Quadruple bonding of bare group-13 atoms in transition metal complexes

InnTl4-nH+ (n = 0∼4): Tetracoordinate Hydrogen in a Planar Fashion?

The recent report of planar tetracoordinate hydrogen (ptH) in In4H+ is very intriguing in planar hypercoordinate chemistry. Our high-level CCSD(T) calculations revealed that the proposed D4h-symmetric ptH In4H+ is a first-order saddle point with an imaginary frequency in the out-of-plane mode of the hydrogen atom. In fact, at the CCSD(T)/aug-cc-pV5Z/aug-cc-pV5Z-PP level, the C4v isomer, with the H atom located 0.70 Å above the In4 plane, is 0.5 kcal/mol more stable than the D4h isomer. However, given the small perturbation from planarity and essentially barrierless C4v ↔ D4h ↔ C4v transition, the vibrationally averaged structure can still be considered as a planar. Extending our exploration to the InnTl4-nH+ (n = 0-3) systems, we found all these ptH structures, except for In2Tl2H+, to be the putative global minimum. The single σ-delocalized interaction between the central hydrogen atom and InnTl4-n ligand rings proves pivotal in establishing planarity and aromaticity and conferring substantial stability upon these rule-breaking ptH species.

BeM(CO)3- (M = Co, Rh, Ir) and BeM(CO)3 (M = Ni, Pd, Pt): Triply bonded terminal beryllium in zero oxidation state

We perform detailed potential energy surface explorations of BeM(CO)3- (M = Co, Rh, Ir) and BeM(CO)3 (M = Ni, Pd, Pt) using both single-reference and multireference-based methods. The present results at the CASPT2(12,12)/def2-QZVPD//M06-D3/def2-TZVPPD level reveal that the global minimum of BeM(CO)3- (M = Co, Rh, Ir) and BePt(CO)3 is a C3v symmetric structure with an 1A1 electronic state, where Be is located in a terminal position bonded to M along the center axis. For other cases, the C3v symmetric structure is a low-lying local minimum. Although the present complexes are isoelectronic with the recently reported BFe(CO)3- complex having a B-Fe quadruple bond, radial orbital-energy slope (ROS) analysis reveals that the highest occupied molecular orbital (HOMO) in the title complexes is slightly antibonding in nature, which bars a quadruple bonding assignment. Similar weak antibonding nature of HOMO in the previously reported BeM(CO)4 (M = Ru, Os) complexes is also noted in ROS analysis. The bonding analysis through energy decomposition analysis in combination with the natural orbital for chemical valence shows that the bonding between Be and M(CO)3q (q = -1 for M = Co, Rh, Ir and q = 0 for M = Ni, Pd, Pt) can be best described as Be in the ground state (1S) interacting with M(CO)30/- via dative bonds. The Be(spσ) → M(CO)3q σ-donation and the complementary Be(spσ) ← M(CO)3q σ-back donation make the overall σ bond, which is accompanied by two weak Be(pπ) ← M(CO)3q π-bonds. These complexes represent triply bonded terminal beryllium in an unusual zero oxidation state.

Diversification of the Carbodicarbene Class by Embedding an Anionic Component in its Scaffold

Carbodicarbene (CDC) has become an emerging ligand in many fields due to its strong σ-donating ability. Collapse

Key Words

• Anionic carbodicarbene
• carbone
• dative bonding model
• geminal bimetallic complexes

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Grants

• NSTC 112-2123-M-001-007 National Science Council
• AS-GC-111-M04 Academia Sinica

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Affiliation(s)

Cheng-Han Yu Institute of chemistry, Academia Sinica, Taipei, Taiwan (R.O.C., 115201
Ka-Chun Au-Yeung Institute of chemistry, Academia Sinica, Taipei, Taiwan (R.O.C., 115201 Corporate R&D Center, LCY Chemical Corporation, Kaohsiung, Taiwan (R.O.C
Ruiqin Liu School of Chemistry and Molecular Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
Chao-Hsien Lee Institute of chemistry, Academia Sinica, Taipei, Taiwan (R.O.C., 115201
Dandan Jiang School of Chemistry and Molecular Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
Bamlaku Semagne Aweke Institute of chemistry, Academia Sinica, Taipei, Taiwan (R.O.C., 115201 Department of Applied Chemistry, National Yang Ming Chiao Tung University, Hsinchu, Taiwan (R.O.C Sustainable Chemical Science and Technology, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan (R.O.C
Chia-Hung Wu Institute of chemistry, Academia Sinica, Taipei, Taiwan (R.O.C., 115201 Department of Chemistry, National Taiwan University, Taipei, Taiwan (R.O.C
Yu-Jou Wang Institute of chemistry, Academia Sinica, Taipei, Taiwan (R.O.C., 115201 Department of Chemistry, National Taiwan University, Taipei, Taiwan (R.O.C
Ting-Hsuan Wang Institute of chemistry, Academia Sinica, Taipei, Taiwan (R.O.C., 115201
Kien Voon Kong Department of Chemistry, National Taiwan University, Taipei, Taiwan (R.O.C
Glenn P A Yap Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, United States
Wen-Ching Chen Institute of chemistry, Academia Sinica, Taipei, Taiwan (R.O.C., 115201
Gernot Frenking School of Chemistry and Molecular Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse, D-35043, Marburg, Germany
Lili Zhao School of Chemistry and Molecular Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
Tiow-Gan Ong Institute of chemistry, Academia Sinica, Taipei, Taiwan (R.O.C., 115201 Department of Chemistry, National Taiwan University, Taipei, Taiwan (R.O.C Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung, Taiwan (R.O.C

