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[ReOCl3(PPh3)2] reacts with phenylbis(2-pyridyl)phosphine (PPhpy2) in boiling THF under the formation of the rhenium(III) compound [ReCl3(PPh3)(OPPhpy2-O,N)]. Reduction of the metal can be avoided by milder reaction conditions, and an asymmetric, oxo-bridged rhenium(V) dimer of the composition (NBu4)[Re2O2Cl5(μ-PPhpy2-P,N,N′)(μ-O)] is obtained from the reaction of PPhpy2 and (NBu4)[ReOCl4] in THF at room temperature. The products have been characterized spectroscopically and by X-ray structure analyses.

The potentially bidentate ligand diphenyl(2-pyridyl)phosphine (PPh2py) reacted with (NEt4)2[MIX3(CO)3] complexes (M=Re, Tc; X=Cl, Br) to give (NEt4)[MIX2(CO)3(PPh2py-P)] or [MIX(CO)3(PPh2py-P)2] depending on the amount of the ligand used. The reaction with (NBu4)[TcVINCl4] yielded [TcVNCl2(PPh2py-P)2] whereas from the reaction with (NBu4)[ReOCl4] the complexes [ReVOCl3(PPh2py-P,N)], [ReVOCl3(OPPh2py-O,N)], [ReIVCl4(OPPh2py-O,N) and [ReIVCl3(OH)(OPPh2py-O,N)] have been isolated. Reduction of the metal center occurs using an excess of PPh2py and heating of the reaction mixtures under reflux. The products have been characterised spectroscopically and by X-ray structure analysis. Monodentate co-ordination via phosphorus has been found for the rhenium(I) carbonyl complexes and [TcVNCl2(PPh2py-P)2]. In the latter compound a trigonal-bipyramidal coordination sphere is formed with the phosphines as axial ligands (bond angle P–Tc–P: 161.69(3)°). The chelated complexes show small N–Re–P and N–Re–O bite angles of 63.6° and 77.7–82.2° due to the four-membered or five-membered chelate rings. The pyridine nitrogen occupies the axial position (trans to “O2−”) in [ReOCl3(PPh2py-P,N)] whereas equatorial co-ordination is found in [ReOCl3(OPPh2py-O,N)].

The diastereoselective synthesis of 6-aroyl-3,5-diarylspiro[cyclohexa-2,4-diene-1,2′-indolines] 4 possessing three stereocenters from 2,4,6-triarylpyrylium perchlorates 1 and chiral methyleneindolines 3 (generated in situ by deprotonation of the corresponding 3H-indolium perchlorates 2) in the presence of triethylamine/acetic acid in ethanol by a 2,5-[C4+C2] pyrylium ring transformation is reported. Structure elucidation is performed by X-ray structure determinations of the spiro[cyclohexadiene-indolines] 4a, 4p and 4t. The influence of various substituents at C-3 of the methyleneindolines 3 on the stereochemistry of the transformation, mechanistic details as well as spectroscopic data of the products 4 are discussed.

A review on the synthesis and properties of the organometallic aqua-ion [M(OH2)3(CO)3]+ (M=Re, 99Tc, 99mTc), as relevant for radiopharmaceutical application, is presented. These important starting compounds can be prepared quantitatively, (a) on the no carrier added (n.c.a.) level (99mTc) in water, or (b) in organic solvents (Re, 99Tc) at atmospheric pressure in a short time and from [MO4]−. The main characteristics of these carbonyl complexes are the high substitution stability of the three CO ligands and the substitution lability of the coordinated water molecules. [M(OH2)3(CO)3]+ can be considered as a ‘semi aquo–ion’. On the macroscopic level, upon titration with OH−, hydroxo-bridged oligomers have been isolated and characterized. The formation of hydroxo-bridged complexes is a consequence of the considerable Bronstedt acidity of [M(OH2)3(CO)3]+, whereas on the n.c.a. level no such behavior was observed. Conditions and products of the water exchange by imidazole (im) and derivatives thereof (histamine, histidine) will be presented. The different mononuclear complexes with these ligands are of extraordinary inertness, which is the basis for potential applications in biology and nuclear medicine. Finally, as a basis for bioorganometallic chemistry, the adoption of the results from basic coordination chemistry to the labeling of biomolecules with an organometallic moiety will be exemplified with a selected penta-peptide and a recombinant single chain fragment.

2-Mercapto-methyltetrazolate, Smetetraz–, acts as monoanionic, monodentate ligand in a number of technetium compounds. Anionic TcV complexes of the types [TcO(Smetetraz)4]– and [TcN(Smetetraz)4]2– are formed when (Bu4N)[TcVOCl4] or (Bu4N)[TcVINCl4], respectively, react with Na(Smetetraz). Reduction of the metal takes place in the latter case. (Bu4N)2[TcN(Smetetraz)4] crystallises in the monoclinic space group Pc (a = 9.701(5), b = 17.570(5), c = 16.821(10) A, β = 96.50(3)°, Z = 2). The Tc atom is situated 0.580(3) A above the basal plane of a square pyramid which is formed by the sulfur atoms and the nitrido ligand as its apex. The Tc–S bond lengths lie between 2.384(3) and 2.410(3) A. [Tc(PPh3)(Smetetraz)3(CH3CN)] is formed during the reaction of [TcCl3(PPh3)2(CH3CN)] with NaSmetetraz as blue needles with co-crystallised solvent toluene (space group C2/c, a = 24.188(4), b = 14.373(1), c = 25.617(5) A, β = 109.48(1)°, Z = 8). The metal atom is coordinated by PPh3 and CH3CN in the axial position of a trigonal bipyramid. All three aryl rings are on the sterically less strained side of the plane defined by the sulfur atoms. The Tc–S bond lengths range between 2.233(2) and 2.247(2) A. Technetiumkomplexe mit 2-Mercapto-methyltetrazolat 2-Mercapto-methyltetrazolat, Smetetraz–, fungiert in einer Reihe von Technetiumkomplexen als einzahniger, monoanionischer Ligand. Ausgehend von (Bu4N)[TcVOCl4] oder (Bu4N)[TcVINCl4] und Na(Smetetraz) werden anionische Komplexe der Zusammensetzung [TcO(Smetetraz)4]– bzw. [TcN(Smetetraz)4]2– gebildet. Im Falle der Nitridoverbindung erfolgt eine Reduktion des Metalls. (Bu4N)2[TcN(Smetetraz)4] kristallisiert in der monoklinen Raumgruppe Pc (a = 9,701(5), b = 17,570(5), c = 16,821(10) A, β = 96,50(3)°, Z = 2). Das Tc-Atom befindet sich um 0,580(3) A uber der Grundflache einer quadratischen Pyramide, die aus den vier Schwefelatomen und dem Nitridoliganden gebildet wird. Die Tc–S-Bindungslangen liegen zwischen 2,384(3) und 2,410(3) A. [Tc(Smetetraz)3(PPh3)(CH3CN)] × 0,5 Toluol entsteht bei der Reaktion von [TcCl3(PPh3)2(CH3CN)] mit NaSmetetraz in Form blauer Nadeln (Raumgruppe C2/c, a = 24,188(4), b = 14,373(1), c = 25,617(5) A, β = 109,48(1)°, Z = 8). Das Tc-Atom ist trigonal-bipyramidal mit PPh3 und CH3CN in den axialen Positionen koordiniert. Die Arylringe der Thiolatliganden befinden sich auf der sterisch weniger belasteten Seite des Molekuls. Die Tc–S-Bindungslangen liegen im Bereich zwischen 2,233(2) and 2,247(2) A.

