2.05 3.112 81.0 99.0 70.1 L = PPh 3 hydroxo 2.06 2.66 3.153 80.3 99.7 99.1 oxo 2.03 2.969 77.4 94.1 101.9

…”

Section: Discussionmentioning

confidence: 99%

“…Donor properties of ligands trans to phosphines in square planar Pt(II) complexes are reflected in the P−Pt coupling constants. Stronger trans donors give a reduced coupling constant . This is observed as the 300−500 Hz drop in the coupling constant on deprotonation of the hydroxo ligand to the strong donor oxo ligand.…”

Section: Discussionmentioning

confidence: 99%

Phosphine-Based Platinum(II) Hydroxo and Oxo Complexes¹

Sharp

1996

Inorg. Chem.

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The platinum(II) hydroxo complexes, [L2Pt(μ-OH)]2(BF4)2 (1), have been prepared from the reaction of L2PtCl2 with AgBF4 for L2 = dppm, dppp, dppb, 2PMe2Ph, and Bu t 2bpy (dppm = bis(diphenylphosphino)methane, dppe = bis(diphenylphosphino)ethane, dppp = bis(diphenylphosphino)propane, dppb = bis(diphenylphosphino)butane, Bu t 2bpy = 4,4‘-di-tert-butyl-2,2‘-bipyridine). The trifluoroacetate (L2 = dppp) and the nitrate (L2 = Bu t 2bpy) salts were also prepared. Two of these new hydroxo complexes, as well as the previously known PPh3 complex, were structurally characterized. Crystals of [(PPh3)2Pt(μ-OH)]2(BF4)2 from CH2Cl2/ether are monoclinic (C2/m) with a = 17.183(5) Å, b = 18.243(4) Å, c = 13.539(4) Å, β = 130.66(2)°, and Z = 2. Crystals of [(dppm)Pt(μ-OH)]2(BF4)2·2DMF from DMF/Et2O are monoclinic (P21/n) with a = 17.193(6) Å, b = 9.341(5) Å, c = 18.666(7) Å, β = 98.73(2)°, and Z = 2. Crystals of [(dppb)Pt(μ-OH)]2(BF4)2·4MeOH from MeOH/Et2O are triclinic (P1̄) with a = 12.547(13) Å, b = 12.858(14) Å, c = 13.039(20) Å, α = 62.89(11)°, β = 63.05(11)°, γ = 60.87(12)°, and Z = 1. The structures of the binuclear dications are all similar, having planar P2Pt(μ-OH)2PtP2 cores with pseudo-D 2 h symmetry. For all but the dppm complex, addition of 2 equiv of LiN(SiMe3)2 results in deprotonation of the hydroxo groups and formation of the oxo complexes [L2Pt(μ-O)]2. The isolated oxo complexes are associated with one (L = PPh3) or two (L = PMe2Ph; L2 = dppe, dppp, dppb, Bu t 2bpy) LiX units (X = BF4 or CF3CO2) by interaction of the oxo ligands with the Li cations. The structure of [(PPh3)2Pt(μ-O)]2·LiBF4 (2) was determined. Crystals of 2·0.5C7H8 from toluene are monoclinic (C2/c), with (173 K) a = 20.469(8) Å, b = 18.085(9) Å, c = 18.152(8) Å, β = 90.34(6)°, and Z = 4. The structure consists of two edge-shared square planar Pt atoms folded at the edge with cis-phosphines and bridging oxygen atoms. The bridging oxo oxygen atoms are coordinated to the Li cation of a LiBF4 contact ion pair. Two fluorine atoms of the BF4 ion also coordinate to the Li cation, resulting in a flattened tetrahedral environment about the Li cation. The oxo complex [(PMe2Ph)2Pt(μ-O)]2·(LiBF4)2 is unstable in solution and converts to the μ3-oxo complex [(L2Pt)3(μ3-O)2](BF4)2 (5) (L = PMe2Ph). Crystals of 5 from THF are orthorhombic (Pbna), with (173 K) a = 16.792(4) Å, b = 17.710(5) Å, c = 19.648(6) Å, and Z = 4. The core structure of the dication consists of a dioxo-bicapped Pt3 triangle. Deprotonation of the dppm hydroxo complex 1 (L2 = dppm) occurs at the dppm methylene group and not at the hydroxo group. The resulting neutral hydroxo complex [(dppm-H)Pt(μ-OH)]2 (6) (dppm-H = bis(diphenylphosphino)methanide) is further deprotonated in THF at the OH group, giving the structurally characterized anionic oxo complex [(dppm-H)Pt(μ-O)]2[Li(THF)2]2 (7). Crystals of 7·4THF from THF are monoclinic (P21/c), with (173 K) a = 10.534(2) Å, b = 21.016(2) Å, c = 18.402(4) Å, β = 103.41(1)°, and Z = 2. The structure has a planar core with the deprotonation of t...

