Four-membered rings from isocyanides: Developments since the mid 1980s
نویسندگان
چکیده
منابع مشابه
Austria: Persistent low fertility since the mid-1980s
This chapter offers an in-depth analysis of fertility in Austria, a country which has experienced a low and relatively stable fertility level and a gradual postponement of childbearing since the mid-1980s. We begin by summarising Austrian population trends in the post-World War II period and highlighting recent relatively high migration levels. We outline the long history of sub-replacement fer...
متن کاملDevelopments in soil microbiology since the mid 1960s
Since the 1960s, soil microbiology underwent major changes in methods and approaches and this review focuses on the developments in some selected aspects of soil microbiology. Research in cell numbers of specific bacterial and fungal groups was replaced by a focus on biochemical processes including soil enzyme activities, and flux measurements of carbon and nutrients. Ecologists focused on soil...
متن کاملElectronic structure of N₂P₂ four-membered rings.
The biradicaloid character of the ground-state structures of N2P2 rings is studied by using the high-level ab initio multiconfigurational CASPT2/CASSCF method. In order to obtain accurate descriptors, we combine two criteria: 1) singlet-triplet energy gaps and 2) relative values of the occupation numbers for bonding and antibonding orbitals associated with the radical sites. The singlet-triplet...
متن کاملCoulomb repulsion versus cycloaddition: formation of anionic four-membered rings from sodium phosphaethynolate, Na(OCP).
Carbon dioxide and two equivalents of Na(OCP) form, in an equilibrium reaction, a CO2 adduct of the composition Na2(P2C3O4). The anion of this salt, [O2C-P(CO)2P](2-), is built up by a four-membered 1,3-diphosphetane-2,4-dione ring and a carboxylate unit attached to one of the phosphorus atoms. A remarkable π-delocalization was observed within the OCPCO moiety. The stepwise reaction mechanism l...
متن کاملMagnetic Circular Dichroism (MCD) of Four-membered Rings with four jr-Electrons
Michl extended the perimeter model of cyclic ^-electron systems, which was originally developed by Piatt [ 1 ] and Moffit [2], to the interpretation of absolute signs in magnetic circular dichroism (MCD) [3-5], A set of rules was derived by him that accounted for a large number of MCD signs in the spectra of all kinds of aromatic JTsystems, i.e. those derived from a (4/V+2)-electron perimeter. ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Arkivoc
سال: 2014
ISSN: 1551-7012
DOI: 10.3998/ark.5550190.p008.224