A. S. Ovsyannikov

Molecular tectonics: control of the dimensionality in tetramercaptothiacalixarenes based coordination networks.

Combinations of tetramercaptotetrathiacalix[4]arene pyridyl-appended positional isomers with HgCl2 lead to the formation of neutral coordination networks with their dimensionality imposed by the position of the N atom on the pyridyl group.

Molecular tectonics: p-H-thiacalix[4]arene pyridyl appended positional isomers as tectons for the formation of 1D and 2D mercury coordination networks

Three p-H-thiacalix[4]arene pyridyl appended coordinating tectons (2-4) in a 1,3-alternate conformation have been prepared and structurally characterised in the solid state. These compounds are positional isomers differing only by the position of the nitrogen atom on the pyridyl ring. Their combinations with HgCl2 lead to the formation of 1- and 2-D neutral mercury coordination networks. Whereas for tecton 2 (ortho isomer) a 2D architecture resulting from the bridging of consecutive tectons by the mononuclear HgCl2 unit is obtained, for tecton 3 (meta isomer) again a 2D network is formed. However, in that case, the interconnection of consecutive organic tectons 3 takes place through a binuclear Hg2Cl4 species. Finally, in the case of tecton 4 (para position), a 1D ribbon type double chain arrangement resulting from the bridging of consecutive tectons by trinuclear Hg3Cl6 units followed by the interconnection of two chains through the fusion of the trinuclear centres into a hexanuclear node is observed.

Molecular tectonics: generation of grid and porous diamondoid coordination networks by calixarene based tectons

Combinations of neutral tetrakis meta-pyridyl appended calix[4]arene derivatives in 1,3-A conformation as tectons 3 (tetrakis-meta-pyridyl-tetrathiacalix[4]arene) and 4 (tetrakis-meta-pyridyltetrathiatetramercaptocalix[4]arene) with MX2, behaving as a neutral metallatecton, lead to the formation of 2- and 3-D neutral coordination networks. In all cases, the metal centre adopts a distorted octahedral geometry with the two anions occupying the two apical positions. For compound 3-CdX2 (X = Cl or Br), 4-CdBr2 and 4-FeCl2 similar porous diamondoid 3D networks, resulting from the tetrakis monodentate behaviour of the organic tectons, are formed. In marked contrast, for 4-CoX2 (X = Cl or Br), only two out of the four pyridyl units take part in the connectivity pattern leading thus to the formation of 2D grid type architectures.

Molecular tectonics: dimensionality and geometry control of silver coordination networks based on pyrazolyl appended thiacalixarenes

Combinations of six new coordinating tectons (3–8) tetrakis-pyrazolyl appended calix[4]arenes, blocked in 1,3-A conformation, based on 1 (tetrathiacalix[4]arene) and 2 (tetrathiatetramercaptocalix[4]arene) derivatives, with AgX salts (X = NO3−, BF4−, XF6− (X = P, As and Sb)) lead to nine new silver coordination networks. The flexible nature of tectons 3–8 (length of the spacer between the macrocycle and the pyrazolyl coordinating unit), their high number of potential coordinating sites and the loose coordination demand of Ag+ cation lead to the formation of a large variety of networks with different dimensionality: from 1D (5-AgSbF6, 5-AgBF4, 7-AgSbF6 and 8-AgNO3) to extended 2D (6-AgBF4 and 8-AgSbF6) and to a series of three isostructural porous diamond-like 3D architectures (6-AgXF6 (X = P, As and Sb)).

Molecular tectonics: silver coordination networks based on tetramercaptothiacalix[4]arene in 1,3-alternate conformation bearing four nitrile groups

Two tetrasubsituted derivatives of tetramercaptothiacalix[4]arene in 1,3-alternate conformation bearing either four (3-cyano)propyl (1) or (4-cyano)benzyl (2) moieties have been synthesized and characterized in solution as well as in the solid state by X-ray diffraction on single crystals. Their propensity to form coordination networks was investigated in the presence of silver cation as connecting metal and hexafluorophosphate as counter ion. Whereas the combination of AgPF6 and 1 bearing four (3-cyano)propyl groups leads to a 1D silver coordination network, for 2, containing four (4-cyano)benzyl units, a 3D diamond-like architecture is obtained.

Molecular tectonics: tetracarboxythiacalix[4]arene derivatives as tectons for the formation of hydrogen-bonded networks

A series of thiacalix[4]arene derivatives blocked in the 1,3-alternate conformation and bearing four carboxylic acids have been designed and synthesized. These compounds, owing to the H-bond donor (OH moiety) and acceptor (CO group) nature of the carboxylic acid moieties, behave as self-complementary tectons and lead to the formation of tubular 1D H-bonded networks in the crystalline phase. Upon deprotonation of the self-complementary neutral compounds, i.e. transformation of carboxylic acid moieties into carboxylates, anionic tectons are generated. Due to their propensity to form H-bonded networks in the presence of a dicationic H-bond donor tecton of the cyclic bis-amidinium type, designed to behave as a molecular staple interconnecting two carboxylates moieties, 1- and 2-D H-bonded networks are formed under self-assembly conditions.

Synthesis of New Photoswitchable Tectons Based on Thiacalix[4]arene Azo Derivatives in the 1,3-Alternate Conformation

The paper describes the first synthesis of molecular tectons, a series of ligands based on thiacalix[4]arenes in the 1,3-alternate stereoisomeric form containing photoswitchable azo groups in the side chain and carboxyl groups as potential binding sites for the synthesis of photoswitchable complexes and coordination polymers. In the case of p-tert-butylcalixarenes, the convergent approach is preferred.

Molecular Tectonics: high dimensional coordination networks based on a methylenecarboxylate appended tetramercaptothiacalix[4]arene in 1,3-Alternate conformation

The combination, under mild conditions, of the methylenecarboxylic-appended tetramercaptotetrathiacalix[4]arene (TMTCA) derivative 4, blocked in the 1,3-alternate conformation, with acetate salts of octahedral copper(II), manganese(II), nickel(II) and zinc(II) leads to the formation, in the crystalline state, of high dimensional coordination networks. Depending on the nature of the used metal cations and bases (pyridine or non-coordinating Et3N), six new different high-dimensional coordination polymers have been evidenced, presenting 4 different coordination patterns. All the compounds present a metal/4 ratio equal to 2/1. The formation of a 2D grid-like compound (4-Zn2(Py)4) and three different pseudodiamondoid-like 3D compounds (4-Co2(Py)6(H2O)2, 4-Ni2(Py)6(H2O)2, 4-Mn2(Py)4(MeOH)2, 4-Mn2(DMF)2(MeOH)4 and 4-Zn2(MeOH)4) is observed.