Tri- and tetracoordinate copper(I) complexes bearing bidentate soft/hard SN and SeN ligands based on 2-aminopyridine

Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9, A-1060, Vienna, Austria.
Dalton Transactions (Impact Factor: 4.2). 07/2011; 40(26):7008-21. DOI: 10.1039/c1dt10377f
Source: PubMed


The coordination properties of the EN ligands N-(2-pyridinyl)amino-diphenylphosphine sulfide, N-(2-pyridinyl)amino-diisopropylphosphine sulfide, N-(2-pyridinyl)amino-diphenylphosphine selenide, N-(2-pyridinyl)amino-diisopropylphosphine selenide towards copper(I) precursors CuX (X = Br, I), [Cu(IPr)Cl] (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), and [Cu(CH(3)CN)(4)]PF(6) were studied. Treatment of CuX with EN ligands resulted in the formation of tricoordinate complexes of the type [Cu(κ(2)(E,N)-EN)X]. The reaction of [Cu(IPr)Cl] with EN ligands, followed by halide abstraction with AgSbF(6), afforded cationic tricoordinate complexes [Cu(κ(2)(S,N)-EN)(IPr)](+), while the reaction of [Cu(CH(3)CN)(4)](+) with two equivalents of EN ligands yielded tetrahedral complexes [Cu(κ(2)(E,N)-EN)(2)](+). Halide removal from [Cu(κ(2)(S,N)-SN)I] with silver salts in the presence of L = CH(3)CN and CNtBu afforded dinuclear complexes of the type [Cu(κ(2)(S,N),μ(S)-SN)(L)](2)(2+) containing bridging SN ligands. With the terminal alkynes HC≡CC(6)H(4)Me and HC≡CC(6)H(4)OMe, complexes of the formula [Cu(κ(2)(S,N)-SN-iPr)(η(2)-HC≡CC(6)H(4)Me)](+) and [Cu(κ(2)(S,N)-SN-iPr)(η(2)-HC≡CC(6)H(4)OMe)](+) were obtained. The mononuclear nature of these compounds was supported by DFT calculations. Most complexes were also characterized by X-ray crystallography.

11 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: A series of cationic palladium ally] complexes of the type [Pd(eta(3)-allyl)(kappa(2)(E,N)-EN-chelate)](+) containing several heterodifunctional EN (E = P, O, S, Se) ligands based on N-(2-pyridinyl)aminophosphines and oxo, thio, and seleno derivatives thereof are prepared. These complexes are studied by one- and two-dimensional NMR techniques together with X-ray and DFT calculations. Variable-temperature and phase-sensitive H-1,H-1 NOESY NMR measurements reveal both allyl and EN ligand dynamics. In the case of palladium, PN complexes' eta(3) to eta(1) isomerization takes place by opening the eta(3)-allyl group selectively at the trans position with respect to the phosphorus center, while for EN (E = O, S, Se) complexes an "apparent" allyl rotation is observed proceeding with Pd E and Pd N bond breaking. DFT calculations indicate that both isomerization processes are solvent assisted, in agreement with the NMR data. In addition, the use of the new palladium allyl complexes has been examined as catalysts for Suzuki-Miyaura coupling of various aryl bromides and arylboronic acids. [Pd(eta(3)-CHPhCHCH2) (ON-Ph)](+), bearing an eta(3)-cinnamyl ligand, is one of the most efficient catalysts, converting aryl bromides and arylboronic acids at 80 degrees C with a catalyst loading of 0.1 mol % quantitatively into the expected biaryl products.
    Organometallics 10/2011; 30(21-21):5928-5942. DOI:10.1021/om200766y · 4.13 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Several new coordinatively unsaturated iron(II) complexes of the types [Fe(EN-iPr)X2] (E = P, S, Se; X = Cl, Br) and [Fe(ON-iPr)2X]X containing bidentate EN ligands based on N-(2-pyridinyl)aminophosphines as well as oxo, thio, and seleno derivatives thereof were prepared and characterized by NMR spectroscopy and X-ray crystallography. Mössbauer spectroscopy and magnetization studies confirmed their high-spin nature with magnetic moments very close to 4.9 μB, reflecting the expected four unpaired d-electrons in all these compounds. Stable low-spin carbonyl complexes of the types [Fe(PN-iPr)2(CO)X]X (X = Cl, Br) and cis-CO,cis-Br-[Fe(PN-iPr)(CO)2X2] (X = Br) were obtained by reacting cis-Fe(CO)4X2 with the stronger PN donor ligands, but not with the weaker EN donor ligands (E = O, S, Se). Furthermore, the reactivity of [Fe(PN-iPr)X2] toward CO was investigated by IR spectroscopy. Whereas at room temperature no reaction took place, at −50 °C [Fe(PN-iPr)X2] added readily CO to form, depending on the nature of X, the mono- and dicarbonyl complexes [Fe(PN-iPr)(X)2(CO)] (X = Cl) and [Fe(PN-iPr)(CO)2X2] (X = Cl, Br), respectively. In the case of X = Br, two isomeric dicarbonyl complexes, namely, cis-CO,trans-Br-[Fe(PN-iPr)(CO)2Br2] (major species) and cis-CO,cis-Br-[Fe(PN-iPr)(CO)2Br2] (minor species), are formed. The addition of CO to [Fe(PN-iPr)X2] was investigated in detail by means of DFT/B3LYP calculations. This study strongly supports the experimental findings that at low temperature two isomeric low-spin dicarbonyl complexes are formed. For kinetic reasons cis,trans-[Fe(PN-iPr)(CO)2Br2] releases CO at elevated temperature, re-forming [Fe(PN-iPr)Br2], while the corresponding cis,cis isomer is stable under these conditions.
    Organometallics 12/2011; 30(24):6587-6601. DOI:10.1021/om200711q · 4.13 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The title compound, C(11)H(20)N(2)PS(+)·BF(4) (-), is a salt of 2-(diisopropyl-thio-phospho-ryl-amino)-pyridine, a chelating bidentate ligand that furnishes an S atom as a soft donor and a pyridine N atom as a hard atom for transition-metal complexation. The title salt crystallizes with two formula units in the asymmetric unit. The two independent cations are protonated at the pyridine N atoms and have the S atoms syn-oriented to them so as to form bent intra-molecular N-H⋯S hydrogen bonds, one of which one is bifurcated by involving also an N-H⋯F inter-action. The phospho-ryl-amino NH groups form near linear hydrogen bonds to proximal tetra-fluoro-borate anions. Five weak C-H⋯F and three weak C-H⋯S inter-actions link the constituents into a three-dimensional framework. As a result of the crystal packing, the two cations differ notably in conformation, as can be seen from the S-P-N-C torsion angles of -18.7 (1)° in the first and -35.1 (1)° in the second cation.
    Acta Crystallographica Section E Structure Reports Online 06/2012; 68(Pt 6):o1835-6. DOI:10.1107/S1600536812022295 · 0.35 Impact Factor
Show more