I Have a Research Support System

After returning to the office, Xu Qiu washed his hands and walked directly to Han Jiaying's desk to sit down.

There are three desks in A501, and the three people sat separately before.

But now that the senior sister already knew about their relationship, the two didn't bother to hide it, and got together in a fair manner.

After playing around with the school girl for a while, Xu Qiu continued to write the review.

The classification of the second part of this review is based on the type of material, and the third part is the three main factors that affect the optoelectronic performance of the device. The literature cited in the two parts is essentially the same.

"Repetitive descriptions are taboo in review writing, so in the second part, we should focus on the cited documents, and in the third part, we should not describe them in a large space again." Xu Qiu reminded the school girl next to her.

"Well," Han Jiaying said thoughtfully, "then the third part will have less content."

"That's right," Xu Qiu nodded, "To focus on the key points, you only need to write a few paragraphs to summarize the current situation, and each paragraph can quote one or two typical articles."

Han Jiaying was not polite to Xu Qiu, and asked directly: "Then what is the main focus of the 'Blend Thin Film Morphology' part that I am in charge of?"

"Well..." Xu Qiu thought for a moment, and said: "The morphology of the blend film itself involves factors such as crystallinity, compatibility, and phase separation between receptors, which can be directly described in words; the corresponding characterization methods, Including transmission electron microscopy, atomic force microscopy, wide-angle grazing incidence X-ray diffraction, etc., each of these characterization methods can be matched with a picture."

"Okay." Han Jiaying smiled sweetly. During the process of Xu Qiu's speech, she did not stop her fingers, and recorded everything he said on the newly created sticky note on the desktop.

Afterwards, the two started working. Han Jiaying asked some questions from time to time, and Xu Qiujun answered them patiently.

For Xu Qiu, although the current work efficiency is slightly reduced, due to the timely communication between the two, the time spent on editing the article will definitely be reduced in the future, and the overall work efficiency may be even higher.

The senior didn't show up all afternoon, and it seemed that she was trapped by the liquid chromatograph.

It wasn't until after five o'clock that Chen Wanqing pushed open the door of A501.

Seeing Xu Qiu and Han Jiaying sitting in a row, she softly "tsk tsk" twice, then while washing her hands, she turned her head and said:

"go for meal?"

"Okay, okay."

"Go."

After dinner, Xu Qiu went directly to the laboratory.

His three Suzuki reactions are almost up, and one nitro reaction will not be completed until after nine o'clock in the evening.

Click the plates one by one to confirm that the yield of the product is not low, then directly shut down the reaction and start the post-processing.

Liquid separation, washing, sample mixing, rotary evaporation, and sample column loading.

The next step is a fortified station. It is now past six o'clock. Today, the products of the four reactions have to pass through the pillars, and it may take until early in the morning.

After installing the sample column, Xu Qiu found that the box of disposable blank silica gel columns presented by the manufacturer of the liquid chromatograph was almost used up, and there were only five left, which were enough for this time.

After that, you have to install the column yourself, or find an old disposable column and reuse it.

Most disposable blank chromatographic columns, after use, will have some raw materials "deadly adsorbed" in the column, forming a red mark. Of course, if it is not a PDI raw material, it may also be a blue mark or a colorless mark.

The so-called "dead adsorption" is also well understood, which refers to the sample molecules that are firmly adsorbed by the silica gel column and cannot be easily desorbed, but no one can guarantee that they will never desorb, and there is a risk of sample contamination if an old column is used.

After setting up the sample column and blank silica gel column, setting up the test tube rack, inserting the A/B solvent tube and the waste liquid bucket, Xu Qiu turned on the liquid chromatograph.

The familiar sound of "duang" and "duang" came, and the test bench began to vibrate slightly.

Recently, there are many columns in the group, and the solvents are used very aggressively, especially the low-polarity petroleum ether. The 16 liters of the four big barrels I bought before have been used up, and I have added four barrels later, but the high-polarity ethyl acetate Esters are used less.

As for dichloromethane, nearly three barrels are used for 4 liters. The main reason is that this solvent can not only be used to pass through the column, but also used to wash the bottle is very good, especially the PDI material, which can be washed dry with a little dichloromethane. clean.

Its toxicity is not high among commonly used solvents, but it is not low either. Its boiling point is only 40 degrees Celsius, it is extremely volatile, and it can penetrate rubber gloves.

Xu Qiu accidentally got it on his hand once. At first, he had gloves to insulate it, so he didn't feel anything. After a few seconds, his hand felt cool. This was because the methylene chloride evaporated and took away the heat. After handling contaminated gloves, the contact area will become red due to the irritation of the skin by the penetrating methylene chloride.

However, there were no other special adverse reactions.

In fact, the waste liquid collected through the column can also be recycled and reused by rotary evaporation.

However, all the mixed solvents are used in the group. It is difficult to understand the specific ratio. It cannot be used indiscriminately. At most, it can only be used to wash bottles. Therefore, no one took on this job, and simply treated it as waste liquid.