trans-Tetrachlorobis(methyl-diphenylphosphinite)rhenium(IV) and trans-tetrachlorobis(ethyl-diphenylphosphinite)rhenium(IV) were obtained by recrystallization of the corresponding rhenium(III) phosphinite complexes, [ReCl3L3], in chlorinated solvents. The structures of the compounds consist of discrete molecules with trans-octahedral coordination geometry around the rhenium atom, having Re–P distances between 2.534(1) and 2.555(2) A and Re–Cl distances in the range 2.321(1)–2.336(1) A. trans-[ReCl4(OPPh3)2] is formed during the reaction of triphenyloxonium tetrafluoroborate with [ReNCl2(PPh3)2]. P–O bond lengths of 2.033(4) A have been found, while the Re–Cl bonds are 2.336(2) and 2.344(2) A, respectively.

Dichloro [2- ( NN -dimethylaminomethyl)phenyl-C 1 N]gold(III) [Au (damp–C 1 N)Cl 2 ]reacts with diphenylthiocarbazone PhNHNHC(S)NNPhunder formation of the cationic species [Au (Hdamp–C 1 ){PhNHNC (S)NNPh}Cl]Cl The reaction goes along with cleavage of the Au–N bond and protonation of the dimethylamino group Diphenylthiocarbazonate coordinates singly deprotonated as N S-chelate There is no evidence for the formation of Au (I) species during this reaction.

Reactions of [ReN(Cl)(Me2PhP)2(HEt2tcb)] (HEt2tcb−=N,N-diethylthiocarbamoylbenzamidinate, Me2PhP=dimethylphenylphosphine) with Lewis acidic compounds such as BBr3, (C6F5)3B or gallium(III) chloride yield nitrogen-bridged binuclear complexes with covalent bonds between the nitrido ligand and boron or gallium. The reactions go along with activation of the transition metal centre which can lead to ligand re-arrangements and reactions with solvent molecules. The reaction with BBr3 results in cleavage of the bonds to the chelating ligand. [Re(NBBr3)Br2(Me2PhP)3] was isolated as the only product with a nitrido bridge. The bis-chelate [ReN(HEt2tcb)2] was formed as a side-product. Upon formation of a nitrido bridge to GaCl3 the first co-ordination sphere of rhenium is retained. The co-ordinated thiocarbamoylbenzamidinate, however, undergoes protonation and is bonded as a neutral, bidentate ligand in the product [Re(NGaCl3)Cl(Me2PhP)2(H2Et2tcb)][GaCl4]. In [Re{NB(C6F5)3}Cl(Me2PhP)2(HEt2tcb)], which can be obtained in good yield from the reaction of [ReN(Cl)(Me2PhP)2(HEt2tcb)] with (C6F5)3B, the co-ordination environment of the metal remains essentially unchanged. X-ray structural studies on the products suggest that the strong structural trans influence of the terminal nitrido ligand in the starting complex decreases significantly as a consequence of the formation of the N–B/Ga bonds. The rhenium–nitrogen multiple bond distances, however, remain almost unchanged.

The complexes cis-Pt(O2CNEt2)2(PR3)2 (R = Ph, Et) and Pt(O2CNEt2)2(DPPE) [DPPE = 1,2-bis(diphenylphosphino)ethane] were prepared by the reaction of the corresponding phosphino-chloro complexes of platinum with Ag(O2CNEt2). The new N,N-diethylcarbamato complexes are excellent precursors for the high-yielding preparation of the corresponding carbonato derivatives Pt(CO3)(PR3)2 or Pt(CO3)(DPPE) by reaction with a stoichiometric amount of water. The carbamato complex cis-Pt(O2CNEt2)2(PPh3)2 reacts with CO producing the carbamoyl derivative cis-Pt[C(O)NEt2]2(PPh3)2. The chloro-carbamoyl complex, prepared by reacting cis-PtCl2(PPh3)2 with NHEt2 and CO, and recrystallized from toluene as the solvated species trans-PtCl[C(O)NEt2](PPh3)2·2 C6H5Me has been structurally characterized.

A novel tridentate thiosemicarbazide-type ligand class with an SNS donor set, H(2)L(1), was prepared by reactions of N-[N',N'-dialkylamino(thiocarbonyl)]benzimidoyl chlorides with thiosemicarbazides. H(2)L(1) ligands readily react with (NBu(4))[TcOCl(4)] in MeOH under the formation of red oxotechnetium(V) complexes of composition [TcOCl(L(1))]. The monomeric, five-coordinate compounds are air-stable and bind (L(1))(2-) tridentate in the equatorial coordination sphere. The compounds represent the first examples of oxotechnetium(V) complexes with NS chelate-bonded thiosemicarbazones.

(NBu4)[ReOCl4] reacts with N-picolyl-N′-benzoylthiourea (H2picbtu) in acetone under formation of the deep-green oxorhenium(V) complex (NBu4)2[{Re2O2Cl5(Hpicbtu)}2O], which was studied by X-ray diffraction. Two dimeric units with each one bridging, singly deprotonated thiourea ligand are connected by an oxo ligand. Inside the subunits, Hpicbtu− coordinates as S,O chelate with a six-membered chelate ring to one rhenium atom, while a five-membered chelate ring is established with the second Re atom and the nitrogen atoms of the picolylamine building block. The compound represents one of the very rare examples of anionic μ-oxorhenium(V) complexes.

A one step synthesis of [TcO3]+[SO3F]− is reported. The compound is volatile at room temperature and has according to calculations a tetrahedral coordination around Tc and a monodentate SO3F group. In the solid state the [SO3F]− anion bridges three [TcO3]+ cations, and vice versa. Space group P21/c, Z = 4, lattice dimensions at 173 K: a = 695.4(11), b = 808.6(12), c = 893.3(14) pm, β = 97.36(8)°.

(NBu4)[ReOCl4] reacts with 2-(diphenylphosphino)benzaldehyde 4-phenylsemicarbazone (HL1) in methanol under formation of the red rhenium(V) complex [ReO(Cl)(OMe)(L1)]. The semicarbazonato ligand is singly deprotonated and coordinates meridionally via the phosphorus atom and two nitrogen atoms. This unusual coordination mode of a semicarbazone is confirmed by IR and NMR spectroscopy and by the solid state structure of the product.

