Monomeric bis(eta(2)-alkyne) complexes of copper(I) and silver(I) with eta(1)-bonded alkyl, vinyl, and aryl ligands

Two synthetic routes to compounds [(eta(5)-C(5)H(4)SiMe(3))2Ti(C drop CSiMe(3))2]MR (abbreviated as [1 . MR]; M = Cu: R = Me (5), CH(2)SiMe(3) (6), Et (7), (n)Bu (8), C(H)=CH2 (9), C(6)H(2)Me(3)-2,4,6 (13), C(6)H(4)Me-4 (14), C(6)H(4)OMe-4 (15), C(6)H(4)NMe(2)-4 (16), C6H5 (17); M = Ag: R = C(6)H(2)Me(3)-2,4,6 (18)) are described. These compounds contain monomeric MR entities, which are eta(2)-bonded by both alkyne ligands of the organometallic 3-titanio-1,4-pentadiyne [(eta-C(5)H(4)SiMe(3))(2)Ti(C drop CSiMe(3))(2)] (1). The X-rays structures of 5, 13, and 18 have been solved. Crystals of 5 are monoclinic, space C2/c, with a = 19.477(1) Angstrom, b = 10.3622(6) Angstrom, c = 16.395(1) Angstrom, beta = 95.287(5)degrees, V = 3294.8(3) Angstrom(3), Z = 4, and final R = 0.030 for 3232 reflections with F greater than or equal to 4 sigma(F) and 240 parameters. Crystals of 13 are orthorhombic, space group Pbcn, with a = 12.4290(9) Angstrom, b = 09.8770(8) Angstrom, c = 15.532(1) Angstrom, V = 3837.2(4) Angstrom 3, Z = 4, and final R = 0.026 for 3082 reflections with I greater than or equal to 2.5 sigma(I) and 217 parameters. The mesitylcopper compound 13 is isostructural with the mesitylsilver compound 18, and crystals of 18 are orthorhombic, space group Pbcn, with a = 12.47(3) Angstrom, b = 20.00(3) Angstrom, c = 15.53(3) Angstrom, V = 3873(13) Angstrom(3), Z = 4, and final R = 0.055 for 2068 reflections with I greater than or equal to 2.5 sigma(I) and 188 parameters. All compounds contain a monomeric bis(eta(2)-alkyne)M(eta 1-R) unit (M = Cu or Ag) in which the group 11 metal atom is trigonally coordinated by the bis(eta(2)-alkyne) chelate 1 and an eta(1)-bonded monoanionic organic ligand. A bonding description of the bis(eta(2)-alkyne)M(eta(1)-R) entity (M = Cu, Ag) is discussed. The alkylcopper compounds 5-8 decompose in solution either via nucleophilic substitution of one SiMe(3) group in 1 to eliminate RSiMe(3) or via beta-hydride elimination (7 and 8) to eliminate the corresponding alkene, whereas arylcopper compounds 14-17, which lack ortho-substituents rearrange in solution via addition of the monomeric arylcopper entity to one of the alkynes within [1 . CuR] is not isolated, while the corresponding addition product is favored. The X-ray structure of [(eta(5)-C(5)H(4)SiMe(3))(2)Ti(C drop CSiMe(3))-{mu-C=C(SiMe(3))(R)}Cu], 22, which is a rare example of a 1,1-bimetallaalkene, has been solved. Crystals of 22 are pseudomerohedrally twinned and monoclinic, space group P2(1)/c, with a = 31.05(2) Angstrom, b = 14.323(3) Angstrom, c = 20.014(8) Angstrom, beta = 108.53(5)degrees, V = 8440(7) Angstrom(3), Z = 8, and final R = 0.1233 for 8564 reflections with F > 4 sigma(F) and 462 parameters.