- Self-assembly of metal-organic hybrid nanoscopic rectangles
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The combination of an amide containing a linear ligand (L1) and an organometallic molecular "clip" (clip-1) leads to the self-assembly of a Pt4 nanoscopic framework representing the first example of a Pt-based molecular rectangle (rectangle-1)
- Ghosh, Sushobhan,Mukherjee, Partha Sarathi
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- 1,3-Bis(α-aminoisopropyl)benzene, meta-C6H4(CMe2NH2)2: An N,N-bridging and N,C,N-cyclometalating ligand
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Saponification of the bis(carbamic acid ester) 1,3-C6H4(CMe2NHCO2Me)2 (1), made by the addition of methanol to commercial 1,3-C6H4(CMe2NCO)2, yielded the me
- Dahlenburg, Lutz,Treffert, Harald,Heinemann, Frank W.
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- 3-Dimethylaminopropyl chalcogenolate complexes of palladium(II): Syntheses and characterization, including the crystal structures of [Pd(OAc)(ECH 2CH2CH2NMe2)]2· H2O (E = S, Se) and [PdCl(TeCH2CH2CH 2NMe2)]2
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The reactions of the sodium salts of 3-dimethylamino-1- propylchalcogenolates, prepared by sodium borohydride reduction of (Me 2NCH2CH2CH2E)2 in methanol, with Na2PdCl4 yielded homoleptic [Pd(ECH 2CH2CH2NMe2)2] 6 (1) (E = S (1a); Se (1b); Te (1c)). When treated with [Pd(OAc) 2]3 or Na2PdCl4, compounds 1 readily gave binuclear redistribution products [PdX(ECH2CH 2CH2NMe2)]2 where X = OAc (2) (E = S (2a); Se (2b); or Cl (3)) (E = S (3a); Se (3b); Te (3c)), respectively. The terminal acetate/chloride ligands in 2b/3b can be substituted by other ionic ligands like PhSe-. The complexes were characterized by elemental analysis, UV-Vis, IR and NMR spectroscopy. The structures of 2a, 2b and 3c were established by X-ray crystallography. Each molecule has a dimeric structure in which there are two chalcogenolate bridges from the chelating 3-dimethylamino-1-propylchalcogenolate ligands. On pyrolysis, compound 2b affords Pd17Se15.
- Dey, Sandip,Jain, Vimal K.,Varghese, Babu,Schurr, Thilo,Niemeyer, Mark,Kaim, Wolfgang,Butcher, Ray J.
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p. 1449 - 1457
(2008/10/09)
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- Synthesis and reactivity of a novel palladium germylene system
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The synthesis of three novel Pd germylene complexes is reported. (Ph3P)2PdGe[N(SiMe3)2]2 (1) was synthesized by ligand substitution of (Ph3P)4Pd, whereas (Et3P)PdGe[N(SiMe3)2]2 (2) and {appePdGe[N(SiMe3)2]2}2 (3b) (dppe = (diphenylphosphino)ethane) were synthesized by photolytic reduction of their corresponding phosphine oxalato complexes followed by addition of the germylene ligand. In solution, 3b exists in equilibrium with the monomeric dppePdGe[N(SiMe3)2]2 (3a). The germylene ligand of 2 was found to be 1 order of magnitude more labile than the analogous Pt system and 2 orders of magnitude less labile than the analogous Ni system. The reactivity of these new palladium germylenes toward O2 is described.
- Cygan, Zuzanna T.,Bender IV, John E.,Litz, Kyle E.,Kampf, Jeff W.,Banaszak Holl, Mark M.