Die paramagnetischen Rhenium(II)-Nitrosylkomplexe [Re(NO)Cl2(PPh3)(OPPh3)(OReO3)], [Re(NO) · Cl2(OPPh3)2(OReO3)] und [Re(NO)Cl2(OPPh3)3](ReO4) entstehen bei der Reaktion von [ReOCl3(PPh3)2] mit NO-Gas in CH2Cl2/EtOH. Im Verlauf der Reaktion konnen diese und zwei weitere ReII-Komplexe mit 5 d5 „low-spin”-Konfiguration EPR-spektroskopisch und massenspektrometrisch nachgewiesen werden. Die Kristallstrukturanalyse weist fur die isolierten Nitrosylkomplexe linear koordinierte NO-Liganden (Re–N–O-Winkel zwischen 171,9 und 177,3°) aus. Im Endprodukt der Reaktion, [Re(NO)Cl2(OPPh3)3][ReO4] (monoklin, P21/c, a = 13,47(1), b = 17,56(1), c = 24,69(2) A, β = 95,12(4)°, Z = 4), sind drei OPPh3-Liganden meridional koordiniert. Die Zwischenprodukte [Re(NO)Cl2(PPh3)(OPPh3)(OReO3)] (triklin, P 1, a = 10,561(6), b = 11,770(4), c = 18,483(8) A, α = 77,29(3), β = 73,53(3), γ = 64,70(4)°, Z = 2) und [Re(NO)Cl2(OPPh3)2(OReO3)] (monoklin P21/c, a = 10,652(1), b = 31,638(4), c = 11,886(1) A, β = 115,59(1)°, Z = 4) konnen neben [Re(NO)Cl3(Ph3P)2], [Re(NO) · Cl3(Ph3P)(Ph3PO)] und [ReCl4(Ph3P)2] bei kurzeren Reaktionszeiten isoliert werden. Synthesis, Structures, and EPR-Spectra of the Rhenium(II) Nitrosyl Complexes [Re(NO)Cl2(PPh3)(OPPh3)(OReO3)], [Re(NO)Cl2(OPPh3)2(OReO3)], and [Re(NO)Cl2(OPPh3)3](ReO4) The paramagnetic rhenium(II) nitrosyl complexes [Re(NO)Cl2(PPh3)(OPPh3)(OReO3)], [Re(NO)Cl2(OPPh3)2 · (OReO3)], and [Re(NO)Cl2(OPPh3)3](ReO4) are formed during the reaction of [ReOCl3(PPh3)2] with NO gas in CH2Cl2/EtOH. These and two other ReII complexes with 5 d5 ”low-spin””-configuration can be observed during the reaction EPR spectroscopically. Crystal structure analysis shows linear coordinated NO ligands (Re–N–O-angles between 171.9 and 177.3°). Three OPPh3 ligands are meridionally coordinated in the final product of the reaction, [Re(NO)Cl2(OPPh3)3][ReO4] (monoclinic, P21/c, a = 13.47(1), b = 17.56(1), c = 24.69(2) A, β = 95.12(4)°, Z = 4). [Re(NO)Cl2(PPh3)(OPPh3)(OReO3)] (triclinic P 1, a = 10.561(6), b = 11.770(4), c = 18.483(8) A, α = 77.29(3), β = 73.53(3), γ = 64.70(4)°, Z = 2) and [Re(NO)Cl2 (OPPh3)2(OReO3)] (monoclinic P21/c, a = 10.652(1), b = 31.638(4), c = 11.886(1) A, β = 115.59(1)°), Z = 4) can be isolated at shorter reaction times besides the complexes [Re(NO)Cl3(Ph3P)2], [Re(NO)Cl3(Ph3P) · (Ph3PO)], and [ReCl4(Ph3P)2].

[Fe(MeCN)6][Fe2OCl6] (2) wird durch Umsetzung einer Losung von FeCl2 in Acetonitril mit trockenem Luftsauerstoff in fast quantitativer Ausbeute erhalten. 2 kristallisiert in der trigonalen Raumgruppe R 3 [a = b = 12.121(1), c = 29.875(6) A; Z = 6]. Das Sauerstoffatom im Fe2OCl6-Anion besetzt die Lage 3 und bedingt damit einen Fe–O–Fe-Winkel von 180°. Eine Verfeinerung in der triklinen Raumgruppe P1 liefert dagegen eine leicht gewinkelte Anordnung des Fe–O–Fe-Fragments. Synthesis and Crystal Structure of [Fe(MeCN)6][Fe2OCl6] [Fe(MeCN)6][Fe2OCl6] (2) is obtained by passing dry air through a solution of FeCl2 in acetonitrile in almost quantitative yield. 2 crystallises in the trigonal space group R 3 [a = b = 12.121(1), c = 29.875(6) A, Z = 6]. The oxygen atom in the Fe2OCl6 anion occupies the 3 position and causes therefore an Fe–O–Fe angle of 180°. The refinement in the triclinic space group P1 leads to a slightly bent arrangement of the Fe–O–Fe fragment.

The formation of mixed-ligand complexes of the type [ReVlNCl4-nFn]- (n = 1 -3) during the reaction of [ReVINCl4]- with [n-(C4H9)4N]F, KF, and HF is reported. Evidence of the individual mixed-ligand compounds is given by their EPR spectral data. In frozen solutions a specific dependence of the EPR data on the composition of the coordination sphere could be detected. This is shown (i) by a nearly linear dependence of gII and AII Re on the Cl/F-content of the [ReVINCl4-nFn]- unit (additivity rules) and (ii) by well-resolved 19F hyperfine splittings.

2,4,6-Triarylpyrylium salts 1 react with the in situ generated anhydrobase of 9,10-dimethylacridinium methosulfate (2a) in the presence of anhydrous sodium acetate in ethanol by a 2,5-[C4+C2] pyrylium ring transformation to give the hitherto unknown 6-aroyl-3,5-diaryl-10′-methylspiro[cyclohexa-2,4-diene-1,9′-9′,10′-dihydro-acridines] 3. When the pyrylium perchlorate 1a is treated under the same conditions with the N-ethyl, N-allyl or N-benzyl substituted acridinium salts 2b-d a dealkylation of these salts occurs and the N-unsubstituted spiro[cyclohexadiene-dihydroacridine] 4a is formed. The same compounds 4 can also be obtained by transformation of the pyrylium salts 1 with 9-methylacridine (7) and triefhylamine/acetic acid in ethanol. Structure elucidation is performed by an X-ray crystal structure determination of the spiro[cyclohexadiene-dihydroacridine] 3a. Spectroscopic data of the transformation products and their mode of formation are discussed.

