Observation of alkaline earth complexes M(CO)8 (M = Ca, Sr, or Ba) that mimic transition metals

@article{Wu2018ObservationOA,
  title={Observation of alkaline earth complexes M(CO)8 (M = Ca, Sr, or Ba) that mimic transition metals},
  author={Xuan Wu and Lili Zhao and Jiaye Jin and Sudip Pan and Wei Li and Xiaoyang Jin and Guanjun Wang and Mingfei Zhou and Gernot Frenking},
  journal={Science},
  year={2018},
  volume={361},
  pages={912 - 916}
}
Carbonyls in the s block Conventional wisdom in chemistry distinguishes transition metals from other elements by their use of d orbitals in bonding. Wu et al. now report that alkaline earth metals can slide their electrons from s- to d-orbital bonding motifs as well (see the Perspective by Armentrout). Calcium, strontium, and barium all form coordination complexes with a cubic arrangement of eight carbonyl ligands and an 18-electron valence shell. The compounds were characterized in frozen neon… 
Transition-Metal Chemistry of the Heavier Alkaline Earth Atoms Ca, Sr, and Ba.
TLDR
It is suggested that the heavier alkaline earth atoms Ca, Sr, and Ba should be classified as transition metals rather than main group atoms in the periodic table of the elements.
Transition‐Metal Chemistry of Alkaline‐Earth Elements: The Trisbenzene Complexes M(Bz)3 (M=Sr, Ba)
TLDR
The synthesis and spectroscopic identification of the trisbenzene complexes of strontium and barium M(Bz)3 in low‐temperature Ne matrix suggest that the heavier alkaline earth atoms exhibit the full bonding scenario of transition metals.
Octa-coordinated alkaline earth metal–dinitrogen complexes M(N2)8 (M=Ca, Sr, Ba)
TLDR
The analysis of the electronic structure reveals that the metal-N2 bonds are mainly due to [M(dπ)]→(N2)8 π backdonation, which explains the observed large red-shift in N-N stretching frequencies.
Synthesis and characterization of crystalline niobium and tantalum carbonyl complexes at room temperature
TLDR
Several unusual niobium and tantalum carbonyl compounds have been prepared as bulk crystalline compounds, including heptacarbonyl salts and the neutral ditantalum dodecacarbONYl.
The Valence Orbitals of the Alkaline‐Earth Atoms
TLDR
Analysis of the electronic structures by charge and energy partitioning methods suggests that the valence orbitals of the lighter atoms Be and Mg are the ( n)s and (n)p orbitals, whereas the valences of the heavier atoms Ca, Sr and Ba comprise the (n−1)d orbitals.
18 electrons and counting
TLDR
Wu et al. (1) demonstrate that the 18-electron guiding principle is not only limited to transition metals but can also be extended to nearby elements, the alkaline earths.
Alkaline Earth Metals Activate N2 and CO in Cubic Complexes Just Like Transition Metals: A Conceptual Density Functional Theory and Energy Decomposition Analysis Study
Abstract Following the recent discovery of stable octa‐coordinated alkaline earth metals with N2 and CO, the role of group II metals in the catalytic reduction of these ligands by means of density
Strongly reducing magnesium(0) complexes.
TLDR
Examples of zero-oxidation-state magnesium (that is, magnesium(0)) complexes that are stabilized by superbulky, monoanionic, β-diketiminate ligands are presented and feature electron-rich Mg centres that are nucleophilic and strongly reducing.
Anti-Electrostatic Main Group Metal-Metal Bonds That Activate CO2.
TLDR
A proof-of-concept study using an ab initio valence bond method called the block-localized wave function (BLW) method demonstrated that heterobimetallic Ae+/Al(I) (Ae represents alkaline earth metals Mg and Ca) Lewis acid/base combinations without transition metals can facilely capture and activate CO2.
d–d Dative Bonding Between Iron and the Alkaline‐Earth Metals Calcium, Strontium, and Barium
TLDR
A comprehensive bonding analysis of all 1‐Ae complexes shows that the heavier species 1‐Ca, 1‐Sr, and 1‐Ba possess genuine Fe→Ae bonds which involve vacant d‐orbitals of the alkaline‐earth atoms and partially filled d‐ orbitals on Fe.
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 40 REFERENCES
Octacarbonyl Anion Complexes of Group Three Transition Metals [TM(CO)8 ]- (TM=Sc, Y, La) and the 18-Electron Rule.
TLDR
The gas-phase synthesis of stable 20-electron carbonyl anion complexes of group 3 transition metals, TM(CO)8- (TM=Sc, Y, La), which are studied by mass-selected infrared (IR) photodissociation spectroscopy, reveal that there is one occupied valence molecular orbital with a2u symmetry.
A Simple Route to Calcium and Strontium Hydride Clusters.
TLDR
The first strontium hydride complex has been obtained by simply treating Sr[N(SiMe3 )2 ]2 with PhSiH3 in the presence of PMDTA with the result that the Sr complex Sr6 H9 crystallizes as an "inverse cryptand", which shows atypically low charges on Ca and H.
"Non-VSEPR" Structures and Bonding in d(0) Systems.
TLDR
This work attempts to provide a comprehensive view, both of the types of deviations of d(0) and related complexes from regular coordination arrangements, and of the theoretical framework that allows their rationalization.
Barium as Honorary Transition Metal in Action: Experimental and Theoretical Study of Ba(CO)+ and Ba(CO).
TLDR
Quantum chemical calculations indicate that Ba(CO)+ has a 2 Π reference state, which correlates with the 2 D(5d1 ) excited state of Ba+ that comprises significant Ba+ (5dπ1 )→CO(π* LUMO) backbonding, letting the Ba( CO)+ complex behave like a conventional transition-metal carbonyl.
Organocalcium-mediated nucleophilic alkylation of benzene
TLDR
Several organocalcium compounds prepared can alkylate benzene by displacing a hydride, with no need for a more conventionally reactive leaving group such as chloride (see the Perspective by Mulvey).
Cesium and barium as honorary d elements: CsN7Ba as an example
Quantum chemical calculations suggest that inverse sandwich compounds with the general formula MN7M′, where M is an alkali metal (K,Rb,Cs), N7 is a ten-π-electron ring, and M′ is an alkaline-earth
Donor–Acceptor Properties of Ligands from the Natural Orbitals for Chemical Valence
Natural orbitals for chemical valence (NOCV) have been used to characterize donor–acceptor properties of ligands in model nickel(II) complexes. NOCV allows for separation of ligand → metal and metal
The Nature of the Transition Metal–Carbonyl Bond and the Question about the Valence Orbitals of Transition Metals. A Bond Energy Decomposition Analysis of TM(CO)6q (TMq = Hf2–, Ta1–, W0, Re1+, Os2+, Ir3+)
The equilibrium geometries and bond-dissociation energies for loss of one CO and loss of six CO from TM(CO)6q (TMq = Hf2-, Ta-, W, Re+, Os2+, Ir3+) have been calculated at the BP86 level using Slater
Infrared Spectra, Structures and Bonding of Binuclear Transition Metal Carbonyl Cluster Ions
Binuclear transition metal carbonyl clusters serve as the simplest models in understanding metal-metal and ligand bonding that are important organometallic chemistry catalysis. Binuclear first row
...
1
2
3
4
...