Novel tetranuclear cubane-like Co(II) complexes involving chelate phosphoramide ligands

Abstract

Interaction of cobalt(II) ions and sodium carbacylamidophosphates Na(L) (HL=PhC(O)NHP(O)(NR 2) 2; where NR 2 are morpholyl, HL 1; NMe 2, HL 2; NEt 2, HL 3) in methanol solution afforded polynuclear alkoxo complexes [Co 4{L 1} 3(OCH 3) 4(OH)(H 2O) 5·3H 2O] 1 and [Co 4{L} 4(OCH 3) 4(CH 3OH) 4] (L=L 2 2, L 3 3). Data of spectral and TGA studies are presented. Coordination compounds 1 and 3 have been characterized by means of X-ray diffraction. Both the structures consist of tetranuclear cubane alkoxo clusters with methoxide ions bridging three metal centers (CoO 2.068(3)–2.093(4) Å) and phosphorylic ligands coordinated in a bidentatechelate fashion via the carbonyl oxygen atoms (CoO 1: 2.050(2); 3: 2.031(4) Å) and the phosphoryl groups (2.093(2) and 2.106(4) Å). Isolation of these cubane alkoxo complexes is an important proof for close resemblance in behavior of carbacylamidophosphate systems and β-diketonates towards transition metal ions.