First metal complexes of 6,6′-dihydroxy-2,2′-bipyridine: from molecular wires to applications in carbonylation catalysis

Water oxidation using earth-abundant transition metal catalysts: opportunities and challenges

“…52). 300 This ligand has previously been employed for other transformations, such as CO 2 reduction 301 and carbonylation reactions, 302 where it was proposed to have a non-innocent role during the catalytic transformations. Lin and co-workers therefore utilized the 6,6′-dihydroxy-2,2′-bipyridine ligand, envisioning that the ligand could be employed as a redox-active entity to modify the reactivity of the metal center to enhance the catalytic activity.…”

Dicarbonylrhodium(I) Complexes of Bipyridine Ligands with Proximate H‐Bonding Substituents and Their Application in Methyl Acetate Carbonylation

“…This tautomer was therefore converted to 6,6Ј-bis(tert-butyldimethylsiloxy)-2,2Ј-bipyridine, which is easily hydrolysed after coordination to the rhodium centre to give the target complex [Rh(2)(CO) 2 ]SbF 6 . [44] A number of metal complexes containing bipyridine ligands with hydroxy substituents in various positions have been reported, for example 3,3Ј-and 4,4Ј-dihydroxy-2,2Ј-bipyridine [47,48] and also 6-hydroxy-2,2Ј-bipyridine; [49] but, to the best of our knowledge, [Rh(2)(CO) 2 ]SbF 6 is the first metal complex containing the 6,6Ј-dihydroxy-2,2Ј-bipyridine ligand.…”

“…[44] For comparison with the other structures, the main features are described briefly. The structure was found to contain five crystallographically independent molecules A-E in the asymmetric unit; complex [Rh(2)(CO) 2 ]SbF 6 -A is shown in Figure 2 (see Table 1 for bond lengths and angles).…”

“…Within these chains there are significant π-π interactions between the pyridyl rings of adjacent complexes, and in each case the rings are inclined by less than 2°. [ 44] The NH 2 -substituted complex [Rh(3)(CO) 2 ]SbF 6 shows a folded geometry whereby the {N(1),C(6),C(7),N(12)} and {N (1),N(12),Rh} planes are inclined by ca. 29°(see Figure 3 and Table 2 for selected bond lengths and angles).…”

“…Previously, we have reported on the application of such ligands in the context of alkane oxidation, [41][42][43] and very recently we have communicated our first results on methyl acetate carbonylation. [44] Here we present the synthesis and characterisation of a series of novel dicarbonylrhodium(I) complexes [Rh(L)(CO) 2 ]SbF 6 containing 2,2Ј-bipyridine ligands with Brønsted-acidic H-bonding substituents in the 6-and 6Ј-position (see Figure 1), with a view to activate the methyl acetate substrate in the vicinity of the metal centre. The functionalities investigated in this study cover a range of pK a values, from weakly acidic OH groups (cf.…”