Observation of highly stable and symmetric lanthanide octa-boron inverse sandwich complexes

Abstract

While boron forms a wide range of metal borides with important industrial applications, there has been relatively little attention devoted to lanthanide boride clusters. Here we report a joint photoelectron spectroscopy and quantum chemical study on two octa-boron di-lanthanide clusters, LnB (Ln = La, Pr). We found that these clusters form highly stable inverse sandwich structures, [Ln-B-Ln], with strong Ln and B bonding via interactions between the Ln 5d orbitals and the delocalized σ and π orbitals on the B ring. A (d-p)δ bond, involving the 5dδ and the antibonding π orbital of the B ring, is observed to be important in the Ln-B interactions. The highly symmetric inverse sandwich structures are overwhelmingly more stable than any other isomers. Upon electron detachment, the (d-p)δ orbitals become half-filled, giving rise to a triplet ground state for neutral LaB In addition to the two unpaired electrons in the (d-p)δ orbitals upon electron detachment, the neutral PrB complex also contains two unpaired 4f electrons on each Pr center. The six unpaired spins in PrB are ferromagnetically coupled to give rise to a septuplet ground state. The current work suggests that highly magnetic Ln…B…Ln inverse sandwiches or 1D Ln…B…Ln nanowires may be designed with novel electronic and magnetic properties.

From inverse sandwich Ta2B7+ and Ta2B8 to spherical trihedral Ta3B12−: prediction of the smallest metallo-borospherene

“…PE measurements and infrared photodissociation (IR-PD) spectra in combination with rst-principles theory calculations have proven to be powerful approaches in characterizing novel clusters in gas phases. [3][4][5][6][7][17][18][19][20][21][22][23][24][25][26][27][28]62 As shown in Fig. 4, the highsymmetry Ta 3 B 12 À (3) exhibits relatively simple IR and Raman spectral patterns, with the major IR active peaks at 507 (e 0 ), 559 (e 0 ), 668 ða 00 2 Þ, and 881 (e 0 ) cm À1 (Fig.…”

High resolution photoelectron imaging of boron-bismuth binary clusters: Bi2Bn− (n = 2–4)

“…[25][26][27][28] Recently, we have found that di-lanthanide The Journal of Chemical Physics ARTICLE scitation.org/journal/jcp octaboron clusters (Ln 2 B 8 − ) can form remarkable inverse sandwiches. 29 There have been few experimental studies of boron clusters doped by group V elements except B n N − (n = 1-3). [30][31][32] Computational studies have been reported on B n N 2 (n = 1-6) and B n P 2 (n = 1-7) clusters, 33,34 as well as a joint experimental and theoretical study on the isoelectronic Bi 2 Al n (n = 1-4) clusters.…”

TGMin: An efficient global minimum searching program for free and surface‐supported clusters

“…To aid in the simulation of PE spectra, a standalone program named AutoPES is also developed. Recent study on PrB 7 − , CoB 18 − , and Ln 2 B 8 − clusters shows that the TGMin‐2 program and the AutoPES program are powerful tools for the global minimum structure search of free and surface‐adsorbed molecules and nanoclusters. With these implementations and improvements, the TGMin‐2 program can become a useful tool for cluster science and heterogeneous catalysis.…”

“…TGMin‐2 has been used to determine global minimum structures of several different metal‐doped boron clusters, which have been published or will be published soon . Here, we provide the global minimum search results of PrB 7 − and CoB 18 − as examples of the application of TGMin‐2.…”

“…Until now, several global optimization programs based on the BH algorithm, in conjunction with density functional theory (DFT), tight‐binding DFT (DFTB), or (semi‐) empirical methods have been proposed . Tsinghua Global Minimum (TGMin), developed in 2011, is one of the most successful BH program as TGMin has already helped researchers identify tens of new clusters, including the hexagonal B 36 − cluster, the all‐boron borophenes and borospherenes B 40 − , B 26 − , B 28 − , B 30 − , B 35 − , B 39 − , metallo‐ borophenes, ‐borospherenes, and ‐nanotubes CoB 18 − , MnB 16 − , RhB 18 − , TaB 20 − , as well as the PrB 7 − , LnB 8 Ln (Ln = La, Pr) sandwich complexes, and others . TGMin was also used to identify atmospheric aerosol clusters and surface‐adsorbed species .…”