title: Structure of salts of lithium chloride and lithium hexafluorophosphate as solvates with pyridine and vinylpyridine and structural comparisons: (C5H5N)LiPF6, [p-(CH2=CH)C5H4N]LiPF6, [(C5H5N)LiCl]n, and [p-(CH2=CH)C5H4N]2Li(μ-Cl)2Li[p-(CH2=CH)C5H4N]2.
abstract: Due to the flammability of liquid electrolytes used in lithium ion batteries, solid lithium ion conductors are of interest to reduce danger and increase safety. The two dominating general classes of electrolytes under exploration as alternatives are ceramic and polymer electrolytes. Our group has been exploring the preparation of molecular solvates of lithium salts as alternatives. Dissolution of LiCl or LiPF6in pyridine (py) or vinylpyridine (VnPy) and slow vapor diffusion with diethyl ether gives solvates of the lithium salts coordinated by pyridine ligands. For LiPF6, the solvates formed in pyridine and vinylpyridine, namely tetrakis(pyridine-κN)lithium(I) hexafluorophosphate, [Li(C5H5N)4]PF6, and tetrakis(4-ethenylpyridine-κN)lithium(I) hexafluorophosphate, [Li(C7H7N)4]PF6, exhibit analogous structures involving tetracoordinated lithium ions with neighboring PF6-anions in the I-4 and Aea2 space groups, respectively. For LiCl solvates, two very different structures form. catena-Poly[[(pyridine-κN)lithium]-μ3-chlorido], [LiCl(C5H5N)]n, crystalizes in the P212121space group and contains channels of edge-fused LiCl rhombs templated by rows of π-stacked pyridine ligands, while the structure of the LiCl-VnPy solvate, namely di-μ-chlorido-bis[bis(4-ethenylpyridine-κN)lithium], [Li2Cl2(C7H7N)4], is described in the P21/n space group as dinuclear (VnPy)2Li(μ-Cl)2Li(VnPy)2units packed with neighbors via a dense array of π-π interactions.
authors.affiliation: Department of Chemistry, Temple University, 1901 N. 13th St., Philadelphia, PA 19122, USA.
authors.forename: AbdelAziz
authors.initials: A
authors.lastname: Jalil
authors.affiliation: Department of Chemistry, Temple University, 1901 N. 13th St., Philadelphia, PA 19122, USA.
authors.forename: Rebecca N
authors.initials: RN
authors.lastname: Clymer
authors.affiliation: Department of Chemistry, Temple University, 1901 N. 13th St., Philadelphia, PA 19122, USA.
authors.forename: Clifton R
authors.initials: CR
authors.lastname: Hamilton
authors.affiliation: Department of Chemistry, Temple University, 1901 N. 13th St., Philadelphia, PA 19122, USA.
authors.forename: Shivaiah
authors.initials: S
authors.lastname: Vaddypally
authors.affiliation: Department of Chemistry, Temple University, 1901 N. 13th St., Philadelphia, PA 19122, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Gau
authors.affiliation: Department of Chemistry, Temple University, 1901 N. 13th St., Philadelphia, PA 19122, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Zdilla
keywords: crystal structure; dimeric lithium unit; lithium chloride; lithium ion battery; one-dimensional coordination polymer; solid electrolyte; solvates; π-stacking