830331-90-3Relevant academic research and scientific papers
Linear homobimetallic palladium complexes
Lang, Heinrich,Taher, Deeb,Walfort, Bernhard,Pritzkow, Hans
, p. 3834 - 3845 (2006)
The oxidative addition of C6H4-1,4-I2 (1) to Pd(PPh3)4 (2) gives mononuclear trans-(Ph3P)2Pd(C6H4-4-I)(I) (3), which can be converted to trans-(Ph3P)2Pd(C6H4-4-I)(OT f) (5) by its reaction with [AgOTf] (4). Complex 5 can be used in the high-yield preparation of a series of unique cationic mono- and dinuclear palladium complexes of structural type [trans-(Ph3P)2Pd(C6H4-4-I)(L )]+ (7, L = C4H4N2; 9a, L = C5H4N-4-C{triple bond, long}N; 9b, L = N{triple bond, long}C-4-C5H4N) and [trans-(C6H4-4-I)(Ph3P)2Pd ← N∩N → Pd(PPh3)2(C6H4-4-I)] 2+ (14a, N∩N = C6H4-1,4-(C{triple bond, long}N)2; 14b, N∩N = (C6H4-4-C{triple bond, long}N)2; 14c, N∩N = 4,4′-bipyridine (=bipy)). Complexes 7, 9 and 14 rearrange in solution to give [trans-(Ph3P)2Pd(C6H4-4-PPh 3)(L)]2+ (10, L = C4H4N2; 12a, L = C5H4N-4-C{triple bond, long}N; 12b, L = N{triple bond, long}C-4-C5H4N) and [trans-(C6H4-4-PPh3)(Ph3P) 2Pd ← N∩N → Pd(PPh3)2(C6H4-4-PPh 3)]4+ (15a, N∩N = C6H4-1,4-(C{triple bond, long}N)2; 15b, N∩N = (C6H4-4-C{triple bond, long}N)2) along with {[(Ph3P)2(Ph3P-4-C6H 4)Pd(μ-I)]2}2+ (11). The solid state structures of 3, 9a, 10, 11 and 15b are reported. Most characteristic for all complexes is the square-planar coordination geometry of palladium with trans-positioned PPh3 ligands. In 3 the iodide and the 4-iodo-benzene are linear oriented laying with the palladium atom on a crystallographic C2 axes. In 9a this symmetry is broken by steric interactions of the PPh3 ligands with the 4-cyanopyridine and 4-iodobenzene groups. Compound 11 contains two μ-bridging iodides with different Pd-I separations showing that the C6 H4 PPh3+ ligand induces a stronger trans-influence than PPh3. In 15b, the Ph3PC6H4{single bond}Pd ← N{triple bond, long}C{single bond}C6H4{single bond}C6H4{single bond}C{triple bond, long}N → Pd{single bond}C6H4PPh3 building block is rigid-rod structured with the C6H4 units perpendicular oriented to the Pd coordination plane, while the biphenylene connecting moiety is in-plane bound.
A new approach to novel homobimetallic palladium complexes
Taher,Walfort,Lang
, p. 1006 - 1009 (2008/10/09)
Mononuclear trans-(PPh3)2Pd(I)(C6H 4-4-I) (3), which is accessible by the oxidative addition of C 6H4-1,4-I2 (2) to (Ph3P) 4Pd (1), reacts with [AgOTf] (4) in a 1:1 molar ratio to give trans-(PPh3)2Pd(C6H4-4-I)(OTf) (5). Complex 5 affords on treatment with 0.5 equivalents of 4,4′- dicyanobiphenyl (6) homobimetallic trans-[(PPh3)2(C 6H4-4-I)Pd ← N≡C-C6H 4]2(OTf)2 (7). The latter species rearranges to give trans-[(PPh3)2(C6H4-4-PPh 3)Pd ← N≡C-C6H4]2(OTf) 4 (8) and [(PPh3)(C6H4-4-PPh 3)Pd(μ-I)]2(OTf)2 (9), respectively. A possible mechanism for the formation of 8 and 9 will be presented. The solid-state structure of 8 is reported. In 8 two [trans-(PPh3)(C 6H4-4-PPh3)Pd]2+ fragments are bridged by the 4,4′-dicyanobiphenyl unit.