Starting originally from the organometallic precursor [NEt4]2[TcBr3(CO)3] (1b), substitution reactions were performed with the macrocyclic thioethers 1,4,7-trithiacyclononane (9-ane-S3), 1,4,7,10,13,16-hexathiacyclooctadecane (18-ane-S6), and 3,6,9,13,16,19-hexathiacycloicosanol (20-ane-S6-OH). The corresponding complexes fac-[Tc(9-ane-S3)(CO)3]Br (2), fac-[Tc2(tosylate)2(18-ane-S6)(CO)6] (3), and fac-[Tc2(20-ane-S6-OH)(CO)6][tosylate]2 (5) were isolated in good yields and characterized spectroscopically by IR, 1H, 99Tc NMR, and X-ray diffraction methods. In the case of 18-ane-S6 and 20-ane-S6-OH the formation of the 1:2 as well as the 1:1 complex could be observed in the 99Tc NMR experiment, depending on the ligand to metal ratio. Complex 2 crystallizes in the monoclinic space group P21/c, a = 14.79(2) A, b = 11.691(2) A, c = 16.94(2) A, β = 94.88(6)°, Z = 8. The tripodal ligand is coordinated through the sulfur atoms to the metal center, forming three favorable five-membered chelate rings. Complex 3 cry...

The reaction of (NBu4) [ReNBr4] with BBr3 in CH2Cl2 gives purple crystals of (NBu4)2[(OH2)Br4ReNReBr4NReBr 4(OH2)]. The centrosymmetric complex anion is formed by three ReBr4 units which are linked by two asymmetric nitrido bridges with ReN distances of 1.69(2) and 2.00(2) A. The coordination spheres of the terminal Re atoms are completed by water ligands. The EPR spectra of the trimer suggest a d2-d1-d2 sequence for the Re atoms. The g, AReand ABr tensor components deviate from those of [ReNBr4] − and indicate an increase in the ReBr covalency.

The synthesized spin trap 3,5-diphenyl-5-methylpyrroline-1-oxide (3), its derivatives and spin adducts were studied using NMR, ESR and ENDOR spectroscopic methods. The structure of 3 was determined using x-ray analysis. The nitrone 3 was found to have a rigid structure. Two species were observed in the EPR and ENDOR spectra of the spin adducts of 3, but not in the NMR spectra of its diamagnetic derivatives. These two species were attributed to those formed when the addends attack carbon-2 from both the re and si sides, resulting in trans (I) and cis (II) adducts in relation to the phenyl substituent in position 3. Therefore, these two species differ only through the substitution on carbon-2, whereby there are different steric interactions of the substituents within both species. The lack of observation of these two species in NMR spectra could be interpreted in terms of unfavourable relaxation times on the NMR time-scale. These species are observed in EPR and ENDOR spectra mainly because of their different β-C—H dihedral angles, which do not play a role in NMR spectroscopy. Both species have the ability to trap stereoselectively carbon- and oxygen-centred radicals, which occupy pseudo-equatorial and pseudo-axial positions, respectively. The occupation of oxygen-centred addends in the pseudo-axial positions is stabilized by the ‘anomeric effects.’ This nitrone 3 was found to have the ability to scavenge short-lived free radicals in both aqueous and non-aqueous solutions. © 1998 John Wiley & Sons, Ltd.

Electron paramagnetic resonance spectroscopic investigations of tetra-n-butylammoniumtetrabromo-nitrodorhenate(VI), [(n-C4H9)4N][ReNBr4], having a 5d1 configuration, in liquid and frozen solution, are reported. In the polycrystalline samples very complex 185,187Re and 79,81Br hyperfine patterns are observed. Hyperfine and ligand hyperfine interactions are used to characterize the bonding properties in the molecular orbital of the unpaired electron and are compared with the results obtained from extended Huckel theory molecular orbital (EHTMO) calculations.

Dichloro[2-(dimethylaminomethyl)phenyl-C1,N]gold(III), [Au(damp-C1,N)Cl2], reacts with 2-mercapto-1,3-thiazoline (HSthiaz), 2-mercaptopyridine (HSpy), sodium 1-methylmercaptotetrazolate (NaSmetetraz), 4-methyl-3-mercapto-1,2,4-triazole (HSmetriaz) or 6-mercaptopurine (HSpur) under cleavage of the Au–N bond and protonation of the dimethylamino group. Compounds of general formulae [Au(Hdamp-C1)Cl(HL)2]2+ (HL = HSthiaz or HSpy), [Au(Hdamp-C1)Cl(L)] (L = Spur–) or [Au(Hdamp-C1)(L)3] (L = Smetetraz–) have been isolated and characterized. The reaction with HSmetriaz leads to a rapid reduction of the metal and the formation of the gold(I) complex [Au(HSmetriaz)2]+. The crystal structures of [Au(Hdamp-C1)Cl(HSthiaz)2]Cl2·Me2CO, [Au(Hdamp-C1)Cl(HSpy)2]·H2O, [Au(Hdamp-C1)(Smetetraz)3] and [Au(Hdamp-C1)Cl(Spur)]Cl have been elucidated showing the gold atoms in distorted square-planar co-ordination environments. Generally, one or more hydrogen atoms of the heterocyclic ligands and/or the NMe2H+ group form hydrogen bonds in the solid-state structures. The reaction of Na[AuCl4] with Na(Smetetraz) and [NEt4]Br yields bright red crystals of [NEt4][Au(Smetetraz)4], the first structurally characterized gold(III) complex with four monodentate thiolate ligands. The structure of the complex shows well separated [Au(Smetetraz)4]– anions with Au–S distances of 2.354(4) A.

[NEt4]2[Tc(Cl)3(CO)3] was prepared directly from [NBu4][TcO4]. Dissolution of [NEt4]2[Tc(Cl)3(CO)3] in water yielded the aqua ion [Tc(OH2)3(CO)3]+ which, upon titration with 1 eq. of OH−, gave the tetranuclear complex [{Tc(μ3-OH)(CO)3}4] in quantitative yield and of which the structure could be elucidated. Reaction of [{Tc(μ3−OH)(CO)3}4] with HC5Me5 gave the important starting material [(C5Me5)M(CO)3] (M = Tc, Re). To achieve complexes in higher oxidation states with the C5Me5− ligand, oxidation was performed with [Br2] for the rhenium and the corresponding technetium complex. Oxidation in trifluoroacetic acid yielded cis/trans-[(C5Me5)M(Br)2(CO)2] (M = Tc, Re). Oxidation in dichloromethane gave in both cases the seven co-ordinate, 18e− M(III) complex [(C5Me5)MBr(CO)3]+. The structure of the rhenium complex was elucidated. It was found that oxidation took place at the metal centre and the C5Me5− ring to yield [(CO)3M(μ−Br)3M(CO)3] as the counterion.

