Atom labels

Multiattached atom labels (MAALs), common in condensed text-style diagrams, are atom labels from which bonds emanate at more than one location. Hitherto we have assumed that all an atom s bonds sprouted from one point. There is no mention of MAALs in the SDG literature the following are ideas that may be implemented in ChemDraw. 

Following the paradigm of this treatise, MAALs may be represented as a series of deputy atoms, one for each attachment point, plus two at the outer atoms if they lack bonds. The bonds between the atoms are collinear, and 

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Drawing-, text-, and structure-input tools are provided that enable easy generation of flow charts, textual annotations or labels, structures, or reaction schemes. It is also possible to select different representation styles for bond types, ring sizes, molecular orbitals, and reaction arrows. The structure diagrams can be verified according to free valences or atom labels. Properties such as molecular... 

The first line of the Z-matrix consists solely of the label for this atom. An atom label is made up of its atomic symbol optionally followed by an integer (no spaces), used to distinguish it from the other atoms of the same type (e.g. HI for the first hydrogen, H2 for the second one, and so on). 

This second input line will include the atom label of the second atom, the label of the atom it is bonded to (the first atom), and the bond length, in that order. Items may be separated by spaces, tabs or commas. 

Draw structural formulas for all the isomers of ethylene (QH ) in which two of the hydrogen atoms have been replaced by deuterium atoms. Label the cis and the irons isomers. 

The biological chemistry of gold a metallo-drug and heavy atom label with variable valency. P. J. Sadler, Struct. Bonding (Berlin), 1976, 29,170-214 (142). 

Figure 19 ORTEP diagram (35% thermal ellipsoids) with atom labelling of (CN-[3-(2-pyridyl)-2-thienyl] tri(p-tolyl)tin(IV). " ...

Sadler PJ (1976) The Biological Chemistry of Gold A Metallo-Drug and Heavy-Atom Label with Variable Valency. 29 171-214 Saillard J-Y, see Halet 1-F (1997) 87 81-110... 

Fig. 18.3 Ball and stick drawing of the centro-symmetric [H2NEt2]2Zr2Clio. Atom labels, bond distances and hydrogen bonds are labeled on the left side of the figure and Zr-CI-H-N hydrogen-bond angles are labeled on the right side of the figure.

Figure 16.4 A more advanced ICAT design uses an acid-cleavable spacer arm to facilitate elution of labeled peptides from a (strept)avidin affinity column. The use of 14C isotopes instead of deuterium labels permits precise reverse phase separations prior to mass spec that show no elution peak time differences between isotope-labeled and normal atom-labeled peptides.

Figure 3.18. Structure of the (N2H4)2ZnTe chains in a-(N2H4)2ZnTe, with the atom labeling shown. For clarity, atoms are represented as spheres, with uniform sizes selected for each atom type.

Figure 1. ORTEP drawing of Cp2-ReCH(Me)OZrMeCp2 showing atom labeling scheme unlabeled ring carbons follow the numerical sequence determined by the atom labels given.

In the spirit of elementary bonding theories, we expect that the dominant contributions to h,(A) come only from the first summation, consisting (for an s/p-block atom) simply of the four contributions (s, px, pv, p-) from the valence shell. At this level, the hybrid can be written simply as (dropping the atom label throughout)... 

In nomenclature for amino acids as ligands, the atoms in the R group are labeled with Greek letters starting with (5 for the first atom attached to the a carbon followed by y and 8 and e. The common bioinorganic ligands histidine, cysteine, and aspartic acid have their atoms labeled in the manner shown in Figure 2.5. The... 

Figure 3. Structural representation of the computational models A-F. Models B, D, and E are combined QM/MM models where the regions enclosed in the dotted polygons represent the QM region. The regions outside the polygons are treated by a molecular mechanics force field. For the electronic structure calculation of the QM region, the covalent bonds that traverse the QM/MM boundary (the dotted polygon), have been capped with hydrogen atoms. In model A the atoms labelled 1 through 4 are the atoms that have been fixed in the calculations of models A through E.

Table 4 Typical structural parameters (average distances, A) in the different families of [Ru3Cln] complexes (atom labelling refers to Figure 3)...

Table 9 Selected interatomic distances (A) for the redox couples [Co5 (tpda)4(X) 2]01 + (atom labelling refers to Figure 5)...

Figure 3. Pseudo-three-dimensional plots of the canonical orbitals for CHj, 1 (A = C). The atom labels are only indicated for the lowest lying carbon 1 s orbital otherwise they are left out for clarity.

Fig. 20. The dimeric La(III)-nicotinate dihydrate. Atoms labeled 2 and 3 are the water molecules...

Optically active possibilities for seven carbon atoms (labeled carbon atoms are chiral). 

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