Transition metal–boron complexes B_nM: From bowls (n = 8–14) to tires (n = 14)

Abstract

Transition metal-boron complexes BnM have been predicted at density functional theory level to be molecular bowls (n = 8-14) hosting a transition metal atom (M) inside or molecular tires (n = 14) centered with a transition metal atom. Small Bn clusters prove to be effective inorganic ligands to all the VB-VIIIB transition metal elements in the periodic table. Density functional evidences obtained in this work strongly suggest that bowl-shaped fullerene analogues of Bn units exist in small BnM complexes and the bowl-to-tire structural transition occur to the first-row transition metal complexes BnM (M = Mn, Fe, Co) at n = 14, a size obviously smaller than n = 20 where the 2D-3D structural transition occurs to bare Bn. The half-sandwich-type B12Cr (C3v), full sandwich-type (B12)2Cr (D3d), bowl-shaped B14Fe (C2), and tire-shaped B14Fe (D7d) and B14Fe- (C7v) are the most interesting prototypes to be targeted in future experiments. These BnM complexes may serve as building blocks to form extended boron-rich BnMm tubes or cages (m > or = 2) or as structural units to be placed inside carbon nanotubes with suitable diameters.

Planar or quasi-planar octa- and ennea-coordinate aluminum and gallium in boron rings

“…Si@B 8 [5] , Ge@B 9 + , and Sn@B 10 2+ [6] represented typical theoretical speculations of planar hyper-coordinate group 14 elements in boron rings. We recently investigated the possibility of the sandwich-typed [η 6 -B 6 X] 2 M (X=C, N; M=Mn, Fe, Co, Ni) [7] and bowl-and tire-shaped B n M [8] at density functional theory (DFT) level. We also presented a universal structural pattern for planar hyper-coordinate Si in B n H 2 Si series [9] .…”

The importance of dynamics studies on the design of sandwich structures: a CrB24 case

“…Some studies done by the Li's group showed that boron clusters could be used to design sandwich structures with transition metal atoms: in the first instance, Li et al showed that the planar B 6 clusters with carbon or nitrogen atoms at the center demonstrate the capability in coordinating transition metal atoms to form sandwich complexes. 21 It is important to note that Boldyrey and Wang et al reported a combined photoelectron spectroscopy and ab initio study on MB 12 − (M = Co, and Rh) clusters. 21 It is important to note that Boldyrey and Wang et al reported a combined photoelectron spectroscopy and ab initio study on MB 12 − (M = Co, and Rh) clusters.…”

Double aromaticity in transition metal centered double-ring boron clusters M@B2n (M = Ti, Cr, Fe, Ni, Zn; n = 6, 7, 8)

“…60 Chemical bonding analysis reveals that delocalized multicenter-two-electron (nc-2e) σ and π bonds in all boron system stabilize the clusters, which makes the formation of metal-doped boron cluster available. 56 The boron-ligand metal compounds of wheel-type 61-65 and bowl-shape 66,67 have been reported. Cheng and Yuan 68 state the ferrocene-like sandwich complexes Cr (B 12 ) 2 , and the spdπ interaction between Cr and boron ligand is investigated.…”