Volume 2 Chapter 1 Build menu GROUPS

Function

GROUPS is used to replace the BUILD menu with the GROUPS sub-menu - see (i) below.

(i)

Remarks

The GROUPS sub-menu contains 26 commonly occurring structural groups which can be used as short-cuts in generating a chemical structure.

Equally they can be used to conserve space when the drawing area is becoming over-crowded.

Example

Suppose we have built the fragment (ii) and we wish to add an aldehyde group to the C atom carrying the chlorine atom.

Select GROUPS
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Either use the cursor to select a GROUP, or type its two-character symbol
(e.g. SU for SO3-)
(Select "CANCEL" if you don't want to select a GROUP)
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The two-letter symbols are displayed beside the groups, to show what should be typed in the BUILD menu to change an atom to that particular functional group.
Select CHO
The BUILD menu is restored and the current element type is now CHO.
Select position a
CHO appears at position a - see (iii).
Select the C atom attached to Cl
Bond is drawn from CHO to C - see (iv).
The structural definition of each group is given in Appendix 8.

You should note that if the program state is DRAW when the GROUPS sub-menu is selected then, for example, selection of CHO will cause the active atom to become CHO.

If, in the GROUPS sub-menu, you type an invalid two-letter code, the terminal beeps, and you are prompted to try again:

ERROR - That was an invalid GROUP symbol

Note:

(i): There can be only one bond to a GROUP symbol atom.
(ii): The XA symbol (-COO) is the only GROUP symbol which can be modified. You can add a terminal H atom or negative charge using the HYDROGENS and CHARGE commands in the 2D-CONSTRAIN sub-menu.

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Volume 2 Chapter 1 Build menu HELP .