Theoretical Design Of New Fluorescence Rotors And Its Performance In Different Solvents

Cell is the basic life unit.Different organisms have different personalities because of their different cellular properties.To this end,the study on cells,especially the environment of cell is carrying out.Due to concern focusing on health,prevention and treatment of diseases have gained more and more people's attention.Fluorescent molecular rotors is a kind of important way to detect solvent and body fluid's viscosity and thus has higher accuracy and reliability on intracellular environment monitoring.The different type of fluorescence rotor probes has each specifity however.For example,different types of fluorescence probes have different characteristics.For different organisms,each probe has sepcific performance..These are what we want to focus on.Here,we design and improve a series of novel fluorescent molecular rotors,based on the structure of a special fluorescent molecular rotors RY3.Following interesting results are obtained:(1)Design and characterization for a series of fluorescent molecular rotors.Recently a new fluorescent molecular rotors named RY3 is reported.The rotor feature dual photon mode.Referring to its structural character,a series of improvements and design are performed so that a better molecular rotor,by which to detect cell's viscosity,is obtained.Firstly we calculate the ground state and excited states of RY3 by using quantum chemical method at the level of B3LYP/6-31G**to verify our calculational schemes,and research for its experimental.Obvious two spectrum peaks are observed.Then we design four groups of different types of fluorescent molecular rotors in gas phase.Group A is a group molecules with substituent(A1 methyl,carboxyl A2-nitroso,A3-carboxyl,A4-sulfinyl)at the hydrogen site of aldehyde group.Group B characterize with shortened main chain and added substituents(B1-instead of benzene,B2-aldehyde group,B3-cyanogroup,B4-nitroso)at terminal of the main chain.Group C is obtained by different substituents(C1-methyl,C2-carboxyl,C3-acylamino,C4-pyridine,C5-phenyl)addition at the terminal of RY3 main chain.Group D molecular rotor is based on C5 in group C.That is,the terminal benzene ring is further modified by different groups at its ortho and para-sites(D1-para methyl,D2-ortho aldehyde,D3-para aldehyde,D4-ortho methyl).(2)Results show that the former two groups A and B change more or less in configuration.By contrast,and B group change more obviously with great torsion of molecular plane.;while the change in A group takes place at the their middle position.Substitution of the carbon of aldehyde group with other functional group also alters the configuration in various degrees.Only the molecular structures of C group and D group did not change.Moreover,the rotors in group D rotor do not appear the second emission peak clearly,so they are not chosen.By contrast,we select C1(RY1)as the best fluorescent molecular rotors and discuss it mechanism in detail(3)In order to simulate the cell microenvironment,we also design ten different solvent environments:methanol,water,ethanol,acetonitrile,two dimethyl sulfoxide(DMSO),chloroform,two ethyl chloride,tetrahydrofuran(THF),toluene,acetone to discuss the absorption spectra and emission spectra of these new rotors in solution.The best performance is from C1 in toluene with strong emission peak.D1 rotor is worse due to its weak second peak..The rotors in groups A and B only hold one emission peak,which is unfavorable to improve the detection effect.The first two groups will be paid less attention,only the third and fourth groups are what we focused on.Our results for these rotors reveal that the two-photon mode molecular rotors are better than traditional fluorescent probes.Especially,rotor C1 hold stronger dual peaks than RY3,synthetized by Peng's group.It would have higher accuracy and reliability in detecting different cellular surroundings by observing dual peaks' changes.The novel fluorescence rotor probe C1 still needs to be improved although it has greater improvement than RY3.Actually,there are currently many researchers working in this filed and various novel rotors are emerging continuously.We believe that in the future scientific and technological achievements obtained in this field will make contributions to preventing and treating disease,as well as to research of biological macromolecules.