Effect of bulky alkyl substituents on the dynamics and stability of platinum complexes with β-agostic bonding

Spencer, John L.; Mhinzi, Gaspar S.

doi:10.1039/dt9950003819

Cited by 34 publications

(26 citation statements)

References 17 publications

(1 reference statement)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pioneering studies on alkyl complexes from Orpen’s and Spencer’s research groups reported the synthesis of cationic [Pt(norbornyl)(P–P)] + complexes A1a – e (P–P = bidentate phosphine ligand) [34–35]. Further studies involved other alkyl ligands such as ethyl ( A2b – c ), 3,3-dimethylbutyl ( A3b – c ) and 2,3,3-trimethylbutyl ( A4 ) [36–38]. NMR spectroscopic data and X-ray structures of A1a [34] and A2b [36] demonstrate that these compounds display a β-agostic interaction filling the fourth coordination site.…”

Section: Reviewmentioning

confidence: 99%

See 1 more Smart Citation

True and masked three-coordinate T-shaped platinum(II) intermediates

Ortuño¹,

Conejero²,

Lledós³

2013

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

SummaryAlthough four-coordinate square-planar geometries, with a formally 16-electron counting, are absolutely dominant in isolated Pt(II) complexes, three-coordinate, 14-electron Pt(II) complexes are believed to be key intermediates in a number of platinum-mediated organometallic transformations. Although very few authenticated three-coordinate Pt(II) complexes have been characterized, a much larger number of complexes can be described as operationally three-coordinate in a kinetic sense. In these compounds, which we have called masked T-shaped complexes, the fourth position is occupied by a very weak ligand (agostic bond, solvent molecule or counteranion), which can be easily displaced. This review summarizes the structural features of the true and masked T-shaped Pt(II) complexes reported so far and describes synthetic strategies employed for their formation. Moreover, recent experimental and theoretical reports are analyzed, which suggest the involvement of such intermediates in reaction mechanisms, particularly C–H bond-activation processes.

show abstract

Section: Reviewmentioning

confidence: 99%

“…7) are in equilibrium with the hydrido–alkene isomers [34–38]. Experimental evidence points out that substituted alkyls and large chelate ring-size diphosphine ligands favor the β-agostic isomer.…”

Section: Reviewmentioning

confidence: 99%

True and masked three-coordinate T-shaped platinum(II) intermediates

Ortuño¹,

Conejero²,

Lledós³

2013

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

show abstract

“…The 'agostic' interaction beween transition metal centres and a C-H bond 1 remains a topic of enduring interest, and current research ranges from fundamental studies into the nature of the chemical bond to highly applied work examining the role of agostic bonds in catalysis. [2][3][4][5][6][7][8][9][10][11][12] In a series of recent papers, 13- 19 we have described the synthesis of a series of alkyl complexes of niobium, Tp Me2 NbX(R)(PhC᎐ ᎐ ᎐ CMe) and Tp Me2 NbX(R)-(MeC᎐ ᎐ ᎐ CMe) (Tp Me2 = hydrotris(3,5-dimethylpyrazolyl)borate) (Fig. 1) and conducted detailed spectroscopic and theoretical investigations into the nature of the agostic interactions between the metal centre and the alkyl substituent.…”

Section: Introductionmentioning

confidence: 99%

C–H and C–C agostic interactions in cycloalkyl tris(pyrazolyl)boratoniobium complexes

et al. 2003

View full text Add to dashboard Cite

H 11 (4),) have been prepared from Tp Me2 NbCl 2 (MeC᎐ ᎐ ᎐ CMe). The cyclopropyl complex 2a shows no sign of C-H agostic interactions either in the solid state (X-ray) or in solution. In contrast, the NMR spectra of 3 and 4 are temperature dependent as a consequence of an equilibrium between a major α-agostic species and a minor non-agostic one. Hybrid QM/MM calculations are used to rationalise the behaviour of these cycloalkyl species, and illustrate the subtle interplay of steric and electronic effects in these systems.

show abstract

“…Moreover, the H14 atoms are positioned on both sides of the PdS4 plan and, consequently they are oriented toward the dz 2 orbital of palladium(II) center, with H14…Pd…H14 angle of 180.000°. These short contacts with the Pd…H separation distance more than 2.2 Å provide a Pd…H-C interaction which can be regarded as a 3 center-4 electron (3c-4e) interaction using the electron pair in the dz 2 orbital of the central atom[39][40][41][42][43][44], whereas many complexes of transition metal showing well-known M…H-C interaction described as agostic interaction (3c-2e) with the M…H separation distance in the range of 1.8-2.2 Å[39,[45][46][47]. For Pd…H14-C14 contact, Intermolecular binding energy, ∆E, was calculated at the M062X/LANL2DZ/6-311++G(d,p)…”

mentioning

confidence: 99%

Synthesis and structural characterization of Pd(II) and Cu(I) complexes containing dithiophosphorus ligand and their catalytic activities for Heck reaction

et al. 2016

View full text Add to dashboard Cite

2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawesson's reagent) was made to react with benzylamine to produce [(PhCH2NH)(p-C6H4OMe)PS2] -[PhCH2NH3] + in a very facile manner. From the abovementioned product, two new complexes {Pd[(PhCH2NH)(p-C6H4OMe)PS2]2} (C1) and {Cu2(PPh3)2[(PhCH2NH)(p-C6H4OMe)PS2]2} (C2) were obtained in high yields whose molecular structures were ascertained by X-ray diffraction analysis, IR and NMR spectroscopy, and elemental analysis. The catalytic properties of both complexes were evaluated in the Heck reaction. High turnover numbers (TONs) and yields were observed for palladium catalyst and It was revealed that dicopper(I) complex by a distance of 2.84 Å between metal ions, bearing triphenylphosphine and dithiophosphorus ligands, can catalyze the Heck reaction. This is the first report of Cu(I) complex as catalyst in the Heck reaction. Natural bonding orbital (NBO) analysis for C1 indicated that natural charge on Pd atom is -0.07e and Pd atom has formed four sigma bonds with S atoms. Similarly, NBO analysis revealed no significant Cu…Cu interaction in dicopper complex C2.

show abstract

Effect of bulky alkyl substituents on the dynamics and stability of platinum complexes with β-agostic bonding

Cited by 34 publications

References 17 publications

True and masked three-coordinate T-shaped platinum(II) intermediates

True and masked three-coordinate T-shaped platinum(II) intermediates

C–H and C–C agostic interactions in cycloalkyl tris(pyrazolyl)boratoniobium complexes

Synthesis and structural characterization of Pd(II) and Cu(I) complexes containing dithiophosphorus ligand and their catalytic activities for Heck reaction

Contact Info

Product

Resources

About