JJ - ¹³C Chemical Shift Searching

This feature allows the user to search a small collection of ¹³C spectral data based on substructure, chemical shift range, name (or part of a name) or reference number.  The database resides in encrypted files installed with NUTS.  The user can also create his/her own database which will also be searched with this command.  See details below.

Typing JJ displays the following dialog box, allowing one of 4 different types of search criteria to be entered.  The "pattern" option refers to a text-based system for describing substructure.  The search is initiated by clicking on the corresponding button to the right.  Only one criterion is searched, even if information is entered in other boxes.  In the sample shown, we are searching for carbon peaks between 190 and 192 ppm, inclusive.

The following response is displayed, showing that the database contains 6 carbon peaks in this range:

Clicking on OK launches the web browser (Windows only) and displays the following report.  (See below for how to configure NUTS to launch your browser.)

Carbon Chemical Shift Search Range Report
Carbon Shift Range is:  190.0 PPM -  192.0 PPM
SHIFT    MOLECULAR FORMULA         REF #  NAME                                     PATTERN
 191.4   C5H8O2                    115    acetylacetone                            5-APHJa
 191.4   C5H8O2                    115    acetylacetone                            9-ALhl
 190.0   C13H16O                   454    2,2,3,3-tetramethyl-1-indanone           (9)-(D)aadVhd
 191.3   C8H8O3                    292    vanillin                                 9-HVhh
 191.6   C9H10O3                   346    3,5-dimethoxybenzaldehyde                9-HUhh
 192.0   C7H6O                     229    benzaldehyde                             9-HVhh

Suppose we now want to know more about vanillin.  We can perform another search, this time by reference number 292.  The following report is generated.

Reference # Report
Reference # is: 292
  56.0   C8H8O3                    292    vanillin                                 1-Ov
 191.3   C8H8O3                    292    vanillin                                 9-HVhh
 127.4   C8H8O3                    292    vanillin                                 10-HHJaOa
 109.4   C8H8O3                    292    vanillin                                 10-HHPH
 114.8   C8H8O3                    292    vanillin                                 10-HHPH
 109.4   C8H8O3                    292    vanillin                                 10-HJhOaH
 114.8   C8H8O3                    292    vanillin                                 10-HJhOaH
 129.5   C8H8O3                    292    vanillin                                 10-JhHHP
 147.5   C8H8O3                    292    vanillin                                 10-OaHPH
 152.3   C8H8O3                    292    vanillin                                 10-PHOaJh

Vanillin has 8 carbons, but notice that the report has 10 entries.  This is due to an ambiguity in the assignment of 2 of the peaks.

As an example of a substructure search, 3-AABc is entered and the Pattern Search button clicked.  (3-AABc represents a methine carbon bearing 2 methyls and a CH₂-CH- group.  See coding explanation.)  The following response is displayed:

In this case, the database contains 5 examples of this substructure.  NUTS displays the average shift of those 5 values, as well as the minimum and maximum values, giving the user an estimate of the possible shift range for this carbon.  Clicking on OK displays the following report in the browser:

Carbon Pattern Report
Carbon Pattern is: 3-AABc
SHIFT    MOLECULAR FORMULA         REF #  NAME                                     PATTERN
  24.8   C6H13NO2                  204    leucine (acidic)                         3-AABc
  24.8   C6H14O                    214    4-methyl-2-pentanol                      3-AABc
  25.2   C6H13NO2                  203    leucine (basic)                          3-AABc
  25.8   C60H92N12O10              499    gramicidin S                             3-AABc
  30.6   C12H24                    445    7,9-dimethyl-1-decene                    3-AABc

Searching by substructure can be done automatically if a molfile is displayed.

Configuring NUTS to work with a web browser (Windows only)

NUTS must first know where to find your computer's web browser.  This is set in the nuts.ini file, in the [DIRECTORIES] section.  Here are the default paths for WinNT and Win98.  You must un-comment (remove semicolon from) the line corresponding to your OS, and verify that the path and file name are correct for your system.

; Default Directory for Window NT 4
BROWSER = C:\\Program Files\\Plus!\\Microsoft Internet\\iexplore.exe
; Default Directory for Windows 98
; BROWSER = C:\\Program Files\\Internet Explorer\\iexplore.exe

Creating a database of your spectral data

NUTS searches both the supplied, encrypted spectral data and also some user-editable files (with file names !myshift.txt and !mynames.txt).  NUTS is supplied with sample files (shown here) that can be edited with any text editor.  Simply follow the syntax shown.  These files must be in the data subdirectory of the NUTS program.

MyShiftTable

; Users Carbon Pattern code and reference number list

;Code Shift Reference #
;1-Ban 23.8 515 ;This is a sample entry, remove seicolon

The syntax for the !myshifts.txt file is 

substructure_code shift reference#       

reference# molecular_formula name

with each item separated by a space.

MyNamesTable

; User Reference Number and names list

;515 C6H15N diisopropylamine ;Sample entry, remove semicolon

Last updated 2/10/04