ISSN:0570-0833    

DOI:10.1002/anie.198707073

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198707171

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractAn unprecedented series of highly reactive alkene‐and diene‐complexes of the early transition metals (Groups 3A–5A of the periodic system) have been isolated recently. Diene complexes of this sort (M  Ti, Zr, Hf, Nb, Ta) prefer, besides the (η4‐s‐cis‐diene)metal structure, either a novel bent η4‐metallacyclo‐3‐pentene structure or the unique (η4‐s‐trans‐diene)metal structure. In bis(diene)metal complexes of Nb and Ta the η4‐s‐cis‐dienes assume an unusualexo‐endo(supine‐prone) geometry. The MC bonds in these diene‐metal complexes generally exhibit highly polarized σ‐bonding along with π‐bonding character. The complexes therefore undergo a variety of regio‐ and stereoselective carbometalations with substrates containing CC, CO, or CN multiple bonds. Examples of the products that can be obtained include ketones, vinyl ketones, unsaturated primary, secondary, and tertiary alcohols, as well as diols and unsaturated acids. Mechanistic studies on the stoichiometric and catalytic conversions of unsaturated hydrocarbons provides, inter alia,

ISSN:0570-0833    

DOI:10.1002/anie.198707231

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractMetal carbonyl clusters possess a complicated chemistry that is only beginning to be understood. One of the main current goals in this area is thus an understanding of their reactivity. This article describes the syntheses and reactions of clusters that contain metal carbonyl fragments bridged by a main‐group element. But what is the sense of making such clusters still more complicated by the incorporation of main‐group elements? The example of μ3‐bridged carbonyl clusters will serve to show that the main‐group element plays an important role in the study of reaction paths; it holds the metal carbonyl fragments together even when the bonds between them are broken in the course of a reaction. Trinuclear μ3‐bridged clusters prove to be small enough to allow the analysis of typical cluster reactions (such as the reversible breaking of metal‐metal bonds) in terms of single reaction steps. They are also large enough to provide surprises by their multifaceted reactivity. It will be shown that a detailed study of trinuclear RX‐bridged metal carbonyl clusters (X  N, P, As, Sb, Bi)—a very small part of carbonyl cluster chemistry—can lead to a better understanding of the general reactio

ISSN:0570-0833    

DOI:10.1002/anie.198707431

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198707611

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198707631

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198707641

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198707651

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198707671

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198707681

出版商:Hüthig&Wepf Verlag    

年代:1987

数据来源: WILEY