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Dative quadruple bonds between d10 transition metals and beryllium in BeM(PMe3 )2 and BeM(CO)2 (M = Ni, Pd, and Pt) complexes: Transition metal fragments as six-electron donor and two-electron acceptor

The structure, chemical bonding, and reactivity of neutral 16 valence electrons (VE) transition metal complexes of beryllium, BeM(PMe₃ )₂ (1M-Be) and BeM(CO)₂ (2M-Be, M = Ni, Pd, and Pt) were studied. The molecular orbital and EDA-NOCV analysis suggest dative quadruple bonds between the transition metal and beryllium, viz., one Be→M σ bond, one Be←M σ bond, and two Be←M π bonds. The strength of these bonding interactions varies based on the ligands coordinated to the transition metal. The Be←M σ bond is stronger than the Be→M σ bond when the ligand is PMe_3, whereas the reverse order is observed when the ligand is CO. This is attributed to the higher π acceptor strength of CO as compared to PMe₃ . Since these complexes have M-Be dative quadruple bonds, the beryllium center is susceptible to ambiphilic reactivity, as indicated by high proton and hydride affinity values.

Two σ- and two π-dative quadruple bonds between the s-block element and transition metal in [BeM(CO)4; M = Fe - Os]

We report the chemical bonding and reactivity of the first example of neutral 18 valence electron transition metal complexes of beryllium, [BeM(CO)₄; M = Fe - Os], in trigonal bipyramidal coordination geometry, where the bonding between the transition metal and the s-block element beryllium (M-Be) can be best described by dative quadruple bonds. In contrast to the conventional multiple bonding pattern, the quadruple bonds comprise two σ-bonds and two π-bonds, viz., one Be → M σ-bond, one M → Be σ-bond, and two M → Be π-bonds. Since the M-Be quadruple bonds are described by dative interactions, the Be centre shows ambiphilic character as indicated by the high proton and hydride affinity values.

Probing the Nature of the Transition-Metal-Boron Bonds and Novel Aromaticity in Small Metal-Doped Boron Clusters Using Photoelectron Spectroscopy

Photoelectron spectroscopy combined with quantum chemistry has been a powerful approach to elucidate the structures and bonding of size-selected boron clusters (B_n^-), revealing a prevalent planar world that laid the foundation for borophenes. Investigations of metal-doped boron clusters not only lead to novel structures but also provide important information about the metal-boron bonds that are critical to understanding the properties of boride materials. The current review focuses on recent advances in transition-metal-doped boron clusters, including the discoveries of metal-boron multiple bonds and metal-doped novel aromatic boron clusters. The study of the RhB^- and RhB₂O^- clusters led to the discovery of the first quadruple bond between boron and a transition-metal atom, whereas a metal-boron triple bond was found in ReB₂O^- and IrB₂O^-. The ReB₄^- cluster was shown to be the first metallaborocycle with Möbius aromaticity, and the planar ReB₆^- cluster was found to exhibit aromaticity analogous to metallabenzenes. Expected final online publication date for the Annual Review of Physical Chemistry, Volume 73 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Is a transition metal-silicon quadruple bond viable?

Quadruple bonding in heavier main group elements is not known albeit having four valence orbitals accessible for bonding. Here we report the unprecedented quadruple bonding between a silicon atom and a transition metal fragment in the 1A1 electronic ground state of C3v symmetric SiRu(CO)3 based on high level theoretical calculations. Various bonding analyses reveal the nature of the Si[quadruple bond, length as m-dash]Ru quadruple bonding interaction, which involves one usual Si-Ru σ bond, two usual Si-Ru π bonds and one additional Si → Ru dative σ bond.

Intriguing structural, bonding and reactivity features in some beryllium containing complexes

We highlighted our contributions to Be chemistry which include bond-stretch isomerism in Be₃²⁻ species, Be complexes bound with noble gas, CO, and N₂, Be based nanorotors, and intriguing bonding situations in some Be complexes.