Transition metal pentacoordination

Rossi, Angelo R.; Hoffmann, Roald

doi:10.1021/ic50144a032

Cited by 666 publications

(401 citation statements)

References 101 publications

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“…Both the iPr substituent and the metal fragment are oriented in the equatorial position. In solution, the observed 31 P NMR chemical shift at d = À45.2 ppm is very similar to that found for 7 a, but the more condensed structure of 7 b is evident from its more shielded 13 C NMR chemical shifts with differences of 6 and 8 ppm for those of the phosphirane ring. Also the 1 H NMR chemical shifts of particularly the endo and exo methylene hydrogen atoms of this ring are more shielded (d = 0.87 and 1.47 ppm) with a larger difference between them (7 b Dd H = 0.61, 7 a Dd H = 0.39).…”

Section: Resultssupporting

confidence: 67%

“…X-ray single-crystal structure determination [12] confirmed the bicyclic structure of 7 b ( Figure 2) and showed it to be in an axial position to the Fe complex, as expected for a weak p-acceptor ligand. [13] We are aware of only one other related crystal structure, namely that of the monocyclic 2,3,3-tri(trimethylsilyl)phosphirane-Fe(CO) 2 Cp complex. [14] The structural data of the C 2 P ring of 7 b compare well with those of W(CO) 5 -complexed phosphiranes.…”

Section: Resultsmentioning

confidence: 99%

“…To verify this we reacted symmetrically substituted 13 with Collmans reagent to synthesize 14 (71 %) as a stable yellow liquid (Scheme 4). Not only are its 1 H, 13 C, and (Figure 4c). These effects are best explained by shuttling of the transient phosphinidene complex between the two double bonds as illustrated in Scheme 5.…”

Section: Dynamic Behaviourmentioning

confidence: 99%

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Strained, Stable 2‐Aza‐1‐Phosphabicyclo[n.1.0]alkane and ‐alkene Fe(CO)₄ Complexes with Dynamic Phosphinidene Behavior

Borst

Riet

Lemmens

et al. 2005

Chemistry A European J

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The synthesis of highly strained bicyclic phosphirane and phosphirene iron–tetracarbonyl complexes, that is, complexes with 2‐aza‐1‐phosphabicyclo[n.1.0]alkanes and ‐alkenes (n=3–5), is explored by using intramolecular cycloaddition of an in situ generated electrophilic phosphinidene complex, [R(iPr)NPFe(CO)4], to its CC‐ and CC‐containing R substituent. Saturated bicyclic complexes 7 a–c with n=4–2 are remarkably stable, as illustrated by the X‐ray crystal structure for 7 b (n=3), yet all readily undergo retroaddition to react with phenylacetylene. Shuttling of the phosphinidene iron complex between two equivalent CC groups is demonstrated for a 1‐butene‐substituted 2‐aza‐1‐phosphabicyclo[3.1.0]hexane by selective 1H NMR magnetization transfer from the phosphirane protons to the olefinic protons. Even the more strained unsaturated bicycles 17 a,b (n=4,3) are surprisingly stable as illustrated by the X‐ray crystal structure for 17 a (n=4), but the smaller phosphabicyclo[3.1.0]hex‐5‐ene (17 c, n=2) dimerizes to tricyclic 19 with a unique ten‐membered heterocyclic ring; an X‐ray crystal structure is reported. Like their saturated analogues also the bicyclic phosphirenes readily undergo retroaddition as shown by the reaction of their phosphinidene iron moiety with phenylacetylene.

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Section: Resultssupporting

confidence: 67%

Section: Resultsmentioning

confidence: 99%

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Strained, Stable 2‐Aza‐1‐Phosphabicyclo[n.1.0]alkane and ‐alkene Fe(CO)₄ Complexes with Dynamic Phosphinidene Behavior

Borst

Riet

Lemmens

et al. 2005

Chemistry A European J

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“…For five-coordinate Cu" complexes, the five Cu--D bond lengths are usually not identical. Tetragonal elongation of the apical bond in SQP (4 + 1 geometry) and less pronounced trigonal compression of the axial bonds in TBP coordination are often observed (Addison, Nageswara Rao, Reedijk, van Rijn & Verschoor, 1984;Rossi & Hoffmann, 1974). Also observed are folded, or tetrahedrally distorted, elongated SQP geometries with C 2 symmetry and two trans apical base valence angles greater than and two less than 90.…”

