This paper reports a convenient, one-pot, easily scalable and readily modifiable synthesis of a novel large-ring bis(1,10-phenanthrolinyl-2,5-pyrrole) macrocycle, H2LMC, and describes its spectroscopic and electrochemical properties, protonation, cooperative amine binding, electrocatalysis of the oxidation of primary amines, photosensitization of the decomposition of dichloromethane, and the first lanthanide complexes of the hexaaza-dianion LMC(2-) including the novel dimer, [(NO3)(LMC)Eu(μ-OH)Eu(LMC )(H2 O)2]·2py.

2,3,13,14‐Tetrakis(bromomethyl)dibenzo‐18‐crown‐6 (1) has been demonstrated to be a versatile synthetic intermediate for constructing multinucleating ligands with a hard‐donor, crown ether centre. By using this intermediate, novel salts of tetrakis(imidazoliomethyl)dibenzo‐18‐crown‐6, [H4L1]X4 (2: X– = Br–; 4: X– = PF6–), and tetrakis(benzimidazoliomethyl)dibenzo‐18‐crown‐6, [H4L2]X4 (3: X– = Br–; 5: X– = PF6–), were prepared. These salts are precursors to novel tetrakis(N‐heterocyclic carbene) complexes spanned by a crown ether bridge capable of binding various hard metal ions. Thetetrakis(imidazoliomethyl) salt 4 was used to prepare the bimetallic rhodium complexes [{(cod)Rh}2(μ‐L1)][PF6]2 (6) and [{(CO)2Rh}2(μ‐L1)][PF6]2 (7). These complexes selectively bind alkali metal ions.

In the title complex salt, [{(η5-C5Me5)Rh}2(μ-Cl)3]PF6, the dinuclear, single-charged cation is formed by the cojoining of two classic (η5-C5Me5)RhCl3 ‘piano-stool’ units by bridging of the three choride ligand ‘legs’. The crystal structure shows several close H⋯F contacts between the hexa­fluorido­phosphate counter-ions and the C5Me5 ligands.

The compound (μ-3,3′,3′′,3′′′-{[2,5,8,15,18,21-hexa­oxatricyclo­[20.4.0.09,14]hexa­cosa-1(22),9,11,13,23,25-hexa­ene-11,12,24,25-tetra­yl]tetra­kis­(methyl­ene)}tetra­kis­(1-methyl-1H-imidazol-2-yl))bis­[(η4-cyclo­octa-1,4-diene)rhodium(I)] bis­(hexa­fluoridophosphate) acetonitrile sesquisolvate dihydrate, [Rh2(C8H12)2(C40H42N8O6)](PF6)2·1.5CH3CN·2H2O, crystallized from acetonitrile under an atmosphere of diethyl ether. In the crystal structure, the complex cation exhibits two square-planar RhI centres, each bound by a cyclo­octa­diene (COD) ligand and by two adjacent imidazolyl­idene N-heterocyclic carbene (NHC) donors from the same phen­oxy ring of the {[dibenzo-18-crown-6-11,12,24,25-tetra­yl]tetra­kis­(methyl­ene)}tetra­kis­(1-methyl-1H-imidazol-2-yl) (L) ligand. The dibenzo-crown ether bridge of L spans the Rh centres and forms hydrogen bonds with water mol­ecules. One water mol­ecule with half occupancy bridges adjacent macrocycles in the lattice. Another water with full occupancy forms weak hydrogen bonds to the crown ether O atoms and is, in turn, part hydrogen bonded by a lattice water with half occupancy. The latter water is within hydrogen-bonding distance of a fourth water also with partial occupancy. The result of these inter­actions is the formation of a layer in the ab plane. Two PF6 − ions, one of which is twofold disordered, and one ordered and one twofold disordered (with 0.5 occupancy) lattice acetonitrile mol­ecules complete the crystal structure.