Solvatochromism in ligand-field absorption bands and solvent-dependent deuteron nuclear magnetic resonance spectra of [CrF3(tri(2-pyridyl)amine)]: implication of trigonal splitting for the first spin-allowed d–d band and evaluation of π bonding peculiarities

Crystal structure of fac-tri-chlorido-[tris-(pyridin-2-yl-N)amine]-chromium(III)

In the neutral complex mol-ecule of the title compound, fac-[CrCl3(tpa)] [tpa is tris-(pyridin-2-yl)amine; C15H12N4], the Cr(III) ion is bonded to three N atoms that are constrained to a facial arrangement by the tpa ligand and by three chloride ligands, leading to a distorted octa-hedral coordination sphere. The average Cr-N and Cr-Cl bond lengths are 2.086 (5) and 2.296 (4) Å, respectively. The complex mol-ecule is located on a mirror plane. In the crystal, a combination of C-H⋯N and C-H⋯Cl hydrogen-bonding inter-actions connect the mol-ecules into a three-dimensional network.

cyclo-Tetra-μ-fluorido-1:2κF;2:3κF;3:4κF;1:4κF-octa-nitrato-1κO,O';3κO,O'-tetra-kis-(1,10-phenanthroline)-2κN,N';4κN,N'-2,4-dichromium(III)-1,3-dineodymium(III) methanol tetra-solvate monohydrate

In the title compound, [Cr(2)Nd(2)F(4)(NO(2))(8)(C(12)H(8)N(2))(4)]·4CH(3)OH·H(2)O, two cis-difluoridobis(1,10-phenanthroline)chromium(III) fragments containing octa-hedrally coordinated chromium(III) bridge via fluoride ions to two tetra-nitratoneodymate(III) fragments, forming an uncharged tetra-nuclear square-like core. The fluoride bridges are fairly linear, with Cr-F-Nd angles of 168.74 (8)°. Cr-F bond lengths are 1.8815 (15) Å, slightly elongated compared to those of the parent chromium(III) complex, which has bond lengths ranging from 1.8444 (10) to 1.8621 (10) Å. The tetra-nuclear complex is centered at a fourfold rotoinversion axis, with the Cr and Nd atoms situated on two perpendicular twofold rotation axes. The uncoordinated water mol-ecule resides on a fourfold rotation axis. The four methanol solvent mol-ecules are located around this axis, forming a cyclic hydrogen-bonded arrangement. The title compound is the first structurally characterized example of unsupported fluoride bridges between lanthanide and transition metal ions.