| Metal-organic crystal networks (MOCNs) have attracted extensive interests in recentyears owing to their intriguing structural topologies and potential applications incatalysis, molecular recognization, gas storage, ion exchange, drug delivery, gas sensor,photoluminescence, proton conductivity, as well as molecular magnet. To date, someexcellent studies have been reported, which provide some useful strategies andexperiences. However, as a result of the many factors during the assembly process, noappropriate methods to tune the structures and properties of MOCNs are detected.Therefore, it is still a challenging task to seek for effective synthetic strategies to obtainMOCNs with expected structures and properties through the rational design of organicmolecules and choice of metal cations.According to our summarization of the current topological structures and propertiesof MOCNs, we choose a few hot topics based on the principle of crystal engineeringand supramolecular chemistry and aim to synthesize a series of metal-organic orsupramolecular crystal networks with novel architectures or excellent photoluminescentproperties, which then provide some valuable strategies for designing and synthesizingsuch types of MOCNs. Accordingly,39MOCNs are synthesized under differentsolution and hydro(solvo)thermal conditions. Their corresponding architectures andproperties have also been studied. These researches mainly include the followingaspects:1. Five aromatic sulfonic molecules, namely,4(1H)-pyridone-3-sulfonic acid (H2L1),2(1H)-pyridone-5-sulfonic acid (H2L2),2-hydroxyl-5-chloro-benzenesulfonic acid(H<sub>2L3),2-hydroxyl-5-carboxylbenzenesulfonic acid (H3L4) and4,6-dihydroxy-1,3-benzenedisulfonic acid (H4L5), have been designed and employed toreact with silver(I) cation which exhibits various coordination numbers and diversecoordination spheres, leading to the formation of seven novel silver(I)-based MPFs, [Ag2(HL1)2]n2nH2O (1),[Ag5(HL1)3(NO3)2(H2O)]n(2),[Ag2(HL1)(NO3)]n(3),[Ag3(HL22(NO3)(H2O)]n(4),[Ag2(HL32]n(5),[Ag6(L42(H2O3]n(6) and [Ag5(L5)(NH32(NO3)]n(7). Structural analyses indicate that the introduction of the hydroxylgroup at the ortho-position of-SO3group can enrich the coordination modes of thesulfonate groups and modulate the final topological structures of silver(I)-sulfonates.Complex1presents the first1-D "butterfly" chain in silver(I) sulfonates. Complexes2-7exhibit diverse silver(I)-based MPFs with different silver polyhedra, in whichcomplex2is the first2-D silver(I)-based MPFs with four different high coordinationnumbers and four types of coordination polydedra, while complex6is the first2-Dsilver(I)-based MPFs with four different low coordination numbers and four types ofcoordination polydedra. Complex7represents the first3-D silver(I)-based MPFsconstructed from different coordination polydedra. Moreover, the IR, TG and PLproperties of these complexes have also been characterized.2. Two flexible bis(pyridyl) ligands with a non-coordinating amine group in theunsymmetrical spacer, N-(pyridin-3-ylmethyl)pyridin-2-amine (L1) andN-(pyridin-3-ylmethyl)pyridin-3-amine (L2), have been designed and synthesized,which then are used to react with isophthalic acid (H2ip) and transition metal cations togenerate eight mixed-ligand MOCNs, namely,[Mn2(ip2(L12(H2O3]n·nH2O (8),[Co(ip)L1(H2O)]n(9),[Zn(ip)L1]n(10),[Cd2(ip)2L1]n(11),[Mn(ip)L2(H2O)]n·nCH3OH (12),[M(ip)L2(H2O)]n·nH2O [M=Co (13) and Ni (14)]and [Zn3(ip2(OH2(L22]n(15). The structural diversities indicate that the nature of themetal cations, the versatile coordination modes of the ip dianions, as well as theconformations of L1and L2play crucial roles in modulating structures and topologiesof these complexes. Complex8exhibits a1-D 'ladder' chain structure, while complexes9,10and12display2-D (4,4) layer networks. Complex11is a3-D pillared layeredframework. Complexes13and14are isomorohous and exhibit3-D tcb net. Complex15is a3-D framework and presents a new topology with the Schl fli symbol of (55.69.7).Moreover, solid-state luminescent properties demonstrate that complexes10,11and15 exhibit blue emission at room