Complexes of the general formula |M(CO)3[(Ph2PS)2N](CH3CN)| (M = Tc, Re) have been prepared by the reaction of (Et4N)2[M(CO)3X3] (M = Tc, Re; X = Cl, Br) with sodium bis(diphenylthiophosphoryl)amide, Na[(Ph2PS)2N], in acetonitrile. The metal is six-coordinate with facially arranged carbonyl ligands. Bis(diphenylthiophosphoryl)amide is deprotonated and bonded as S,S′-chelate with TcS distances of 2.526(3) and 2.546(3) A. Acetonitrile occupies the sixth coordination position. The rhenium compound is isomorphous and the bonding situation in |Re(CO)3[Ph2PS)2N](CH3CN)| is similar to that in its technetium analogue. (Et4N)[Re(CO)3Br2(CH3CN)] crystallizes from a hot acetonitrile solution of (Et4N)2[Re(CO)3Br3] despite the fact that in solution only [Re(CO)3(CH3CN)3]+ can be detected spectroscopically. It has a facial arrangement of CO groups in an octahedral co-ordination geometry.

The compound [NBu4][ReNCl4] has been found to be easily accessible by the reaction of [NBu4][ReO4] with sodium azide and HCl gas in ethanol and represents an excellent precursor for the synthesis of further rhenium nitrido complexes. It has been studied by X-ray crystallography. Rhenium(VI) compounds of the general formula [ReNX4(5)]–,2– (X = Br or NCS) were obtained when [NBu4][ReNCl4] reacts with HBr or KSCN. The products as well as mixed-ligand intermediates which are formed during the ligand exchange have been studied by EPR spectroscopy. The EPR parameters of the individual mixed-ligand compounds are clearly correlated to the composition of the co-ordination sphere and can be used to characterize the mixed-ligand species unambiguously. This is shown by a nearly linear dependence of g0, g||, a0Re and A||Re on the spin–orbit coupling constants of the equatorial donors. Reactions of [NBu4][ReNCl4] with most organic ligands yielded rhenium(V) compounds. A number of phosphine complexes and chelates with sulfur-containing ligands have been prepared and spectroscopically characterized. A crystallographic study on [ReN(Hdetcb)2] (Hdetcb– = N 2-diethylthiocarbamoylbenzamidinate) shows cis co-ordination for the chelating S,N-donor ligands. Weak intermolecular hydrogen bridges have been found between the co-ordinated nitrogen atoms and the lone pair of the nitrido nitrogen. A comparison between the crystal structural data of [NBu4]2[ReN(mnt)2] (mnt2– = 1,2-dicyanoethene-1,2-dithiolate), prepared from [NBu4][ReNCl4] and Na2mnt, and [NBu4][ReO(mnt)2] shows longer Re–S bonds in the nitrido anion but markedly higher O–Re–S bond angles indicating higher steric requirements of the oxo ligand compared with ‘N3–’.

The synthesis and characterization of novel indium(III) complexes with pyridine-thiosemicarbazone ligands are reported as well as ligand exchange reactions on the products. 2,6-Diacetylpyridine-bis(thiosemicarbazone), C5H3N(C3N3SH6)2 (H2DAPTSC), and 2-acetylpyridine-thiosemicarbazone, C5H4N(C3N3SH6) (HAPTSC), were reacted with indium(III) halides and indium(III) nitrate, respectively, to give [InX2(HDAPTSC)], {O[In(HDAPTSC)(OH)]2}, [InX2(APTSC)(MeOH)] and [In(APTSC)2]PF6.

Das Ditellurid [(2,4,6-Ph3C6H2)Te]2 bildet mit Iod das Aryltellurenylhalogenid (2,4,6-Ph3C6H2)TeI, das mit Sauerstoff weiter zu [(2,4,6-Ph3C6H2)Te(μ2-O)I]2 reagiert. Die Verbindungen kristallisiert mit zwei Molekulen Dichlormethan in der monoklinen Raumgruppe P21/c: a = 911,3(4); b = 1153,3(2); c = 2244,1(9) pm; β = 93,53(2), Z = 2. Die analoge Bromverbindung [(2,4,6-Ph3C6H2)Te(μ2-O)I]2 entsteht bei der Umsetzung von [(2,4,6-Ph3C6H2)Te(μ2-O)I]2 mit NH4Br. Sie kristallisiert mit zwei Molekulen Xylen in der monoklinen Raumgruppe P21/n: a = 1067,5(5); b = 1018,4(4); c = 2486,5(8) pm; β = 101,71(2)°; Z = 2. Beide Verbindungen sind aus jeweils zwei (2,4,6-Ph3C6H2)TeX-Einheiten (X Br, I) aufgebaut, die uber zwei Sauerstoffbrucken verbunden sind. Im Zentrum der Te2O2-Ringe befindet sich jeweils ein Inversionszentrum. Die TeOTe-Winkel betragen 102°. Es wurden jeweils zwei unterschiedliche TeO-Abstande gefunden 191,4(2) und 208,6(2) pm in [(2,4,6-Ph3C6H2)Te(μ2-O)I] bzw. 189,8(4) und 208,4(5 pm in der Bromverbindung). Synthesis, Structures, and Reactivity of [(2,4,6-Ph3C6H2)Te(μ2-O)X]2 (X Br, I) [(2,4,6-Ph3C6H2)Te]2 reacts with iodine affording the aryltellurenic halide (2,4,6-Ph3C6H2)TeI, which is oxidized by oxygen to yield [(2,4,6-Ph3C6H2)Te(μ2-O)I]2. It crystallizes with two molecules of dichloromethane in the monoclinic space group P21/c with a unit cell of the dimensions a = 911.3(4); b = 1153.3(2); c = 2244.1(9) pm; β = 93.53(2)°, Z = 2). The analogues bromo compound [(2,4,6-Ph3C6H2)Te(μ2-O)Br]2 is obtained by the reaction of [(2,4,6-Ph3C6H2)Te(μ2-O)I]2 with NH4Br. It crystallizes with two molecules of xylene in the monoclinic space group P21/n (a = 1067.5(5); b = 1018.4(4); c = 2486.5(8) pm; β = 101.71(2)°; Z = 2). Both compounds are built up by two (2,4,6-Ph3C6H2)TeX units (X Br, I) which are linked by two oxgen bridges to form centrosymmetric molecules. The TeOTe angles are 102°. Distinct TeO bond lengths have been found (191.4(2) and 208.6(2) pm in [(2,4,6-Ph3C6H2)Te(μ2-O)I]2 and 189.8(4)/208.4(5 pm in the bromo compound).

1,3-Dimethyl-2-iminoimidazolin (8, ImNH) reagiert mit Methyllithium in Diethylether zu [ImNLi]n (9). In Tetrahydrofuran werden Kristalle von [Li12O2Cl2(ImN)8(THF)4] · 8 THF (10) erhalten. In 10 liegt ein Li12Cl2N8O2-Kafig in Form gestapelter Leiterfragmente mit O22 als zentraler Einheit vor. Hieran sind uber die Lithium- und Stickstoffatome insgesamt vier Tetrahydrofuran- und acht Imidazolin-Liganden koordiniert. Imidazole Derivatives. XXIV. [Li12O2Cl2(ImN)8(THF)4] · 8 THF: a Peroxo Lithium Fragment in a Novel Cage Structure 1,3-dimethyl-2-iminoimidazoline (8, ImNH) reacts with methyl lithium to give [ImNLi]n (9). In tetrahydrofuran, crystals of C56H96Cl2Li12N24O6 · 8 C4H8O (10) are obtained. The structure of 10 consists of a Li12Cl2N8O2 core in which a peroxo unit is incorporated into a stack of ladder fragments. Over all, four tetrahydrofuran and eight imidazoline ligands are attached at the lithium and nitrogen atoms.

