Stabilization of Molecular LiF and LiFHF inside Metallamacrocyclic Hosts

Abstract

Complexes of molecular LiF and LiFHF were synthesized using the metallamacrocyclic receptors [(cymene)Ru(C(5)H(3)NO(2))](3) (1), [CpRh(C(5)H(3)NO(2))](3) (2), and [CpIr(C(5)H(3)NO(2))](3) (3). LiBF(4) complexes of 1-3 were prepared and subsequently treated with F(-) or FHF(-) to give the desired products in an anion-exchange reaction. All complexes were characterized by multinuclear NMR spectroscopy ((1)H, (13)C, (19)F, (7)Li). Strong scalar coupling between (7)Li and (19)F is observed for the LiF and the LiFHF complexes ((1)J(LiF) = 91-103 Hz). The LiFHF adduct of 1 displays fluxional behavior with fast exchange of the two fluorine atoms. The structures of the complexes 1.LiBF(4), 2.LiBF(4), 1.LiF, 2.LiF, 1.LiFHF, and 3.LiFHF were determined by single-crystal X-ray analysis. Li-F bond lengths between 1.77 and 1.81 A were found. The LiFHF complexes show a hydrogen difluoride anion coordinated in a bent fashion via one fluorine atom to the lithium ion.

Organometallic Compounds in Biomedical Applications

“…55 One such cage structure is depicted below. For instance, there is a need to develop quick ways to test for lithium.…”

New Catalysts and Receptors by Self-Assembly and Combinatorial Chemistry

“…The class of compounds that we are focusing on are macrocycles which are obtained by reaction of tridentate ligands with organometallic complexes of (arene)Ru II [23][24][25][26][27][28][29][30][31][32], Cp*Ir III [31][32][33], Cp*Rh III [24][30] and (CO) 3 Re I [34] (Fig. 2).…”

“…Similar to their organic counterparts they can bind lithium and sodium ions, although with much higher affinity and selectivity [23][24][25]. This was used to develop a specific chemosensor for Li + [28] and to stabilize the unusual molecular forms of LiF [31] and Na 2 SiF 6 [26]. If 2,3-dihydroxypyridine ligands with amino-substituents are employed, it is possible to generate trinuclear macrocycles, which are soluble in water at neutral pH.…”

Novel 18-membered hexanuclear metallamacrocycle: Synthesis, crystal structure, and magnetic properties

“…The magnetic properties of the metallacrown molecules are characterized by a weak antiferromagnetic exchange interaction, with l eff = 5.12 l B at 300 K between the Mn 3+ ion spins with S = 2 in the cyclic system. Growing interest in the rational design and construction of metallamacrocycles is motivated principally by their diverse molecular architectures [1][2][3], their utilization as motifs for coordination networks [4][5][6][7][8] and their potential as host systems in various guest recognition chemistries [9][10][11][12][13][14][15]. Metallacrowns known as the first of a new class of metallamacrocycles, have been readily assembled using a trianionic pentadentate ligand, N-acylsalicylhydrazide, with a trivalent octahedral metal ion such as manganese, iron, cobalt or gallium [16][17][18].…”