Novel Organometallic Macrocycles Containing Linear Cr₂E Structural Units:  Synthesis and Characterization of {[(CO)₂Cr⋮E⋮Cr(CO)₂][η⁵-C₅H₄C(O)CH₂]₂}_n (E = Se, S; n = 1, 2)

Abstract

The four novel organometallic macrocyclic compounds {[(CO)2Cr⋮Se⋮Cr(CO)2][η5-C5H4C(O)CH2]2} n (1, n = 1; 2, n = 2) and {[(CO)2Cr⋮S⋮Cr(CO)2][η5-C5H4C(O)CH2]2} n (3, n = 1; 4, n = 2) were prepared via a facile “one pot” synthetic route. While a possible pathway leading to such macrocycles is suggested, products 1−4 have been characterized by elemental analysis and spectroscopy and, for 1, by X-ray crystallography.

19 Organometallic chemistry of bi- and polymetallic complexes

“…23 The compound [Cr 3 Cl 2 (dpa) 4 ] is accurately described as consisting of a [CrCr] 4+ quadruply bonded fragment [Cr-Cr 2. 24 A ˚] and an isolated high-spin Cr 2+ centre in the solid state. Replacement of the axial ligands by strong donors (CN, CMCPh), or use of the more basic supporting ligand depa gives rise to systems with more symmetrical [Cr-Cr-Cr] 6+ chains.…”

“…The construction of macrocycles featuring CrMEMCr (E = S, Se) linkages, by direct reaction of E 8 with a [Cr 2 (CO) 6 Cp 2 ] based precursor has been reported. 24 The photolability of the Mo-Mo bond in [Mo 2 (CO) 6 Cp 2 ] dimers has been utilised to help better define the roles of mechanical stress and radical reactions in the photochemical degradation of polymers. 25…”