Binuclear complexes crystal structure

Marmorstein, R., Harrison, S.C. Crystal structure of a PPRl-DNA complex DNA recognition by proteins containing a Zn2Cys6 binuclear cluster. Genes Dev. 

A crystal-structure determination on [Ni(PhCH2CS2)2] showed evidence of a Ni-Ni bond (Ni—Ni distance, 256 pm) in a bridging, acetate-cage, binuclear complex (363). Each nickel atom is 5-coordinate and is in a tetragonally distorted, square-pyramid spectroscopic evidence for a Ni-Ni bond has been obtained (364). The polarized crystal spectra showed more bands than predicted for a mononuclear, diamagnetic, square-planar nickel(Il), and the spectra are indicative of substantial overlap of the d-orbitals between the two nickel atoms. The bis(dithiobenzation)nickeKII) complex was found to exhibit unusual spectrochemical behavior (365). 

Mono- and binuclear gold(I) and gold(III) complexes with S2C-PR3 ligands. X-ray crystal structures of tris (pentafluorophenyl)... 

Further examples of emissive cyclometallated gold(III) complexes are [Au(L)Cl] (L = tridentate carbanion of 4 -(4-methoxyphenyl)-6 -phenyl-2,2 -bipyridine) [53], as well as mono- and binuclear bis-cyclometallated gold(III) complexes, namely [Au (C N C )L ]" (C N C = tridentate dicarbanion of 2,6-diphenylpyridine L = depro-tonated 2-mercaptopyridine (2-pyS ), n = 0 L = PPh3 or 1-methylimidazole, n = 1) and [Au2(C N C )2(P P)](C104)2 (P P = dppm, dppe) respectively [54]. The crystal structures of the binuclear derivatives show intramolecular interplanar separations of 3.4 A between the [Au(C N C)] moieties, implying the presence of weak n-n interactions. The mononuclear complexes show absorption with vibronic structure at 380-405 nm (e > 10 cm ), attributed to metal-perturbed intraligand transition. 

Luminescent gold(l) acetylide complexes. Photophysical and photoredox properties and crystal structure of [ Au(C = CPh) 2 (p-Ph2PCH2CH2PPh2)]. Journal of the Chemical Society, Dalton Transactions, 2929-2932 (d) Che, C.-M., Wong, W.-T., Lai, T.-F. and Kwong, H.-L. (1989) Novel luminescent binuclear gold(I) isocyanide complexes. Synthesis, spectroscopy, and X-ray crystal structure of Au2(dmh)(CN)2 (dmb = 1,8-di-isocyano-p-menfhane). Journal of the Chemical Society, Chemical Communications, 243-244. 

In contrast with the Schiff base salen, salicylaldehyde oxime (79) (salox) complexes of Co have received comparatively little attention, but a series of bis-bidentate divalent complexes of the form iraiis-Co(sa 1 ox)2( D M SO)2 have been reported.343 The heterocyclic bidentate oxime violurate (lH,3H-pyrimidine-2,4,5,6-tetrone 5-oximate, Hvi) (80) and its /V-methyl (mvi) and /V,/V -dimethyl (dmvi) derivatives form high-spin divalent [Co(vi)]+ and Co(vi)2 complexes, whereas [Co(vi)3] is low spin.344 The mixed-ligand Co(dmvi)2(phen) complex is also low spin. The crystal structure of m-Co(pxo)2Br2 (pxo = 2-acetylpyridine-l-oxide oxime) is isostructural with the Ni11 relative.345 The dichloro complex also adopts a cis configuration. The tridentate dioximes 2,6-diformyl-4-methylphenol dioxime and 2,6-diacetyl-4-methylphenol dioxime (Hdampo) form binuclear complexes of the type (81a) and (81b) respectively.346 Cobalt oxide nanoparticles were prepared by... 

The one-step reaction of H2prCl6] with MeC02Li under 02 in a mixed solvent of acetic acid and acetic anhydride yields the Ir11 binuclear complex [Ir2(/u-02CMe)2Cl2(C0)2].483 Crystal-structure determinations of [Ir2(/x-02CMe)2Cl2(C0)2L2], (295), where L = MeCN, DMSO, and py, are reported. The one-electron oxidation product for (295), L = py, is EPR active at 77 K the odd electron occupies the 6Ir Ir orbital. 

The dark red Ir11 binuclear complex [Ir(CO)(P(/i-tolyl)3)(mnt)]2, formed via one-electron oxidation of [Ir(CO)(P(/ -tolyl)3(mnt)] by ferrocenium, contains chelating mnt ligands bridging the Ir—Ir bond.639 The X-ray crystal structure shows square-pyramidal geometry at each Ir, and an Ir—Ir bond length of 2.706(2) A. 

Comba and co-workers described a simple and efficient method for the determination of solution structures of weakly coupled binuclear copper(II) complexes.54 The technique involves the combination of molecular mechanics55,56 and EPR spectroscopy. From this standpoint they reported the structure of the complex (29). Using an acyclic tertiary tetraamine ligand, Bernhardt reported57 crystal structure of the complex (30), along with its redox properties. 

Literature data are available on the electronic structures of two more binuclear technetium complexes [(NHjLlOHLTcf/i-O TcfOH NHj ] (a hypothetical complex with the structure and composition analogous to those of the ethylen-diamminetetra-acetate complex [54,55]) and Tc2(CO)10 (a binuclear complex with strong crystal field ligands [168,169]. We shall consider the results of these calculations in greater detail. 

Rate and equilibrium constant data, including substituent and isotope effects, for the reaction of [Pt(bpy)2]2+ with hydroxide, are all consistent with, and interpreted in terms of, reversible addition of the hydroxide to the coordinated 2,2 -bipyridyl (397). Equilibrium constants for addition of hydroxide to a series of platinum(II)-diimine cations [Pt(diimine)2]2+, the diimines being 2,2 -bipyridyl, 2,2 -bipyrazine, 3,3 -bipyridazine, and 2,2 -bipyrimidine, suggest that hydroxide adds at the 6 position of the coordinated ligand (398). Support for this covalent hydration mechanism for hydroxide attack at coordinated diimines comes from crystal structure determinations of binuclear mixed valence copper(I)/copper(II) complexes of 2-hydroxylated 1,10-phenanthroline and 2,2 -bipyridyl (399). 

A single crystal X-ray structural determination of the binuclear complex [Fe2(CO)6(C8H8)] (64a) shows it to have the structure (XVIII) and not one of the previously suggested structures 22, 54,152,166,174) including tub and planar forms of the cyclo-octatetraene ring. The cyclo-octatetraene ring in the complex approximates to a chair form in which the four carbon atoms associated with each iron atom are planar or very nearly so. The observed Fe—C and C—C distances in this complex are compared... 

Reaction of B20(0Ac)4 with sodium acetate results in the formation of Na[B20(0Ac)5] with O and OAc bridges, whereas acetatoborates, M[B(OAc)4] (M = K, Rb, Cs, Tl), are obtained when the reaction is conducted in the presence of acetic anhydride. These borates are easily hydrolyzed in the case of [B(OAc)4]- the rate determining step seems to be dissociation of the complex. Binuclear "borates M2[B20(0Ac)6] and M2[B202(0Ac)4], were detected, inter alia, during thermal decomposition of tetraacetatoborates.132 The crystal structure of K[B(OAc)4] has been determined.133... 

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