1021913-52-9Relevant academic research and scientific papers
Heterotrimetallic and heterotetrametallic transition metal complexes
Packheiser, Rico,Ecorchard, Petra,Walfort, Bernhard,Lang, Heinrich
, p. 933 - 946 (2008)
The synthesis of the ruthenium σ-acetylides (η5-C5H5)L2Ru-C{triple bond, long}C-bipy (4a, L = PPh3; 4b, L2 = dppf; bipy = 2,2′-bipyridine-5-yl; dppf = 1,1′-bis(diphenylphosphino)ferrocene) is possible by the reaction of [(η5-C5H5)L2RuCl] (1) with 5-ethynyl-2,2′-bipyridine (2a) in the presence of NH4PF6 followed by deprotonation with DBU. Heterobimetallic Fc-C{triple bond, long}C-NCN-Pt-C{triple bond, long}C-R (10a, R = bipy; 10b, R = C5H4N-4; Fc = (η5-C5H5)(η5-C5H4)Fe; NCN = [1,4-C6H2(CH2NMe2)2-2,6]-) is accessible by the metathesis of Fc-C{triple bond, long}C-NCN-PtCl (9) with lithium acetylides LiC{triple bond, long}C-R (2a, R = bipy; 2b, R = C5H4N-4).The complexation behavior of 4a and 4b was investigated.Treatment of these molecules with [MnBr(CO)5] (13) and {[Ti](μ-σ,π-C{triple bond, long}CSiMe3)2}MX (15a, MX = Cu(N{triple bond, long}CMe)PF6; 15b, MX = Cu(N{triple bond, long}CMe)BF4; 16, MX = AgOClO3; [Ti] = (η5-C5H4SiMe3)2Ti), respectively, gave the heteromultimetallic transition metal complexes (η5- C5H5)L2Ru-C{triple bond, long}C-bipy[Mn(CO)3Br] (14a: L = PPh3; 14b: L2 = dppf) and [(η5-C5H5)L2Ru-C{triple bond, long}C-bipy{[Ti](μ-σ,π-C{triple bond, long}CSiMe3)2}M]X (17a: L = PPh3, M = Cu, X = BF4; 17b: L2 = dppf, M = Cu, X = PF6; 18a: L = PPh3, M = Ag, X = ClO4; 18b: L2 = dppf, M = Ag, X = ClO4) in which the appropriate transition metals are bridged by carbon-rich connectivities. The solid-state structures of 4b, 10b, 12 and 17b are reported. The main structural feature of 10b is the square-planar-surrounded platinum(II) ion and its linear arrangement. In complex 12 the N-atom of the pendant pyridine unit coordinates to a [mer,trans-(NN′N)RuCl2] (NN′N = 2,6-bis-[(dimethylamino)methyl]pyridine) complex fragment, resulting in a distorted octahedral environment at the Ru(II) centre. In 4b a 1,1′-bis(diphenylphosphino)ferrocene building block is coordinated to a cyclopentadienylruthenium-σ-acetylide fragment. Heterotetrametallic 17b contains a (η5-C5H5)(dppf)Ru-C{triple bond, long}C-bipy unit, the bipyridine entity of which is chelate-bonded to [{[Ti](μ-σ,π-C{triple bond, long}CSiMe3)2}Cu]+. Within this arrangement copper(I) is tetra-coordinated and hence, possesses a pseudo-tetrahedral coordination sphere. The electrochemical behavior of 4, 10b, 12, 17 and 18 is discussed. As typical for these molecules, reversible oxidation processes are found for the iron(II) and ruthenium(II) ions. The attachment of copper(I) or silver(I) building blocks at the bipyridine moiety as given in complexes 17 and 18 complicates the oxidation of ruthenium and consequently the reduction of the group-11 metals is made more difficult, indicating an interaction over the organic bridging units. The above described complexes add to the so far only less investigated class of compounds of heteromultimetallic carbon-rich transition metal compounds.
