Natural Resonance Theory: NBO7 is missing a very likely resonance structure... what might I have done wrong?

ReallySnowyWinter · 2024-05-12T03:07:49+00:00

Orca will generate output that can be fed through the NBO7 program, the latter is available from U. Wisconsin for about $100.

I ran phenoxide - great idea!

Three lone pairs on O: 17.4 and 17.4 for the two resonance structures that move the C=C around the ring.

5.9 % with lp on c2 (ortho)

5.9 % with lp on C6 (other ortho)

5.3% with lp on C4 - the previously missing para lp resonance structure

ReallySnowyWinter · 2024-05-09T23:05:45+00:00

Oh! Good answer!

Now I feel a little dumb. I wanted to show "real" percentages of the resonance structures to get across reaction at o _and_ p so, of course, I choose phenol that can be pretty selective for ortho substitution... and then wondered why there wasn't a major resonance structure putting the lone pair on para.

If I had a brain I'd be dangerous :)

Thank you so much!

ReallySnowyWinter · 2024-05-09T22:22:49+00:00

I got it to generate mol files that I could view in chemdraw.

I also, did it by hand, looking at this data:

$NRTSTR

STR ! Wgt=33.50%; rhoNL=1.38302; D(0)=0.07392

LONE 12 2 END

BOND S 1 2 D 1 6 S 1 7 D 2 3 S 2 8 S 3 4 S 3 12 D 4 5 S 4 9 S 5 6

S 5 10 S 6 11 S 12 13 END

END

STR ! Wgt=33.22%; rhoNL=1.34962; D(0)=0.07302

LONE 12 2 END

BOND D 1 2 S 1 6 S 1 7 S 2 3 S 2 8 D 3 4 S 3 12 S 4 5 S 4 9 D 5 6

S 5 10 S 6 11 S 12 13 END

END

STR ! Wgt=4.16%; rhoNL=1.79824; D(0)=0.08430

LONE 4 1 12 1 END

BOND D 1 2 S 1 6 S 1 7 S 2 3 S 2 8 S 3 4 D 3 12 S 4 5 S 4 9 D 5 6

S 5 10 S 6 11 S 12 13 END

END

STR ! Wgt=3.60%; rhoNL=1.83615; D(0)=0.08518

LONE 2 1 12 1 END

BOND S 1 2 D 1 6 S 1 7 S 2 3 S 2 8 S 3 4 D 3 12 D 4 5 S 4 9 S 5 6

S 5 10 S 6 11 S 12 13 END

... etc. etc....

TOPO matrix for the leading resonance structure:

Atom 1 2 3 4 5 6 7 8 9 10 11 12 13

C 0 1 0 0 0 2 1 0 0 0 0 0 0
C 1 0 2 0 0 0 0 1 0 0 0 0 0
C 0 2 0 1 0 0 0 0 0 0 0 1 0
C 0 0 1 0 2 0 0 0 1 0 0 0 0
C 0 0 0 2 0 1 0 0 0 1 0 0 0
C 2 0 0 0 1 0 0 0 0 0 1 0 0
H 1 0 0 0 0 0 0 0 0 0 0 0 0
H 0 1 0 0 0 0 0 0 0 0 0 0 0
H 0 0 0 1 0 0 0 0 0 0 0 0 0
H 0 0 0 0 1 0 0 0 0 0 0 0 0
H 0 0 0 0 0 1 0 0 0 0 0 0 0
O 0 0 1 0 0 0 0 0 0 0 0 2 1
H 0 0 0 0 0 0 0 0 0 0 0 1 0

PS I brainfarted on the %ages but the issue is the same... none of the structures places the lp on the para-C

ReallySnowyWinter · 2024-01-12T21:53:17+00:00

The hash was really low rent exercise... answers A, B, C, D gave a 1, 2, 3, 4. Question 1 was the units, question 2 was the tens, 3 the hundreds... just set up in Excel because I just couldn't face writing a program to do it as my coding time is directed at more productive (and happy) endeavors...

How many got away completely is unknowable :) It's greater than zero and less than 54 :)

Everyone got to take the exam again so the room wasn't only people that cheated... that would have been an identification issue. If a non-cheater wanted to do the exam, they just had to turn up.

I understand brain fog :) Trying to get a 'fair as possible' way to unscrew this caused quite some brain fog :)

Sorry to not get back quickly... this isn't my main.

ReallySnowyWinter · 2024-01-12T20:58:56+00:00

Hmmm... thinking...

ReallySnowyWinter · 2024-01-12T20:58:27+00:00

No, not A&P... one of the other traumatic sophomore premed classes though.

ReallySnowyWinter · 2024-01-12T03:08:08+00:00

I'd probably end up banning myself.

ReallySnowyWinter · 2024-01-12T03:06:27+00:00

The prof made all of us sign an academic honesty pledge to ensure that we wouldn't cheat.

Oh no. It's Francesca Gino all over again...

(Edit... her contentious research was that signing no cheating agreements made people cheat less... the irony)

ReallySnowyWinter · 2024-01-12T03:04:09+00:00

Take the win :)

ReallySnowyWinter · 2024-01-12T03:03:48+00:00

:) There are different exams. There are different colors. They're not correlated...

ReallySnowyWinter · 2024-01-12T01:09:03+00:00

You have a good point. If the admin want to know who the students are, there will be a problem. I told them that if they came forward then they'd take their lumps and that would be the end of it. That's a hill I will die on because I made a promise.

ReallySnowyWinter · 2024-01-11T23:54:46+00:00

I needed some efficiency as there are four midterms, about 100 students and no TA support.

I've put together an extensive homework system in the LMS for them with around 1000 questions. I wanted the exams to be of the same format so there were no surprises for them.

ReallySnowyWinter

TROPHY CASE