| 19093856 |
Imaji M, Tanabe Y, Mutoh Y, Ishii Y: Core expansion reactions of cyanamido/carbodiimido-bridged polynuclear iridium complexes. Inorg Chem. 2009 Jan 19;48(2):773-80.
Core expansion reactions of di- and tetrairidium complexes [Cp*Ir (mu (2)-NCN-N,N)](2) (1; Cp* = eta (5)-C (5) Me (5)), [Cp*Ir (mu (3)-NCN-N,N,N)](4) (2), and phosphine derivatives of 1 have been investigated, and it has been revealed that cyanamido ligands in these complexes can change their coordination modes flexibly on reactions with a second transition metal complex. Treatment of diiridium complex 1 with [Cp*IrCl (2)](2) gives the tetrairidium complex [(Cp*Ir)(2)(mu (3)-NCN-N,N,N')(2)(IrCp*Cl (2))(2)] (6) with mu (3)-kappaN,kappaN,kappaN' cyanoimido (2-) ligands. On the other hand, the reaction of 1 with [PdCl (eta (3)-C (3) H (5))](2) affords the NCN-bridged Ir (2) Pd (4) hexanuclear complex [(Cp*IrCl)(2)(mu (4)-NCN-N,N,N',N')(2){Pd (2)(mu-Cl)(eta (3)-C (3) H (5))(2)}(2) ] (7) and Ir (4) Pd (4) octanuclear complex [(Cp*Ir)(4)(mu (4)-NCN-N,N,N,N')(4){PdCl (eta (3)-C (3) H (5))}(4)] (8). The NCN-bridges in 7 provide the first example of the crystallographically determined mu (4)-kappaN,kappaN,kappaN',kappaN' carbodiimido (2-) ligand. Complex 8 with mu (4)-kappaN,kappaN,kappaN,kappaN' cyanoimido (2-) ligands can also be synthesized selectively by the reaction of the parent cubane complex 2 with [PdCl (eta (3)-C (3) H (5))](2). Diphosphine derivative of 1, [{Cp*Ir (mu (2)-NCN)}(2)(mu-dppm)] (4; dppm = Ph (2) PCH (2) PPh (2)), behaves differently on reactions with [PdCl (eta (3)-C (3) H (5))](2) and [MCl (cod)](2) (cod = cycloocta-1,5-diene) to form the NCN-bridged Ir (2) M (2) (M = Pd, Rh, Ir) tetranuclear complexes [(Cp*Ir)(2)(mu (3)-NCN-N,N,N')(2){PdCl (eta (3)-C (3) H (5))}(2)(mu-dppm)] (9) and [(Cp*Ir)(2)(mu (3)-NCN-N,N,N')(2){MCl (cod)}(2)(mu-dppm)] (11a, M = Rh; 11b, M = Ir), respectively. The molecular structures for 6, 7, 8, 11a, and 11b have been determined by single-crystal X-ray analyses. |
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