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Localized molecular orbitals of C 2 Al 4 H 4-01 obtained by AdNDP analysis. " ON " denotes the occupation number on the localized orbital.
Source publication
It is well-known that the chemistry of aluminum is dominated by Al(III) in the +3 oxidation state. Only during the past 2 decades has the chemistry of Al(I) and Al(II) been rapidly developed. However, if Al(I) and Al(III) are combined, the inherently high reactivities of Al(I) and Al(III) mostly result in their coupling with each other or interacti...
Citations
For over 100 years, known bent C 00000000000000000 00000000000000000 00000000000000000 01111111111111110 00000000000000000 01111111111111110 00000000000000000 01111111111111110 00000000000000000 00000000000000000 00000000000000000 C compounds have been limited to those with organic (I) and all-carbon (II) scaffoldings. Here, we computationally report a novel type (III) of bent CC compound, i.e., C2Al4F6-01, which is the energetically global minimum isomer and bears an inorganic–metallic scaffolding and unexpected click reactivity.
The design of planar tetracoordinate carbon (ptC) has always been a challenge due to its unique bonding mode that necessitates the perfect balancing between the carbon center and surrounded ligands both electronically and mechanically. A unique class of 18-valence-electron (18ve) template, i.e., CAl42ˉ, has been found very effective in designing various novel 18ve-species upon skeletal substitution. In this work, we showed that though ptC is not the global structure for the parent 16ve-CAl4, suitable skeletal substitution can allow for a series of global ptC species. Theoretical calculations at the level of CCSD(T)/def2-QZVP//B3LYP/def2-QZVP level for the 35 carbon-group_13 systems with 16-ve, i.e., CXaYbZcKd (X, Y, Z, K=Al/Ga/In/Tl; 0 ≤ a, b, c, d ≤ 4, a+b+c+d=4), showed that 9 systems (CAl3Tl, CGa3Tl, CGa2Tl2, CAl2GaTl, CAl2InTl, CGa2InTl, CAlGa2Tl, CGa2InTl and CAlGaInTl) possess the global ptC and 2 systems (CAl3In and CAl2Tl2) have quasi-GM ptC. Except for CAl3Tl and CAl3In, all the ptC were predicted for the first time. All these stable ptC structures have the same skeleton and can be described as the ionic sub-structure, i.e., [Aˉ]B+. This study not only enriches 16ve-ptC, but also directly demonstrates that utilizing ionic strategy, non-ptC CAl4 also can be as the template to extend the ptC family.
Metal cyanide/isocyanide and hydrometal cyanide/isocyanide compounds are key metal-carriers in interstellar space. Lighter group 14 elements (X = C/Si/Ge) cyanides/isocyanides and hydrocyanides/hydroisocyanides have been studied theoretically and experimentally. However, no reports are available on the analogues of tin (Sn) and lead (Pb). In this work, we carried out the first theoretical study on the structures and stabilities of [X,C,N] and [H,X,C,N] (X = Sn/Pb) at the CCSD(T)/def2-QZVPP//B3LYP/def2-QZVPP level. Comparisons were made with the lower analogues (X = C/Si/Ge) concerning the structural, energetic and bonding properties. Significantly different from that of c-C2N, a dative-bonded valence structure of c-XCN for heavier X was revealed for the first time, which can account for the rather worse kinetic stability of cyclic [X,C,N] for heavier X = Si/Ge. A unique kind of agostic bonding was found within three isomers of [H,Pb,C,N], whereas it is absent for X = C/Si/Ge/Sn. The computed structural and spectroscopic data could aid future laboratory and astrophysical detection of the [X,C,N] and [H,X,C,N] (X = Sn/Pb) isomers.
In cluster studies, the isoelectronic replacement strategy has been successfully used to introduce new elements into a known structure while maintaining the desired topology. The well-known penta-atomic 18 valence electron (ve) species
C
Al
4
2
-
and its Al- /Si or Al/Si+ isoelectronically replaced clusters CAl3 Si- , CAl2 Si2 ,
C
AlSi
3
-
, and
C
Si
4
2
+
, all possess the same anti-van't Hoff/Le Bel skeletons, that is, nontraditional planar tetracoordinate carbon (ptC) structure. In this article, however, we found that such isoelectronic replacement between Si and Al does not work for the 16ve-CAl4 with the traditional van't Hoff/Le Bel tetrahedral carbon (thC) and its isoelectronic derivatives CAl3 X (X = Ga/In/Tl). At the level of CCSD(T)/def2-QZVP//B3LYP/def2-QZVP, none of the global minima of the 16ve mono-Si-containing clusters CAl2 SiX+ (X = Al/Ga/In/Tl) maintains thC as the parent CAl4 does. Instead, X = Al/Ga globally favors an unusual ptC structure that has one long C─X distance yet with significant bond index value, and X = In/Tl prefers the planar tricoordinate carbon. The frustrated formation of thC in these clusters is ascribed to the CSi bonding that prefers a planar fashion. Inclusion of chloride ion would further stabilize the ptC of CAl2 SiAl+ and CAl2 SiGa+ . The unexpectedly disclosed CAl2 SiAl+ and CAl2 SiGa+ represent the first type of 16ve-cationic ptCs with multiple bonds. © 2019 Wiley Periodicals, Inc.
Dicarboranes generally adopt global minimum predicted by the well-known Wade-Mingos rules, although one classical non-closo structure in benzvalene form has long been pursued and later synthesized. Here we predicted two...
