Rainer Hübener

Isothiocyanato complexes of rhenium II. Synthesis, characterization and structures of ReN(NCS)2(Me2PhP)3 and Re(NS)(NCS)2(Me2PhP)3

Abstract Novel rhenium isothiocyanato complexes have been prepared by ligand exchange procedures starting from [ReNCl 2 (Me 2 PhP) 3 ] and KSCN or trimethylsilylisothiocyanate, Me 3 SiNCS. The reaction with KSCN yields the rhenium(V) nitrido complex [ReN(NCS) 2 (Me 2 PhP) 3 ], whereas with Me 3 SiNCS the rhenium(I) thionitrosyl compound [Re(NS)(NCS) 2 (Me 2 PhP) 3 ] is formed. Both complexes are air-stable. They have been characterized spectroscopically and studied by X-ray diffraction. [ReN(NCS) 2 (Me 2 PhP) 3 ] crystallizes in the triclinic space group P 1 ( a =9.986(9), b =12.49(1), c =13.21(1) A, α=95.23(5), β=101.61(5), γ=110.80(4)°) with Z =2. The final R value is 0.049. The coordination sphere of the rhenium atom is a distorted octahedron, with an ReN bond length of 1.66(1) A. [Re(NS)(NCS) 2 (Me 2 PhP) 3 ] crystallizes in the monoclinic space group P 2 1 ( a =11.442(4), b =11.005(1), c =12.770(4) A, β=91.96(2)°) with Z =2. The final R value is 0.041. The coordination geometry about the rhenium atom is a distorted octahedron. The ReNS bond distance is 1.85(3) A.

A simple single-step synthesis of [99Tc3H3(CO)12] from [99TcO4]– and its X-ray crystal structure. Application to the production of no-carrier added [188Re3H3(CO)12]

Reduction of no-carrier added [188ReO4]–(ng range) in thf–[NBu4]Cl with BH3·thf under an atmosphere of CO yields [188ReCl3(CO)3]2– and [188Re3(µ-H)3(CO)12]; under similar conditions as with [188ReO4]–, the first µ-hydrido-bridged 99Tc hydrido carbonyl complex is prepared and structurally characterised.

Synthesis, characterization and X-ray crystal structure of cis-tetrakis-(isothiocyanato)(triphenylphosphine)-(triphenylphosphine oxide)rhenium(IV), [Re(NCS)4(Ph3P)(Ph3PO)]

Abstract cis-Tetrakis(isothiocyanato)(triphenylphosphine)(triphenylphosphine oxide)rhenium(IV), [Re(NCS)4(Ph3P)(Ph3PO)], is formed during the reaction of [ReOCl3(Ph3P)2] and tri- methylsilylisothiocyanate, Me3SiNCS. The compound crystallizes monoclinic in the space group P21/n, a=9.981(3), b = 37.447(6), c = 11.761(4) A, β = 111.21(1)° and Z = 4. Structure refinement converged at R = 0.037. Ph3P and Ph3PO are cis-coordinated with ReP and ReO distances of 2.511(3) and 2.018(7) A, respectively. The NCS ligands are coordinated via nitrogen.

[Cl3Ga–NReCl2(PMe2Ph)3] and [Cl3Ga–NReCl(PMe2Ph)3(NCMe)][GaCl4]: the first complexes with nitrido bridges between main group and transition metals

Almost linear nitrogen bridges between rhenium and gallium are formed during the reaction of rhenium(V) complexes containing terminal ‘N3–’ ligands with gallium trichloride.

Reactions of carbonylchlorogold(I) with thiolates and thiols. Crystal and molecular structures of [NaL(H2O)][(AuCl)3SBut], [NaL][AuCl2], [NaL]4[AuCl2]2[Au4Cl6S2] and [NaL]2[Au4Cl6S2](L = 1,4,7,10,13-pentaoxacyclopentadecane)

By the reaction of [AuCl(CO)] with the thios RSH (R = But, C6H3Me2-2,6 or C6F5) amorphous gold(I) thiolates Au(SR) were obtained. With 2,6-dimethylbenzenethiolate under CO at atomospheric pressure in CH2Cl2 as solvent, gold metal and RSSR were formed, while with H2S amorphous Au2S was the product. The reaction of [AuCl(CO)] with [Na(15-crown-5)][SBut] in 1:1 ratio yielded [Na(15-crown-5)(H2O)][(AuCl)3SBut]1 and [Na(15-crown-5)][AuCl2]2(15-crown-5 = 1,4,7,10,13-pentaoxacyclopentadecane). The crystal structure of 1 revealed that the anionic part contains three AuCl groups co-ordinated to the ButS– ligand forming a tetrahedral arrangement around the sulfur. The [AuCl2]– anions in 2 are co-ordinated through the chlorine atoms to two [Na(15-crown-5)]+ cations; thus, the sodium cation has a distorted pentagonal-pyramidal co-ordination to five oxygen atoms of the crown ether with the axial position occupied by the chlorine atoms of the AuCl2– anion. The reaction of [AuCl(CO)] with [Na(15-crown-5)][SBut] in 3:1 molar ratio afforded the mixed-valence AuI–AuIII complexes [Na(15-crown-5)]4[AuCl2]2[Au4Cl6S2]3 and [Na(15-crown-5)]2[Au4Cl6S2]4. There crystal structures revelaed that in the [Au4Cl6S2]2–-anion two AuCl2 units are connected by the sulfur atoms of two SAuCl groups forming a centrosymmetric planar Cl2Au(µ-S)2AuCl2skeleton. The structure of 3 also contains linear [AuCl2]– anions.

