Wydział Chemii

Agnieszka J. Nawara-Hultzsch

Michael Stollenz

Michał Barbasiewicz

Sławomir Szafert

Tadeusz Lis

Frank A. Hampel

Nattamai Bhuvanesh

John A. Gladysz

2014

Chemistry-A European Journal

20

4617-4637

10.1002/chem.201304419

Naukowa

Angielski

Artykuł

Threefold intramolecular ring‐closing metatheses of trans‐[MCl₂(P{(CH₂)_mCHCH₂}₃)₂] are effected with Grubbs’ catalyst. Following hydrogenation catalyzed by [RhCl(PPh₃)₃], the title complexes trans‐[MCl₂(P((CH₂)_n)₃P)] (n=2m+2; M/n=Pt/14, 4 c; Pt/16, 4 d; Pt/18, 4 e; Pd/14, 5 c; Pd/18, 5 e) and sometimes isomers partly derived from intraligand metathesis, trans‐[MCl₂{P(CH₂)_n(CH₂)_n}P(CH₂)_n)] (4′c–e, 5′e), are isolated. These react with LiBr, NaI, and KCN to give the corresponding MBr₂, MI₂, and M(CN)₂ species (58–99 %). ¹³C NMR data show that the MX₂ moieties rapidly rotate within the diphosphine cage on the NMR timescale, even at −120 °C. The reaction of 4 c and KSCN gives separable Pt(NCS)₂ and Pt(NCS)(SCN) adducts (13 c, 28 %; 14 c, 20 %), and those of 4 c,e and Ph₂Zn give PtPh₂ species (15 c, 61 %; 15 e, 90 %). ¹³C NMR spectra of 13 c–15 c show two sets of CH₂ signals (ca. 2:1 intensity ratios), indicating that MX₂ rotation is no longer rapid. Reactions of 4 c or 4′c and excess NaCCH afford the free diphosphines P{(CH₂)₁₄}₃P (91 %) and (CH₂)₁₄P(CH₂)₁₄P(CH₂)₁₄ (90 %). The latter has been crystallographically characterized as a bis(BH₃) adduct. The crystal structures of eight complexes with P(CH₂)₁₄P linkages (PtCl₂, PtBr₂, PtI₂, Pt(NCS)₂, PtPh₂, PdCl₂, PdBr₂, PdI₂) and 15 e have been determined, and intramolecular distances analyzed with respect to MX₂ rotation. The conformations of the (CH₂)₁₄ moieties and features of the crystal lattices are also discussed.

diphosphine, ligands, Hydrogenation, olefin metathesis, palladium, platinum, substitution reactions

http://dx.doi.org/10.1002/chem.201304419

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