Novel Structural Transformation around Ln(III) and Unusual Bending of Acetylacetonato Chelate in A Series of New 3d–4f Dinuclear Complexes [(hfac)3Ln(μ-bpypz)Cr(acac)2]

Abstract

A new series of discrete [(hfac)3Ln(μ-bpypz)Cr(acac)2] dinuclear complexes has demonstrated the novel LnIII ion size depedent structural transformation around LnIII as well as diastereospecifically assembled chiral configuration along with the unusual bending of the acetylacetonate chelate ring in CrIII.

Stereochemistry and solid-state circular dichroism spectroscopy of eight-coordinate chiral lanthanide complexes

“…This rule could also be applied to assign the absolute configurations of nine-coordinate lanthanide complexes with a tricapped triangular prism [10] or a single cap square antiprism [17] . However, related research pointed out that the TPR units in some heterodinuclear 3d-4f complexes with the same chelate ligands would exist as different coordination forms (Figure 1(b) and (c)) depending on the Ln ionic radii [7] . As a result, it is arbitrary to designate the absolute configuration of the Ce moiety in Figure 1(b) in view of the relative orientation of the top and bottom planes as similarity for the SAP unit in the above rule despite the fact that the rule does work for the Yb unit in Figure 1(c).…”

“…Up to now, such research has been just focused on 4-to 9-coordinate complexes [2][3][4][5][6][7][8][9][10][11][12][13] , and this doesn't match well with the extensive attentions to the structures and applications for 7-to 12-coordinate lanthanide complexes. In relation to the kinetic liability of most lanthanide complexes, investigation of their chiral-at-metal configurations and kinetic stability basing on the spectra-absolute configuration correlation methods is of great importance to elucidation of diagnosis and treatment mechanisms of chirality discrimination and chirality sensing in life science [4,[10][11][12][13] .…”

“…As illustrated in Figure 1(a), four prisms that stand for four chelate rings connect the top and bottom planes respectively. In terms of the skew-line convention, Kaizaki et al set up a rule to assign the absolute configuration of chiral SAP unit [5,6] : if the arrangement of the four prisms gives rise to a right-handed helicity about the Figure 1 (a) Assignment of the absolute configuration of square antiprisms [8] ; (b) and (c) Schematic diagrams of structures of chiral heterodinuclear Ln-Cr complexes [7] . For the type of the Yb-dotma complexes, there are chelate rings between coordination nitrogen and oxygen atoms in (a) [11] ; the markers of absolute configuration of Cr centre in the original chart are erroneous.…”

Structural comparison in a series of 3,5-bis(2-pyridyl)pyrazolato bridged Ln(III)–Cr(III) dinuclear complexes

“…The Ce-N bond lengths change to a much larger extent than the other Ln-N ones as shown in Table 3; the Ln-N3 bond length by 4.5% and the Ln-N4 one by 9% from complex 1 to 7. The X-ray structure of the complexes 1-7 demonstrated a discrete dinuclear Ln-Cr complex [13], two neighboring of which are -stacked with intermolecular distance (3.3-3.4Å) between two bpypz planes. Each dinuclear complex has a distorted six coordinate octahedral OC-6 Cr III and an eight coordinate bicapped trigonal prismatic TPRS-8 Ln III configuration comprising two caps (O5 and O7) on the lateral faces (O9-O10-O8-O6 and and B forms with about equal amounts.…”

“…This paper will report structural comparison of stereochemistry of new discrete bpypz bridged Ln-Cr dinuclear complexes [(hfac) 3 Ln(-bpypz)Cr(acac) 2 ] (Ln = Ce(1), Nd(2), Sm(3), Gd(4), Dy(5), Er(6), Yb (7)). The novel structural transformation has been already communicated elsewhere [13]. …”