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Two noncentrosymmetric haloplumbate hybrids, [C6H10(NH3)2][PbCl4] (1) and [C6H10(NH3)2][PbBr4] (2), have been synthesized. Crystals of 1 and 2 belong to the chiral space group P212121. The inorganic parts comprise a one-dimensional chain structure for 1 and a two-dimensional sheet structure for 2. Both compounds exhibit thermochromic luminescence originating from dual emission and have potential applications as self-referencing luminescent thermometers.

Two novel lead-based coordination polymers, namely [Pb(cbdcp)]·0.5H2O·0.5CH3OH (1) and [Pb(cbdcp)] (2), have been solvothermally constructed by using a zwitterionic ligand 4-carboxy-1-(3,4-dicarboxy-benzyl)-pyridinium chloride (abbreviated as H3cbdcpCl). Compound 1 has a three-dimensional framework displaying a valence-bonded SrAl2 topology with the 42·63·8 symbol, while compound 2 has a two-dimensional sheet structure that can be simplified into a three-dimensional ππ interaction-connected topology with the {44·62}2{48·615·85} symbol. Notably, compound 1 proved to be a promising potential luminescent sensor capable of selectively detecting anions, cations and small organic molecules, especially Cr2O72-, CrO42-, Fe3+ and nitrobenzene.

The self-assembly process of a Pd2L4 cage consisting of flexible ditopic ligands and Pd(II) ions was revealed by QASAP (quantitative analysis of self-assembly process), which enables one to obtain information about the intermediates transiently produced during the self-assembly as the average composition of all the intermediates. It was found that the dominant pathway to the cage is the formation of a submicrometre-sized sheet structure, which was characterized by dynamic light scattering (DLS) and scanning transmission electron microscopy (STEM), followed by the addition of free ditopic ligands to the Pd(II) centres of the sheet structure to trigger the cage formation. This assembly process is completely different from that of a Pd2L4 cage composed of rigid ditopic ligands, indicating that the flexibility of the components strongly affects the self-assembly process.

Four new silver(I) coordination polymers (CPs) based on 3-nitrophthalic acid (H2npt), [Ag2(NH3)2(npt)]n (1), [Ag2(NH3)(npt)]n (2), {(NH4)[Ag(npt)·H2O]}n (3) and [Ag4(NH3)4(npt)2·H2O]n (4), have been synthesized and structurally characterized. Compound 1 shows a 1D chain based on a binuclear Ag(I) SBU (secondary building unit). The [Ag(NH3)2] units are bound on the two sides of the 1D chain through the ligand-unsupported argentophilic interactions. Compound 2 is a 2D 44-sql net constructed from npt ligand-bridged centrosymmetric Ag4 rhombus SBUs. Compound 3 exhibits an anionic 2D sheet, in which the infinite chain-like [Ag2(COO)2]n SBUs are observed along the b axis. In compound 4, infinite silver nets are fabricated by ligand-unsupported argentophilic interactions and the npt ligands are anchored on the net to form the 2D sheet structure. Four CPs exhibit unprecedentedly high structural diversity dependent on the solvent and induction agent. In detail, 1, 2 and 3, 4 are mainly controlled by the induction agent, but 1, 3 and 2, 4 are controlled by the solvent systems. The thermal stabilities and photoluminescence behaviours of the compounds were also discussed.

Self-assembly of 5,10,15,20-tetra(4-pyridyl)porphyrin and trans-[Cu(hfacac)2(H2O)2] (hfacac = 1,1,1,5,5,5-hexafluoroacetylacetonate) including in situ Cu2+ metalation of the porphyrin core afforded a rhomboidally distorted (4,4)-net based polymeric 2D layer structure.

The topologically unique sheet structure of [Ag(tcm)] [tcm=the tricyanomethanide ion, C(CN)3-] is retained in the derivative [Ag(tcm)(phz)1/2] (phz=phenazine). The sheet structure is composite, consisting of two independent hexagonal grid nets which are corrugated so as to allow one to interpenetrate the other. The Ag+ ion is three-coordinate and provides half the three-connecting nodes of the hexagonal grid net, the others being provided by the tcm central carbon. [Ag(tcm)(phz)1/2] contains essentially the same composite double sheets linked together by phenazine units that bridge between silver centres which thereby become four-coordinate. The topology of [Ag(tcm)(pyz)] (pyz=pyrazine) is very different; in this case the Ag(tcm) component forms a planar, non-corrugated hexagonal grid and each such sheet is connected on both sides to neighbouring sheets by pyrazine bridging ligands whereby the silver becomes five-coordinate and trigonal bipyramidal. Two such 3,5-connected three-dimensional nets then interpenetrate.

