Se-donor Ligands

Se-Donor ligands. As part of the investigation of the complexing behaviour of the ligand (PhO)2P(S)Se, the red-brown complex [PdL2] has been isolated. 

-visible spectral studies indicate that the ligand generally forms a chelate structure (35) with four-membered rings, and that the crystal field of Se is weaker than S. However, nephelauxetic parameters indicate that replacement of S by Se leads to a slight increase in the covalent character of the M-chalcogen bond. Another interesting paper describes the synthesis of the first selenocar-bamato complexes  

Molecular weight and i.r. measurements suggest that the selenocarbamato ligand is unidentate in the solid state, but that in solution partial dissociation of PPh3 occurs, causing the ligand to become bidentate as in (59a M = Pd). 

Complexes of the ligands EtOCSe (sexant) have also been reported, including [Pd(sexant)2]. U.v.-visible spectral studies confirm the value of ca. 2.5 for Se-containing ligands, and place (sexant) in the following spectro-chemical series, (sexant) (dsc) (dtc) for Pd . 

The thiazolidine-2-thione (ttz) (48) pentacarbonyl complex of chromium, [Cr(CO)s(ttz)], has been prepared by u.v. irradiation of a solution of [CdCO) ] and ttz. Spectroscopic studies indicate that the ligand is co-ordinated via the S atom of the thioketone group. The methylthio-bridgcd complexes [M(SMe)Cr(CO)5] [M = ( r-Cp)(CO)2Fe, (7i-Cp)(CO)3Mo, ( r-Cp)(CO)3W, or Ph3PAu] have been prepared by the reaction of MeSM with [CrfCOij], or MCI with [Mc3Sn(SMe)Cr(CO)5], and characterized by their i.r. and H n.m.r. spectra.  

Distefano, A. Foffani, G. Innorta, and S. Pignataro, Internal. J. Mass Spectrometry I on Phys., 

DeFilippo, F. Devillanova, C. Preti, E. F. Tragu, and P. Vigllno, Inorg. Chim. Acta, 1972,6, 

and Sh-donor Ligands. [Cr(CO) (bipy)] has been reduced by sodium in THF. Electronic and e.s.r. spectra of the resulting complex suggest that it involves co-ordination of the uni-negative ion of bipy. The complex loses CO to afford either a five-co-ordinate complex or a dimeric species.  

The pyridine-2-carboxyaldehyde imines (49) react with [Cr(CO)6] under u.v. irradiation to afford the intensely coloured complexes (50). Reaction of the 

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Gold(I) complexes with P,S (or Se) donor ligands are in many cases derived of phosphine sulfides or selenides as [Au2(PPh2CH2PPh2Se)2](C104)2,3140 and [Au(PPh2CH2PPh2Se)2]+ (595),1403,3141 [Au2(PPh3)2(p-SPPh2Py)](BF4)2,1427 or phosphine thioethers such as... 

S and Se-Donor Ligands. The potentially terdentate ligand thiodiethanol, S(CH2CH20H)2, forms navy-blue [Cr S(CH2CH20H)2 Cl2] on refluxing... 

S- and Se-donor ligands. The e.s.r. and electronic spectra of [Co(sacsac)2] and [Co(sacsac)2L] (sacsac = dithioacetylacetonate, L = py or piperidine) have been studied, and a polarographic study of [Co(sacsac)J (n = 2 or 3) in acetone has shown the complexes to have a well-defined capacity to accept one or two electrons in a reversible stepwise manner. The magnitude of the potentials and their reversible nature suggest that isolation of cobalt-sacsac complexes of low formal oxidation states should be possible." Co complexes of l,5-bis-(2-methylmercaptoethylthio)pentane are both hydrated and polymeric, and thermal decomposition in air or nitrogen leads to oxida tion to Co . Ethylenethiourea (etu) and tetramethylthiourea (tmtu) form the complexes [Co(etu) ](N03)2 and [Co(tmtu) ](C10 )2, which are tetrahedral, and [Co(etu)2(N03)2] and [Co(tmtu)2(N03)2] which have distorted octahedral co-ordination. 3-Diphenylphosphinothioyl-l-phenylthiourea, -1,1-diethyl-thiourea, and -1,1-dimethylthiourea form complexes with Co in which the ligands are bidentate. ... 

The data on complexes of N,Se-donor ligand systems are practically absent in the most extensive issue on coordination chemistry [1], That can be explained by the... 

As observed previously for soft donor ligands such as thioethers and phosphines, mercury(n) reacts with selenoethers and telluroethers to form complexes of the general type HgLX2, where X is a halide or pseudohahde. In addition, mercury(II) forms complexes with various Se-donor ligands such as diethylselenocarbamate and selenourea. 

Arsenic(III) has a considerable affinity for charged O- or S-donor ligands, the latter including dithioacid chelates, but complexes with neutral O, S, or Se donor ligands are much rarer. Here complexes of neutral ligands are discussed first and then complexes with charged anions. 

S- and Se-Donor Ligands. The majority of the reported work once more relates to dithiocarbamate and related ligands, and some novel selenium work has appeared. 

S- and Se-Donor Ligands. Magnetic data (down to liquid helium temperatures) confirm the dinuclear structure of [Cu(dtc)X]2, e.g. (143). The stoicheiometry of the... 

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