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ACD/Labs Blog

Ryan Sasaki
I’ve blogged several times about the progress and applications of automated structure verification with the help of ACD/Labs software. There are really two main approaches right now: Combined verification which includes automatically verifying the correspondence between a proposed chemical structure and the 1D 1H and 2D HSQC spectra. I’ve blogged about the publications and applications...

Arvin Moser
Experiments such as 1H-13C HMQC, HSQC, or HETCOR can be used to suspect the presence of fluorine but not necessarily rule out the absence of fluorine. The stipulation behind this assessment is that a carbon from either a CH, CH2 or CH3 group must experience 13C-19F coupling(s). The spectrum below is a region of an...

Arvin Moser
Without a set routine to acquire a 19F NMR spectrum for every single sample, an elucidator must resort to routine NMR experiments for clues to the presence or absence of fluorine. For the elucidator who routinely acquires a proton decoupled 13C NMR, the spectrum can provide some clues into the presence of fluorine. Carbons in...

Ryan Sasaki
As I am closely approaching my one year anniversary of this blog (how time flies!), Arvin’s post entitled, “How Do I Know if my Unknown Contains a Fluorine Atom”,  reminded me an X-nuclei related post from almost a year ago. In that post I highlighted a best practice document written by Gary Martin for acquiring...

Arvin Moser
Ideally, identifying whether a fluorine atom(s) is present is as simple as acquiring a 19F NMR. However, running ‘uncommon’ experiments is not usually my first step in an elucidation (MDE). Imagine a scenario where the elucidator is unsure whether fluorine is present. He/she acquires a 19F NMR and sees no 19F resonances. Therefore the extra...

Arvin Moser
When faced with a crowded region in a 1H NMR spectrum, a 2D NMR experiment can assist in removing the ambiguity and in narrowing down the proton count. For the 1H NMR spectrum below, Multiplet F (the region between 1.4 to 1.8 ppm) displays an integral of 6.71. Although several factors may contrbute to the...

Arvin Moser
A very useful bit of information on the proton count comes from integrating a 1H NMR spectrum. However, overlapping resonances can make integration less than straightforward and in some cases ambiguous. Integration involves the following decisions to be made by the elucidator: which resonances to integrate, where the integral begins and ends, and what the...

Ryan Sasaki
To follow my post from yesterday, Rich made a very interesting comment that I was hoping to address in today’s post. He suggests that perhaps a NMR Lite would be a good approach. I gave reason as to why we didn’t take that approach and strip away existing features from 1D NMR Processor when developing...

Ryan Sasaki
I had a conversation with Geoff, one of my ACD/Labs colleagues just yesterday. He provided me with a great quote from a person he was talking to about software and usability. He said: "User-Friendly…hrmph…what that means to me is: love it for the first week, hate it forever!" I think that’s a great quote. I...

Arvin Moser
Here is a lesson I learnt over time while working on small molecules—my Elucidation Evolution. Thinking back to when I started doing elucidations of unknowns, my mindset was to collect loads of data (NMR, MS, IR, etc.) whether I needed it or not. Initially inexperienced, I was extracting bits and pieces of information from various...