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p. 5373 - 5381
(2008/10/08)
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- Structure and reactivity of (η3-indolylmethyl)palladium complexes generated by the reaction of organopalladium complexes with o-alkenylphenyl isocyanide
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Structure and reactivity of (η3-Indolylmethyl)palladium complexes generated by the reaction of organopalladium complexes with o-alkenylphenyl isocyanide were analyzed. The reaction of methylpalladium complexes with o-alkenylphenyl isocyanides r
- Onitsuka, Kiyotaka,Yamamoto, Mari,Suzuki, Shinobu,Takahashi, Shigetoshi
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p. 581 - 583
(2008/10/08)
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- Palladium-catalyzed insertion of 1,2- And 1,4-quinones into Si-Si bonds and its application to the modification of Si-Si-bond-containing polymers
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Me3SiSiMe3 reacted with 1,2- and 1,4-quinones (p-benzoquinone (2a), its derivatives, 1,2-and 1,4-naphthoquinone, 9,10-phenanthraquinone (2f), 9,10-anthraquinone) in the presence of palladium catalysts to give the corresponding bis(trimethylsiloxy) aromatics in excellent to moderate yields. Active palladium catalysts were PdCl2L2 (L = tertiary phosphine) and Pd(dibenzylideneacetone)2-2P(OCH2)3CEt, among which PdCl2(PEt3)2 was in general the most efficient. A 1,2-disilacyclohexane cleanly underwent the reaction with 2f to form a 10-membered cyclic adduct. The reaction of Me3SiSiMe2SiMe3 with 2a also afforded p-(Me3SiO)2C6H4, via formal extrusion of a silylene unit. Treatment of cis-(PhMe2Si)2Pt(P-Me2Ph)2 with 2a gave p-(PhMe2SiO)2C6H4, indicative of the involvement of bis(silyl)palladium species in the catalysis. Quinones 2a,f smoothly underwent the palladium-catalyzed insertion into the Si-Si bonds of (SiMePhSiMePh-p-C6H4)n (9a), (SiMe2SiMe2CH2CH2)n, and (SiMe2SiMe2O)n to give partially or exhaustively modified polymers with arylenedioxy units incorporated in the backbones. A polysilane, (SiMe2)n, also reacted with 2a to provide a polymer with -SiMe2-O-p-C6H4-O- linkages. Upon UV irradiation, a partially modified polymer obtained from 9a and 2f showed a smaller extent of decrease in molecular weight than did the original polymer. Modification with 2f improved the thermal stability of 9a in thermogravimetric analysis.
- Yamashita, Hiroshi,Reddy, N. Prabhakar,Tanaka, Masato
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p. 5223 - 5233
(2008/10/08)
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- Synthesis, reactions, and rearrangement of X(PR′3)2M[C(=PR)X] (M = Pt, Pd; X = Cl, Br; R′ = Et, Ph; R = 2,4,6-tri-tert-butylphenyl): Mechanism of the transition metal promoted conversion of X2C=PR to R-C≡P
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Oxidative addition reactions of X2C=PR (X = Cl, Br; R = 2,4,6-tri-tert-butylphenyl) with M(PEt3)4 (M = Pt, Pd) or (C2H4)Pt(PPh3)2 initially yield the cis isomer of square planar (X)-(PR′3)2M[C(=PR)X] (II); these complexes (IIa-IId), where PR′3 is PEt3, rearrange rapidly in the presence of free PEt3 to give the trans isomers (Ia-Id). In contrast, the cis isomers (IIe and IIf), where PR′3 is PPh3 and M is Pt, react further to give R-C≡P and cis-X2Pt(PPh3)2. In polar solvents (CH2Cl2 and CHCl3), all the addition products (I and II) convert to R-C≡P and cis- or trans-X2M(PR′3)2 via the surprising phosphabicyclo intermediate (X)(PR′3)2Pt-(X-PBC) (III and IV); the structure of IIIa was established crystallographically. In the presence of H2O, (X)(PEt3)2Pt[C(=PR)X] (Ia and Ib where X = Cl, Br) give the oxophosphabicyclo complex (X)(PEt3)2Pt[(H)O=PBC] (Va and Vb) which was characterized by X-ray diffraction. A mechanism for the conversion of (X)(PR′3)2M[C(=PR)X] to R-C≡P and X2M-(PR′3)2 is proposed.
- Jun, Hyoung,Young Jr., Victor G.,Angelici, Robert J.
