Syntheses, Structures And Performances Of Acylhydrazidate-based Coordination Polymers By In Situ Acylation Reactions

To design and synthesise novel coordination polymers?CPs?with potential functional properties is of current hot topic in the field of inorganic chemistry.In recent decades,the concept of organic-inorganic hybrid has promoted the birth of a large number of coordination polymers.These materials not only have fascinating structures,but also show potential applications in some fields such as gas adsorption,ion exchange,optics,electricity,magnetism,catalysis and etc..Moreover,most of the organic ligands are derived from commercial or traditional organic synthesis process,most of which have already been widely used in coordination polymers' synthesis.Therefore,it is urgent to search for a new strategy for obtaining new organic ligands.Luckily,in situ ligand synthesis just provides such a new way.So-called in situ ligand synthesis is when ligand precursors are used in place of the ligands to react with metal ions,finally producing the ligand-containing complexes.Compared with the conventional synthetic method,in situ ligand synthesis possesses the following merits:?i?simplifying the synthesis steps;?ii?creating a variety of new organic ligands,in particular those that are inaccessible through routine synthetic methods.More than ten types of in situ ligand reactions have been found so far.The typical reactions have oxidative hydroxylation of aromatic rings,dehydrogenative coupling of carbon–carbon bonds,alkylation,acylation of N2H4 with aromatic polycarboxylic acids,cycloaddition of organic nitriles with azide or ammonia,and so on.In this paper,we mainly focus on syntheses,structures and performances of acylhydrazidate-based coordination polymers by in situ acylation reactions.Since hydrazide molecules contain a plurality of O/N atoms,it may show versatile coordination modes with metal centers.On the other hand,both O and N atoms are easily involved in hydrogen-bonded synthons,thus more conducive to the construction of high-dimensional supramolecular networks.Based on these considerations,a series of organic carboxylic acids were selected to serve as the acidic precursors.The reactions of metal ions?main group/transition/rare earth?,aromatic polycarboxylic acids and N2H4 were hydrothermally carried out,affording 5 series of 23 new acylhydrazidate-based CPs.The effect factors influencing the final structures of the products were discussed in detail.The XRD,IR,UV,TG-DTA,fluorescence spectra,magnetism and adsorption have also been studied,which may lay a certain foundation exploring the relationship of structures and functions for CPs.The toltal paper is divided into seven chapters.In the first chapter,the concept,development,classification and applications of CPs were systematically introduced.In addition,in situ ligand synthesis was also elaborated in detail.In the end,we pointed out the importance of the project and summarized the main results we got.In the second chapter,phthalic acid with different substituents were selected to serve as the acidic precursors,affording 7 new acylhydrazidate-based CPs and 1 monoacylhydrazidate molecule: [Zn?npth?₂]?1?,[?chpth?₂]?2?,[Ba2?cpth?₂?H₂O?₂]?3?,[Zn?3-cppth??H₂O?]?4?,[M?bmth??H₂O?]×1.5H₂O?M2+ = Zn₂+ 5a,Cd2+ 5b?,[Mn2?ox??bmth?₂?H₂O?6]×2H₂O?6?,[Pb?dcpth?]×H₃O?7?,[Cd?dcpth??bpy?]?8?,?Hnpth = naphthalhydrazidate,chpth = 4-chloro-5-hydrazinophthalhydrazide,H₂ cpth = 4-carboxylphthalhydrazidate,H₂?3-cppth?= 4-?3-carboxyphenoxy?phthalhydrazidate,H₂ bmth = benzimidazole-5,6-dihydrazide,H₃ dcpth = 4,5-di?3'-carboxylphenyl?phthalhydrazide,H₂ ox = oxalic acid,bpy = 2,2'-bipyridine?.It is noteworthy that apart from the acylation,one Cl was substituted by N2H4,generating a new monoacylhydrazide molecule of compound 2.The solid-state photoluminescence analysis revealed that compounds 1-3 and 7 emit green light,whereas compounds 4-5 show blue light emitting.5a is isomorphic to 5b.5a shows 1-D tube-like chain with a diameter of 11 ?,which can adsorb 0.3 I2 per molecule.Compound 7 can be used as a fluorescence probe to sense nitro aromatic explosives at ppm concentrations.In the third chapter,we selected several diacylhydrazide molecules,having four acylamino groups,and possess the potential to form extended networks with metal ions.Luckily,3 new diacylhydrazidate-extended CPs [Ba?pmdh?]