The reactions of N-diethylaminothiocarbonyl-benzamidines Et2N-C(S)-N=C(NHR)-Ph (1: R = Ph, 2: R = C3H7, 3: R = H) with gold(III) compounds were studied. Treatment of 1 and 2 with equivalent amounts of tetrachlorogold acid gives 2,3-substituted 5-diethylamino-1,2,4- thiadiazoliumdichloroaurates(I) (1a, 2a). With tetrachlorogold acid in excess 1 yields 2,3-diphenyl- 5-diethylamino-l,2,4-thiadiazolium-tetrachloroaurate(III) 1b. With 3 and Na[AuCl4] bis(3-phenyl-5- diethylamino-1,2,4-thiadiazolium)-chloride-tetrachloroaurate(III) 3b is produced. The structures of la, 2a and 3b were investigated by X-ray structure analysis. In la and 2a the dichloroaurate(I) ions are linear. In the 1,2,4-thiadiazolium cations the N-C-bond lengths alternate characteristically. In 3b the tetrachloroaurate(III) ion is square planar. The 1,2,4-thiadiazolium cation shows a different alternation of N-C bond lengths in comparison with la and 2a which suggests changes in the thiadiazolium ring in 3b to a tautomeric form as confirmed by the localization of the H atom at the N atom in ring position 4 instead of ring position 2. The structures of 1a, 1b, 2a and 3b were confirmed by elemental analysis, ES-MS, FAB-MS, 1H and 13C NMR and IR spectroscopy.

Hydrolytic pathways of the organometallic aqua ion [Re(CO)3(H2O)3]+ (2) in aqueous media were investigated by means of potentiometric titration experiments. The aqua complex 2 was obtained quantitatively by dissolving (NEt4)2[Re(CO)3Br3] (1) in water. Conventional alkalimetric titrations (0.1 M KNO3, 25 °C) allowed the determination of the formation constants of [Re3(CO)9(μ2-OH)3(μ3-OH)]- (3) and [Re2(CO)6(μ2-OH)3]- (4). The neutral dinuclear [Re2(CO)6(μ2-OH)2(H2O)2] (5) was observed as a minor species. A fast titration technique was used to investigate a rapid preequilibrium, consisting of the formation of the mononuclear deprotonation products [Re(CO)3(OH)(H2O)2] (6) and [Re(CO)3(OH)2(H2O)]- (7). The corresponding pKa values are 7.5(2) and 9.3(3). The immediate extraction of an aqueous solution of 2 with diethyl ether after base addition (1 equiv) led to the quantitative isolation of the well-known cubane cluster [Re(CO)3(OH)]4 (8), which was obtained as a DMF (8b) or OPPh3 adduct (8c). Attempts to isol...

The title complex, [ReNCl(C 24 H 20 NP 2 S 2 )(C 8 H 11 P) 2 ], is formed during the reaction of [ReNCl 2 (Me 2 PhP) 3 ] with a stoichiometric amount of Na(SPh2PNPPh2S) in dichloromethane/methanol. The equatorial sphere of the six-coordinate complex is occupied by two Me2PhP ligands and the tetraphenyldithioimidodiphosphinate anion, which binds in a bidentate manner via the sulfur donors. The chloro ligand is arranged in a position trans with respect to the terminal nitrido N atom, with exceptionally long Re-Cl bond lengths [2.598(4) and 2.632 (5) A for the two crystallographically independent molecules] due to the structural trans influence of 'N 3-' .

[InCl3(L1)(MeOH)] [L1 = pyridine-2,6-bis(acetyloxine), 2,6-C5H3N(C2H3NOH)2] reacts with bidentate ligands by ligand exchange. A seven-coordinate complex of the composition [In(L1)Cl(ox)(OH2)] is formed with potassium oxalate (K2ox). The oxalato ligand occupies the equatorial plane of a pentagonal bipyramid together with the tridentate amine oxime. With sodium 1,2-dicyanoethene-1,2-dithiolate (Na2mnt) the analogous reaction produces a six-coordinate mixed ligand complex, [In(L1)Cl(mnt)], which has a distorted octahedral coordination sphere. Ligands which form four-membered chelate rings like dialkyldithiocarbamates, R2dtc−, or pyridine-2-thiolate, pythio−, are able to replace all ligands of [InCl3(L1)(MeOH)] to form neutral tris chelates. The structure of [In(pythio)3] has been elucidated showing a strong distortion of the coordination polyhedron from the idealized octahedral geometry.

A detailed investigation of the one-pot synthesis of [NEt4]2[MX3(CO)3] [M=Tc (1a) or Re (1b); X= Cl−, Br−] is presented. The intermediates [NEt4][Tc2-(μ-Cl)3(CO)6] (2a), [NBu4][Tc3(μ3-H)(μ-H)3(CO)9] (3) and [Tc3(μ-H)3(CO)12] (4) have been isolated and characterized. The X-ray structure of (2a) is described. Complex (2a) crystallizes in the monoclinic space group P21/c with a=19.491(6), b=18.323(2) and c=17.497(9)AA, and β=97.59(2)°. Quantitative conversion of (2a), (3) and (4) into the aqua-ion [M(OH2)3(CO)3]+ [M=Tc (5a) or Re (5b)] is described. To evaluate an optimal and simple chelating group for the “fac-M(CO)3” moiety, the reaction with the bidentate thioether ligand Cl(CH2)2S(CH2)2S(CH2)2Cl (qyp) has been investigated and the structure of the neutral complex [ReBr(qyp)(CO)3] (6) is described. Complex (6) crystallizes in the monoclinic space group P21/c with a=15.935(6), b=2.788(4) and c= 7.955(10)AA, and β=98.57(1)°. To extend the knowledge about substitution chemistry of organometallic complexes in aqueous solution, the acetato ligand [OOCCH3]− has been reacted with (1b), resulting in the formation of the dinuclear, acetato-bridged complex [NEt4][Re2(μ-OH)2(μ-OAc)(CO)6], which converted into [Re2(μ-OEt)2(μ-OAc)(CO)6]− (7) after recrystallization from EtOH. The X-ray structure of (7) has been determined. Complex (7) crystallizes in the monoclinic space group P21/c with a=16.288(3), b=12.4272(10) and c=13.620(3)AA, and β=76.63(1)°. For a future application of the small “fac-M(CO)3” moiety, it seems thus advantageous to combine these two ligand groups in one simple chelating function.

