Palladium phosphine complexes from 8-(thio)-theophylline, 8-(methylthio)-theophylline and 8-(benzylthio)-theophylline

Romerosa, Antonio; López-Magaña, Carlos; Saoud, Mustapha; Mañas, Sonia; Colacio, Enrique; Suárez‐Varela, José

doi:10.1016/s0020-1693(00)00177-8

Cited by 16 publications

(12 citation statements)

References 10 publications

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“…In the present study, the tetrahedral distortion is limited to 6.5°, a value similar to that of 6.1°found by Mak and co-workers [35] in cis-[(Ph 2 Ppym) 2 PdCl 2 ] AE 1/ 2CH 2 Cl 2 and smaller than those found either by Jensen and co-workers [36] in cis-PdCl 2 [P(CH 3 ) 3 ] 2 and Romerosa et al [37] in [cis-Pd(8-BzTT) 2 (PPh 3 ) 2 ] (8.9°and 13.2°, respectively). The little steric demand of the two coordinated water molecules in the present complex, if compared to the bulk of other ligands [35][36][37], also contributes to keep the tetrahedral distortion to a minimum and help in stabilizing the cis geometry.…”

Section: X-ray Structure Analysis Of the Complexes Ia And Iia á 2ch 2supporting

confidence: 90%

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Synthesis, characterization and catalytic activity in the carbonylation of ethene of cis-[Pd(H2O)2(PPh3)2]X2·nH2O (X=p-CH3C6H4SO3, n=2; X=CH3SO3, n=0). X-ray structure of cis-Pd(H2O)2(PPh3)2](p-CH3C6H4SO3)2·2H2O and of cis-[Pd(H2O)2(PPh3)2](CH3SO3)2·2CH2Cl2

Cavinato¹,

Vavasori²,

Toniolo³

et al. 2004

Inorganica Chimica Acta

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The complexes cis-[Pd(H 2 O) 2 (PPh 3 ) 2 ]X 2 AE nH 2 O (Ia: X ¼ p-CH 3 C 6 H 4 SO 3 , n ¼ 2; IIa: X ¼ CH 3 SO 3 , n ¼ 0) have been synthesized by reacting Pd(OAc) 2 , PPh 3 and HX in acetone in the presence of H 2 O. They have been characterized by IR, 1 H and 31 P NMR spectroscopy and TA analysis. By re-crystallization of these complexes, crystals of Ia and IIa AE 2CH 2 Cl 2 suitable for the X-ray analysis have been obtained. The solid-state investigation of Ia reveals that the two p-toluenesulfonato units act as counter anions of a dicationic complex, in which the metal atom is surrounded in a square planar environment realized by two water molecules and two PPh 3 moieties that are cis to each other. The X-ray investigation of IIa AE 2CH 2 Cl 2 shows that also in this case the two PPh 3 are cis to each other and that in the acentric triclinic cell there are two independent [Pd(H 2 O) 2 (PPh 3 ) 2 ] 2þ units, together with two methanesulfonato counter anions and two crystallization molecules of CH 2 Cl 2 . The cationic complexes Ia and IIa are easily interconverted with the neutral species trans-[Pd(p-CH 3 C 6 H 4 SO 3 ) 2 (PPh 3 ) 2 ] (Ib) and trans-[Pd(CH 3 SO 3 ) 2 (PPh 3 ) 2 ] (IIb), respectively, depending on temperature and solvent. In chloroform at r.t., complex Ia catalyzes the carbonylation of ethene to a polyketone; at higher temperature in methanol it catalyzes the hydroesterification of ethene. In both cases catalysis is accompanied by CO 2 evolution. These results suggest that catalysis occurs via initial formation of a Pd(II)-H species by interaction of H 2 O with CO on the metal center though a reaction closely related to that of the water gas-shift.

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Section: X-ray Structure Analysis Of the Complexes Ia And Iia á 2ch 2supporting

confidence: 90%

“…The little steric demand of the two coordinated water molecules in the present complex, if compared to the bulk of other ligands [35][36][37], also contributes to keep the tetrahedral distortion to a minimum and help in stabilizing the cis geometry.…”

Section: X-ray Structure Analysis Of the Complexes Ia And Iia á 2ch 2mentioning

confidence: 99%

Synthesis, characterization and catalytic activity in the carbonylation of ethene of cis-[Pd(H2O)2(PPh3)2]X2·nH2O (X=p-CH3C6H4SO3, n=2; X=CH3SO3, n=0). X-ray structure of cis-Pd(H2O)2(PPh3)2](p-CH3C6H4SO3)2·2H2O and of cis-[Pd(H2O)2(PPh3)2](CH3SO3)2·2CH2Cl2