?H₂pmdh = pyromellitdihydrazidate??9?,[Ba?sdpth??H₂O?₂]×0.5H₂O?H₂sdpth = 4,4'-sulfoyldiphthalhydrazidate??10?,[Zn?N2H4??dphkh?]×H₂O?H₂dphkh = 4,4'-diphthalhydrazidatoketone hydrazone??11?and 2 diacylhydrazidate molecules [bpth]×0.5H₂O?bpth = 3,3'-biphthalhydrazide??12?,[dbpth]?13?were obtained.Note that in compound 9 is a 3-D network;While in compound 10,the sdpth molecules link the Ba2+ ions to form a 1-D square tube with a diameter of 8 ?.Interestingly,the tubes are further linked into a 3-D supramolecular network via the N–H…O interactions,creating synchronously bigger channels of 16 × 8 ?2.Moreover,the activated 10 can adsorb N2 in amounts of 80 cm3×g-1;The in situ nucleophilic addition of the keto spacer with N2H4 also occurred in 11;Compounds 12-13 are both acylhydrazide molecules originated from the in situ acylation of 3,3'-biphthalic acid with N2H4,but structure differs.The photoluminescence analysis reveals that 11,13 emit green light,whereas 12 shows blue light emitting.In the fourth chapter,we selected the rigid V-shaped triacylhydrazide ligand H₃ L,expecting to get porous CPs.Luckily,we got the first and unique example of triacylhydrazide-extended CP: [Zn?HL??H₂O?]×3H₂O(H₃L = 4,5-(di-?3',4'-phthalhydrazide??14?.14 is 3-D network with the channel of 11×11 ?2.It emits green light and also can rapidly adsorb 0.69 I2 per molecule.Other metal ions have also been tried to replace Zn₂+,and blue crystaled [Ni?ox??N2H4?]×H₂O?15?was got.Although H₃ L did not appear in the final structure of 15.Mixed ligands of H₂ ox and N2H4 link the Ni2+ centers into a 3-D network,in which the Ni?ox?chain exhibits a left-hand helical structure.Magnetic susceptibility study indicates that there exist antiferromagnetic interactions between Ni2+ centers.In the fifth chapter,we are attempting to introduce H₂ox/triazole/tetrazole ligands into the metal-acylhydrazidate system for the first time.Thus generating 9 novel acylhydrazide-extended CPs : [Zn₂?pdh?₂?ox?]×H₂O?16?,[Zn5?OH?₂?Hpth?₂?pth?₂?trz?₂]?17?,[Zn3?OH?₂?Hpth?₂?R-trz?₂]?R =3-NH₂-18a;R = 3,5-?NH₂?₂-18b?,[Zn₂?R-pth??atez?₂]?R = 4-H-19a;R = 4-NH₂-19b;R = 4-CH₃-19c?,[Zn5?OH?₂?ox??3-apth?₂?datrz?₂]?20?,[Zn₂?3-apth??atrz?₂]?21??Hpdh = pyridine-2,3-dicarboxylhydrazidate,H₂ pth = phthalhydrazidate,H₂?3-apth?= 3-aminophthalhydrazidate,Htrz = 1,2,4-triazolate,Hatez = 5-aminotetrazolate,Hdatrz = 3,5-diamino-1,2,4-triazolate,Hatrz = 3-amino-1,2,4-triazolate?.For compound 17,by changing the solvent into DMF,[?CH₃?₂NH₂]3[Zn6?ox?4.5?trz?6]×4H₂O?22?was obtained.Note that compounds 18a/18 b,19a/19b/19 c are isomorphic respectively.Compound 22 is a 3-D network only extended by mixed ligands of H₂ ox and Htrz.The acylhydrazide ligands did not appear in the final structure.The photoluminescence analysis reveals that compounds 16,20 emit green light,while 21-22 emit blue light.19a/19b/19 c are isomorphic,but the fluorescence behavior differ greatly due to different substituent groups of H₂ pth.19a does not emit light,19 b exhibits strong blue light emitting,19 c emits violet light.Moreover,the activated 16 can adsorb 38.38 cm3×g-1 N2 at 77 K.Compound 22 can be used as a fluorescence probe to sense nitrobenzene at ppm concentrations.For the sixth chapter,rare earth ions were successfully introduced into the acylhydrazidate system and a group of isomorphous Ln³⁺-acylhydrazide CPs were achieved: [Ln?epdh?₃?H₂O?]?23?(Ln³⁺ = Dy³⁺ 23a;Eu³⁺ 23b;Tb³⁺ 23c;Gd³⁺ 23d;Y³⁺ 23e;Lu³⁺ 23f;Hepdh = 5-ethylpyridine-2,3-dicarboxylhydrazidate).Photoluminescence analysis revealed that 23 b and 23 c exhibit the characteristic transitions of the Eu³⁺ or Tb³⁺ ion,whereas compounds 23 a,23d-23 f emit green light,which are dominated by Hepdh molecules.In the seventh chapter,a brief conclusion and outlook of this thesis are given.