This work reports on a designed construction of new porphyrin-based supramolecular architectures assembled with the aid of halogen bonds and a combination of halogen and hydrogen bonding interactions. The tinIV(L)2-tetraarylporphyrin building unit (L = axial ligand) was used to this end, wherein suitable donor and acceptor functions for such bonds have been introduced in a complementary manner on the axial ligands and the porphyrin periphery. We reveal in this context eight structures involving differently substituted metalloporphyrin entities: 5,10,15,20-tetra­(4′-iodophenyl)­porphyrin (A4-P), 5,10,15,20-tetra­(4′-pyridyl)­porphyrin (B4-P), 5-(4′-pyridyl)-10,15,20-tris­(4′-iodophenyl)­porphyrin (A3B-P), and 5,15-bis­(4′-pyridyl)-10,20-bis­(4′-iodophenyl)­porphyrin (A2B2-P), and various axial ligands attached to the tin center and bearing molecular recognition capacity. The latter include 3-hydroxypyridine (L1), hydroxyl (L2), 1-hydroxybenzotriazole (L3), 5-bromopyridine-3-carboxylic acid (L4), 5-bromoisophthalic acid (L5), 5-hydroxyisophthalic acid (L6), and 2,5-thiophenedicarboxylic acid (L7). The various porphyrin-Sn­(L)2 combinations that could be obtained in a single-crystal form were structurally analyzed by single-crystal X-ray diffraction, and their intermolecular interaction patterns were rationalized by computational methods. The versatile (A2B2-P) system deserved the most attention, and the crystal structure of this free-base porphyrin was determined as well. The occurrence of supramolecular halogen interactions between neighboring porphyrin moieties, as structure directing agents, was successfully manifested in our systems. Other findings of particular interest are that the assembly of [Sn­(3-hydroxypyridine)2­(A4-P)] (compound 1) displays a short intermolecular I···O halogen interaction at 2.949 Å, facilitated by a self-activation process through concomitant involvement of the iodine substituents in I···I contacts. Compound 2 [{Zn­(A4-P)}2­Sn­(OH)2­(B4-P)] illustrates the first porphyrinic trimer assembly driven by halogen bonding interactions. Then, compounds 6 [Sn­(5-bromoiso-phthalate)2­(A2B2-P)­·(PhNO2)], 7 [Sn­(5-bromo-isophthalate)2­(A2B2-P)­·(DMF)], 8 [Sn­(5-hydroxyisophthalate)2­(A2B2-P)], and 9 [Sn­(2,5-thiophene-dicarboxylate)2­(A2B2-P)­·(PhNO2)3] reveal strong halogen interactions alongside tight hydrogen bonding contacts. In 9 the relatively rare I···S halogen bonding has been detected in porphyrin assemblies for the first time.

A novel synthetic methodology has been applied to obtain sizeable single crystals of wide-pore porphyrin-based MOFs.

Six cobalt(II) containing coordination polymers {Co(hfipbb)(L1)0.5} n (1), {Co(hfipbb)(L2)0.5} n (2), {Co(oba)(L1)0.5} n (3), {Co(oba)(L2)} n ·nH2O (4), {Co(1,2-pda)(L1)0.5} n (5), and [Co(1,2-pda)(L2)(H2O)] n ·nH2O (6), that are formed from two positional isomeric bis(pyridyl) ligands with a long flexible spacer 1,4-bis(2-pyridylaminomethyl)benzene (L1) and 1,4-bis(3-pyridylaminomethyl)benzene (L2) and three different bent carboxylic acids 4,4′-(hexa-fluoroisopropylidene)bis-(benzoicacid) (H2hfipbb), 4,4′-oxybenzoic acid (H2oba), and 1,2-phenylenediaceticacid (1,2-H2pda), have been synthesized under hydrothermal conditions. Compounds 1–6 are characterized by single crystal X-ray diffraction analysis, IR spectroscopy, and thermogravimetric (TG) and elemental analysis. In the crystal structures of compounds 1, 3, and 5, two-dimensional (2D) metal-carboxylic acid layers, composed of dicobalt tetracarboxylate paddle-wheel clusters, are formed whereby these layers are pillared by the secondary ligand L1 in a typical trans–trans–trans conformation to result in a three-dimensional (3D) layered-pillared structure. However, in the crystals of compounds 2, 4, and 6 with secondary ligand L2, it does not favor the formation of paddle-wheels resulting in three completely different coordination polymers. The geometry of the carboxylic acid influences the formation of 2D metal acid layers in the compounds 1, 3, and 5 to form interpenetrated helical double layers to single layers. In compound 2, the secondary ligand L2 diagonally connects the 3D metal acid framework in a regular trans–trans–trans conformation. In compound 4, the ligand L2 exists in cis–cis–trans conformation to form [Co2L22] loops (metallo-macrocycles) which are connected by the oba2– ligand to form polyrotaxane-like 2D polymers. In compound 6, ligand L2 exists in an unusual cis–trans–cis conformation to allow the pda2– in a rare cis conformation to form one-dimensional (1D) ladders. The conformations of the pyridyl ligands L1 and L2 have been explained based on the torsion angle measurement. The steric hindrance created by the isomeric flexible pyridyl ligands at the metal coordination sphere plays an important role in the modulation of the conformation of the secondary ligand that drives the self-assembly of the coordination polymers. Finally, temperature-dependent magnetic susceptibility studies for the compounds 1–5 have been described.

Four new MnII- and CoII-containing magnetic coordination polymers, [{Mn­(Br-isa)­(bpe)·​1/2H2O} n (1), {Co­(Br-isa)­(bpe)1.5·​1/2H2O} n (2), [{Mn­(Br-isa)­(4-bpmh)}4·​6H2O] n (3), and [{Co­(Br-isa)­(4-bpmh)}2·​21/2H2O] n (4)] [isa = iso­phthalic acid, bpe = 1,2-bis-(4-pyridyl)­ethylene and 4-bpmh = N,N′-bis­pyridine-4-yl-methyl­ene-hydra­zine], have been synthesized at room temperature, using 5-bromo isophthalic acid (Br-H2isa) and two different N-donating ancillary ligands. The complexes have been characterized by single-crystal X-ray diffraction and other physicochemical techniques. Structure determination reveals two-dimensional (2D) coordination network architectures for all the complexes. In 1, 3, and 4, MnII and CoII dinuclear units are connected via Br-H2isa ligands to form infinite 1D chains. The ancillary N,N′-donor spacer ligands interconnect the 1D chains into 2D coordination layers. Complex 2, on the other hand, can be viewed as being composed of cationic [{Co­(bpe)}4]8+ square units that are joined by anionic Br-isa2– bridges into a 2D gridlike framework. Topology analysis shows an sql/​Shubnikov tetragonal plane net topology for complexes 1, 3, and 4, and an SP 2-periodic net (4, 4) Ia topology for complex 2. Complexes 1 and 3 show a field-dependent change in magnetic behavior which is confirmed from the susceptibility measurements at varying fields, field-dependent magnetization measurements, as well as from hysteresis data. Complex 2 exhibits a slow magnetization relaxation phenomenon manifested by the AC susceptibility measurements at different temperatures and frequencies. Finally, complex 4 exhibits a magnetic feature that can be interpreted as antiferromagnetic exchange interactions between two syn-syn carboxylate-bridged CoII atoms.