Crystal Engineering Of Novel Azocyclic Supramolecular Structures Based On Hydrogen-bond Synthons

Based on the concepts of supramolecular synthon and crystal engineering, we obtain twenty-four crystals in four series suitable for X-Ray crystallographic diffraction with trans-4,4-azobispyridine (AZP) or 1,2-bis(4-pyridyl)ethylene (BPE) as one of the building blocks. The crystals can be classified to organic molecular, organic-inorganic ionic, organometallic helical structural supermolucules via hydrogen bonding, π-πstacking and coordinated self-organization. The novel structures were solved by direct method, and the refinements were carried out using SHELXTL v. 6.14 program. 1. AZP or BPE with fatty diacid construct crystal engineering via O-H…N/C-H…O synthon. Furthermore, the crystals of p-(4-pyridyl) ethylene toluene with succinic acid and capric acid with BPE were produced for comparison. A conclusion drawn from the investigation of these ten crystals is shown below: (1) In one-dimensional space, AZP or BPE with fatty diacid arrange alternately to tape-like structure. Maleic acid closes to ring, and then aggregates to a dimer with another one via intramolecular O-H…O hydrogen bond. The dimer of maleic acids arrange with BPE alternately to tape-like structure. Two p-(4-pyridyl) ethylene toluene and two capric acids interact via Van der Waals force and hydrophobic interaction worked as a diacid and di-pyridyl base, respectively. (2) In two-dimensional space, when the dimension of diacid comparable to that of di-pyridyl base, interlaced arrangement of the two building blocks in adjacent tape is observed; when the dimension of the former is much longer than that of the latter, the former arrange side-by-side with a little shift as well as the latter between adjacent tapes under the hydrophobic interaction; when the dimension of the former is much shorter than that of the latter, the former shifts left and right along the tape between adjacent tapes forming zig-zag arrangement as well as the latter. (3) In three-dimensional space, π-πinteraction only is observed in the crystals of succinic acid and adipic acid with AZP and BPE. 2. Supramolecular crystals are obtained from BPE with 2,3-dihydroxynaphthalene (2,3-DHN) and 2,7-dihydroxynaphthalene (2,7-DHN) , respectively or AZP with 2,7-DHN as building block via O-H…N synthon. The try to produce crystal of AZP with 2,3-DHN failed. (1) Crystal of BPE with 2,3-DHN form ternary cyclic dimer with the participator of latticed ethanol. The dihedral angle between BPE and 2,3-DHN is 74.1o, and the separation of BPE in a dimer is 3.46? indicating the existence of π-πinteraction. As a result of packing to two-dimensional structure, one BPE (2,3-DHN) couple is encompassed by four 2,3-DHN (BPE) couples. In three-dimensional space, one BPE (2,3-DHN) couple stands above and beneath one 2,3-DHN (BPE) couple. In other word, the first layer overlaps with the third layer exactly. (2) In the crystal of BPE and 2,7-DHN, two building blocks arrange alternately to chain via O-H…N synthon with 50.6o dihedral angle. Under C-H…O intermolecular interaction two building blocks arrange also alternately between adjacent chains to form a layer. Inthree-dimensional space two building blocks arrange alternately between adjacent layers, too, similar with the crystal of BPE wirh 2,3-DHN. (3) Crystal of AZP with 2,7-DHN in C2/c space group form '8'shaped helical structure with alternant building blocks via O-H…N synthon. The dihedral angle between AZP and 2,7-DHN neighbour is 12o. As a result of transfer equivalently, there exist π-πinteraction between two pyridyl ring of AZP with 2,7-DHN and another pyridyl, respectively. 3. According to the tendency of protonation and further participate in hydrogen bond, BPE and AZP are used to crystallize with transition metal in acid environment via hydrogen bonding and electrostatic interaction. We obtained ten ionic supramolecular crystals in which metal forms coordinated square planar, tetrahedral and octahedral geometry, respectively. (1) H2BPE2+ with square planar [CuCl4]2-arrange alternately via N-H…Cl2 three-center bifurcate synthon to one-dimensional tape-like structure. Adjacent tapes link to corrugated sheet via α-CH…Cl interaction. Viewed along the direction of tape, every tape is surrounded by six tapes with π-πstacking. (2) Here exhibit three motifs of solid supramolecular structure of H2BPE2+ and H2AZP2+ crystallized with tetrahedral [ZnCl4]2+ and [HgCl4]2+: zig-zag chain induced by N-H…Cl hydrogen bond; grommet chain induced by N-H…Cl/C-H…Cl synthon; cyclic dimer induce by a couple of N-H…Cl/C-H…Cl synthon. Under the influence of tetrahedral geometry of inorganic part the former two are corrugated sheet and the later is herring-bond-like packing structure in two-dimensional space. (3)H2BPE2+ and H2AZP2+ with six-coordinated Fe(II) and Fe(III) form novel supramolecular crystal structure in HCl. H2BPE2+ with [FeCl4(H2O)2]2-form cyclic dimer via N-H…Cl/C-H...Cl synthon which packs to not herring-bond-like structure but zig-zag chain linked by O-H…Ohydrogen bonding. C-H…Cl interchainar interaction contributes to the formation of sheet. Latticed water and HCl solvent cross-link adjacent sheets to three-dimensional structure except for the contribution of π-πstacking. Redox reaction happens when AZP cocrystallizes with FeCl2 in HCl in which azo translates to hydrazine along with Fe(II) to Fe(III). A couple of torsional H4AZP2+ and [FeCl6]3-aggregate to a cyclic dimer with [FeCl4]-in their loop. Crystal of BPE and FeCl3 crystallized in HCl forms the rare sandwich structure of [H2BPE]2+[FeCl3(H2O)3]2 positive sheet and [H2BPE]2+·4Cl-negative sheet alternately. 4. Although this part work is not about AZP or BPE, another Schiff base 2-metheneepridyl-1-aminonaphthalene (L) was used. The chiral construction of complex supramolecular systems is receiving much interest, especially with achiral building units. In this part, we investigated the helical supramolecular structure of an achiral rhenium complex crystal, [Re(CO)3(C16H12N2)(MeCN)].ClO4, which was formed by coordination of Re(CO)5Cl with L and acetonitrile. X-ray diffraction analysis suggests that homohelical column metallosupramolecular architecture results from the array of six-coordinated Re around and along a line: the helical axis in chiral in P 1 21 1 space. There is rare example of constructing helical architectures with both coordinated and hydrogen bonds from achiral units. The helical self-assembly process is induced by the intrastrand interaction and crystal growth. Here, the perchlorate acts as both the counter ion and the bridge linking the neighboring coordinated parts together by weak non-covalent interaction. Furthermore, the two-dimensional arrangement adopts double-edged axe-shaped motif, which is different from the common herringbone or brick-wall pattern in coordination polymers. Our investigationintroduced the special arrangement model into complicated helical architecture, especially homochiral single-colony. In summary, twenty-four crystals'structures have been analyzed and discussed in this thesis, and related crystal engineering character and orderliness have been brought forward which is predictive to the architecture of similar building blocks and synthons.