George A. Koutsantonis

Reactions of transition metal σ-acetylides: VII. Synthesis and properties of complexes containing halovinylidene ligands. X-ray structure of [Ru(CCIPh)(PPh3)2(η-C5H5)][I3]

Addition of halogen (Cl 2 , Br 2 or I 2 ) to ruthenium or osmium acetylide complexes has afforded cationic halovinylidene derivatives; in one case, halogenation of the phenyl group of a phenylacetylide ligand also occurred. The structure of [Ru(CCIPh)(PPh 3 ) 2 (η-C 5 H 5 )][I 3 ] has been determined; crystals are monoclinic, space group P 2 1 / c , with a 18.693(5), b 15.460(5), c 15.679(5) A, β 101.49(2)° and Z 4; 5180 data with I > 2σ( I ) were refined to R 0.045, R w 0.051. Significant distances are RuC 1.839(7), CC 1.31(1) A; angle RuCC is 171.0(7)°.

Variations on a Cage Theme: Some Complexes of Bicyclic Polyamines as Supramolecular Synthons

Dedication: One of Alan Sargeson’s great abilities was to seek out knowledge on topics of which he was not the master from those people with the expertise. This led occasionally to publications with a ‘cricket team’ of authors but with a rich brew of information, often international. Alan also insisted that all authors were equal since, without any one, the paper would not be what it was. Hence, he endeavoured to pursue the policy, difficult to maintain over a period where an obsession with absurdities such as the order of authors and point-scoring based on meaningless publication indices became so important in the maintenance of research, of listing authors simply in alphabetical order. In describing work begun while he was still with us, we have attempted to adhere to his principles. Analysis of a body of crystallographic information concerning metal(ii) and metal(iii) complexes of macrobicyclic hexamine ligands and some of their derivatives provides evidence for the action of a variety of intermolecular forces within the lattices. Hydrogen bonding is universal and its forms depend strongly upon the oxidation state and the particular nature of the metal ion bound to the macrobicycle. The introduction of both aliphatic and aromatic substituents leads to lattices in which these substituents associate, although, in the case of aromatic substituents, this is not necessarily a consequence of ‘π-stacking’, despite the fact that the aromatic ring planes form parallel arrays. At least in the case of CoIII, stable enantiomers of the complexes can be obtained, and in {Δ-(+)589-[Co{(NH3)(CH3)sar}]}2Cl2(C6(CO2)6)·26H2O (sar = 3,6,10,13,16,19-hexa-azabicyclo[6.6.6]icosane), the benzene hexacarboxylate anion adopts a chiral conformation in the presence of the optically active cation.

Alkali Metal Complexes of Aromatic Polycarboxylates—a Balance of π-Stacking and Coordinate Bonding Interactions?

Crystal structure determinations of, in most cases, hydrated, alkali metal derivatives of the dicarboxylic acids, 2,2′-bipyridine-3,3′-dicarboxylic acid (H2BDC) and chelidamic acid (4-hydroxypyridine-2,6-dicarboxylic acid, H2CHEL) show numerous similarities, such as in the predominance of O-coordination in generating solid state polymers in which parallel arrays of the essentially planar ligand ring units are apparent, though not necessarily indicative of conventional π-stacking interactions, and some unanticipated differences. In particular, all species derived from chelidamic acid, including its diammonium compound, appear to be complexes of the partially deprotonated pyridone form of this ligand. In both systems, close contacts between atoms constituting the aromatic entities take a variety of forms depending upon the associated metal.

Phosphine substituted Ru3(μ-dppm)(CO)10: structural trends within [Ru3(μ-dppm)(PR3)(CO)9] (R=Et, Ph, Cy and Pri)

Abstract The complexes [Ru3(μ-dppm)(PR3)(CO)9] (R=Et, Ph, Cy, Pri} were prepared from [Ru3(μ-dppm)(CO)10] by simple phosphine substitution reactions at room temperature and their structures determined by single crystal X-ray studies. Variations in the RuRu bond adjacent to the phosphine ligand suggest the enhanced reactivity of [Ru3(μ-dppm)(CO)10] over the parent carbonyl [Ru3(CO)12] to be consequent on the inability of [Ru3(μ-dppm)(CO)10] to effectively relieve steric congestion imposed by the presence of the bulky, bidentate dppm ligand.

