Giuliano Bandoli

Ligating ability of 1,1′-bis(diphenylphosphino)ferrocene: a structural survey (1994–1998)

Abstract This paper outlines the ligating ability of 1,1′-bis(diphenylphosphino) ferrocene. The focus is on the extensive coordination chemistry exhibited by this ligand to transition metals. The structural parameters of mono-, bi- and polynuclear species are reviewed and simple relationships between some of these parameters are reported and discussed. The review mainly covers the X-ray structure determinations published over the 1994–98 period.

Structural survey of technetium complexes

Abstract The review, with 294 references and 41 figures, reports on the main structural features of 240 Tc complexes whose X-ray crystal structure has been determined during the period 1986–1992. It comprises seven major sections: oxo-; nitrido-; diazenido-, hydrazido- and imido-; Schiff base-; chalcogenide-; pnictide-; nitrosyl- and thionitrosyl-technetium complexes. The survey concludes with two comprehensive tables summarizing some properties of Tc complexes vs . oxidation state.

Crystal structures of technetium compounds

A. B. C. D. E. F. Introduction .__ _......_._ _.._....._....._...._........_....._ _ 191 Remarks . . . . . . . . .._ _..~ ~._.. 193 Oxides, technetate, and pertechnetate compounds _ _ _ _ . . . _ _ _ _ _ _ _ _ . . _ _ _ _ _ . . 194 Halideandoxyhalidecompounds _____.______...___.______________.... 195 Polyhalide and polypseudohalide complexes . _ . _ _ . _ . . _ . _ . . . . . . . . _ _ _ . . . . . 197 Complexes _._..._ _ _ _ _ _ _ _ _ _...._._ _ _ _ _ _ __.._ _ ___ _._.._ _ _ ___... 199 (i) Complexes containing Ir-acceptor ligands _ . . . . . . . _ _ _ . . . . _ _ _ _ . . . . . _ _ _ 199 (ii) Complexes containing the TFO group . _ _ . . _ . . . . . . . . . . . . . . . . . . . . . . 208 (iii) Othercomplexes 211 G. Miscellaneous 215 H.Conclusions ___......___ .... 216 (i) General 216 (ii) Bondlengths 218 (iii) Summary 222 Acknowledgments 224 References 224

Structural overview of technetium compounds (1993–1999)

Abstract This paper investigates the structural aspects of technetium-containing complexes. The focus is on the description of the various coordination environments around the technetium center. The complexes are divided according to the coordination sphere and the most significant structural parameters are reviewed and discussed. The review covers the crystallographic determinations published in the years between 1993 and 1999.

Synthesis, characterization and electrochemical studies on technetium(V) and rhenium(V) oxo-complexes with N,N'-2-hydroxypropane-1,3-bis(salicylideneimine)

Ligand-exchange reactions of potential quinquedentate Schiff base ligands derived from salicylaldehyde and 1,3-diamino-2-hydroxypropane (H 3 L) with [MOCl 4 ] − (M = Tc and Re) have been investigated. The complexes [MOCl 2 (ROH)(H 2 L·HCl)] ( I ) (R = Me, Et), [ReOCl(HL)] ( II ) and μ-O[MO(HL)] 2 ( III ) were synthesized and characterized by the usual physicochemical measurements. Cyclic voltammetries for both III complexes reveal two separate and single-electron redox processes. The crystal structure of μ-O[TcO(HL)] 2 was determined by single-crystal X-ray diffraction methods. Crystals are monoclinic, space group P 2 1 / c , with a = 9.423(6), b = 19.666(9), c = 22.785(11) A, β = 99.41(4)° and Z = 4. X-ray diffraction provides 2842 observed reflections (up to θ = 40°) and the structure has been refined by full-matrix least-squares methods to R = 0.10. The ‘dimeric’ structure of μ-O[TcO(HL)] 2 consists of two distorted octahedral TcO(HL) moieties bridged by an oxygen atom which occupies the sixth coordination site of each moiety with the TcOTc angle nearly linear (173°).

Preparation, crystal and molecular structure of aquadichlorocaffeinecopper(II)

Abstract Preparation, crystal and molecular structure of aquadichlorocaffeinecopper(II), determined by three-dimensional X-ray data, are reported. The darkish green crystals are orthorhombic, space group P212121 with cell dimensions: a = 16.370(9), b = 13.432(7), c = 5.814(6) A and Z = 4. The structure was solved by the heavy-atom method from 1221 reflections collected by counter, and refined by least-squares method to R = 0.028. The geometry around copper is tetragonal pyramidal distorted towards trigonal bipyramidal, the C2V symmetry being maintained. The caffeine imidazole nitrogen atom (Cuz.sbnd;N 1.98 A), oxygen atom from water (Cuz.sbnd;O 1.96 A) and trans chlorine atoms (CuCl(1) 2.32, Cuz.sbnd;Cl(2) 2.25 A) lie at the corners of an approximate square as closest ligands to the copper. Through a screw-axis parallel to c, Cl(1) atom is placed at the apex of the pyramidal configuration (Cuz.sbnd;Cl(1)′ 2.79 A); since only one chlorine atom forms a bridge between successive symmetry related copper atoms a polynuclear chain with alternating short and long CuCl distances is formed. The single chain is further strengthened by Cl- - -HOH hydrogen bonds; moreover, symmetry-related chains are held together by O- - -HOH hydrogen bonds.

