Rhenium, tris structure

Rhenium, tris(dithiodibenzoyl)-structure, 1, 63 Rhenium bromide Re3Br9... 

Several research groups have studied the chemistry of tris(pyrazolyl)borate tricarbonyl complexes of technetium and rhenium. As depicted in Scheme 28, these studies allowed the synthesis of/ac-[M(CO)3Tp ] [M is Tc, Re, Tp is Tp (111/113), Tp (112/114)] complexes, which were all structurally characterized. Complexes 111-114 were synthesized by reaction of the classical starting materials [M(CO)5Br] with the sodium or potassium salts of the correspondent Tp ligands [121-123]. 

Technetium oxide tetrafluoride like the pentafluoride is formed as a by-product of TcFf, in the lluorination of technetium metal [59,78,79]. TCOF4 forms two phases that may be separated from TcFs and from one another by vacuum sublimation. One phase of TcOF forms blue needles, has a chain structure, and is isostructural with its rhenium analogue. The other modification is a more volatile green compound of tri-meric structure [78,79]. 

The methylation of Re[S2C2Ph2]3" gives a purple monomethyl derivative (20), Re[(CH3)(S2C2Ph2)3], which possesses all properties of a dithiolate. The existence of 19 confirms the ground state description of the neutral group VI metal trisdithienes (12, 13, 14) and shows that the complexes are electron deficient and two electrons short of the tris-dithiolato structure (15). With these conclusions and the results of the methylation experiment, we formulate the neutral trisdithiene of rhenium as a resonance-hybrid of the three limiting structures, 21, 22, 23 ... 

The reactions of rhenium(V) oxo-alkyl-phosphine complexes with various alkynes were studied and the X-ray crystal structure of [Re(=0)Mc3(PhC>CPh)] was reported OO. The synthesis of a number of ibenium(I) tris-alkyne complexes was reported and [Re(OSiMe3)(MeCjCMe)3] characterised by X-ray diffraction Oi. The synthesis of a series of bis-imido alkyne and imido bis-alkyne rhenium complexes of the type [Re(NAr)2Cl(RCSCR)] and [ReCl(NAr)(NpGCNp)2] has been reported302 and the electrtxiic structures of the compounds investigated by Extended Huckel molecular mbital calculations. 

This new heteroscorpionate is a potential building block for copolymers with methylmethacrylate and ethylene glycol dimethacrylate able to mimic the 2-His-l-carboxylate facial triad and capable to produce copolymer-bound manganese and rhenium tricarbonyl complexes.M(CO)3 derivatives (M = Mn or Re) containing two tris(oxazolinyl)phenylborate Hgands (Scheme 25) demonstrated to produce significant structural protection... 

Even G12-Tc-bonded complexes have been prepared. The tris(arylimido)technitium anion (90) reacted readily with 0.5 or 1 equiv. of HgBr2 to afford [Hg Tc(NAr)3 2] (91) or [BrHgTc(NAr)3] (Ar = 2,6-diisopropylphenyl) (92), respectively (Scheme 12.29) [70]. The crystal structure of Hg[Tc(NAr)3]2 shows a linear geometry around the mercury atom and the bond length of Tc-Hg is 2.615(1) A. Also the rhenium analog [Hg Re(NAr)3 2] (93) was obtained through reduction of tris(arylimido)rhenium chloride with sodium amalgam (Scheme 12.29) [70]. 

The structure of a rhenium(V) complex with l,3,5-trideoxy-l,3,5-tris (2-hydroxybenzylamino)-c /i -inositol has been described, and the metal ion sequestering abilities of borate esters of 2-amino-2-deoxy-D-gluconate and 2-amino-2-deoxy-D-galactonate have been studied. The largest effects were measured upon adding Cd(ll) or Ni(II) to the borate - 2-amino-2-deoxy-D-gluconate system. A ribonucleoside technetium chelate prepared from 2, 3 -diamino-2, 3 -dideoxyadenosine is mentioned in Chapter 20. 

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