Reactions of metalloalkynes 3. Facile synthesis of pentanuclear ruthenium clusters. X-ray structures of [Ru5(μ5-CC)(η-C5H4R)2(dppm)(μ2-CO)2(CO)7] (R=H, CH3)

Abstract The reaction of the activated cluster compound, Ru3(CO)10(dppm), 1, with two ethyne-1,2-diyl compounds, [{Ru(CO)2(η-C5H4R)}2(μ-CC)], (2a, R=H; 2b, R=CH3) has resulted in a facile and high yielding synthesis of medium nuclearity cluster compounds, [Ru5(μ5-CC)(η-C5H4R)2(dppm)(μ2-CO)2(CO)7], (3a, R=H; 3b, R=CH3). The core of these compounds incorporate an open and accessible carbide ligand bound to a relatively rare example of a spiked butterfly metal framework. Both of these clusters, 3, have been characterised by X-ray crystallography.

A thermally stable alane–secondary amine adduct: [H3Al(2,2,6,6-tetramethylpiperidine)]

Metallation of 2,2,6,6-tetramethylpiperidine, HN[CMe2CH2]2CH2(HL), by H3AlNMe3 in diethyl ether affords a monomeric, Lewis base-stabilised amidoalane Me3NAIH2L, 1[Al–Namido, Namine 1.838(2), 2.058(2)A], whereas treating AIH3 generated in situ with the same amine in diethyl ether yields a remarkably stable secondary amine adduct of alane H3Al(HL), 2(decomp. > 115 °C), also as a monomer in the solid [Al–NHL 2.04(1)A].

Competition between cluster fragmentation, C–C bond coupling and C–X bond activation in silver hexynyl cluster cations, [(C4H9CCAg)nAg]+. Size does matter!

Silver hexynyl cluster cations, [(C(4)H(9)CCAg)(n)Ag](+), exhibit a rich unimolecular chemistry that is dependant on the cluster size, n (1-5), cluster fragmentation (for all n > 1); C-C bond coupling (n = 3 & 4); C-H bond activation with comcomitant silver hydride formation (n = 1 & 4); C-C bond activation (n = 1 & 4).

Reactions of metalloalkynes: Part 6. Synthesis of open tetrametallic clusters. Reaction of [Ru(CO)4(ethene)] with ethyne-1,2-diyl compounds. Single crystal X-ray structural determinations of [Ru4(μ4-CC)(η-C5H4R)2(μ-CO)2(CO)8] (R=H, Me)

Abstract The reactions between [Ru(CO)4(η2-C2H4)], generated in situ, and ruthenium ethyne-1,2-diyl complexes, [{Ru(CO)2(η-C5H4R)}2(μ-CC)] (R=H, Me) have provided the new air-sensitive complexes [Ru4(μ4-CC)(η-C5H4R)2(μ-CO)2(CO)8] (R=H, Me) with a permetallated ethene structure, in good yield. The complexes were characterized spectroscopically and by single-crystal X-ray diffraction studies. They have an almost planar open geometry, rendering the C22− ligand accessible to reaction. The resonances attributed to the C22− ligand in the 13C{1H}-NMR spectra of the complexes have been unequivocally assigned with the aid of labeling experiments.

Authentication of a sodium primary phosphide: synthesis and crystal structure of [Na{PH(C6H11)}(pmdeta)]2(pmdeta =N,N,N′,N″,N″-pentamethyldiethylenetriamine)

The reaction of the primary phosphine PH2(C6H11) with NaBun in the presence of pmdeta gives the first sodium phosphide containing simple organo substituents [Na{PH(C6H11)}(pmdeta)]21(pmdea =N,N,N′,N″,N″-pentamethyldiethylenetriamine) to be structurally characterised.

Hydride-bridged heterobimetallic complexes of gallium and zinc: the first X-ray structural determination of the gah4–moiety

Reaction of 2 equivalents of LiGaH4 or 1 equivalent of NaGaH4 with [ZnCl2(pmdeta)](pmdeta =N,N,N′,N″,N″-pentamethyldiethylenetriamine) in diethyl ether at 0 °C gives the heterobimetallic species, [Zn(η1-GaH4) Cl (pmdeta)]1, whereas reaction of [M′GaH4] with [ZnCl2(tmen)](tmen =N,N,N′,N′-tetramethylenediamine) in 2 : 1 (M′= Li) or 1 : 1 (M′= Na)·molar ratio, gives [Zn(η2-GaH4) Cl (tmen)]2; the analogous [Zn(η2-BH4)(Cl(tmen)]3 is prepared from reaction with 2 molar equivalents of LiBH4 or with 1 equivalent of NaBH4; complexes 1 and 3 are structurally characterised, the former represents the first reported structure of the GaH4 moiety.