Scandium complexes with the tetraphenylethylene and anthracene dianions

摘要

The structural study of Sc complexes containing dianions of anthracene and tetraphenylethylene should shed some light on the nature of rare‐earth metal–carbon bonding. The crystal structures of (18‐crown‐6)bis(tetrahydrofuran‐κ O )sodium bis(η 6 ‐1,1,2,2‐tetraphenylethenediyl)scandium(III) tetrahydrofuran disolvate, [Na(C 4 H 8 O) 2 (C 12 H 24 O 6 )][Sc(C 26 H 20 ) 2 ]·2C 4 H 8 O or [Na(18‐crown‐6)(THF) 2 ][Sc(η 6 ‐C 2 Ph 4 ) 2 ]·2(THF), ( 1b ), (η 5 ‐1,3‐diphenylcyclopentadienyl)(tetrahydrofuran‐κ O )(η 6 ‐1,1,2,2‐tetraphenylethenediyl)scandium(III) toluene hemisolvate, [Sc(C 17 H 13 )(C 26 H 20 )(C 4 H 8 O)]·0.5C 7 H 8 or [(η 5 ‐1,3‐Ph 2 C 5 H 3 )Sc(η 6 ‐C 2 Ph 4 )(THF)]·0.5(toluene), ( 5b ), poly[[(μ 2 ‐η 3 :η 3 ‐anthracenediyl)bis(η 6 ‐anthracenediyl)bis(η 5 ‐1,3‐diphenylcyclopentadienyl)tetrakis(tetrahydrofuran)dipotassiumdiscandium(III)] tetrahydrofuran monosolvate], {[K 2 Sc 2 (C 14 H 10 ) 3 (C 17 H 13 ) 2 (C 4 H 8 O) 4 ]·C 4 H 8 O} n or [K(THF) 2 ] 2 [(1,3‐Ph 2 C 5 H 3 ) 2 Sc 2 (C 14 H 10 ) 3 ]·THF, ( 6 ), and 1,4‐diphenylcyclopenta‐1,3‐diene, C 17 H 14 , ( 3a ), have been established. The [Sc(η 6 ‐C 2 Ph 4 ) 2 ] ? complex anion in ( 1b ) contains the tetraphenylethylene dianion in a symmetrical bis‐η 3 ‐allyl coordination mode. The complex homoleptic [Sc(η 6 ‐C 2 Ph 4 ) 2 ] ? anion retains its structure in THF solution, displaying hindered rotation of the coordinated phenyl rings. The 1D 1 H and 13 C{ 1 H}, and 2D COSY 1 H– 1 H and 13 C– 1 H NMR data are presented for M [Sc(Ph 4 C 2 ) 2 ]· x THF [ M = Na and x = 4 for ( 1a ); M = K and x = 3.5 for ( 2a )] in THF‐ d 8 media. Complex ( 5b ) exhibits an unsymmetrical bis‐η 3 ‐allyl coordination mode of the dianion, but this changes to a η 4 coordination mode for (1,3‐Ph 2 C 5 H 3 )Sc(Ph 4 C 2 )(THF) 2 , ( 5a ), in THF‐ d 8 solution. A 45 Sc NMR study of ( 2a ) and UV–Vis studies of ( 1a ), ( 2a ) and ( 5a ) indicate a significant covalent contribution to the Sc—Ph 4 C 2 bond character. The unique Sc ate complex, ( 6 ), contains three anthracenide dianions demonstrating both a η 6 ‐coordination mode for two bent ligands and a μ 2 ‐η 3 :η 3 ‐bridging mode of a flat ligand. Each [(1,3‐Ph 2 C 5 H 3 ) 2 Sc 2 (C 14 H 10 ) 3 ] 2? dianionic unit is connected to four neighbouring units via short contacts with [K(THF) 2 ] + cations, forming a two‐dimensional coordination polymer framework parallel to (001).