temperature.3.5,5'-Methylenedisalicylic acid (H4MDSA) with excellent chromophore isemployed to react with Zn(II), Cd(II), and2,2'-bipy or phen under hydrothermalcondition, thus giving rise to three mixed-ligand MOCNs,[Zn(H2MDSA)(phen)(H2O)]n(16),[Cd(H2MDSA)(2,2'-bipy)]n(17) and [Cd2(H2MDSA)2(phen)2(H2O)]n(18).Structural analyses indicate that these three complexes exhibit different1-D helical (16),wave-like (17) chain, and3-D pcu net (18). The structural evolutions are mainlydepending on the radii of the metal cations and the coordination modes of the H4MDSA.However, complexes16-18present weak emission and poor water solubility at roomtemperature. Thus, in order to improve such situation, the H4MDSA molecule isdecorated with hydroxyl groups on the ortho-position of sulfonate groups, and a newwater soluble molecule of5,5'-methylenedisulfonic-salicylic acid (H6MDSSA) isobtained. Three water soluble MOCNs based on the reaction of H6MDSSA and K(I)cation, namely,{2(NH4)·[K2(H2MDSSA)(H2O)3]}n(19),{(NH4)·[K3(H2MDSSA)(H2O)4]}n·2nH2O (20) and [K4(H2MDSSA)(H2O)6]n(21), have been synthesized.Complex19exhibits2-D layer structure while complexes20and21present3-Dnetworks. Moreover, careful investigation on the luminescent properties of complex21in the aqueous solution demonstrates that it could be used as pH indicator andluminescent probe for detecting Fe(III) and Cu(II) cations.4. Self-assembly of four bis(pyridyl) organic molecules with long flexible spacer,1,4-bis(2-pyridylaminomethyl)benzene (M1),1,4-bis(3-pyridylaminomethyl)benzene(M2),1,3-bis(2-pyridylaminomethyl)benzene (M3) and1,3-bis(3-pyridylaminomethyl)-benzene (M4), and different inorganic acids (HNO3and HClO4) leads to the formationof eight supramolecular complexes, H2M1·2NO3(22), H2M2·2NO3(23), H2M3·2NO3(24), H2M4·2NO3(25), H2M1·2ClO4(26), H2M2·2ClO4(27), H2M3·2ClO4(28) andH2M4·2ClO4(29). For the same organic cations, the NO3-induced supramolecularaggregations are all packed in a better layer-by-layer mode than the ClO4-induced ones,owing to the coplanarity of the NO3-anion. The four flexible bis(pyridyl) cations exhibit various conformation modes of trans-trans-trans, trans-trans-cis and cis-trans-trans.Moreover, the perchlorates exhibit strong emission intensities, which provides a strategyfor the rational design of organic supramolecular crystal networks with excellentluminescent properties.5. Ten cocrystals assembled by1,5-naphthalenedisulfonic acid (H2NDS) withhydrazine, four flexible aliphatic diamines, three rigid and one semi-rigid aromaticdiamines (Scheme1), namely,(H2HA)·(NDS)(30),(H2EDA)·(NDS)(31),(H2PDA)·(NDS)(32),(H2BTDA)·(NDS)(33),(H2BDMA)·(NDS)·2H2O (34),2(o-HBDA)·(NDS)(35),(m-H2BDA)·(NDS)(36),(H2MBDA)·(NDS)·3H2O (37),(H2SDA)·(NDS)·H2O (38) and2(HSDA)·(NDS)·H2O (39)(HA=hydrazine, EDA=1,2-ethanediamine, PDA=1,3-propanediamine, BTDA=1,4-butanediamine, BDMA=1,3-benzenedimethanamine, o-BDA=1,2-benzenediamine, m-BDA=1,3-benzenediamine, MBDA=4-methyl-1,3-benzenediamine, SDA=4,4'-sulfonyldiamiline), have been synthesized and characterized. The nature of thediamines can effectively influence the final architectures of the cocrystals throughdifferent hydrogen bonding interactions and other non-covalent bonding interactions,such as π···π stacking, N-H···π, C-H···π, as well as the the anion···π interactions.Different hydrogen bonding modes formed by–SO3and–NH3groups result in diverse[1+1],[2+2],[2+4],[3+3],[4+4] and [5+5] hydrogen bonding rings, which thengenerate six types of architectures with the assistance of the above non-covalentbonding interactions. Luminescent investigations demonstrate that the cocrystalscontaining aliphatic diamines exhibit stronger emission intensity than those containingaromatic diamines. Therefore, the H2NDS might be used to distinguish the aliphaticdiamine from aromatic diamine qualitatively in the mixed water-methanol solution,especially, H2NDS might be a potential luminescent detector for o-BDA molecule.Keywords: metal-organic crystal network; metal-polyhedra framework; supramolecularcomplex; luminescent property...
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