Cavinato¹,

Vavasori²,

Toniolo³

et al. 2004

Inorganica Chimica Acta

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“…This alludes to the instability of complexes of this nature. There is a single example of a related complex with cis ‐PPh 3 ligands and cis ‐monodentate N‐donor ligands, where the monodentate nature of the coordinated ligands in this case makes this scenario possible.…”

Section: Resultsmentioning

confidence: 99%

Structural and theoretical studies of the methoxycarbonylation of higher olefins catalysed by (Pyrazolyl‐ethyl)pyridine palladium (II) complexes

Zulu

Alam

Ojwach

et al. 2019

Applied Organom Chemis

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Reactions of 2-[1-(3,5-dimethylpyrazol-1-yl)ethyl]pyridine (L1) and 2-[1-(3,5diphenylpyrazol-1-yl)ethyl]pyridine (L2) with the [Pd (COD)Cl 2 ] or [Pd (COD)MeCl] produced palladium (II) complexes [Pd(L1)ClMe] (1), [Pd(L1) Cl 2 ] (C2), [Pd(L2)ClMe] (3), and [Pd(L2)Cl 2 ] (4) in quantitative yields. Solid state structures of complexes 1, 3 and 4 established the formation of mononuclear compounds, containing one bidentate ligand unit per metal atom, to give square planar complexes. All the other spectroscopic characterization data and elemental analyses were consistent with the observed structures. All the palladium (II) complexes 1-4 gave active catalysts in the methoxycarbonylation of 1-octenes. The catalysts demonstrated 100% chemoselectivities towards esters and favored the formation of linear isomers. Reaction conditions such as the type of phosphine derivative, acid promoter, solvent system, time, pressure and temperature have been investigated and shown to affect both the catalytic activity and regio-selectivity of the catalysts. Solid-angle modelling established the comparable steric contributions from the ligands, consistent with the similar regioselectivities of the resultant catalysts.

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“…Different synthetic strategies may be used to prepare 6: (i) [9] We could conclude that the palladium complex 6 contains a PPh 3 group, a chloride ligand and an 8-TTH Ϫ ligand, the latter coordinated through the S donor…”

Section: Characterisation and Mechanistic Studies Of The Formation Ofmentioning

confidence: 99%

New Dinuclear Palladium Phosphane Complexes Stabilised by 8‐Thiotheophylline

et al. 2003

Self Cite

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The new purine derivatives SS‐bis‐8‐(thio)‐theophylline (8‐BTTH2) and 8‐phenylthiotheophylline (8‐PhTTH), have been synthesised and characterised by elemental analysis, mass spectrometry and standard spectroscopic measurements. Reaction of 8‐BTTH2 with cis‐[PdCl2(PPh3)2] leads to the formation of the binuclear palladium complex [Pd(PPh3)(μ‐Cl)(8‐TT)]2 (8‐TTH2 = 8‐thiotheophylline) in which PPh3‐induced cleavage of the S−S bridge takes place. This complex reacts with pyridine to give a different dimeric palladium complex, [Pd(μ‐S,N‐8‐TT)(PPh3)Py]2, in which each of the two 8‐thio‐(theophylline) anions binds two metals through the N7 and S atoms. The process leading to the palladium complex has also been elucidated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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Palladium phosphine complexes from 8-(thio)-theophylline, 8-(methylthio)-theophylline and 8-(benzylthio)-theophylline

Cited by 16 publications

References 10 publications

Synthesis, characterization and catalytic activity in the carbonylation of ethene of cis-[Pd(H2O)2(PPh3)2]X2·nH2O (X=p-CH3C6H4SO3, n=2; X=CH3SO3, n=0). X-ray structure of cis-Pd(H2O)2(PPh3)2](p-CH3C6H4SO3)2·2H2O and of cis-[Pd(H2O)2(PPh3)2](CH3SO3)2·2CH2Cl2

Synthesis, characterization and catalytic activity in the carbonylation of ethene of cis-[Pd(H2O)2(PPh3)2]X2·nH2O (X=p-CH3C6H4SO3, n=2; X=CH3SO3, n=0). X-ray structure of cis-Pd(H2O)2(PPh3)2](p-CH3C6H4SO3)2·2H2O and of cis-[Pd(H2O)2(PPh3)2](CH3SO3)2·2CH2Cl2

Structural and theoretical studies of the methoxycarbonylation of higher olefins catalysed by (Pyrazolyl‐ethyl)pyridine palladium (II) complexes

New Dinuclear Palladium Phosphane Complexes Stabilised by 8‐Thiotheophylline

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