A series of eight 1-halo-8-(alkylchalcogeno)naphthalene derivatives (1-8; halogen=Br, I; alkylchalcogen=SEt, SPh, SePh, TePh) containing a halogen and a chalcogen atom occupying the peri positions have been prepared and fully characterised by using X-ray crystallography, multinuclear NMR spectroscopy, IR spectroscopy and MS. Naphthalene distortion due to non-covalent substituent interactions wa...

Introduction Noncovalent interactions modulate the structure, function, and dynamics of the molecules of life [1]. We have discovered a noncovalent interaction in proteins and nucleic acids, termed the n→π* interaction, in which the lone pair (n) of a donor group (typically a carbonyl oxygen) overlaps with the antibonding orbital (π*) of an acceptor group (typically a carbonyl group) (Figures 1...

In this work we present a set of force fields for nine synthetically relevant and/or structurally interesting N-heterocyclic carbenes, including imidazol-, thiazol-, triazol-, imidazolidin-, and pyridine-ylidenes. The bonding parameters were calculated by using a series of geometry optimizations by ab initio methods. For fitting the non-bonding interactions, a water molecule was employed as a p...

Electronic delocalization, a central concept in organic chemistry, is being invoked increasingly in biological contexts [1–3]. We have discovered a non-covalent interaction in proteins, termed the n→π* interaction, in which the lone pair (n) of the oxygen (Oi–1) of a peptide bond overlaps with the antibonding orbital (π*) of the carbonyl group (C′i=Oi) of the subsequent peptide bond (Figure 1A,...

We here present a statistical model of hydrogen bond induced network structures in liquid alcohols. The model generalises the Andersson-Schulz-Flory chain model to allow also for branched structures. Two bonding probabilities are assigned to each hydroxyl group oxygen, where the first is the probability of a lone pair accepting an H-bond and the second is the probability that given this bond al...

Oligoethylene glycols are used as crowding agents in experiments that aim to understand the effects of intracellular environments on DNAs. Moreover, DNAs with covalently attached oligoethylene glycols are used as cargo carriers for drug delivery systems. To investigate how oligoethylene glycols interact with DNAs, we incorporated deoxythymidine modified with oligoethylene glycols of different l...

The electronic structure and reactivity of neutral tricoordinated Be(0) compounds BeL(3), L = CO (1), NHC (2) and PMe(3) (3) are explored by quantum mechanical calculations. These BeL(3) complexes are found to be planar or nearly planar like electron deficient BH3 but isoelectronic with NH3 and possess three L→Be donor-acceptor bonds. The Be atom can be considered as sp(2)-hybridized with a lon...

Two nitrogen atoms and a flexible carbon skeleton make N,N,N0,N0-tetramethylethylenediamine (TMEDA) an important model system to study the interplay of conformeric motions and charge delocalization. Ionization of one of the nitrogen atoms generates a localized charge that may (partially) transfer to the other nitrogen. The structural motions, conformation dependent electron lone pair interactio...

ReceiVed: May 7, 2004; In Final Form: September 24, 2004 In a recent paper by Chamorro and Notario (CN),1 the pericyclic or pseudopericyclic character of the thermal cyclization of (Z)-1,2,4,6-heptatetraene (C) and its heterosubstituted analogues (A and B) (see Scheme 1) was discussed by means of a topological electron localization function (ELF) analysis applied to the corresponding transition...