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“…)2W(CO)4 complexes the couplings were ~40 Hz larger for trans than cis isomers. 39 This may be construed to imply that couplings should be lower when CO is trans to phosphorus. Hence, the higher field resonance in the allyl bisphosphine complexes should be assigned to an equatorial phosphorus on the basis of tungsten-phosphorus coupling in agreement with the correlation from the arphos derivative.…”

Section: Discussionmentioning

confidence: 99%

Aspects of chirality retention in rearrangements of pseudooctahedral molybdenum and tungsten complexes

Faller¹,

Haitko²,

Adams³

et al. 1979

J. Am. Chem. Soc.

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A mechanistic analysis of the rearrangements and structural investigation of a series of p3-allyl molybdenum and tungsten dicarbonyl bisphosphine complexes are presented. A three-dimensional crystallographic analysis revealed the structure of (p3-C3H5)Mo(CO)2(diphos)Cl to be unlike that of the analogous diether and diamine chelates. Analysis of variabletemperature *H, 13C, and 3IP NMR spectra have allowed the elucidation of the dynamic properties of these complexes. A trigonal twist rearrangement is proposed for the dynamic behavior of these complexes in which a rotation of the triangular face formed by the halogen and two phosphorus atoms relative to the face formed by the aliyl and two carbonyl groups is involved. Barriers for this process are between 10 and 12 kcal/mol in the iodide derivatives. The twist process interconverts certain pairs of isomers while retaining particular elements of chirality, indicating that when complexes of this type rearrange a pathway for racemization may not necessarily be present.

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Tungsten-phosphorus spin-spin coupling in tungsten carbonyl derivatives

Cited by 16 publications

References 4 publications

Phosphine-Based Dinuclear Platinum(II) Diamido, Amido−Hydroxo, Oxo−Amido, Oxo−Imido, Diimido, and Dihydrazido Complexes¹

Phosphine-Based Dinuclear Platinum(II) Diamido, Amido−Hydroxo, Oxo−Amido, Oxo−Imido, Diimido, and Dihydrazido Complexes¹

Phosphine-Based Platinum(II) Hydroxo and Oxo Complexes¹

Aspects of chirality retention in rearrangements of pseudooctahedral molybdenum and tungsten complexes

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Tungsten-phosphorus spin-spin coupling in tungsten carbonyl derivatives

Cited by 16 publications

References 4 publications

Phosphine-Based Dinuclear Platinum(II) Diamido, Amido−Hydroxo, Oxo−Amido, Oxo−Imido, Diimido, and Dihydrazido Complexes1

Phosphine-Based Dinuclear Platinum(II) Diamido, Amido−Hydroxo, Oxo−Amido, Oxo−Imido, Diimido, and Dihydrazido Complexes1

Phosphine-Based Platinum(II) Hydroxo and Oxo Complexes1

Aspects of chirality retention in rearrangements of pseudooctahedral molybdenum and tungsten complexes

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Phosphine-Based Dinuclear Platinum(II) Diamido, Amido−Hydroxo, Oxo−Amido, Oxo−Imido, Diimido, and Dihydrazido Complexes¹

Phosphine-Based Dinuclear Platinum(II) Diamido, Amido−Hydroxo, Oxo−Amido, Oxo−Imido, Diimido, and Dihydrazido Complexes¹

Phosphine-Based Platinum(II) Hydroxo and Oxo Complexes¹