Enticing Cobalt into Planarity: Can a Pair of Diolato Ligands Make It Happen?

Abstract

They can′t do it alone: The Jahn–Teller instability found in the iron(II) species is missing in the homologous bis(perfluoropinacolato) cobalt(II) complex. Thus the stable conformation of the cobalt center is closer to tetrahedral than square planar, as shown by a DFT approach, and also in an isolatable salt (see structure).

Geometry and Spin Change at the Heart of a Cobalt(II) Complex: A Special Case of Solvatomorphism

“…The CoO bond length in 1‐green is also comparable with those found in cobalt complexes of α ‐imino alkoxide‐5 and carbohydrazide‐type17 ligands (compounds 7 and 8 , Table 1), whereas the CoN bond is longer in 1‐green versus 7 and 8 . In 1‐orange , the mean CoO bond length (1.951(7) Å) is similar to the corresponding values reported for tetrahedral (HS) cobalt(II) complexes of fluorinated alkoxide ligands14a (1.952(3) Å), and α ‐iminoketone‐type ligands (compound 10 , Table 1). The mean CoN bond length 1.989(8) Å is comparable to those found in tetrahedral cobalt complexes of triazene 1‐oxide ligands6 (compound 9 , Table 1) and β ‐ketoaminato ligands18 (compound 11 , Table 1).…”

[Fe19] “Super‐Lindqvist” Aggregate and Large 3D Interpenetrating Coordination Polymer from Solvothermal Reactions of [Fe2(OtBu)6] with Ethanol

“…[38,39] In one case,t wo Fe(OR) 4 groups are connected by ac ommon edge to aF e 2 (OR) 6 fragment. [40] Thef act that five more or less square planar Fe(OR) 4 groups are aligned in the asymmetric unit of 2 makes this compound unique. In many (10,3)-b nets,d ifferent net layers are 3D interpenetrating each other.…”

“…[38,39] In one case,t wo Fe(OR) 4 groups are connected by ac ommon edge to aF e 2 (OR) 6 fragment. [40] Thef act that five more or less square planar Fe(OR) 4 groups are aligned in the asymmetric unit of 2 makes this compound unique. Figure 3B shows that curved hexagonal rings are formed in 2.T he smallest ring with az igzag-shape contains 42 iron ions.Larger rings with aC -shape consist of 46 iron ions.T he rings are expanded by the Fe III sites to a3Dnet.…”

“…There are only very few examples found 38. 39 In one case, two Fe(OR) 4 groups are connected by a common edge to a Fe 2 (OR) 6 fragment 40. The fact that five more or less square planar Fe(OR) 4 groups are aligned in the asymmetric unit of 2 makes this compound unique.…”

Ein [Fe19]‐“Super‐Lindqvist”‐Aggregat und ein großes, sich durchdringendes, dreidimensionales Koordinationspolymer aus Solvothermalreaktionen von [Fe2(OtBu)6] mit Ethanol

“…[38,39] In einem Fall sind zwei {Fe(OR) 4 }-Gruppen über Kanten zu einem {Fe(OR) 6 }-Fragment verknüpft. [40] Die Tatsache,d ass nun fünf mehr oder weniger quadratisch-planare {Fe(OR) 4 4 (pz = Pyrazol-1-yl), [43] [CrP 3 S 9+x ]( x % 0.25), [44] und [Ag(bipy)]NO 3 (bipy = 2,2'-Bipyridin). [45] Zusammengefasst hat die ¾nderung der Reaktionsbedingungen einen großen Einfluss auf unser System.…”