W.L. Kwik

Thermal, spectroscopic, and structural properties of aqua(malonato-O,O′)(1,10-phenanthroline)copper(II) hydrate (1/1.5)

Aqua(malonato-O,O′)(1,10-phenanthroline)copper(II) crystallizes in the triclinic space group P with a= 11.560(4), b= 11.734(5), c= 12.491(2)A, α= 92.12(2), β= 105.50(2), γ= 109.28(3)°, and Z= 2. The structure consists of two independent monomeric [Cu(phen)(mal)(H2O)] molecules with three water molecules in the lattice. The CuN2O2O′ chromophore is distorted square pyramidal with a symmetrically co-ordinated phen molecule (mean Cu–N 2.018 A) and a symmetrically co-ordinated malonate ion (mean Cu–O 1.914 A) in the plane of the square pyramid and a water molecule at 2.266 A. The relatively short Cu–O distance has been attributed to phen being a stronger π-acid. The compound and its several related complexes show complete loss of water molecules at ca. 100 °C followed by stepwise degradation of the organic ligands. Thermogravimetric analysis and visible reflectance spectral results are discussed in relation to the known structure of the title compound.

Synthesis of mercury-linked ruthenium clusters: the X-ray structure of the new cluster dianion [{Ru6C(CO)16}2Hg]2– and the cluster [{Ru5C(CO)14(µ-Cl)}2Hg2Cl2]

Reaction of the hexaruthenium dianion [Ru6C(CO)16]2–1 as its [N(PPh3)2]+ salt in CH2Cl2 with an equimolar quantity of Hg(CF3CO2)2 leads to an uncharacterised black polymer of probable formula [Ru6C(CO)16Hg]n. However, treatment of 2 equivalents of 1 in CH2Cl2 with 1 equivalent of Hg(CF3CO2)2 or 2 equivalents of HgCl2 in the same solvent has yielded the new dodecaruthenium dianion [{Ru6C(CO)16}2Hg]2–2. This red dianion has been characterised as its [N(PPh3)2]+ salt by single-crystal X-ray diffraction analysis and shown to contain two octahedral Ru6C units linked through a mercury atom. It is probably produced from the uncharacterised intermediate monoanion [Ru6C(CO)16(HgX)]–3a(X = Cl or CF3CO2). In agreement with this suggestion, treatment of 1 with the compound Hg(CF3)(CF3CO2) yields the monoanion [Ru6C(CO)16(HgCF3)]–3b which has been fully characterised on the basis of its spectroscopic data. We have also observed that the neutral pentaruthenium cluster [Ru5C(CO)15]4 reacts with HgCl2 to produce the dark red decaruthenium species [{Ru5C(CO)14(µ-Cl)}2Hg2Cl2]5. On the basis of single-crystal X-ray diffraction analysis this cluster has been shown to consist of two distorted bridged-butterfly Ru5C(CO)14(µ-Cl) units linked by a Hg2(µ-Cl)2 unit. In solution, it appears that the dimeric cluster 5 undergoes dissociation to a monomer believed to be [Ru5C(CO)14(µ-Cl)(HgCl)]6. The mass spectrum of cluster 5 is not totally consistent with this unit and in the fast atom bombardment mass spectrum, the ion corresponding to [Ru5C(CO)13(µ-Cl)(HgCl)]7 is observed.

HPLC studies of Os3(CO)12-n(CH3CN)n (n = 0, 1, 2)

Abstract Normal and reverse phase chromatographic separation of Os3(CO)12, Os3(CO)11- (CH3CN) and Os3(CO)10(CH3CN)2 have been examined. On a silica column good separation of these clusters can be achieved with CH2Cl2/petroleum ether as the mobile phase but better reproducibility is attained with a Hypersil ODS C18 column and a mobile phase of MeOH/CH3CN. The relative retention times correlate qualitatively with molecular structures. The identities and purities of the chromatographic peaks were determined by use of a Data Evaluation Pack.

Synthesis, and 19F NMR and X-ray structural studies of triosmium clusters (μ-H)Os3(CO)10L[ON(CF3)2] (L PPh3, AsPh3 and SbPh3)

Abstract Bis(trifluoromethyl)nitroxyl radical reacts with H 2 Os 3 (CO) 10 L (L  PPh 3 , AsPh 3 , SbPh 3 ) to afford the derivatives (μ-H)Os 3 (CO) 10 L[ON(CF 3 ) 2 ] in which the (CF 3 ) 2 NO moiety is revealed by single crystal X-ray determinations to assume an axial position. Variable-temperature 19 F NMR spectral studies indicate that the two CF 3 groups of the(CF 3 ) 2 N moiety become magnetically different at lower temperature due to restricted rotation about the NO bond. The activation energies estimated from the coalescence temperatures are 54.4 and 52.3 kJ/mole for (μ-H)Os 3 (CO) 10 PPh 3 [ON(CF 3 ) 2 ] and for (μ-H)Os 3 (CO) 10 AsPh 2 -[ON(CF 3 ) 2 ] respectively.

