TY - JOUR
T1 - Mixed-Metal Cluster Chemistry. 23. Synthesis and Crystallographic and Electrochemical Studies of Alkyne-Coordinated Group 6-Iridium Clusters Linked by Heterocyclic Groups
AU - Notaras, Eleni G.A.
AU - Lucas, Nigel T.
AU - Humphrey, Mark G.
AU - Willis, Anthony C.
AU - Rae, A. David
PY - 2003/9/1
Y1 - 2003/9/1
N2 - Reaction between the tetrahedral cluster compound Mo2Ir 2(CO)10(η5-C5H 4Me)2 (1) and 2-iodo-5-(oct-1′-ynyl)thiophene afforded the pseudooctahedral cluster Mo2Ir2{U 4-n2Me(CH2)5C2-5-C4H 2S-2-I}(CO)8(n5-C5H 4Me)2 (17) by formal insertion of the alkyne C≡C group into the Mo-Mo bond. Similar reactions of 1 or W2Ir 2(CO)10(n5-C5H4Me) 2 (2) with heterocyclic di- or triynes afforded the related mono-, di-, or tricluster compounds [M2lr2(CO)8(n 5-C5H4Me)2]2{u8-n 4-Me(CH2)5C2-2-C4H 2-E-5-C2(CH2)5Me} [E = S, M = Mo (20), W (21); E = Se, M = Mo (30), W (31)], [M2Ir2(CO) 8(n5-C5H4Me)2] 2{u8n4-Me(CH2)5C 2-2-C4H2S-5-(E)-CH=CH-2C4H 2S-5-C2(CH2)5Me} [M = Mo (22), W (24)], M 2Ir2{u4-n2-Me(CH2)5C 2-2-C4-H2S-5-(E)-CH=CH-2-C4H 2S-5-C≡C(CH2)5Me}(CO)8(n 5-C5H4Me)2 [M = Mo (23), W (25)], [M2Ir2(CO)8(n5C5H 4Me)2]3{u12-n6-Me(CH 2)5C2-2-C4H2S-5-C 2-2-C4H2S-5-C2(CH2)5Me} [M = Mo (26), W(28)], and[M2Ir2(CO)8(n 5-C5H4Me)2]2{u8-n 4-Me(CH2)5C2-2-C4H 2S-5-C2-2-C4H2S-5-C≡C(CH 2)5Me}[M = Mo (27), W (29)]. Compounds 27 and 29 correspond to the 1,2-dicluster adducts of the linear triyne Me(CH2)5C=C-5-C 4H2S-2-C≡C-2-C4H 2S-5-C≡C(CH2)5Me. No 1,3-dicluster isomer was isolated from direct reaction, but the molybdenum-containing 1,3-dicluster isomer was prepared by exploiting organic reaction chemistry on precoordinated functionalized alkyne ligands. Thus, Sonogashira coupling of 17 with trimethylsilylacetylene and subsequent desilylation gave Mo2Ir 2{u4-n2-Me(CH2)5C 2-5-C4H2S-2-C≡CR}(CO)8(n 5-C5H4Me)2 [R = SiMe3 (18), H (19)]. Sonogashira coupling of 17 and 19 gave the 1,3-isomer [Mo 2Ir2(CO)8(n5-C5H 4Me)2]2{u8n4-Me(CH 2)5C2-2-C4H2S-5-C≡C-2-C 4H2S-5-C2(CH2)5Me} (32), as well as the homocoupling product [Mo2Ir2(CO)8(n 5-C5H4Me)2]2{u8-n 4-Me(CH2)5C2-2-C4H 2S-5-C≡CC≡C-2-C4H2S5-C 2(CH2)5Me} (33). The identities of 21, 29, and 31 were confirmed by single-crystal X-ray diffraction studies. Cyclic voltammetric scans for these complexes all show a reversible/quasi-reversible oxidation followed by an irreversible oxidation process. Dicluster compounds linked by one heterocycle, and tricluster compounds, show two reduction processes, whereas dicluster compounds with longer bridges reveal only one reduction process.
