Organometallic pnicogen complexes. III. Preparation and structural characterization of the triarsenic-cobalt atom cluster system As3Co(CO)3. The first known X3-transition metal analog of group VA tetrahedral X4 molecules

Arsido iron carbonyl clusters

“…The reaction of AsX3 (X = CI or Br) with Na2Fe(CO)4 in THF solution gives a dark brown mixture from which the reddish brown As2Fe3(CO)9, (1), and the dark brown XAsFe4 (CO)14 complexes, (2), (X = C1 or Br) and Fe3 (CO)12 may be isolated by column chromatography in rather low (2-5%) yields (Equation 1). AsX3 Na2Fe(CO)4 ~As2Fe3(CO)9 + Fe3(CO)12 + XAsFe4(CO)t4…”

Aromaticity and Antiaromaticity in Zintl Clusters

“…The existence of 6 π electron [Pn 3 ] 3− rings was proposed initially by Zintl eighty years ago, but their structures have not been characterized in binary phases or in solvate crystals. The first known example of an η 3 ‐Pn 3 species was reported by Dahl and co‐workers in the complex [( η 3 ‐cyclo‐As 3 )Co(CO) 3 ], where a triangular cyclo ‐As 3 unit coordinates to a Co(CO) 3 fragment . Such cyclo ‐As 3 moiety typically carries an overall charge of −3 and is considered as a 6 π‐electron donor, thus satisfying the Hückel's rule of aromaticity.…”

Darstellung und Kristallstruktur von [Co2(CO)6(μ-S2)]2+(AsF6 -)2 · 1/2 SO2<br />Preparation and Crystal Structure of [Co2(CO)6(μ-S2)]2+(AsF6 -)2 · 1/2SO2

“…Die strukturelle Verwandtschaft des Co-,S^-Dikations zu der Reihe gemischter organischer und anorganischer Tetrahedrane (CR)4_n(Co(CO)3)" (w = 0 -3 ) [19] sowie zu AsCo3(CO)9 und As2Co(CO)6 [20] stimmt gut mit dem Konzept der IsolobalAnalogie [19] der Fragmente überein:…”

“…• CR s-> • Co(CO)3 <-rr-> • As | -«-s-* • S | + Die Erweiterung auf Pnicogen-und Chalkogenatome durch Dahl [20,21] …”