2,6-Bis(acetyloxime)pyridine, 2,6-C5H3N(C2H3NOH)2 (L1), reacts with indium(III) chloride in methanol to give the seven-coordinate complex [InCl3(L1)(MeOH)]. The structurally similar Schiff base ligand 2,6-bis(1-phenyliminoethyl)pyridine (L2), 2,6-C5H3N(C2H3NC6H5)2, however, forms a six-coordinate indium(III) complex of the composition [InCl3(L2)]. The InN bond distances are longer by 0.03–0.12 A in the seven-coordinate compound compared with those in the Schiff base complex. The MeOH ligand in [InCl3(L1)(MeOH)] can be replaced by Cl− or H2O to give the complex anion [InCl4(L1)]− and [InCl3(L1)(OH2)], respectively. The pentagonal-bipyramidal coordination environment of the metal is preserved during these reactions.

Dichloro-2-(N,N-dimethylaminomethyl)-phenylgold(III), [Au(damp-C,N)Cl2], hergestellt durch Umsetzung von [Hg(damp)Cl] mit Na[AuCl4], kristallisiert monoklin, Raumgruppe P21/c mit a = 7,896(3); b = 9,487(2); c = 15,107(6) A; β = 100,22(3)°, Z = 4. Die Kristallstruktur besteht aus monomeren [Au(damp-CN)Cl2]-Einheiten mit quadratisch-planar koordinierten Goldatomen. Die kleinsten Gold-Gold-Abstande betragen 4,977 A. [Au(damp-C,N)(OOCCH3)2] wird durch Reaktion von [Au(damp-C,N)Cl2] mit AgOOCCH3 in CH2Cl2 hergestellt und aus feuchtem CH2C12 als [Au(damp-C,N)(OOCCH3)2] · 0,5 H2O kristallisiert: monoklin, Raumgruppe C2/c a = 16,626(8); b = 10,640(1); c = 16,271(7) A; β = 91,90(2)°, Z = 8. Das Goldatom ist quadratisch-planar koordiniert. Die Acetatoliganden binden jeweils einzahnig. Das in das Kristallgitter eingebaute Losungsmittel ist durch Wasserstoffbrucken in die Festkorperstruktur eingebunden. Die Chloroliganden von [Au(damp-C,N)Cl2] konnen leicht durch zweifach negativ geladene Chelatliganden ausgetauscht werden. Die Reaktion mit Na2mnt in Aceton er gibt in nahczu quantitativer Ausbeute den Neutralkomplex [Au(damp-C,N)(mnt)], der in der orthorhombischen Raumgruppe Pna21 kristallisiert (a = 7,651(1); b = 14,476(1); c = 13,353(1) A, Z = 4). Das Goldatom befindet sich in einer quadratisch-planaren Koordinationsumgebung. Die Au-S-Abstande betragen 2,363(2) bzw. 2,270(2) A. Gold(III) Complexes with 2-(N,N-dimethylaminomethyl)phenyl (damp−). Syntheses and Structures of [Au(damp-C,N)Cl2], [Au(damp-C,N)(OOCCH3)2] and [Au(damp-C,N)(mnt)] (mnt2− = 1.2-dicyanoethene-1.2-dithiolate) Dichloro-2-(N,N-dimethylaminomethyl)phenylgold(III), [Au(damp-C,N)Cl2], was prepared by the reaction of [Hg(damp)Cl] with Na[AuCl4] and crystallizes monoclinic, space group P21/c a = 7.896(3), b = 9.487(2), c = 15.107(6) A, β = 100.22(3)°, Z = 4. The crystal structure consists of monomeric [Au(damp-C,N)Cl2] units with square-planar coordinated gold atoms. The shortest Au-Au distances are 4.977 A. [Au(damp-C,N)(OOCCH3)2] can be synthesized by the reaction of [Au(damp-C,N)Cl2] and AgOOCCH3 in CH2Cl2. Single crystals of the composition [Au(damp-C,N)(OOCCH3)2]. 0.5 H2O were obtained from moist CH2Cl2: monoclinic, space group C2/c, a = 16.626(8), b = 10.640(1), c = 16.271(7) A, β = 91.90(2)°, Z = 8. The gold atom is square-planar coordinated. The acetato ligands are bound monodentately. The solvent water forms strong hydrogen bridges to the complex molecules in the solid state structure. The chloro ligands in [Au(damp-C,N)Cl2] can easily be replaced by dianionic chelate ligands. The reaction with Na2mnt (mnt2− = 1.2-dicyanoethene-l.2-dithiolate) gives in almost quantitative yield the neutral complex [Au(damp-C,N)(mnt)], which crystallizes orthorhombic, space group Pna21 with a = 7.651(1), b = 14.476(1), c = 13.353(1 ) A, Z = 4. The gold atom is square-planar coordinated. The Au-S distances are 2.363(2) A and 2.270(2) A, respectively.

Technetium(V) and rhenium(V) nitrido complexes of the compositions [MNL 2 ] and [MN(Cl)(PPhMe 2 )L] have been synthesized by reaction of Na[N(SPPh 2 ) 2 ] and [MNCl 2 (PPh 3 ) 2 ] or [MNCl 2 (PPhMe 2 ) 3 ] complexes, respectively [M = Re or Tc; L = N(SPPh 2 ) 2 - ]. The amide anion acts in all isolated complexes as a chelating ligand co-ordinated via the sulfur atoms. The complexes [TcN{N(SPPh 2 ) 2 } 2 ], [ReN{N(SPPh 2 ) 2 } 2 ] and [TcN(Cl)(PPhMe 2 ) 2 {N(SPPh 2 ) 2 }] have been studied by X-ray crystallography. The bis-chelates are five-co-ordinate with the nitrogen atoms at the apexes of square pyramids. The Tc atom in [TcN(Cl)(PPhMe 2 ) 2 {N(SPPh 2 ) 2 }] has a distorted-octahedral co-ordination sphere with Cl bonded trans to the nitrido function. The complex [ReN{N(SPPh 2 ) 2 } 2 ] is the first five-co-cordinate nitride which reacts with BCl 3 to form a nitrido bridge between rhenium and boron; [Re(NBCl 3 ){N(SPPh 2 ) 2 } 2 ] is characterized by a covalent N–B bond of 1.539(5) A. The Re–N multiple bond distance is only slightly influenced by addition of the Lewis acid. The complex [ReN(Cl)(PPhMe 2 ) 2 {N(SPPh 2 ) 2 }] reacts with BCl 3 with substitution of N(SPPh 2 ) 2 - and formation of the well known [Re(NBCl 3 )Cl 2 (PPhMe 2 ) 3 ]. The corresponding technetium complexes do not form Tc–N–B bridges upon reactions with BCl 3 . The [MN(Cl)(PPhMe 2 ) 2 {N(SPPh 2 ) 2 }] (M = Tc or Re) complexes reacted with S 2 Cl 2 to give thionitrosyl compounds with the metals in lower oxidation states; [Re(NS)Cl 2 (PPhMe 2 ) 3 ] and [Re(NS)Cl 3 (PPhMe 2 ) 2 ] have been characterized spectroscopically, [Tc(NS)Cl 3 (PPhMe 2 ) 2 ] was studied by X-ray diffraction and EPR spectroscopy. The phosphine ligands are trans to each other.