Xu Qiu looked at the waste liquid area in the shade under the next window. There was a row of waste liquid buckets, most of which looked red, and most of them were waste liquids related to PDI. They needed to go to the School of Pharmacy to deal with them when they had time. one time.

In the middle of the experiment, Han Jiaying and Chen Wanqing went to the laboratory respectively, processed their responses, and each submitted a new response.

Because Xu Qiu’s three reactions were all samples of about 500 mg, which was not too much, he was on hold, so he didn’t ask his schoolgirl to help him, and he went through the column and rotary evaporation at the same time, and took some time to save some dirty bottles, The test tube is pulled out from the alkali tank, rinsed and thrown into an ultrasonic cleaner for cleaning.

At around 9:10, the two systems, PDI3-B-5 and PDI3-B-6, have been separated and purified.

Xu Qiu was about to go to the fume hood to check the progress of the nitration reaction, when Han Jiaying suddenly ran in and said, "Brother, we are going back to Handan, so be careful when you do the experiment alone, or... I will stay with you tonight." you?"

Xu Qiu was taken aback, and just about to say something, the junior girl smiled slyly, "I'm kidding, I'm leaving, send me a message when it's over."

"Okay, goodbye." Xu Qiu could only smile helplessly, and then waved to the senior sister waiting at the door of the laboratory.

Seeing the backs of the two leaving, Xu Qiu sighed softly, "They're all gone, we need to speed up the progress."

Then, he walked quickly towards the fume hood, and dipped the reaction solution with a capillary tube to spot the plate.

"Damn it?" Xu Qiu was stunned when he saw the result of the board ordering.

There is no raw material point in the climbing board results, indicating that the raw material reaction is complete and the yield is close to 100%, but there are three product points, which are very close to each other and stacked together.

These three products are very dark in color, and it is difficult to judge which is the main product, and the polarity difference between them is very small, and they must be inseparable if they pass through the pillars.

Xu Qiu frowned, feeling that the matter was not simple.

His brain is racing...

Not long after, a light bulb suddenly appeared next to Xu Qiu's head.

I see!

3D-PDI molecules, each PDI has two available reaction sites, which can be numbered as (1, 2), (3, 4), (5, 6), and each molecule can only be substituted by one nitro group , that is, take a number from each of the three brackets.

Since the molecule is centrosymmetric, there are only three cases of 135, 136 and 145.

In these three cases, the position of the three nitro groups in the molecule changes slightly, which has an impact on the polarity of the molecule, but the effect is not large, so the three product points are almost overlapped.

Thinking of this step, the problem is easily solved.

100% yield, no need to go through the column, just use the anti-solvent to separate the solid product, and then dry it.

As soon as he said it, Xu Qiu took about 150 ml of methanol with a disposable PE cup, and slowly dropped the solution in the reaction bottle into the methanol directly with a disposable dropper.

As the solution was added dropwise, a dark red solid precipitated out.

After adding all the reaction solutions dropwise, Xu Qiu began to install the Buchner funnel.

The main body is a ceramic funnel, the name is Buchner funnel, there are many small holes on it, which can be used for filtering, but to use it with filter paper, you need to use scissors to cut the filter paper into a circular shape, and spread it inside the funnel to cover all the small holes. hole;

Below is a liquid-receiving bottle, in the shape of a conical flask, with a branch pipe, which is connected to a water pump and can be used for vacuuming;

In addition, there is a rubber gasket between the Buchner funnel and the liquid contact bottle, which can ensure the high airtightness of the system.

Then, Xu Qiu turned on the water pump, fixed the Buchner funnel, poured the methanol solution mixed with the product into the Buchner funnel, and carried out vacuum filtration.

During this process, rinse with water repeatedly to remove possible residual nitric acid, and constantly check the acidity and alkalinity of the filtrate with pH test paper until the pH of the filtrate is maintained at about 7.

Finally, scrape off the product on the Buchner funnel with a stainless steel scraper, wrap it with filter paper, transfer it to a vacuum oven, and dry it at 70 degrees Celsius under high vacuum.

"It's done." Xu Qiu tried to snap his fingers, but when he failed, he realized that he was wearing multiple layers of gloves.

Looking around, the laboratory is empty.

Xu Qiu couldn't help singing a song, "Only the oven is left to talk with me for a day, and the liquid chromatograph that fell asleep..."

After surfing for a while, continue the experiment.

It took more than an hour to complete the separation and purification of PDI3-B-8.

Counting the products, this time it was a bumper harvest. The three first-generation 3D-PDI molecules all obtained 300-400 mg of products, with an average yield of about 70%.

Copy the three into the simulation laboratory, let the simulation experimenters traverse different donor materials, and explore the photoelectric properties of the three acceptor molecules.

Although there are two molecules that have been tried once before, after all, there may be differences due to different batches, and considering the fixed cost of device preparation, the more systems you explore, the higher the cost performance. Handed over to the simulation experimenter.

The focus of this study is mainly to increase the length of the side chain at the position of the nitrogen atom of the PDI molecule, whether it can improve its photoelectric performance.