Syntheses,Assemblies And Catalytic Properties Of Cu(?) Pyrimidine-2-thiolate Clusters

Copper N-heterocycle thiolate clusters have attracted much interest due to not only their diverse structures,but also their potential applications in semiconductor materials,fluorescence,biological activity.But their catalytic properties have been less explored in organic reactions.These complexes are also promising candidates as visible-light-responsive photocatalysts owing to their strong absorption in the visible region and long fluorescent lifetime.However,these clusters have rarely been used as visible-light photoredox catalysts for organic transformations.Some Cu(?)/pyrimidine-2-thiolate complexes with uncoordinated N atoms can be used as metalloligands for the construction of MOFs,which remains rarely explored.In this thesis,we synthesized a series of Cu(?)N-heterocycle thiolate clusters,and explored their catalytic activities for transfer hydrogenation reactions.In addition,some of the complexes as a photosensitizer efficiently catalyze reduction or reductive dimerization of aldehydes and ketones,chemoselective reduction of ?,?-unsaturated carbonyls,the oxidative hydroxylation of various arylboronic acids.The assembly of[Cu6(dmpymt)6](Hdmpmt=4,6-dimethylpyrimidine-2-thiol)as metalloligand with CuI or(Ph3P)CuI afforded two bifunctional cluster-based MOFs,which could act as recyclable heterogeneous photocatalysts toward the acceptorless dehydrogenation of alcohols under irradiation of blue LEDs.The main work of this thesis is as follows:1.Cu(?)N-heterocycle thiolate clusters[Cu6(L)6](L=Hpyt(pyridine-2-thiol)(1a),Hdmpymt(4,6-dimethylpyrimidine-2-thiol)(1b),Hbtt(2-benzothiazolethiol)(lc),Hqlt(quinoline-2-thiol)(1d),Hmnee(2-mercapto-nicotinic acid ethyl ester)(1e),4-Hphpymt(4-phenylpyrimidine-2-thiol)(If),4,5-Hdiphpymt(4,5-diphenylpyrimidine-2-thiol)(1g),[Cu6(4,6-diphpymt)6](4,6-Hdiphenylpyrimidine-2-thiol)(1h),Hmtpmt(5-methyl-4-(p-tolyl)pyrimidine-2-thiol)(1i))and[Cu3(pymt)3]n(Hpymt=pyrimidine-2-thiol)(1j)as catalysts,using 20%NaOH as a base,i-PrOH as solvent and the hydrogen source,these complexes display high catalytic activity toward chemoselective transfer hydrogenations of unsaturated aldehydes to afford the corresponding unsaturated alcohols with high yields.The chemoselectivity are controlled by in-situ generated protonated Cu(?)hydride complexes in the catalytic system.2.Cu(?)N-heterocycle thiolate clusters are used as photocatalysts for efficient and convenient visible-light-activated reduction or reductive homocoupling of aldehydes or ketones,affording a series of primary alcohols,secondary alcohols and piancol compounds.These clusters also efficiently photocatalyze chemoselective reduction of ?,?-unsaturated carbonyls to yield unsaturated alcohols.3.The reaction of a preformed cluster[Cu6(dmpymt)6]as metalloligand with Cul and(Ph3P)CuI afford bifunctional cluster-based metal organic frameworks(MOFs)1k and 1l,respectively.Under the irradiation of blue LEDs,they display high photocatalytic activity toward the acceptorless dehydrogenation of alcohols.The catalytic system has a good tolerance for functional groups.The photocatalytic activity of 1k and 1l is 1.58,1.63 times higher than that of their precursor 1b.Furthermore,they can be simply recycled and reused without significant loss of activity.4.The solvothermal reactions of CuX(X=Br,1)with 5-phenylpyrimidine-2-thiol(5-phpmtH)in different molar ratios under 120? generated one hexanuclear cluster[Cu6(?3-5-phpymt)6](1m),two tetranuclear clusters[{(Cu2Br)(?-5-phpymtH)}(?3-5-phpymt)}]2(1n)and[Cu2(?-5-phpymtH)(?5-phpymt)(?3-I)]2(1p),and two 2D coordination polymers[Cu4(?5-5-phpymt)2(?-Br)2]n(lo)and[Cu6I2(?4-I)2(?4-5-phpymt)2],(1q).The halide and the molar ratio of the two reactants do have a significant effect on the coordination modes of 5-phpymt,the coordination environment of Cu+ and the structures and properties of the resulting Cu(?)/5-phpymt complexes.At room temperature,the solvent-dependent photoluminescence of lm may allow the development of a luminescent probe that can detect the hydrogen-bond-donating species in aprotic solvents.Compound lm also works as an acid/base-induced "on-off" luminescence switch material.lm-lq display high photocatalytic activity toward the oxidative hydroxylation of various arylboronic acids to produce the corresponding phenols.Compound 1q shows highest catalytic activity,and it can be reused for several times.5.The reaction of[Zn(dmpymt)2]n with Ni(NO3)2�6H2O gives Ni(?)N-heterocycle thiolate cluster[Ni(dmpymt)2]6(1s),which can be used for the efficient and chemoselective C-C cross-coupling of secondary and primary alcohols to generate?,?-unsaturated ketones,?-alkylated ketones or ?-alkylated secondary alcohols,just through simply manipulating reaction conditions.The reaction system is mild and the substrate is widely applicable.This catalytic system also displays high activity for cross-coupling annulation of 2-aminobenzyl alcohols with secondary alcohols to yield quinolines.