Cyanuric acid forms a hydrogen-bonded framework with 2,7-diazapyrene that adopts a threefold interpenetrated two-dimensional sheet structure with an unexpected 44 topology, generated via the supramolecular assembly of dimeric cyanuric acid nodes.

A linear Cu(II) coordination polymer was transformed to a sheet or ladder structure by the loss of coordinated DMF when the single crystals or the ground powder, respectively, were used. Further, the sheet structure rearranged to a ladder polymer when the desolvated single crystals were ground to powder, as monitored by 1H-NMR spectroscopy.

A new compound (C5H6N2)Zn(HPO3) has been prepared hydrothermally; it consists of left-handed and right-handed helical chains that are connected through oxygen atoms to form an undulated sheet structure with 4.8-net.

A series of 1-(2-amino-2-oxoethyl)-4-carbamoylpyridin-1-ium salts with different anions (PF6− (1), OTf− (2), BPh4− (3) and Br− (4)) have been synthesized and characterized by single crystal X-ray diffraction. The results demonstrate that the unparallel diamide-substituted pyridinium salts form a dimerized rectangular building block and a 2-D rectangular structure via N–H⋯O and C–H⋯O hydrogen bonding (PF6− (1) and OTf− (2), respectively), a 2-D sheet structure (BPh4− (3)) via N–H⋯O hydrogen bonding catemers and a 2-D plate structure via N–H⋯O and C–H⋯O hydrogen bonding catemers (Br− (4)). The effects on the hydrogen bonding motifs, building blocks and structures by the four anion species with different hydrogen bonding acceptor abilities, sizes and shapes have been discussed.

Solvothermal reactions of nitrate salts with the promising multifunctional organic ligand, 2-(2-naphthyl)-1H-imidazole-4,5-dicarboxylic acid (H3NIDC), lead to two new polymers, [Sr(μ5-HNIDC)(H2O)]n (1) and [Cd(μ3-HNIDC)(CH3CH2OH)]n (2). Polymer 1 exhibits a sheet structure containing infinite distorted hexagonal rings. Polymer 2 presents an interesting 3D open architecture possessing infinite one-dimensional channels. The thermal analyses and solid-state photoluminescence properties of polymers 1 and 2 have been investigated as well.

The reactions of Cu(I) ion with {BF4−, ClO4−, or PF6−} anions and 6,6′-dimethyl-4,4′-bipyrimidine (Me2bpm) under C2H4 or CO in MeOH preferentially afforded three 2D sheet Cu(I)–Me2bpm/{C2H4, CO} adducts [Cu4(Me2bpm)3(C2H4)3(MeCN)](BF4)4·0.33MeOH}n (2), {[Cu4(Me2bpm)3-(C2H4)3(MeOH)0.33](ClO4)4}n (3), and {[Cu4(Me2bpm)3(CO)3(MeCN)](PF6)4·0.33MeCN}n (4), whereas the similar reaction of Cu(I) ion with a BF4− anion and Me2bpm under CO in MeOH gave the metallamacrocyclic tetranuclear Cu(I)–Me2bpm/CO adduct [Cu4(Me2bpm)4(CO)4]-(BF4)4·4MeOH (5). In Cu(I)–Me2bpm/{C2H4, CO} adducts 2–4, it should be noted that the metallacalix[3]arene structures of the [Cu3(Me2bpm)3]3+ framework are linked through another Cu atom with MeCN (2 and 4) or MeOH (3) to produce a chiral 2D sheet structure with small Cu3 and large Cu9 cavities. In the small triangular Cu3 cavities, one MeOH (2) or MeCN (4) molecule is encapsulated in complexes 2 and 4, whereas these Cu3 cavities are empty in complex 3. In the large Cu9 cavities, one anion (X = BF4− (2), ClO4− (3) or PF6− (4)) is surrounding by six Me groups of three Me2bpm on the upside and three anions (X) are functionally accommodated on the downside for complexes 2–4, respectively. In the Cu(I)–Me2bpm/CO adduct 5, two of the four BF4− anions are accommodated in the upper and lower cavities of the [Cu4(Me2bpm)4] framework. We demonstrated that the metallamacrocyclic and polymeric 2D sheet Cu(I)–Me2bpm/{C2H4, CO} adducts can be reasonably self-assembled under the direction of anions and solvents.

