Study On Chemosensors For F~- Based On Iron And Synthesis Of Carboxylate-Bridged Iron Thiolate Clusters

Fluorescent chemosensors for F- based on metal have attracted much attention because of their high sensitivity and long frorescent life time. A lot of chemosensors with Ru for F" have been reported. Iron is characterized with cheap, abundantness and biocompatibility. For element substituting strategy and friendly environment, the research on fluorescent detection of F" based on iron has been expanded in this thesis.Two chemosensors,1-(anthracen-9-ylmethyl)urea (7a) and 1-(anthracen-9-ylmethyl)-thiourea (7b), were synthesized from 9-anthraldehyde.7a and 7b could selectively detect Fe3+ with fluorescent quenching and the complex stoichiometries of Fe3+is 1:1 for 7a. The ensemble 7a-Fe3+ and 7b-Fe3+ complexes show rapid and high selectivity toward F" over other anions and the detection limit of the ensemble 7a-Fe3+ response to F- ion is 74 μM. Qualitatively detecting Fe3+ and F- have been realized by naked eyes.Four Diiron sulfur complexes [Cp*Fe(μ-SR1)2(μ-η2-OOCR2)FeCp*][PF6] (R2=4-(3-(anthracen-9-ylmethyl)ureido) phenyl (marked R3) or 4-(3-(anthracen-9-ylmethyl)thioureido)-phenyl (marked R4),17a:R1=Me, R2=R3; 17b:R1=Et, R2=R3; 17c:R1=Me, R2=R4; 17d: R1=Et, R2=R4) and two complexes based on Ru and Co [Cp*M(μ-SEt)2(μ-η2-OOCR2)-MCp*][PF6](17e:M=Ru, R2=R3;17f:M=Co, R2=R3) were synthesized from carboxylate ligand bearing anthracene and precursor Cp*M(μ-SR)2(MeCN)2MCp*][PF6]2 (16a:M=Fe, R =Me; 16b:M=Fe,R=Et; 16c:M=Ru,R=Et; 16d:M=Co, R=Et). These six complexes were characterized by 1H NMR、HRMS and IR and 17a,17b,17e and 17f were characterized by X-ray.17a,17b,17c and 17d show rapid and selective recognition for F- over other anions with strong enhancement of emission intensities. The detection limits of 17a and 17b response to F- ion were 9 μM and 6.7 μM, respectively. From the Job’s plot and 1H NMR, it can be concluded that the complex stoichiometries of F- is 1:1 for 17a and 17b, that is to say six member cycle has been formed between N-H of urea and F- though hydrogen bonding.Alcohols or aldehydes could be in situ oxidized in the presence of [Cp*Fe(μ-SEt)2-(MeCN)2FeCp*][PF6]2 (16b) and base under air to give the corresponding carboxylate-bridged diiron clusters [Cp*Fe(μ-SEt)2(μ-η2-OOCR)FeCp*][PF6] (18:R=H, Me, Et, n-Pr, phenyl and 4-methylphenyl) in moderate to high yield. MeCN ligands and unique diiron sulfur structure of 16b play an important role for the oxidation reaction.