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p. 2444 - 2453
(2008/10/08)
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- Synthesis and Characterization of Cyclometallated Complexes of Benzalazines. Crystal and Molecular Structure of 2>
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The reaction of benzalazines, (p-RC6H4CH=N-)2 (R=H, Cl, NO2, or NMe2), with PdCl2 leads in the first two cases to the formation of cyclometallated polymeric species that react with phosphines to yield dimetallated compounds 2> (R'=Et or Ph) and/or .Phosphine exchange reactions give the complex 2>.The molecular structure of 2> has been determined by a single-crystal X-ray analysis.The crystals are monoclinic, space group P21/n, a=11.124(3), b=10.062(2), c=22.566(5) Angstroem, β=102.95(3) degree, and Z=2; R=0.052 for 3 306 reflections.Palladium atoms are five-co-ordinated, the Pd-N distance being 2.743 Angstroem.However, n.m.r. spectra show that, in solution, free rotation around the C(aromatic)-C(azomethine) bonds does occur even at -100 deg C.
- Granell, Jaime,Sales, Joaquim,Vilarrasa, Jaume,Declercq, Jean P.,Germain, Gabriel,et al.
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p. 2441 - 2446
(2007/10/02)
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- Synthesis and characterization of tungsten oxo neopeniyiidene complexes1
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Tantalum complexes of the type Ta(CHCMe3)X3(PR3)2 (X = Cl or Br) react with W(O)(OCMe3)4 to give [Ta(OCMe3)4X]2 and W(O)(CHCMe3)X2(PR
- Wengrovius, Jeffrey H.,Schrock, Richard R.
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p. 148 - 155
(2008/10/08)
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- Photochemical Preparation of the cis Isomers of Dichlorobis(tri-n-alkyl-phosphine)palladium(II) (alkyl = Et, Prn, or Bun); the Crystal-structure Analysis of the Overcrowded n-Propyl Homologue
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Ultraviolet irradiation of the trans forms of the title compounds in nitromethane gives up to 70percent of the labile cis isomers, which can be isolated in crystalline form.Irradiation of a 1:1 mixture of trans- and trans-n3)2Cl2> gives almost entirely a 1:1 mixture of the corresponding cis isomers and only a few percent of cis-n3)Cl2>, indicating a predominantly intramolecular mechanism.Crystals of cis-n3)2Cl2> are monoclinic, with space group P21/m, a=9.729(1), b=13.816(3), c=9.614(1) Angstroem, β=100.77(1) deg, and Z=2.The structure has been refined to R=0.029 for 1 873 reflections collected by a four-circle diffractometer.The cis-planar structure reveals considerable overcrowding .The Pd-P distances are short (mean 2.322 Angstroem) and the Pd-Cl distances long (mean 2.407 Angstroem), attributable to the trans effect.
- Alcock, Nathaniel W.,Kemp, Terence J.,Wimmer, Franz L.
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p. 635 - 638
(2007/10/02)
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- Studies of trinuclear palladium clusters by 31P NMR spectroscopy: Reactivity of [Pd3Cl(PPh2)2(PR3) 3][BF4] complexes (R = et or Ph) and the synthesis of [Pd3(PPh2)3(PR3) 3][BF4]
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A study of the reactivity of the new palladium clusters [Pd3(μ-Cl)(μ-PPh2)2(PR3) 3][BF4] (R = Et or Ph) is described. The products are characterized mainly by 31P NMR studies, and these spectra are discussed in detail. The bridging chloride and terminal tertiary phosphine ligands are all labile, and, in particular, reaction with diphenylphosphine and p-toluidine leads to elimination of HCl and formation of [Pd3(μ-PPh2)3(PR3) 3][BF4] clusters. [Pd3(μ-PPh2)3(PPh3) 3]+ is also formed by reaction of [Pd(PPh3)4] with [Pd2Cl2(μ-PPh2)2(PHPh 2)2]. Reaction of [Pd3(μ-Cl)(μ-PPh2)2(PR3) 3][BF4] with H2O2 and HCl leads to a remarkable, stereospecific ring opening with oxidation of all the palladium atoms to PdII. The product, cis,cis,cis-[Cl(PR3)Pd(μ-PPh2)(μ-Cl)Pd(μ-PPh 2)(μ-Cl)PdCl(PR3)], reacts with 2 mol of PR3 to yield trans-[PdCl2(PR3)2] and [Pd2Cl2(μ-PPh2)2(PR 3)2]. This entire oxidative degradation sequence is almost quantitative.
- Cartwright, S. James,Dixon, Keith R.,Rattray, Alexander D.
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p. 1120 - 1124
(2008/10/08)
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