The coordination polymer {p-C6H4[CH2OCH2C(pz)3]2(AgSbF6)2}∞ crystallizes into two supramolecular structures, one organized into a 3D structure of argentamacrocycles stacked in a tubular network connected by helically oriented organic spacers and the other into argentachains arranged in a 2D sheet structure.

To systematically explore the influence of the pyridyl N-donor spatial positions of benzotriazol-1-yl-based pyridyl tectons on structural assemblies of coordination polymers, three closely related ligands, 1-(2-pyridylmethyl)-1H-benzotriazole (2-pbt), 1-(4-pyridylmethyl)-1H-benzotriazole (4-pbt), and 1-(3-pyridylmethyl)-1H-benzotriazole (3-pbt), were designed and prepared. Their reactions with CuI under hydrothermal conditions afforded three new copper(I)-iodide coordination polymers, namely, [CuI(2-pbt)]∞ (1), [Cu2I2(4-pbt)]∞ (2), and [Cu3I3(3-pbt)]∞ (3). Single-crystal X-ray diffraction analysis shows that 1 has a two-dimensional (2D) (4,4) sheet structure containing rhomboid [Cu2I2] dimeric units, which are further extended to form a three-dimensional (3D) framework by interlayer C–H⋯π supramolecular interactions. Complexes 2 and 3, with one-dimensional (1D) looped-chain [Cu2I2]n and 1D staircase double-chain [Cu3I3]n copper(I)-iodide arrays, show an unusual 3D six-connected self-penetrating rob net with the Schlafli symbol of (48.66.8) and a 3D four-connected homochiral diamond net, respectively. The results reveal that the different spatial positions of pyridyl N-donors in this series of ligands play an important role in constructing coordination polymers 1–3. Moreover, the photoluminescent properties and thermal stability of 1–3 in the solid state have also been investigated.

The title compound [Cp2PbCpthfNa]·0.5thf 1, obtained from the addition reaction of Cp2Pb with [CpthfNa·thf], provides the first opportunity to assess the structural impact of internal donation on aggregation within a p block metal cyclopentadienide anion system; the result being the adoption of an unusual polymeric sheet structure composed of [Cp2PbCpthfNa]3 rings.

Molecules of crystalline 1-(pyridin-2-yl)tetrazole associate through three unique C–H⋯N interactions into a 3 34 2 sheet structure. In contrast, 5-(pyridin-2-yl)-1H-tetrazole forms a six-connected 2-D network, that can be described as a self-penetrating 4 6 net.

Treatment of cuprous halide (Cu(I)X, X = Cl, Br, and I) and a tripodal tripyridine ligand (L) consisting of a 1,3,5-triethylbenzene spacer gave a unique two-dimensional (2D) polymer sheet structure involving a rare Cu(I)(6)X(6) hexagon prism cluster unit, which exhibits intense fluorescence around 448-476 nm.

A family of two-dimensional coordination polymers formed from the reaction of Cd(NO(3))(2) with pyrazine or pyrimidine is reported, including rare examples of polymorphic coordination polymers which crystallise as multiple crystals. Six coordination polymers have been structurally characterised, four for pyrazine and two for pyrimidine-based systems, all of which form two-dimensional arrays utilising pyrazine/pyrimidine bridging, in some instances in combination with nitrate bridging. The compounds form either 4(4) grids (1,3,4,5), or in one instance, a 6(3) herringbone sheet structure (2). In the case of 3, two polymorphs have been identified, 3a and 3b, in which the three-dimensional arrangements of the coordination polymers differ only in the relative ordering of adjacent two-dimensional sheets. It was found that these two polymorphs crystallise in a simultaneous fashion such that each crystal studied was found to contain regions of both polymorphs and was believed to be a multiple crystal. Assessment of the phase purity of the product from the reaction of Cd(NO(3))(2) with either pyrazine or pyrimidine indicates that compounds 1and 5 are not formed when the products are formed by rapid precipitation but only when using slow-diffusion methods. It is also apparent that in almost all instances more than one product is formed from a given reaction thereby illustrating the complexity of coordination polymer formation even when using simple building-blocks. For the crystal engineer this complexity is perhaps best illustrated by the simultaneous formation of 3a and 3b where no chemical interactions differentiate the two polymorphs, presenting a seemingly insurmountable complexity in the engineering of these systems.

The structural characterisation of a 2D sheet complex {[Mn2(Hetheidi)2(μ-H2O)(H2O)]·3H2O}n1 [Hetheidi = DL-N-(1-hydroxymethylpropyl)iminodiacetic acid] assembled from the tetradentate ligand Hetheidi and MnCl2 reveals the presence of rare unsupported μ-aqua bridges and novel hydrogen-bonded water channels, which bind the sheets together.

