58466-03-8Relevant academic research and scientific papers
Combinatorial approach to chiral tris-ligated carbophilic platinum complexes: Application to asymmetric catalysis
Pradal, Alexandre,Gladiali, Serafino,Michelet, Veronique,Toullec, Patrick Y.
supporting information, p. 7128 - 7135 (2014/06/09)
A straightforward methodology for the synthesis of libraries of chiral tris-ligated cationic platinum complexes and their in situ evaluation as asymmetric carbophilic catalysts in a model domino hydroarylation/cyclization reaction of a 1,6-enyne was developed. A catalyst-generation process based on a combination of a monodentate and a bidentate phosphorus ligand allowed the formation of 108 chiral complexes. One-pot screening of the stereoinduction obtained with this library in a test domino addition/cyclization reaction validated this approach and stressed the key role played by the monodentate ligand partner in obtaining high enantioselectivities. In the case of two challenging substrate/nucleophile combinations, the combinatorial approach resulted in a significant gain in enantioselectivity.
Synthesis and characterisation of 2,2-bis(hydroxymethyl)-1,3-diselenolato metal(II) complexes bearing various phosphanes
Niksch, Tobias,Goerls, Helmar,Friedrich, Manfred,Oilunkaniemi, Raija,Laitinen, Risto,Weigand, Wolfgang
, p. 74 - 94 (2010/04/01)
An improved synthesis of 4,4-bis(hydroxymethyl)-1,2-diselenolane and the complexation properties of the corresponding diselenolato dianion to group-10 metals are reported. We describe an efficient and straightforward procedure that bypasses the isolation of the malodorous and airsensitive diselenol and starts with the diselenide appropriate group-10 metal complex bearing phosphane and chlorido ligands. A series of complexes with various monoand bidentate phosphanes is prepared and characterised by multinuclear NMR spectroscopy, mass spectrometry, and elemental analysis. Furthermore, the structure of most complexes is studied by single-crystal X-ray diffraction to establish their supramolecular arrangement in the solid state. Consequently, several group-10 metal complexes with P-M-P angles (bite angles) in the range from 71-108° are investigated. The use of the sterically demanding bridging phosphane 4,5-bis(diphenylphosphanyl)-9,9-dimethylxanthene, which exhibits a large bite angle yields a mixture of a di- and trinuclear complex. While the platinum-containing complexes are proven to be rather stable, the palladium and nickel analogues tend to decompose. Especially, the nickel complexes were found to be sensitive against: oxidation. This circumstance leads to the formation of the so far unknown 1,8-bis(diphenylphosphanyl)naphthalene monooxide, the formation and structure of which could be confirmed from NMR spectroscopic data and single-crystal X-ray diffraction.
Luminescent diphosphine dithiolate complexes of platinum(II): Synthesis, characterization, and structure
Bevilacqua, Joanne M.,Zuleta, Juan A.,Eisenberg, Richard
, p. 258 - 266 (2008/10/08)
The synthesis, characterization, and emission properties of a series of Pt(diphosphine)(dithiolate) complexes are reported. Diphosphine ligands include 1,2-bis(diphenylphosphino)ethane (dppe), 1,2-bis(diphenylphosphino)ethylene (dppv), 1,2-bis(diphenylphosphino)benzene (dppb), 1,2-bis(dicyclohexylphosphino)ethane (chpe), bis(diphenylphosphino)methane (dppm), 1,2-bis(dimethoxyphosphino)ethane (pompom), triphenylphosphine (PPh3), dimethylphenylphosphine (PMe2Ph), tricyclohexylphosphine (PCy3), triphenyl phosphite (P(OPh)3), and triisopropyl phosphite (P(O-i-Pr)3). Dithiolate ligands include maleonitriledithiolate (mnt) and 1-(ethoxycarbonyl)-1-cyanoethylene-2,2-dithiolate (ecda). The complexes are readily synthesized by the addition of the diphosphine ligand to Pt(COD)(dithiolate). On the basis of characterizations using NMR and infrared spectroscopies, all of the complexes are assigned square planar coordination geometries with varying degrees of distortion determined by ligand steric and electronic effects. The assignment of square planar coordination is confirmed by single crystal structure determinations of Pt(dppe)(mnt) (1a) and Pt(dppb)(mnt) (3a). Pink crystals of Pt(dppe)(mnt) (1a) (C30H24N2P2PtS2) are monoclinic, space group P21/n (No. 14), with a = 11.491(4) ?, b = 12.484(2) ?, c = 19.822(7) ?, β = 91.34(1)°, V = 2842.90 ?3, Z = 4, and final R = 0.029 (Rw = 0.031) for 4793 unique reflections. Orange crystals of Pt(dppb)(mnt) (3a) (C34H24N2P2PtS2) are monoclinic, space group P21/n (No. 14), with a = 10.050(7) ?, b = 19.301(3) ? c, = 15.800(6) ?, β = 94.36(6)°, V = 3056.28 ?3, Z = 4, and final R = 0.030 (Rw = 0.036) for 5576 unique reflections. The average Pt-S (2.299(7) ? for 1a and 2.301(2) ? for 3a) and Pt-P (2.257(2) ? for 1a and 2.256(7) ? for 3a) bond distances in each structure agree well with previously reported structural results. The metrical parameters of the mnt chelate ring indicate some degree of metal-ligand delocalization in both structures. The 31P NMR spectra of the phosphines resonances for all of the complexes show platinum satellites (1JPt-P = 1100-2500 Hz). In addition, the ecda complexes exhibit complex second-order coupling patterns, arising from the asymmetry of the ecda ligand. All of the complexes exhibit strong emission in the solid state and in frozen glasses at 77 K. Emission spectra are structured for the mnt complexes and broad and featureless for the ecda complexes. Solid-state emission lifetimes at 77 K are in the microsecond range.
UEBER DEN MECHANISMUS DER LICHT-INDUZIERTEN ELIMINIERUNG DES BIPHENYL-SYSTEMS AUS cis-BIS(PHENYL)PLATIN(II)-VERBINDUNGEN
Klotzbuecher, Rainer,Brune, Hans Albert
, p. 399 - 407 (2007/10/02)
We report the light-induced reductive elimination of the biphenyl system from compounds of the types bis(phenyl)2-1,2-bis(diphenylphosphano)ethan>platinum(II), bis(phenyl)2-cis-1,2-bis(diphenylphosphano)ethene>platinum(II) and bis(phenyl)2-1,2-bis(diphenylphosphano)benzene>platinum(II) with substituents in the platinum-bound phenyl rings.The elimination proceeds via a concerted reaction mechanism without any observable free radical involvement.
