Cod Complex Research Articles

Bridge-splitting reaction of a dinuclear platinum(II) complex cross-linked by tetra-acetylethane dianion [Pt 2(L 2) 2(dahd-O 2O′ 2)][BF 4] 2 (dahd = tetra-acetylethane; L = SEt 2, PMe 2Ph; L 2 = 1,5-cyclooctadiene); metal-carbon bonded platinum(II) complex of tetra-acetylethane with (C 3,O′)-chelate

A Pt(II) complex of tetra-acetylethane (dahd = 3,4-diacetyl-2,4-hexadiene-2,5-diol) dianion bonding with (C 3,O′)-chelate, Pt(L)(L′)(dahd-C 3,O′){L = L′= SEt 2; L = L′= PMe 2Ph; L = SEt 2, L′ = PPh 3; L = L′ = 2,9-R 2-1,10-phen(R = H, Me) where L′ is trans to C 3} has been prepared. cis-PtCl 2L 2(L = SEt 2, PMe 2Ph) reacts with K 2-dahd in CH 3OH to produce a dinuclear cationic complex [Pt 2L 4(dahd-O 2,O′ 2)] 2+ in which dahd is cross-linked with symmetrical bifunctional chelation. An analogous COD (1,5-cyclo-octadiene) complex [Pt 2(COD) 2(dahd-O 2,O′ 2)][BF 4] 2 has been prepared by treating PtCl 2(COD) with AgBF 4 and H 2-dahd. [Pt 2L 4(dahd-O 2O′ 2)][BF 4] 2, by treating with K 2-dahd, readily transforms into PtL 2(dahd-C 3,O′) (L = SEt 2, PMe 2Ph). This PtL 2(dahd-C 3,O′)(L = SEt 2, PMe 2Ph) in HBF 4/acetone solution converts to the dinuclear complex [Pt 2L 4(dahd-O 2,O′ 2)][BF 4] 2, liberating H 2-dahd in a stoichiometric yield. These anomalous Pt(II) complexes linked by the dahd dianion are characterized using IR, 1H, 13C-NMR and fast atom bombardment mass spectroscopy, conductance and molecular weight measurements.

Rhodium(I) complexes containing bidentate pyrazolylgallate ligands. X-ray crystal structures of [Me2Gapz2]Rh(COD), [Rh(μ-3,5-Me2pz)(CO)2]2, and [Rh(μ-3,5-Me2pz)(COD)]2

The synthesis and characterization of the complexes [Me2Gapz2]Rh(LL) (where LL = COD, (CO)2, (PPh3)2, or (PPh3)(CO)), incorporating the bidentate, chelating, dimethylbis(1-pyrazolyl)gallate ligand are described. Non-rigidity in solution has been demonstrated by 1H nmr studies for some of the complexes. A crystal structure determination of the COD complex has confirmed the boat conformation for the Ga—(N—N)2—Rh six-membered ring in this complex in the solid state. In addition, the solid state structures of the 3,5-dimethylpyrazolyl bridged dirhodium complexes [Rh(μ-3,5-Me2pz)(CO)2]2 and [Rh(μ-3,5-Me2pz)(COD)]2 have been determined. Crystals of [Me2Gapz2]Rh(COD) are orthorhombic, a = 22.7447(8), b = 11.9776(5), c = 6.4635(3) Å, Z = 4, space group Pnma; those of [Rh(μ-3,5-Me2pz)(CO)2]2 are monoclinic, a = 8.7403(6), b = 16.3594(6), c = 25.434(2) Å, β = 95.286(3)°, Z = 8, space group P21/c; and those of [Rh(μ-3,5-Me2pz)(COD)]2 are triclinic, a = 10.350(2), b = 11.401(2), c = 12.355(2) Å, α = 112.485(7), β = 99.394(9), γ = 105.387(8)°, Z = 2, space group [Formula: see text]. All three structures were solved by conventional heavy atom techniques and were refined by full-matrix least-squares procedures to final conventional R values of 0.026, 0.024, and 0.037 for 1824, 5135, and 6109 reflections with I ≥ 3σ(I), respectively. In each case the Rh atoms have distorted square planar coordination geometry. Important mean structural parameters are Rh—N = 2.087(2), Rh—C = 2.129(2), [Formula: see text] for [Me2Gapz2]Rh(COD); Rh—N = 2.063(6), Rh—CO = 1.852(9), [Formula: see text] for [Rh(μ-3,5-Me2pz)(CO)2]2; and Rh—N = 2.084(1), Rh—C = 2.131(7), [Formula: see text] for [Rh(μ-3,5-Me2pz)(COD)]2.