A Novel, Tunable Manganese Coordination System Based on a Flexible “Spacer” Unit:  Noncovalent Templation Effects

Abstract

The reaction of bis(hexafluoroacetylacetonato)manganese(II) trihydrate (2), an approximately 90 degrees corner unit, with flexible linking unit 4,4'-trimethylenedipyridine (1) allows for the potential formation of three different types of solid-state coordination species: infinite helical polymers, closed dimeric systems, and infinite one-dimensional polymers. While the un-templated starting material is known to give a coordination helix, the other two possible species can be realized through the selective use of a variety of simple, organic guests: toluene (3), diphenylmethane (4), cis-stilbene (5), 1,3-diphenylpropane (6), benzyl alcohol (7), nitrobenzene (8), and cyanobenzene (9). When solutions of 1 and 2 are crystallized in the presence of all of these clathrates, the dimeric macrocycles result in all cases, except for that of 6, in which a syndiotactic, wedge-shaped polymer forms. Employing a linker that is less rigid than is typically used in crystal engineering, such as 1, enables the nucleophilic donor subunit to be more than just a simple "spacer", instead making it an essential, tunable component in the overall crystal lattice. In so doing, a great deal of molecular "information" is lost, but this is compensated for by an in-depth investigation into the weaker host-guest and/or guest-guest interactions, such as nonclassical hydrogen bonding and an assortment of hydrophobic interactions, present in the various systems.

Synthesis, Crystal Structures and Photoluminescent Properties of Three Novel Cadmium(II) Compounds Constructed from 5‐Sulfoisophthalic Acid (H3SIP)

“…[29,30] In the present case, the monodentate dpp has a conformation of TG with an N···N distance of 8.9 Å and the bridging ones adopt TT conformation with an N···N separation of 9.5 Å. The 1D ladders are connected by the bridging dpp ligands to form a 2D nanolayer with a thickness of about 1.5 nm, as shown in Figure 7; the cavity is filled in by the monodentate dpp.…”

Self-assembly of the cyclic dimer [Cu(hfac)2(bpmu)]2 (bpmu=N,N′-bis(3-pyridylmethyl)urea; hfac=hexafluoroacetylacetonate ion) using coordination chemistry and predictable OC(N–H)2⋯OC hydrogen bonds

“…The accomplishment of these objectives implies to choose a coordination metal system that allows to form specifically complexes with bis(pyridyl) bridging ligands (L) in a 1:1 molar ratio, including escort counter-ions that do not interfere with the design of the H-bonding network controlled by the bpmu ligand. An appropriate type of compounds are the metal(II) complexes [M(hfac) 2 ] (M = Mn, Co, Cu, Zn; hfac = hexafluoroacetylacetonate), which show a high affinity towards rigid or flexible N,N 0 -bidentate spacers, producing either coordination polymers or discrete molecular species with a 1:1 metal-to-ligand ratio [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. In this reaction, the [M(hfac) 2 ] complexes serve as the source of the coordinatively unsaturated fragments {M(hfac) 2 }.…”

“…More specifically, the coordination polymers are formulated as the cis-or trans-[M(hfac) 2 (L)] species in which the cations are octahedrally coordinated by four oxygen atoms of the chelating hfac units, and two nitrogen atoms from two different linkers [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. On the other hand, the known discrete molecular compounds are only the solvated binuclear metallacycles cis-[Mn(hfac) 2 (bpyp)] 2 AE nS (bpyp = 1,3-bis(4-pyridyl)propane; n = 1,2; S = organic solvent) [21,22]. The assembly of the bpyp-based dimeric species is dependent on the reaction conditions and concretely of the solvents used in the crystallization process.…”

Template-assisted assembly of porous lanthanide coordination polymers with 2-aminoterephthalic acid

“…For example, in the compound [Yb 2 (OH)(atpt) 2.5 (phen) 2 ] n AE 1.75H 2 O (phen = 1,10-phenanthroline)[9] which was synthesized previously by us, the cavity in the 2-D structure is fairly large, but the channel in 3-D structure decreases due to the interpenetration of metal-organic frameworks (MOFs). Several tactics have been proven useful in precluding interpenetration: (1) applying branched chain or substituent group to avoid inserting [10]; (2) designing the crystal with specified structure, such as diamond network and NbO network [11]; (3) constructing a porous structure with appropriate guest or template [12][13][14].As is known, 4,4 0 -bpy belongs to soft base, while lanthanide ions belong to hard acid. Based on ''soft-hard acidbase theory'', it is much harder for lanthanide ions to coordinate with nitrogen atoms of 4,4 0 -bpy [15-17] than for transition metal ions [18][19][20][21][22][23][24][25][26][27][28][29][30][31].…”

“…For example, in the compound [Yb 2 (OH)(atpt) 2.5 (phen) 2 ] n AE 1.75H 2 O (phen = 1,10-phenanthroline) [9] which was synthesized previously by us, the cavity in the 2-D structure is fairly large, but the channel in 3-D structure decreases due to the interpenetration of metal-organic frameworks (MOFs). Several tactics have been proven useful in precluding interpenetration: (1) applying branched chain or substituent group to avoid inserting [10]; (2) designing the crystal with specified structure, such as diamond network and NbO network [11]; (3) constructing a porous structure with appropriate guest or template [12][13][14].…”