The co-crystallisation of thiourea (tu) with tetra-n-butylammonium terephthalate gave either [NBu4]2[C6H4(CO2)2-1,4]·6tu·2H2O 1 or [NBu4]6[C6H4(CO2)2-1,4]3·6tu·4H2O 2, depending on the solvent and stoichiometry employed. Both compounds have structures containing hydrogen-bonded linear thiourea hexads, though these hexads are connected via additional hydrogen bonds into a three-dimensional network in 1 and a two-dimensional sheet structure in 2. The compound [NBu4]Br·2tu 3, resulting from an impurity in one of the starting materials, has also been isolated and structurally characterised. An analysis of the Cambridge Structural Database has demonstrated that the flattened conformations observed for the NBu4+ cations in these compounds are not atypical.

Co-ordination polymers with Ag∶1,3-dithiane molar ratios of 1∶1, {[Ag2(1,3-dithiane)2][X][Y]}∞ (X = Y = NO3, 1; X = Y = PF6, 2; X = Y = BF4, 3; X = BF4, Y = Cl, 4; X = Y = NO2, 5, and 2∶1, {[Ag2(1,3-dithiane)(SO4)(H2O)2]·H2O}∞6, the extended structures of which are 1-D chains and 2-D sheets, respectively, have been synthesised and structurally characterised. The recurrent structural motif is the [Ag2(μ-1,3-dithiane)2]2+ cationic dimer in which two chair-conformation 1,3-dithiane molecules act as two-connecting units to bridge two Ag(I) centres. In 1, 2, and 6, the dimers are linked into near-linear chains by pairs of bridging anions via formation of an Ag2X2 rhomboid dimer. In 3, instead of forming the Ag2X2 (X = F) rhomboid dimer, two [BF4−] anions form μ2-F,F′-bridges which support weak Ag–S interactions between cations to give a saw-tooth chain structure. This extra Ag–S contact makes the 1,3-dithiane a three-connecting unit. In 4 and 5, the Ag(I) centres of the cationic dimer are bridged not only by two 1,3-dithiane molecules but also by a Cl− or NO2− anion, respectively, to give [Ag2(μ-1,3-dithiane)2(μ2-Cl)]+ (4) and [Ag2(μ-1,3-dithiane)2(μ2-O,O′-NO2)]+ (5). In 4, the Cl− anion acts as a μ4-bridge to link three [Ag2(μ-1,3-dithiane)2]2+ moieties and generate a zig-zag chain. In 5, one oxygen of the bridging NO2− anions acts as a μ2-bridge to link two [Ag2(μ-1,3-dithiane)2]2+ dimers and generate a saw-tooth chain. Although the chains in 1, 2, 3 and 5 are uncharged, that in 4 is cationic and that in 6 is anionic. Charge balance in 4 is maintained by a non-co-ordinated [BF4−] anion; that in 5 is maintained by ‘Ag(H2O)2+’, the co-ordination polyhedron of which is completed by sulfur donors from separate 1,3-dithiane molecules, which thus act as four-connecting units, and by two oxygens of separate SO42− anions to give a two-dimensional sheet structure.

Recrystallisation of [CuL2e][BF4]2 [L2e = 1,2-bis(amidino-O-ethylurea)ethane] from methanol affords [CuL2e][BF2(OMe)2][BF4], the basic building block of which is a 1-D linear chain of [CuL2e]2+ cations linked by difluorodimethoxyborate-mediated hydrogen-bonded supramolecular synthons. Hydrogen-bonded [BF4]− anions link the chains to form a 2-D sheet structure; weak co-ordinate interactions between Cu(II) centres and [BF4]− anions in adjacent sheets generate a 3-D network. Recrystallisation of [CuL2m][BF4]2 [L2m = 1,2-bis(amidino-O-methylurea)ethane] from methanol leaves it unaltered. The [CuL2m]2+–[BF4]− system does not give rise to the same sort of supramolecular synthon and linear 1-D chain as the [CuL2e]2+–[BF2(OMe)2]− system. Instead the basic building block is a zigzag chain of [CuL2m]2+ cations linked through a different arrangement of hydrogen-bonded [BF4]− anions. The [BF4]− anions also act as hydrogen-bonding acceptors to connect the chains, firstly into 2-D sheets and ultimately into a 3-D network.

Hydrothermal synthesis and crystal structure of a lamellar hydrated sodium zinc arsenate with an unusual sheet structure are reported.