Section: The Reference Sqp and Tbp Polyhedra On The Tbp~-~sqp Paths Amentioning

confidence: 99%

The Deformation of Di-μμ-halide Dinuclear Five-Coordinate Copper(II) Complexes in the Crystalline State

Bukowska-Strzyżewska¹,

Maniukiewicz²,

Sieroń³

1997

Acta Crystallogr Sect B

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The coordination geometries of 154 dinuclear di-/zchloro, di-#-bromo and di-/z-fluoro five-coordinate (4 + 1) copper(II) complexes have been analyzed by the structural correlation method. Two reference Cu n polyhedra have been established: (i) a trigonal bipyramid (TBP) in which the equatorial bond lengths are equal, but with the symmetry at the metal often deformed from D3h to C2, and (ii) an elongated square pyramid (SQP), with either a pyramidally or tetrahedrally distorted base, in which the trans valence angles are equal. Six different paths for the SQP~TBP deformation of the Cu n coordination have been established from three criteria: (a) the location of the bridging ligands (axial and equatorial or equatorial and equatorial in TBP); (b) the nature of the deformation of the SQP base plane (pyramidal or tetrahedral); (c) whether a bridging or nonbridging bond is elongated in a SQP. The causes of the angular distortions from C 2 symmetry along the apical bond of a SQP, typical for the TBP~SQP Berry path, are analyzed. A progressive reduction of the tetragonal elongation of the Cu--D apical (SQP) bond length along the SQP~,-~-TBP transformation path and trigonal equalization of the three equatorial Cu--D (TBP) bonds are observed. The dependence of the average Cu--Cu' distance and Cu--X--Cu' angles on the deformation path are also established.

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“…Theoretical calculations (Rossi & Hoffmann, 1975) suggest that 7r-donor ligands (such as Br and N3) will prefer axial positions in d 8 tbp complexes. This is borne out only in the present case.…”

Section: Introductionmentioning

confidence: 99%

Azidotetrakis(trimethylphosphine)nickel(II) Tetrafluoroborate

Carson¹,

Pike²,

Carpenter³

1995

Acta Crystallogr C

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Transition metal pentacoordination

Cited by 666 publications

References 101 publications

Strained, Stable 2‐Aza‐1‐Phosphabicyclo[n.1.0]alkane and ‐alkene Fe(CO)₄ Complexes with Dynamic Phosphinidene Behavior

Strained, Stable 2‐Aza‐1‐Phosphabicyclo[n.1.0]alkane and ‐alkene Fe(CO)₄ Complexes with Dynamic Phosphinidene Behavior

The Deformation of Di-μμ-halide Dinuclear Five-Coordinate Copper(II) Complexes in the Crystalline State

Azidotetrakis(trimethylphosphine)nickel(II) Tetrafluoroborate

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Transition metal pentacoordination

Cited by 666 publications

References 101 publications

Strained, Stable 2‐Aza‐1‐Phosphabicyclo[n.1.0]alkane and ‐alkene Fe(CO)4 Complexes with Dynamic Phosphinidene Behavior

Strained, Stable 2‐Aza‐1‐Phosphabicyclo[n.1.0]alkane and ‐alkene Fe(CO)4 Complexes with Dynamic Phosphinidene Behavior

The Deformation of Di-μμ-halide Dinuclear Five-Coordinate Copper(II) Complexes in the Crystalline State

Azidotetrakis(trimethylphosphine)nickel(II) Tetrafluoroborate

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Product

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Strained, Stable 2‐Aza‐1‐Phosphabicyclo[n.1.0]alkane and ‐alkene Fe(CO)₄ Complexes with Dynamic Phosphinidene Behavior

Strained, Stable 2‐Aza‐1‐Phosphabicyclo[n.1.0]alkane and ‐alkene Fe(CO)₄ Complexes with Dynamic Phosphinidene Behavior