On the Structural and Electronic Properties of [Zn₂(4,4′-bipyridine)(mes)₄]ⁿ⁻(n= 0–2), a Homologous Series of Bimetallic Complexes Bridged by Neutral, Anionic, and Dianionic 4,4′-Bipyridine

Abstract

Addition of 1 equiv of potassium metal to a tetrahydrofuran (THF) solution of Zn(2)(4,4'-bipyridine)(mes)(4) (1; mes =2,4,6-Me(3)C(6)H(2)) in the presence of 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) yielded the radical anionic species [Zn(2)(4,4'-bipyridine)(mes)(4)](•-), which was characterized by single crystal X-ray diffraction in [K(18-crown-6)(THF)(2)][Zn(2)(4,4'-bipyridine)(mes)(4)] (2). A similar reaction employing 2 equiv of alkali metal afforded the related complex [K(18-crown-6)](2)[Zn(2)(4,4'-bipyridine)(mes)(4)] (3). The [Zn(2)(4,4'-bipyridine)(mes)(4)](n-) (n = 0-2) moieties present in 1-3 are largely isostructural, yet exhibit significant structural variations which arise because of differences in their electronic structure. These species represent a homologous series of complexes in which the ligand exists in three distinct oxidation states. Structural data, spectroscopic measurements, and density functional theory (DFT) calculations are consistent with the assignment of 1, 2, and 3 as complexes of the neutral, radical anionic, and dianionic 4,4'-bipyridyl ligand, respectively. To the best of our knowledge, species 2 and 3 are the first crystallographically characterized transition metal complexes of the 4,4'-bipyridyl radical and dianion.

Group 12 Metal Complexes of N-Heterocyclic Ditopic Carbanionic Carbenes

“…Addition of half of an equivalent of 18-crown-6 to the mother liquor that yielded crystals of 3 allowed for the crystallization of a [K(18-crown-6)] + salt of [Zn(mes) 3 ] − (a compound that has previously been structurally authenticated by our research group). 28 A similar transformation to that giving rise to 3 and 4, involving the deprotonation of a C2-coordinated carbene followed by migration of the Lewis acid to the C4 position, has previously been reported by Bertrand and co-workers. 29 Species 3 30 The structures adopted by these complexes are closely related to a Mn(II) species previously reported by our research group, [{:C[N-(2,6-i Pr 2 C 6 H 3 )] 2 (CH)C} 2 Mn(mes)(THF)] − .…”

A novel samarium complex with interesting photoluminescence and semiconductive properties

“…Recently, 4,4′-bipyridine (bipy) with delocalized -electrons of the pyridyl rings obtains increasing attention in preparing light emitting complexes in different technical applications, such as emitting materials for organic light emitting diodes, sensitizers in solar energy conversion, chemical sensors and so forth [6][7][8][9]. The ability of bipy to act as a rigid, rod-like organic building block in the self-assembly of coordination frameworks is well-known, such as, acting as a charge-compensating cation, a pillar bonding to inorganic skeletal backbone, an uncoordinated guest molecule and organic template, a bridge connecting two metal complex moieties, or linking a metal and an inorganic framework [10][11][12].…”

Crystal structure of tetraaquabis(4-carboxypyridine-2,6-dicarboxylato- κ3N,O,O')(µ2-4,4'-bipyridine-κ2N:N')dizinc(II)dihydrate, [Zn2(C8H3NO6)2(C10H8N2)(H2O)4]·2H2O, C26H26N4O18Zn2

“…Pyridine-2,4,6-tricarbolylic acid (H 3 L) has been used as a versatile building block to construct various coordination polymers or metal-organic frameworks [4][5][6]. 4.4'-Bipyridine (4,4'-bpy) has also been used as a good bridging ligand to form a metal complexes and metal-organic frameworks [7]. Herein we report the crystal structure of the title compound prepared by the reaction of zinc nitrate with the H 3 L and 4,4'-bpy ligands.…”