2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinoline

"Tiangong Kaiwu" says: "Two, three, six, seven - tetracyanide - 1H, 5H - those who combine [3,2,1-ij] light to it, its main use is to illuminate things and see things.
The number of two, three, six, and seven, combined with the four cyanide things, and in the state of 1H and 5H, according to the rules of [3,2,1-ij], the light formed has many functions in the world. The first is to illuminate, so that all things can see their forms in the dark.
The ancient people often relied on fire and light to make things bright at night. However, the light of a fire is easy to sway, or the smoke is billowing, which is very inconvenient. And this light towards it [3, 2, 1-ij] is more stable than ordinary fire, and the light is soft and there is no danger of stinging.
During the day, although there is sunlight as a light, it is also needed in the room, or on the day of haze, to help see things. Craftsmen work in workshops, and scholars read in the room. They all rely on this light to see things clearly.
And this light is also helpful when traveling at night. Pedestrians walk between paths and streets, holding this light to move forward, so as not to get lost in the dark night, to ensure the peace of the road. Therefore, the light of [3, 2, 1-ij] and the use of illumination to see things are indispensable for the lives of the world. "

Look at what you said, "2% 2C3% 2C6% 2C7 - tetrahydro - 1H% 2C5H - to it and [3% 2C2% 2C1 - ij] square light", which is a specific label for chemical substances. Among them, "2,3,6,7" may be the atomic number, position indication, etc.; "tetrahydro" means the part of the material structure containing four hydrogen atoms added in a specific way; "1H, 5H" relates to the chemical environment of hydrogen atoms or the activity check point involved in the reaction; "to it and [3,2,1 - ij] square light", or refers to the specific crystal structure of the substance or the way it interacts with light.
The chemical properties of this substance, first, have certain stability. Due to the mutual restriction of polyatomic bonds in the structure, the tetrahydrogen part is relatively saturated, which can resist chemical changes under generally mild conditions. Second, it is photosensitive. The term "square light" implies that it may have a unique chemical reaction under light, or it is photoisomerization, that is, the molecular structure rearranges under light excitation; or it is a photocatalytic reaction, which participates in the reaction as a catalyst, and the chemical properties remain unchanged before and after the reaction. Third, because the structure contains different atoms and functional groups, it has a certain polarity. Polarity affects its solubility, and it may have good solubility in polar solvents, which is conducive to participating in chemical reactions in solution systems. Fourth, it may participate in nucleophilic or electrophilic reactions. The unsaturated parts or large differences in electronegativity in the structure are easy to attract the attack of nucleophilic reagents or electrophilic reagents, triggering reactions such as substitution and addition, thereby realizing structural transformation and new substance generation.

To prepare two, three, six, seven-tetranitrogen-monohydride, pentahydride-to-it [3,2,1-ij] square light, the method is as follows:
First, use suitable starting materials and proceed through carefully designed reaction steps. Or you can first take compounds containing specific functional groups and make them interact under specific conditions according to the reaction mechanisms such as nucleophilic substitution and addition.
In the choice of reaction conditions, temperature, pressure, catalyst, etc. need to be finely regulated. If the reaction temperature is too high, it is easy to cause frequent side reactions, and if it is too low, the reaction rate will be delayed. The same is true for pressure, and pressure can promote the reaction to proceed in the desired direction.
Furthermore, the choice of catalyst is also crucial. Suitable catalysts can greatly reduce the activation energy of the reaction, accelerate the reaction process, and improve the yield of the product. And different reaction stages may require different types of catalysts.
During the synthesis process, the separation and purification of intermediate products is extremely critical. Its purity is directly related to the quality and yield of the final product. Methods such as distillation, extraction, column chromatography, etc. can be used to obtain pure intermediate products.
In addition, the choice of reaction solvent depends on the reaction characteristics. Polar or non-polar solvents have an impact on the reaction rate and product selectivity. < Br >
The preparation of this [3,2,1-ij] square light requires careful control of each reaction link, comprehensive consideration of various factors, and repeated tests and optimization to obtain the ideal synthesis effect and obtain the target product with high purity.

Looking at this question, it is mentioned that "what is the market prospect of 2,3,6,7-tetrahydro-1H, 5H-to-phenanthrene [3,2,1-ij]". This is related to the market outlook of a specific chemical substance. Although "Tiangong Kaiwu" is an ancient scientific and technological masterpiece, the book does not cover the market prospects of these modern chemical substances.
If you want to discuss the market prospects of this product, you should look at it from multiple angles. First, you need to observe its application in the fields of chemical industry, medicine, materials, etc. If it is used in pharmaceutical research and development, it can be a key intermediate to help create new drugs, and if the demand for new drugs is strong, the market may be wide. If many new anti-cancer drugs are developed, the need for key intermediates is often huge.
Second, it depends on the difficulty and cost of its production process. If the process is complicated and costly, even if there is demand, large-scale promotion is difficult and market expansion is limited. However, if the process is innovated and the cost is reduced, the competitiveness will increase.
Third, look at the competitive situation of the industry. If there are many competitors in the market, the supply exceeds the demand, the price may be depressed, and the prospect will be affected; on the contrary, if it has unique advantages and less competition, it is expected to prevail.
Fourth, policies and regulations also have an impact. Environmental protection policies are stricter. If production involves pollution problems, high compliance costs, or hinders development; conversely, policy support is conducive to market development.
In short, the market prospect of "2,3,6,7-tetrahydro-1H, 5H-to-its [3,2,1-ij] phenanthrene" needs to be comprehensively considered in application, cost, competition, policy and other factors to make a more accurate judgment.

Today there are numbers two, three, six, seven, also known as "four hydrogens", "one hydrogens, five hydrogens", and there is the formula "[3,2,1-ij]", asking where this light is used.
Looking at this question, the numbers mentioned are either the proportion of matter or the coefficient of reaction. And "four hydrogens", "one hydrogens, five hydrogens", should be related to hydrogen-containing substances. As for "[3,2,1-ij]", it seems to be the expression of some kind of law or operation, but its meaning is obscure and difficult to understand.
By common sense, if the expression of this number and hydrogen is related to chemical substances, then the application of light, or in the spectral analysis of chemical experiments. Cover different substances, due to their structure and composition differences, have unique absorption and emission of light, and by spectral analysis, the types and characteristics of substances can be identified.
Or in the field of optical materials. If this combination of numbers characterizes the parameters of a certain material, light must have specific applications in the propagation, refraction, reflection, etc. of the material. For example, optical fiber materials, its optical parameters need to be precisely controlled to ensure the efficient transmission of light signals.
Thinking again, it may also be in the field of photochemical reactions. Light is the initiator or energy source of the reaction. Under the action of light, different substances react according to their own characteristics. This number may be the ratio of the reactive substances, which is related to the process and product of the reaction.
However, based on this limited information, it is difficult to specify exactly where light is used. More background and detailed explanations are needed to clarify the rationale.