Isothiocyanato complexes of rhenium III. Synthesis and characterization of [ReN(NCS)2(Ph3P)2] and [ReN(NCS)2(CH3CN)(Ph3P)2]. X-ray crystal structure of [ReN(NCS)2(CH3CN)(Ph3P)2]·CH3CN

Abstract Novel rhenium isothiocyanato complexes have been prepared by ligand exchange procedures starting from [ReNCl 2 (Ph 3 P) 2 ] and KSCN. The reaction with KSCN yields the rhenium(V) nitrido complex [ReN(NCS) 2 (Ph 3 P) 2 ]. [ReN(NCS) 2 (CH 3 CN)(Ph 3 P) 2 ]· CH 3 CN has been prepared by the reaction of [ReN(NCS) 2 (Ph 3 P) 2 ] with CH 3 CN. Both complexes are air-stable. They have been characterized spectroscopically. The crystal and molecular structure of [ReN(NCS) 2 (CH 3 CN)(Ph 3 P) 2 ]·CH 3 CN has been determined by single-crystal X-ray diffraction. [ReN(NCS) 2 (CH 3 CN)(Ph 3 P) 2 ]·CH 3 CN crystallizes in the monoclinic space group P 2 1 / n ( a =9.242(3), b =18.506(3), c =21.773(6) A, β=93.84(2)° with Z =4. The final R value is 0.042. The compound consists of discrete [ReN(NCS) 2 (CH 3 CN)(Ph 3 P) 2 ] molecules with an additional CH 3 CN solvent molecule per complex in the crystal lattice. The coordination sphere of the rhenium atom is a distorted octahedron, with a ReN bond length of 1.66(1) A. The strong trans influence of the nitrido group is evident in the exceptionally long ReN bond distance (2.42(1) A) to the CH 3 CN ligand.

The reaction of TcCl3(Me2PhP)3 with dithio ligands. Synthesis, characterization and X-ray crystal structures of [TcCl2(Me2PhP)2(Me2dtp)] and [Tc(Me2PhP)(Etxan)3] (Me2PhP=dimethylphenylphosphine, Me2dtp−=O,O′-dimethyldithiophosphate, Etxan−=ethylxanthate)

Abstract Trichlorotris(dimethylphenylphosphine)technetium(III), [TcCl3(Me2PhP)3], reacts with dithio ligands to form chelate complexes of different compositions and coordination geometries. The reaction with ethylxanthate (Etxan-) yields the diamagnetic seven-coordinate [Tc(Me2PhP)(Etxan)3], which crystallizes monoclinic in the space group P21/c with Z=4 (a=18.44(5), b=9.2(1), c=15.36(6) A, β=104.3(2)°). The final R value is 0.029. The metal has a pentagonal-bipyramidal environment. With ammonium dimethyldithiophosphate, (NH4)Me2dtp, [TcCl3(Me2PhP)3] forms the paramagnetic [TcCl2(Me2PhP)2(Me2dtp)] in which the technetium atom has a distorted octahedral coordination sphere. The compound crystallizes orthorhombic, space group Pbcn, with Z=4 (a=16.207(1), b=10.445(1), c=14.878(1)). The final R value is 0.031. The chloro ligands are in trans arrangement.

Synthesis, characterization and reactions of [Tc(NS)X4]− complexes (XCl, Br, NCS)

The anions [Tc(NS)X 4 ] − (XCl, Br or NCS) can be prepared from the reaction of TcCl 6 2− and TcBr 6 2− , respectively, with trithiazyl chloride, (NSCI) 3 . The equatorial ligands are kinetically labile and the complexes undergo ligand exchange reactions to form [Tc(NS)Cl n Br 4− n ] − mixed-ligand complexes ( n =1−3) or the isothiocyanate analogue [Tc(NS)(NCS) 4 ] − . The new compounds have been studied by EPR and the obtained parameters have been used to describe bonding properties. [Tc(NS)Cl 4 ] − and [Tc(NS)Br 4 ] − are instable in solution. Spontaneous decomposition results in nitridotechnetium(VI) complexes. The products have been characterized by EPR and X-ray diffraction.

Isothiocyanato complexes of rhenium VI. Synthesis, characterization and structures of cis-and trans-[ReCl2(NCS) (Me2PhP)3]☆

Abstract The reaction of [ReCl 3 (Me 2 PhP) 3 ] with excess KSCN or trimethylsilylisothiocyanate leads to the replacement of only one chloro ligand. Initially, mer,trans -[ReCl 2 (NCS) (Me 2 PhP) 3 ] is formed. The compound crystallizes in the monoclinic space group P 2 1 / n with unit cell of dimensions a = 14.992(2), b = 10.846(1), c = 19.117(6) A , β = 112.89(2)°, Z = 4 . The chloro ligands are coordinated in trans position to each other. An ReN bond length of 2.071(4) A was found for the nitrogen bound NCS − ligand. Mer,trans -[ReCl 2 (NCS) (Me 2 PhP) 3 ] isomerizes to mer,cis -[ReCl 2 (NCS) (Me 2 PhP) 3 ] at longer reaction periods. The cis complex crystallizes in the monoclinic space group P 2 1 / n , Z = 4. A unit cell of dimensions a=14.824(7), b = 13.158(2), c = 16.212(7) A , β = 112.92(2)° was determined for this compound. The rhenium atom is six-coordinate with cis -positioned chloro ligands. The ReN bond distance is shortened by 0.038 A with respect to mer,trans -[ReCl 2 (NCS) (Me 2 PhP) 3 ]. The coordination geometry of the two isomers of mer -[ReCl 2 (NCS) (Me 2 PhP) 3 ] can be derived from FAB-MS studies. Fragmentation occurs by the loss of complete ligands. It takes place in a strong dependence on the structural trans influences of the coordinated ligands. The relative intensities of the main fragments clearly indicate the geometry of the coordination sphere.