cis-[Re2O3Cl4(py)4] reagiert mit N-Trimethylsilylanilin zu [Re(NPh)(OSiMe3)Cl(NH2Ph)(py)2][ReO4]. Es kristallisiert triklin in der Raumgruppe P1, mit a = 1085,0(6); b = 1185,2(6); c = 1331,4(6)pm; α = 65,91(5); β = 76,98(4); γ = 87,01(4)°, Z = 2. Im einkernigen Komplexkation ist Rev verzerrt oktaedrisch koordiniert; die beiden Pyridinliganden haben cis-Anordnung. Die Trimethylsilyloxogruppe befindet sich in trans-Stellung zum Phenylnitrenliganden. Letzterer weist eine lineare Bindungsfunktion ReNPh mit einem Bindungswinkel Re2N1C10 = 176,6(8)° und einem Abstand Re2N1 = 170,6(9) pm auf. Beim Edukt cis-[Re2O3Cl4(py)4] wurde eine Isomerisierung zur trans-Form beobachtet. Sie kristallisiert in der monoklinen Raumgruppe P21/n mit a = 895,5(3); b = 2278,4(2); c = 1259,2(3) pm; β = 102,23(1)°, Z = 4. Im Zweikernkomplex mit einem linearen O1Re1O2Re2O3-Gerust und den Strukturparametern: Re1O1 = 168,5(5); Re2O3 = 168,9(5); Re1O2 = 193,1(4); Re2O2 = 192,4(4) pm und Re1O2Re2 = 178,8(2)° sind die Rev-Atome oktaedrisch koordiniert. Die beiden Chloratome und die Pyridinliganden nehmen jeweils eine trans-Anordnung ein. Die IR- und Massenspektren der Verbindungen werden diskutiert. Synthesis of Phenylnitrene Complexes with N-Trimethylsilylaniline. III. Characterization and X-Ray Crystal Structure of [Re(NPh)(OSiMe3)Cl(NH2Ph)(py)2][ReO4] and trans-[Re2O3Cl4(py)4] The reaction of cis-[Re2O3Cl4(py)4] with N-trimethylsilylaniline yields [Re(NPh)(OSiMe3)Cl(NH2Ph)(py)2][ReO4]. It crystallizes in the triclinic space group P1 with a = 1085.0(6); b = 1185.2(6); c = 1331.4(6) pm; α = 65.91(5); β = 76.98(4); γ = 87.01(4)°, Z = 2. In the mononuclear complex cation Rev exhibits an octahedral coordination with the two pyridine molecules in cis arrangement and the trimethylsilyloxo group in trans position to the phenylnitrene ligand. The phenylnitrene ligand forms a Re≡N multiple bond and an almost linear ReNPh arrangement with Re2N1 = 170.6(9) pm and Re2N1C10 = 176.6(8)°. An isomerization of the educt cis-[Re2O3Cl4(py)4] to the corresponding trans form was observed. The trans isomer crystallizes in the monoclinic space group P21/n with a = 895.5(3); b = 2278.4(2); c = 1259.2(3) pm; β = 102.23(1)°, Z = 4. In the binuclear complex with a linear O1Re1O2Re2O3 backbone and the structural parameters: Re1O1 = 168.5(5); Re2O3 = 168.9(5); Re1O2 = 193.1(4); Re2O2 = 192.4(4) pm and Re1O2Re2 = 178.8(2)° the Rev atoms are octahedrally coordinated. The pyridine molecules and the Cl ligands of each Re atom are in trans arrangement. The i. r. and mass spectra of both products are discussed.

Nitrido bridges between technetium and boron were formed during reactions of [TcN(PMe2Ph)(Et2dtc)2] (Et2dtc− = diethyldithiocarbamate) and BH3 or BPhCl2 at low temperatures. X-Ray structure determinations show that the products contain almost linear Tc–N–B bonds with Tc–N distances which are only slightly lengthened with respect to the triple bonds in the precursor molecule. However, a significant lengthening of the Tc–S bond trans to the nitrido ligand is detected by the decrease of the structural trans influence of “N3−”N. The compounds are instable and decompose at room temperature under cleavage of the N–B bonds. A reaction between [TcNCl2(PPh3)2] and BCl3 does not yield a product with a nitrido bridge. Prolonged heating in dichloromethane results in decomposition of the technetium complex and the formation of (HPPh3)2[TcCl6]. Hydrogen bonds are established between the complex anion and each two counter ions.

Air-stable, orange-red single crystals of [{ReN(PMe2Ph)3}{ReO3N}]2 are formed when mer-[ReNCl2(PMe2Ph)3] reacts with strong bases in MeOH. The resulting centrosymmetric tetranuclear complex contains each two {ReN(PMe2Ph)3}2+ and {ReO3N}2− building blocks. They are connected by two oxygen and two nitrogen atoms giving an almost planar {Re4O2N2} ring. The Re–N–Re bridges are only slightly bent (175.2(2)°), while the Re–O–Re angles are 160.9(1)°. The coordination environment of the rhenium atom in the nitridotrioxorhenate(VII) anion is a slightly distorted tetrahedron with O–Re–O and O–Re–N angles between 108.7(1)° and 111.3(1)°.

Reactions of [TcNCl2(PPhR2)3] complexes (R = Me, Et) with 1,3-diethyl-4,5-dimethylimidazol-2-ylidene yield air-stable nitridotechnetium(V) complexes with N-heterocyclic carbenes with up to four of these bulky ligands and, depending on the reaction conditions applied, 1,1,3,3-tetramethyldisiloxane-1,3-diolato coligands which were abstracted from silicon-based grease.

[NEt4] 2 [Tc(CO) 3 Cl 3 ] reacts with thiosemicarbazones derived from 2,2'-dipyridyl ketone (HL 3 ) and 4-acetylpyridine (HL 4 ) to form stable technetium(I) complexes of the compositions [Tc(CO) 3 Cl-(HL 3 -N p y ,N p y )] and [Tc 2 (CO) 6 Cl 2 (μ-HL 4 -N p y ,S)]. Whereas exclusively the pyridine nitrogen atoms are involved in coordination in the monomeric complex, the binuclear compound represents the first technetium complex with a coordinated thiosemicarbazone functionality.

[Tc(NO)(NH3)4F]4[TcF6] [HF2]2 is obtained in almost quantitative yield by reaction of K2[TcF6] with acetohydroxamic acid (Ac-NH-OH) in aqueous HF solution.