Manganese, Technetium and Rhenium

The IR spectra of matrix-isolated reaction products of Mn atoms and H2O include vMnH and vMnO bands for a range of species, e.g. 1663.4 cm (vMnH), 648.6 cm- (vMn-OH) for HMnOH 1644.4 cm (vMnH) 875.1 cm (VasMnOMn) for HMnOMnH.  

Laser-ablated Mn atoms and CO/NO mixtures give products trapped in low-temperature matrices and characterised by IR spectroscopy. Among the species identified were Mn(CO)(NO)3 (VasMnN 542.5 cm ) and OMn(NCO) 

FTIR matrix-isolation spectra were reported for isolated MnOF and MnOF2 species. Raman bands were assigned to MnO modes, associated with Mn02 planes, from spectra of double-layered manganites.  

The FTIR spectrum of gaseous MnF2 has a vMnF band at 699.5 cm For MnFs the data are consistent with C2v symmetry (non-equivalent bonds stretches 758.5, 711.2 cm , bend 181.9 cm ). MnF4 has V3 at 794.5 cm and V4 at 176.6/172.9 cm (Td symmetryV  

The Raman spectrum of TcOFs has been assigned with the aid of a normal coordinate analysis. The results are summarised in Table 4  

Decacarbonylmanganese has been cited as a precuisor for the synthesis and XPS characterization of dimanganese carbonyl phosphites 

Tedinetiam cartxmyl chemistry is, once i in, lejnesented in this iepc t with the publication of a simple method for the preparation of Tc(CO)3 complexes and a detailed study of Tc(CX))n bonded to C5Me5 ring  

Specific catalytic chemistry of the Group VII carbonyls has also been reported 61,62,63,64 

The chemistry of Fe, Ru and Os carbonyls is dominated by low nuclearity carbonyl clusters, although a small number of reports concentrate on mono- and dinuclear complexes. The evidence for the radical anion [Fe(CO) has been reviewed using ligand effect constants and it would appear that the molecule observed in low temperature matrices is actually [Fe(CO)3]. The syntheses of the sodium carbonyl ferrates (viz. Na2(Fe(CD) Na2(Fc2(CX))g), and Na2(Fe3(CX))jj)) are also discussed. The equilibrium between Ru3(CX)) I 2 Ku(CO)5 + CO has been investigated by Bor Interestingly die rate at which equilibrium is attained doubles when hydrogen is present in small quantities. 

A series of papers dealing with derivatives of Os3(CO)j 2 published 72,73,74 high-performance liquid-chromatography of substituted trinuclear 

Relatively simple Mn carbonyl complexes are still open for investigation as can be seen with Huang and co-workers study of the reactivity of Mn(CO)5Br on the surface of zeolites by FTIR and IR spectroscopy. In the same vein Marynick and Derecskei-Kovacs have taken a new look at an old reaction. They have investigated the potential energy surface for the thermal carbonyla-tion of Mn(CO)5CH3 and the role of competitive intermediates on the reaction surface. They also comment on the photodecarbonylation of Mn(CO)5(COCH3). 

In recent years, this section of this report has been dominated by the photochemical and photophysical properties of Re(CO)3(diimine)X complexes. Although the main deluge of research is over, there are still examples to be found. The photochemical/physical properties of monomer and polymer species with ReI(CO)3(phen) chromophores has been investigated by Wolcan and Ferraudi, and proton-controlled photoisomerisation of rhenium(I) tricarbonyl bipyridine linked to amine or azacrown ether groups by a styryl pyridine bridging ligand has been discovered by Perutz et alP 

The metal carbonyl nitrosyls never make much of an appearance in this report, so it was of some interest to see that Belkova and co-workers have made a detailed study of the structural and energetic aspects of hydrogen bonding and proton transfer to ReH2(CO)(NO)(PR3)2 and ReHCl(CO)(NO)(PMej)2 by combining IR and X-ray information. 

The complex [ (trans -cyclam)Mn (N) 2(fi-N3)], where cyclam= 1,4,8,11-tetra-azacyclo-tetradecane, has vMn = N at 1031 cm. An IR band in the range 640-668 cm was assigned as vMn-NO in Mn(N0)(CN)2(L)2(H20), where L = 2- or 3-pyrazoline-5-ones. IR spectra were reported for a range of Schiff base complexes of Mn(III). These showed bands with considerable vMnN characteristics near 369 cm, with vMnO near 329 cm and vMnCl near 303 cm.  

The complexes [Tc02(PR3)3], where R = Et or Pr, show vTcO at about 850 The anion Tc02F4 has a Raman spectrum which can be assigned under C2v symmetry. Some of the assignments are listed in Table 

The IR spectra of ReO(L), where L is an A 2 A, S-peptidic chelating ligand, contain vRe=0 at 986 cm h vReO modes were seen near 940 cm for oxorhenium(V) complexes with Z)-penicillamine methyl ester. Rhenium ditho-carbamate complexes such as [Re0(S2CNEt2)2]2(06H402-l,4) have vRe=0 at 960 cm h ReOCl3(HL), where HE is a Schiff base derived from 2,6-diformyl-4-methylphenol and C6H5NH2, shows vRe=0 at 1000 cm and vReCl at 320 cm h  

The matrix-isolation technique has been qiplied to die idiofolysh of CpMn(CO)3 in a mixture of Ar/02- Not surprisingj, after UV (diolx sis die com dcx loses its CO groups and the eventual product is CpMn02 with the Mn in a formal oxidation state of +S. 

Rheniiim caibonyls are, like previous years, well-represented in this report. Using simple caib( i as a starting point a number of complexes have been prepared containing 0X0-and ace ide ligmids.  

Rhenium cluster complexes are in short suppfy, but are not foigotten. The polyhydtide complex [NEt4][Re 7(CO) g] has been prepared by Yang and Cheng.  

These metals form chalcogenolate complexes in several oxidation states, and from the application-oriented point of view manganese compounds have been synthesized as models for hydrodesulfurization processes and rhenium and technetium derivatives as models for radiopharmaceuticals. 

Technetium and rhenium coordination chemistry has actively developed in order to design materials as potential radiopharmaceuticals diagnostic imaging agents for technetium and potential therapeutic reagents based on rhenium. Continuous efforts are still applied to find efficient chelating systems for the [MO]3+ cores (M=Tc, Re). Thus several complexes with monodentate and 

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E° for some manganese, technetium and rhenium couples in acid solution at 25°C... 

Table 24.3 Oxidation states and stereochemistries of manganese, technetium and rhenium...

Manganese, Technetium and Rhenium Table 24.6 Oxohalides of Group 7... 

Pirs and Magee have used the resin Amberlite IRA-400 in the chloride form to separate manganese, technetium, and rhenium. Manganese is easily separated by... 

Kemmitt, R. D. W., Peacock, R. D. The chemistry of manganese, technetium and rhenium. Oxford, New York Pergamon Press (1973)... 

Electrochemistry of the Group 7 Elements Manganese, Technetium, and Rhenium... 

I 76 Electrochemistry of the Croup 7 Elements Manganese, Technetium, and Rhenium Tab. 3 Electrochemical data for manganese porphyrins in aqueous media ... 

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