AB - Reaction between the tetrahedral cluster compound Mo2Ir 2(CO)10(η5-C5H 4Me)2 (1) and 2-iodo-5-(oct-1′-ynyl)thiophene afforded the pseudooctahedral cluster Mo2Ir2{U 4-n2Me(CH2)5C2-5-C4H 2S-2-I}(CO)8(n5-C5H 4Me)2 (17) by formal insertion of the alkyne C≡C group into the Mo-Mo bond. Similar reactions of 1 or W2Ir 2(CO)10(n5-C5H4Me) 2 (2) with heterocyclic di- or triynes afforded the related mono-, di-, or tricluster compounds [M2lr2(CO)8(n 5-C5H4Me)2]2{u8-n 4-Me(CH2)5C2-2-C4H 2-E-5-C2(CH2)5Me} [E = S, M = Mo (20), W (21); E = Se, M = Mo (30), W (31)], [M2Ir2(CO) 8(n5-C5H4Me)2] 2{u8n4-Me(CH2)5C 2-2-C4H2S-5-(E)-CH=CH-2C4H 2S-5-C2(CH2)5Me} [M = Mo (22), W (24)], M 2Ir2{u4-n2-Me(CH2)5C 2-2-C4-H2S-5-(E)-CH=CH-2-C4H 2S-5-C≡C(CH2)5Me}(CO)8(n 5-C5H4Me)2 [M = Mo (23), W (25)], [M2Ir2(CO)8(n5C5H 4Me)2]3{u12-n6-Me(CH 2)5C2-2-C4H2S-5-C 2-2-C4H2S-5-C2(CH2)5Me} [M = Mo (26), W(28)], and[M2Ir2(CO)8(n 5-C5H4Me)2]2{u8-n 4-Me(CH2)5C2-2-C4H 2S-5-C2-2-C4H2S-5-C≡C(CH 2)5Me}[M = Mo (27), W (29)]. Compounds 27 and 29 correspond to the 1,2-dicluster adducts of the linear triyne Me(CH2)5C=C-5-C 4H2S-2-C≡C-2-C4H 2S-5-C≡C(CH2)5Me. No 1,3-dicluster isomer was isolated from direct reaction, but the molybdenum-containing 1,3-dicluster isomer was prepared by exploiting organic reaction chemistry on precoordinated functionalized alkyne ligands. Thus, Sonogashira coupling of 17 with trimethylsilylacetylene and subsequent desilylation gave Mo2Ir 2{u4-n2-Me(CH2)5C 2-5-C4H2S-2-C≡CR}(CO)8(n 5-C5H4Me)2 [R = SiMe3 (18), H (19)]. Sonogashira coupling of 17 and 19 gave the 1,3-isomer [Mo 2Ir2(CO)8(n5-C5H 4Me)2]2{u8n4-Me(CH 2)5C2-2-C4H2S-5-C≡C-2-C 4H2S-5-C2(CH2)5Me} (32), as well as the homocoupling product [Mo2Ir2(CO)8(n 5-C5H4Me)2]2{u8-n 4-Me(CH2)5C2-2-C4H 2S-5-C≡CC≡C-2-C4H2S5-C 2(CH2)5Me} (33). The identities of 21, 29, and 31 were confirmed by single-crystal X-ray diffraction studies. Cyclic voltammetric scans for these complexes all show a reversible/quasi-reversible oxidation followed by an irreversible oxidation process. Dicluster compounds linked by one heterocycle, and tricluster compounds, show two reduction processes, whereas dicluster compounds with longer bridges reveal only one reduction process.
UR - http://www.scopus.com/inward/record.url?scp=0041823197&partnerID=8YFLogxK
U2 - 10.1021/om030253b
DO - 10.1021/om030253b
M3 - Article
SN - 0276-7333
VL - 22
SP - 3659
EP - 3670
JO - Organometallics
JF - Organometallics
IS - 18
ER -