TY - JOUR
T1 - Polycarbon ligand complexes
T2 - synthesis, molecular structures, and selected EHMO studies of Ru4, Ru5, and Ru6 clusters with carbon ligands derived from phosphinodiynes
AU - Blenkiron, Peter
AU - Enright, Gary D.
AU - Low, Paul J.
AU - Corrigan, John F.
AU - Taylor, Nicholas J.
AU - Chi, Yun
AU - Saillard, Jean-Yves
AU - Carty, Arthur J.
PY - 1998/6/8
Y1 - 1998/6/8
N2 - Thermolysis of the monosubstituted cluster Ru3(CO)11(Ph2PC≡C-C≡CR) (R = But, Ph, SiMe3), obtained via CO substitution in Ru3(CO)12, results in P-C and Ru-Ru bond cleavage. Recombination of the fragments yields a range of polyruthenium compounds containing -(C≡C)-n ligands (n = 2-4). The complexes Ru4(CO)9(μ-PPh2) 2{μ4-η1,η2,η 1-C≡C-C=C-(But)-C≡C-C≡CBut} (2), Ru4(CO)10(μ-CO)(μ4-PPh){μ 4η1 η1η2η2-(Bu tC≡C)C≡CPh} (3), Ru4-(CO)10(μ4-PPh)(μ 4-η1,η1η3η 3-PhC≡C-C≡CBut) (4), Ru5(CO)11(μ-CO)(μ-PPh2) 2(μ3-η1,η1,η 1-C≡C-C=CBut)(μ4-C)(μ 2-η1,η1-C-C≡CBut) (5), Ru6(CO)13(μ-CO)2(μ-PPh 2)(μ5-C)(μ3-η1,η 1,η1-C-C≡CR) (6a, R = But; 6b, R = Ph), and {Ru2(CO)6(μ-PPh2} 2(μ-η1,η2:μ-η 1,η2-C≡C-C≡C-) (7) have been fully characterized. The crystal structure of 2 revealed a polyunsaturated C8 chain formed by the head-tail coupling of two diynyl units bound to the metal core in μ4-η3 mode to produce a pendant penta-1-enediyne functionality. Clusters 3 and 4 feature squareplanar arrangements of metal atoms capped on one side by a μ4-PPh ligand and on the other side by a -C≡C-C≡C- group. The hydrocarbyl units in 3 and 4 arise as a result of phenyl migration from a PPh2 group to a terminal carbon of the diynyl fragment. On heating, 3 readily decarbonylates to generate 4. The pentanuclear cluster 5 and hexanuclear cluster 6 both contain unusually coordinated C4 chains which may be considered as being comprised of carbido- and alkynyl-substituted alkylidyne ligands. The alkylidyne carbide ligand is coordinated across the basal face of a pentagonal pyramid in 6 and across a distorted spiked square in 5. The latter also features a second C4 group which forms a rare μ3-η1-butadiynyl ligand. An EHMO analysis of the model compound Ru6(CO)13(μ-CO)2(μ-PH 2)(μ5-C)(μ3η1,η 1,η1-C-C≡CH) (6a′) suggests that the cluster is best described in terms of an Ru4C2 octahedron bicapped by a phosphido-bridged Ru2 unit, with the C-C-R (R = C≡CH) radical contributing a total of seven electrons to the CVE count of the entire polyhedron.
AB - Thermolysis of the monosubstituted cluster Ru3(CO)11(Ph2PC≡C-C≡CR) (R = But, Ph, SiMe3), obtained via CO substitution in Ru3(CO)12, results in P-C and Ru-Ru bond cleavage. Recombination of the fragments yields a range of polyruthenium compounds containing -(C≡C)-n ligands (n = 2-4). The complexes Ru4(CO)9(μ-PPh2) 2{μ4-η1,η2,η 1-C≡C-C=C-(But)-C≡C-C≡CBut} (2), Ru4(CO)10(μ-CO)(μ4-PPh){μ 4η1 η1η2η2-(Bu tC≡C)C≡CPh} (3), Ru4-(CO)10(μ4-PPh)(μ 4-η1,η1η3η 3-PhC≡C-C≡CBut) (4), Ru5(CO)11(μ-CO)(μ-PPh2) 2(μ3-η1,η1,η 1-C≡C-C=CBut)(μ4-C)(μ 2-η1,η1-C-C≡CBut) (5), Ru6(CO)13(μ-CO)2(μ-PPh 2)(μ5-C)(μ3-η1,η 1,η1-C-C≡CR) (6a, R = But; 6b, R = Ph), and {Ru2(CO)6(μ-PPh2} 2(μ-η1,η2:μ-η 1,η2-C≡C-C≡C-) (7) have been fully characterized. The crystal structure of 2 revealed a polyunsaturated C8 chain formed by the head-tail coupling of two diynyl units bound to the metal core in μ4-η3 mode to produce a pendant penta-1-enediyne functionality. Clusters 3 and 4 feature squareplanar arrangements of metal atoms capped on one side by a μ4-PPh ligand and on the other side by a -C≡C-C≡C- group. The hydrocarbyl units in 3 and 4 arise as a result of phenyl migration from a PPh2 group to a terminal carbon of the diynyl fragment. On heating, 3 readily decarbonylates to generate 4. The pentanuclear cluster 5 and hexanuclear cluster 6 both contain unusually coordinated C4 chains which may be considered as being comprised of carbido- and alkynyl-substituted alkylidyne ligands. The alkylidyne carbide ligand is coordinated across the basal face of a pentagonal pyramid in 6 and across a distorted spiked square in 5. The latter also features a second C4 group which forms a rare μ3-η1-butadiynyl ligand. An EHMO analysis of the model compound Ru6(CO)13(μ-CO)2(μ-PH 2)(μ5-C)(μ3η1,η 1,η1-C-C≡CH) (6a′) suggests that the cluster is best described in terms of an Ru4C2 octahedron bicapped by a phosphido-bridged Ru2 unit, with the C-C-R (R = C≡CH) radical contributing a total of seven electrons to the CVE count of the entire polyhedron.
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U2 - 10.1021/om9800593
DO - 10.1021/om9800593
M3 - RGC 21 - Publication in refereed journal
SN - 0276-7333
VL - 17
SP - 2447
EP - 2458
JO - Organometallics
JF - Organometallics
IS - 12
ER -