Gyroscope-Like Platinum and Palladium Complexes with Trans-Spanning Bis(pyridine) Ligands

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• 作者：Paul D. Zeits ; Giovanni Pietro Rachiero ; Frank Hampel ; Joseph H. Reibenspies ; John A. Gladysz
• 刊名：Organometallics
• 出版年：2012
• 出版时间：April 9, 2012
• 年：2012
• 卷：31
• 期：7
• 页码：2854-2877
• 全文大小：1036K
• 年卷期：v.31,no.7(April 9, 2012)
• ISSN：1520-6041

文摘

Pyridines with one or two substituents terminating in vinyl groups are prepared. Intramolecular ring-closing metatheses of trans-MCl₂ adducts and hydrogenations supply the title compounds. Williamson ether syntheses using the alcohols HO(CH₂)_nCH鈺怌H₂ (n = 1 (a), 2 (b), 3 (c), 4 (d), 5 (e), 6 (f), 8 (h), 9 (i)) and appropriate halides give the pyridines 2-NC₅H₄(CH₂O(CH₂)_nCH鈺怌H₂) (1a,b), 3-NC₅H₄(CH₂O(CH₂)_nCH鈺怌H₂) (2a鈥?b>e,h,i), and 2,6-NC₅H₃(CH₂O(CH₂)_nCH鈺怌H₂)₂ (4a鈥?b>d) in 92鈥?5% yields. Reactions of 3,5-NC₅H₃(COCl)₂ and HO(CH₂)_nCH鈺怌H₂ afford the diesters 3,5-NC₅H₃(COO(CH₂)_nCH鈺怌H₂)₂ (5a鈥?b>f,h, 90鈥?1%). The reaction of 3,5-NC₅H₃(4-C₆H₄OH)₂, Br(CH₂)₅CH鈺怌H₂, and Cs₂CO₃ yields 3,5-NC₅H₃(4-C₆H₄O(CH₂)₅CH鈺怌H₂)₂ (8; 32%). Reactions of PtCl₂ with 1a,b, 2a鈥?b>e,h,i, 4a,b (but not 4c,d), 5a,c鈥?b>f,h, and 8 afford the corresponding bis(pyridine) complexes trans-10a,b (40鈥?2%), trans-12a鈥?b>e,h,i (84鈥?6%), trans-17a,b (88鈥?2%), trans-19a,c鈥?b>f,h (94鈥?3%), and trans-22 (96%). Selected adducts are treated with Grubbs鈥?catalyst and then H₂ (Pd/C) to give trans-PtCl₂[2,2鈥?(NC₅H₄(CH₂O(CH₂)_2n+2OCH₂)H₄C₅N)] (trans-11a,b; 79鈥?3%), trans-PtCl₂[3,3鈥?(NC₅H₄(CH₂O(CH₂)_2n+2OCH₂)H₄C₅N)] (trans-13,d,h,i; 93鈥?0%), trans-PtCl₂[2,6,2鈥?6鈥?(NC₅H₃(CH₂O(CH₂)_2n+2OCH₂)₂H₃C₅N)] (trans-18a,b; 22鈥?0%), trans-PtCl₂[3,5,3鈥?5鈥?(NC₅H₃(COO(CH₂)_2n+2OCO)₂H₃C₅N)] (trans-20d鈥?b>f,h; 45鈥?4%), and trans-PtCl₂[3,5,3鈥?5鈥?(NC₅H₃(4-C₆H₄O(CH₂)₁₂O-4-C₆H₄)₂H₃C₅N)] (40%). A previously reported ring-closing metathesis of trans-PdCl₂[2,6-NC₅H₃(CH₂CH₂CH鈺怌H₂)₂]₂ is confirmed, and the new hydrogenation product trans-PdCl₂[2,6,2鈥?6鈥?(NC₅H₃((CH₂)₆)₂H₃C₅N)] (trans-16; 62%) is isolated. Additions of CH₃MgBr to 12b,h and 13d,h afford the corresponding PtClCH₃ species (94鈥?1%), but analogous reactions fail with 2-substituted pyridine adducts. The reaction of trans-19c with PhC鈮H and CuI/i-Pr₂NH gives the corresponding PtCl(C鈮Ph) adduct (18%). The crystal structures of trans-17a, trans-11b, trans-13d, trans-13h路CH₂Cl₂, trans-16, trans-18a,b, and trans-20e路2CHCl₃ are determined. Steric effects in the preceding data, especially involving 2-substituents and the MCl₂ or MCl(X) rotators, are analyzed in detail.