The reactivity of the [Re≡O]3+ core toward aromatic 1,2-diamines: the formation of rhenium(V)-imido complexes

The reaction of the aromatic diamines 1,2-diaminobenzene, 2,3-diaminophenol (H 2 L), 2,3-diaminotoluene and 3,4-diaminobenzophenone (H 2 NRNH 2 ) with trans -ReOCl 3 (PPh 3 ) 2 in an equimolar ration in ethanol gave the products trans -[Re(NRNH 2 )Cl 3 (PPh 3 ) 2 ] in good yield. IR 3 H NMR and X-ray crystallographic results indicate that the diamine ligands coordinate to rhenium(V) in a dianionic monodentate imido form. The structure of trans -[Re(L)Cl 3 (PPh 3 ) 2 ] was determined and shows that only the deprotonated amino nitrogen in the 2-position of the potentially ambidenatate 2,3-diaminophenol molecule is coordinated to the metal.

Rhenium(V) oxo complexes with schiff base ligands containing four or five coordination sites. X-ray molecular structure of [N,N′-3-azapentane-1,5-diylbis(salicylideneiminato)(3-)-O,O′,N,N′,N″]oxorhenium(V)

Abstract The reactions of [ReOCl4]− with Schiff base ligands derived from salicylaldehyde and 1,5-diamino- pentane (H2L1a), -hexane (H2L1b), -heptane (H2L1c) or diethylentriamine (H3L2) have been investigated. The complexes ReOCl2(EtOH)HL1n (I) (n=a, b or c), Re2O2(MeOH)2Cl4HL2 (II), ReOClL1n (III) and ReOL2 (IV), have been synthesized and characterized with the usual physicochemical measurements. The crystal structure of ReOL2 was determined by single crystal X-ray methods. Crystals are monoclinic, space group P21/c, with a=9.470(7), b=9.358(8), c=21.859(12) A, β=99.23(8)16° and Z=4. X-ray diffraction provides 5601 observed reflections (up to 2⊖=60°) and the structure has been refined by full-matrix least-squares methods to R=0.061. The monomeric structure consists of distorted octahedral ReOL2 units. One oxygen atom of the N3O2 pentadentate ligand is located trans to the rheniumoxo oxygen bond, while the remaining four coordinating atoms lie on the equatorial plane of the octahedron assuming that the oxo-oxygen occupies an apex. The arrangement of the two iminophenolate groups is explained as a function of the length of the aliphatic chain joining the two imine groups.

Monooxorhenium(V) complexes with the tridentate Schiff baseN-(2-hydroxyphenyl)salicylideneimine

SummaryThe reactions of the tridentate Schiff base ligandN-(2-hydroxyphenyl) salicylideneimine (HOPhsalH) with oxotetrachlororhenate (IV) have been investigated. The complexes (Bu4N)[ReOCl3(HOPhsal)], (Bu4N)[ReOCl2(OPhsal)],cis- [ReOCl(MeOH)(OPhsal)],trans-[ReOCl(MeOH)(OPhsal)] (1), trans-[ReOCl(OH2)(OPhsal)] · Et2O (2), trans-[ReOCl(OH2)(OPhsal)] · Me2CO,cis-[ReOCl(PPh3)(OPhsal)],cis-[ReOCl(PMe2Ph)(OPhsal)](3) have been synthesized and characterized. The crystal structures of(1), (2) and(3) have been solved from three-dimensional x-ray data by Patterson and Fourier methods and refined by least-squares methods to R 0.10 for(1), 0.042 for(2) and 0.059 for(3). In all the three complexes, the ligands surrounding the rhenium atom are at the apices of a distorted octahedron, with the equatorial ONO donor atoms of the tridentate Schiff base bent away from the Ooxo and toward the loosely bound MeOH in(1), H2O in(2) and Cl in(t3). The fourth equatorial substituent is Cl (1 and2) and PMe2Ph(3) and the rhenium atoms lie 0.30–0.37 Å above the best plane through the four equatorial atoms, in the direction of the Ooxo. All interatomic distances and angles are normal.

Some palladium(II) and platinum(II) lead bonded complexes

Abstract Complexes of the type M(PPh 3 ) 2 (PbPh 3 ) 2 [M = Pd, (Ia) and Pt, (Ib)] have been prepared by oxidative addition of hexaphenyldilead to M(PPh 3 ) 4 . The compound Pt(PPh 3 ) 2 (PbPh 3 ) 2 , (Ib), slowly decomposes in dichloromethane to give cis -Pt(PPh 3 ) 2 (PbPh 3 )Ph, (II). which can also be obtained by treating (Ib) with the stoichiometric amount of LiPh. Reaction of Pt(PPh 3 ) 4 with hexamethyldidead gives the complex Pt(PPh 3 ) 2 (PbMe 3 )Me directly. The MPb bonds are easily cleaved by bromine, iodine and hydrogen bromide. The X-ray structure of (II) has been determined using three-dimensional counter data and refined by the least-square method ( R = 0.07). The crystals are monoclinic a = 22.501, b = 10.502, c = 24.120 A, β = 113.43°, space group P 2 1 / c with Z = 4. The complex exhibits a cis configuration, with the coordination around the platinum atom essentially square-planar: the PtPb and PtC(phenyl)bond lengths are 2.698(1) and 2.055(3)A, respectively.