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Abstract Reactions oftrans‐(C6F5)(p‐tol3P)2Pt(C≡C)nSiEt3(PtC2nSi;n=5, 7, 9) and excessPtClin the presence of wetn‐Bu4N+F−(to effect protodesilylation) under Sonogashira‐type conditions (CuCl, base, other additives) afford the title compoundsPtC10Pt,PtC14Pt, andPtC18Ptin 42–32 % yields. A four‐fold substitution of the phosphine ligands inPtC10Ptby PEt3affordsPt'C10Pt’(78 %), and a Sonogashira reaction ofPt'C2HandPt'ClaffordsPt'C2Pt’(68 %). The analogous reaction withPtC2SiandPtClis unsuccessful, presumably for steric reasons. The crystal structures ofPtC10Pt,PtC14Pt,Pt'C10Pt′, andPt'C2Pt’exhibit a number of interesting trends and features. Certain sp chain extension reactions that lead to or employ the precursorsPtC10Si,PtC12Si,PtC14Si, andPtC18Sisometimes give byproducts derived from C2loss, and possible origins are discussed. Related phenomena have been reported by others in the course of synthesizing extended conjugated polyynes.
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When the Ferrocene Analogy Breaks Down: Metallocene Transmetallation Chemistry
Abstract Ferrocene1and its dianionic Fe(bis)(dicarbollide) analogue2are classical compounds that display unusual stability. These compounds are not known to undergo transmetallation chemistry of the Fe‐center and have been used extensively as chemical building blocks with consistent integrity. In this manuscript we describe the preparation of a charge compensated Fe(bis)(dicarbollide) species3 Feand its unprecedented transmetallation chemistry to Ir. Such reactions are hitherto unknown for any transition metal metallocene or metallacarborane complex. Additionally, we show that3 Fecan be deprotonated to afford the corresponding bis(NHC) Li‐carbenoid5that also displays unique reactivity. When5is reacted with [Ir(COD)Cl]2it also undergoes a rapid transmetallation of the ferrocene “like” core to afford6but with the added twist that the Li‐carbenoid moiety stays intact and does not transmetalate. However, when6is subsequently treated with CuCl, the Li‐carbenoid transmetalates to Cu, which allows the controlled formation of the corresponding heterobimetallic Ir/Cu aggregate. Lastly, when Li‐carbenoid5is treated directly with CuCl, a double transmetallation occurs from both Fe to Cu and Li‐carbenoid to Cu, resulting in the trimetallic Cu cluster8. These novel reactions pave the way for new synthetic methods to build complicated polymetallic clusters in a controlled fashion.
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- PAR ID:
- 10443917
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 62
- Issue:
- 39
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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