Gas-phase structure of bis(trifluoromethyl) arsinous azide (CF3)2As N3

Abstract Bis(trifluoromethyl) arsinous azide was synthesized by reacting bis (trifluoromethyl) arsinous chloride with sodium azide. Its geometric structure was studied by gas-phase electron diffraction. The molecule possesses C s symmetry and the orientation of the azide group is trans to the CAsC bisector. The following geometric parameters were derived ( r a distances in A and ∠ α angles in degrees, error limits are 3σ values and refer to the last digit): As−C=2.013(5), As−N=1.849(8), C−F=1.338(2), N α −N β =1.224(10), N β −N ω =1.124(10), CAsC=97.8(1), CAsN=99.3(10), FCF=107.9(3), AsN α N β =119.1(29), N α N β N ω =176(3). The structural parameters of the azide group are compared to those for other azides, for which gas-phase structures have been reported.

Coordinating properties of 2-pyridyldiphenylphosphine with some metal carbonyls

Abstract The reaction of 2-pyridyldiphenylphosphine with iron carbonyl affords 2-(C5H4N)P(C6H5)2Fe(CO)4 in which the ligand is bonded through the phosphorus donor atom. Similar substitution reactions occur with Mn2(CO)10, Re2(CO)10, Cr(CO)6 and Mo(CO)6 to give 2-C5H4NP(C6H5)2Mn2(CO)8, [2-C5H4NP(C6H5)2Re(CO)4]2 and 2-C5H4NP(C6H5)2M(CO)5 (M = Cr, Mo), respectively.

Triosmium carbonyl cluster derivatives containing pentameric phenyl cyclopolyphosphine

Abstract The reactions of the pentaphenylcyclopentaphosphine with [Os 3 (CO) 10 (NCCH 3 ) 2 ] afforded a pair of inversion isomers, ( 1 ) and ( 2 ). [Os 3 (CO) 11 (C 6 H 5 P) 5 ] ( 3 ) and [{Os 3 (CO) 11 } 2 (C 6 H 5 P) 5 ] ( 4 ) were obtained by the treatment of the same ligand with [Os 3 (CO) 11 (NCCH 3 )]. The four new triosmium clusters have been shown by X-ray crystallography to contain an intact cyclopolyphosphine ring in each case.

Formation of novel delocalised diphosphazene upon complexation—the preparation and X-ray structure of Os3(CO)10[(CF3)2PNPPh3]2

Abstract The compound Os 3 (C) 10 [(CF 3 ) 2 PNPPh 3 ] 2 obtained from the reaction of Os 3 (CO) 10 (CH 3 CN) 2 with (CF 3 ) 2 P−NPPh 3 , has been characterized by X-ray crystallography. The osmium atoms from an approximate isoceles triangle. Both diphosphazene ligands which assume equatorial sites, contain unusually short PN bonds, from PNP to PNP upon coordination to osmium metals.

Synthesis, X-ray structural and spectroscopic study of new silyl-substituted triosmium clusters

Abstract The 2-pyridyldimethylsilane, 2-(CH3)2SiHC5H4NLH reacts with Os3(μ-H)2(CO)10] to afford the novel cluster [Os3(μ-H)2(CO)10 L2] 1 in which each of the ligands L has been shown from single crystal X-ray diffraction study to bond to one osmium atom through the silicon atom only. In addition, several silyl-substituted triosmium clusters of general formula [Os3(μ-H)(CO)11{2BrC 6H4CH2Si(CH3)2nHn}] (n = 0, 2A, 1, 2B; 2, 2C), Os 3(μ-H)CO)10(CH3 CN){2-BrC6H4CH2Si(CH3)2-nHn}] (n = 0, 3A; 1, 3B) have been synthesized from the reactions of the silane derivatives BrC6H4CH2Si(CH3)3-mHm [m = 1, I; 2, II; 3, III] with the activated clusters [Os3(CO)11CH3CN] and Os3(CO)10(CH3CN)2], respectively. The acetonitrile molecule in 3A is readily substituted by a triphenylphosphine molecule to yield Os3(μ-H)(CO)10(Ph3P){2-BrC6H4CH2Si(CH3)2})] (4). Reaction of [Os3(μ-H) 2(CO)10] with 2-BrC6H4Si(CH3)2H affords the cluster [Os3(μ-H)3(CO)9{2-BrC6 H4CH2Si(CH3)2}] (5). In the case of 3A the silane moiety bonds to an osmium atom at a position equatorial to the OS3 triangle while the acetonitrile molecule takes up an axial position. The molecular structure of 4 contains both the silane and the triphenylphosphine moieties at the terminal, equatorial positions on two separate osmium atoms. The behaviour under high performance liquid chromatography of these clusters has been determined and correlated with the nature of the ligands and with the molecular weights and sizes of the clusters.

Mixed-ligand complexes of copper(II) containing a monocondensed schiff base and an amino acid or amine

A series of mixed-ligand complexes of CuII containing a monocondensed Schiff base and an amino acid/amine have been isolated and characterised via