2004; Bernstein 2006; Pavlov et al. 2006; Pizzarello 2006; Sandford 2008; Bada
2009; Glavin and Dworkin 2009; de Duve 2011; Sojo 2015).
Chirality plays a crucial role in the current struggle to unravel this important
principal scientific question. Thus, refined enantiomer-selective separation methods
were actively applied earlier for the identification and characterisation of chiral
organic molecules in extra-terrestrial materials (Engel et al. 1990; Cronin and
Pizzarello 1997; Pizzarello and Cronin 2000). As a further step, enantiomer-selective
chromatography coupled to a mass-selective detector was installed on the Rosetta
Mission of the European Space Agency (ESA) in the early 2000s aiming at in situ
identification and enantiomer-selective analysis of amino acids and other chiral
organic molecules in surface samples from the Churyumov-Gerasimenko comet
(Szopa et al. 2002a, b; Evans et al. 2012). However, due to challenges during the
landing procedures of the Philae lander, the representative measurements could not
be completed and the final proof for the presence of enantiomeric amino acids on
extra-terrestrial objects still remains to be confirmed.
1.6 General Principles of Chirality in Chemistry
Nowadays, the general principles of chirality and the associated nomenclature for
enantiomeric compounds are included in basic lectures of organic chemistry (Prelog
1976; Helmchen 2016). Therefore, we do not wish to duplicate this general information in the present monograph but rather refer to the general literature in chemistry. On the other hand, scientists of other disciplines may not be that familiar with
the terminology and basic rules, which are assumed to be crucial for a comprehensive understanding of molecular structures determining chiral molecules and
enantioselective processes, as discussed in the present monograph. Therefore, we
decided to form a uniform “stage” for readers of all disciplines by giving a brief
survey on some crucial aspects ruling chiral molecules and enantioselective processes. In order to meet the requirements of the present monograph as closely as
possible, examples for the different types of chirality will be represented by chiral
environmental pollutants discussed herein.
Chirality in chemistry is a very important field of Stereoisomerism according to
the following definitions: stereoisomers are chemical substances made up of the
same atoms, bonded by the same sequence of bonds, but possessing different threedimensional structures which are not interchangeable. These three-dimensional
structures are called configurations. In the same way as many things around us,
such as our hands and pairs of shoes, are not identical, but the mirror images of one
another, non-identical stereoisomers exist, in which the only distinction between
them is that one is the mirror image of the other. However, these mirror images are
not superimposable. A simple example of this type of stereoisomerism is represented
by the herbicide dichlorprop (or DCPP), that is, 2-(2,4-dichlorophenoxy)propionic
acid (Fig. 1.3), which can exist in two spatial configurations that correspond to
reflections of each other. These stereoisomers are specifically called enantiomers. A
6
1 Introduction
2009; Glavin and Dworkin 2009; de Duve 2011; Sojo 2015).
Chirality plays a crucial role in the current struggle to unravel this important
principal scientific question. Thus, refined enantiomer-selective separation methods
were actively applied earlier for the identification and characterisation of chiral
organic molecules in extra-terrestrial materials (Engel et al. 1990; Cronin and
Pizzarello 1997; Pizzarello and Cronin 2000). As a further step, enantiomer-selective
chromatography coupled to a mass-selective detector was installed on the Rosetta
Mission of the European Space Agency (ESA) in the early 2000s aiming at in situ
identification and enantiomer-selective analysis of amino acids and other chiral
organic molecules in surface samples from the Churyumov-Gerasimenko comet
(Szopa et al. 2002a, b; Evans et al. 2012). However, due to challenges during the
landing procedures of the Philae lander, the representative measurements could not
be completed and the final proof for the presence of enantiomeric amino acids on
extra-terrestrial objects still remains to be confirmed.
1.6 General Principles of Chirality in Chemistry
Nowadays, the general principles of chirality and the associated nomenclature for
enantiomeric compounds are included in basic lectures of organic chemistry (Prelog
1976; Helmchen 2016). Therefore, we do not wish to duplicate this general information in the present monograph but rather refer to the general literature in chemistry. On the other hand, scientists of other disciplines may not be that familiar with
the terminology and basic rules, which are assumed to be crucial for a comprehensive understanding of molecular structures determining chiral molecules and
enantioselective processes, as discussed in the present monograph. Therefore, we
decided to form a uniform “stage” for readers of all disciplines by giving a brief
survey on some crucial aspects ruling chiral molecules and enantioselective processes. In order to meet the requirements of the present monograph as closely as
possible, examples for the different types of chirality will be represented by chiral
environmental pollutants discussed herein.
Chirality in chemistry is a very important field of Stereoisomerism according to
the following definitions: stereoisomers are chemical substances made up of the
same atoms, bonded by the same sequence of bonds, but possessing different threedimensional structures which are not interchangeable. These three-dimensional
structures are called configurations. In the same way as many things around us,
such as our hands and pairs of shoes, are not identical, but the mirror images of one
another, non-identical stereoisomers exist, in which the only distinction between
them is that one is the mirror image of the other. However, these mirror images are
not superimposable. A simple example of this type of stereoisomerism is represented
by the herbicide dichlorprop (or DCPP), that is, 2-(2,4-dichlorophenoxy)propionic
acid (Fig. 1.3), which can exist in two spatial configurations that correspond to
reflections of each other. These stereoisomers are specifically called enantiomers. A
6
1 Introduction