Sulfoxides coordination compounds

Acid-base strength in MejSO The chemistry of MejSO (general) Coordination compounds of sulfoxides The chemistry of MejSO (inorganic)... 

It has recently been shown that alkyl sulfoxides are good solvents for transition metal halides, and many adducts can be isolated 42, 84, 167, 227, 231). Nickel perchlorate takes up six dimethyl sulfoxide ligands, but the chloride apparently only three. It has been shown from the reflectance spectrum and from the high magnetic moment 42) that this compound should be formulated as [Ni(DMSO)6][NiCl4], in which the anion is tetrahedral. Infrared spectra 43, 127) show that the dimethyl sulfoxide coordination is through oxygen. Similar compounds are found with tetrahydro-thiophenoxide 84) ... 

Many common reactions of aliphatic amines, ethers and sulfides (1) involve initial attack by an electrophilic reagent at a lone pair of electrons on the heteroatom salts, quaternary salts, coordination compounds, amine oxides, sulfoxides and sulfones are formed in this way. Corresponding reactions are very rare (c/. Section 3.3.1.3) with pyrroles, furans and thiophenes. These heterocycles react with electrophilic reagents at the carbon atoms (2-3) rather than at the heteroatom. Vinyl ethers and amines (4) show intermediate behavior reacting frequently at the (3-carbon but sometimes at the heteroatom. 

On the basis of 535 have been synthesized, and studied in detail, coordination compounds with practically all metals [931-933]. Two groups of complex compounds with O-coordinated (535) and S-coordinated (536) ligands were isolated. A detailed summary of complexes containing sulfoxides in different coordination modes, and the results of their x-ray diffraction studies including the evaluation of structural parameters for M — O and M — S bonds, have been reviewed [933]. It is emphasized [112] that the O-coordination 535 is formed with hard and intermediate metals, while the S-coordination 536 is a characteristic feature for soft Pearson acids (see Sec. 1.2.2). For complexes obtained on the basis of organoseleno-oxides 535 (E = Se) and organotelluro-oxides 535 (E = Te), the hard-hard or soft-soft interactions could also be expected [112]. However, direct proofs of such coordination modes for complexes of type 534 (E = Se, Te), described elsewhere [112], are absent in the available literature. 

The HSAB principle very clearly explains the competitive reactions of organo-sulfoxides, amongst which DMSO is the most commonly used as ligand [1,2,19]. The coordination compounds of these ligands are described in monographs [62,63] and also in Sec. 3.1.1 [Eqs. (3.21)—(3.24)]. The main reaction of these syntheses is represented by a simple equation (4.11) ... 

Figure 3.6 shows 12 structures that may correspond to the abbreviation DPA. Six of them can be output by the ACD/Name to Structure software package, and six more were found by browsing the Internet. Note that even a specific context cannot guarantee an exact meaning. For example, both structures 3 and 8 were found in publications about coordination compounds. In general, chemical abbreviations are not unique and can rarely be distinguished from other trivial names except for the rather weak criterion that all letters are capitalized. We can conclude that conversion of any trivial name shorter than about five or six characters is not safe. A few rarer exceptions do exist, but this is a very short list. Examples include reserved abbreviations such as those for dimethyl sulfoxide (DMSO) and ethylenediaminetetraacetic acid, EDTA. 

Also, coordination compounds and metal carbonyls are able to undergo a PET, resulting in initiating radicals [63]. Recently investigated examples are iron chloride based ammonium salts [149], vanadium(V) organo-metallic complexes [150], and metal sulfoxide complexes [151]. However, the polymerization efficiency of some systems is only low due to redox reactions between the central metal ion and the growing polymer radical, and the low quantum yields of PET. 

This work showed that the stereochemistry of the 3-covalent sulfur in these metallic coordination compounds was not essentially different from that in the sulfinic esters, the sulfoxides, and the sulfilimines, which were resolved by Phillips et al. (4, 13j 47). 

The scope of the article requires, first, a brief summary of the nature of DMSO as a ligand in coordination compounds. The discussion is then divided into simple complexes containing DMSO as the only donor ligand and the recently-developed mixed amine-sulfoxide complexes, where DMSO plays the role of the leaving group. 

Mizuoka and Ikeda [378] observed that the V3 of the (U 02) ion at 895 cm in DMSO (dimethyl sulfoxide) solution is shifted to 770 cm when reduced electro-chemically to the (U 02) ion. Vibrational spectra of coordination compounds containing dioxo(0=M=0) groups are discussed in Chapter 3 (in Part B). 

Sulfoxide ruthenium complexes have received attention in part from the fact that they are useful starting materials for new organometallic and coordination compounds and in part from their role in biology and catalytic processes see Metal-related Diseases of Genetic Origin). Potential applications are found in medicinal chemistry. 

To synthesize coordination compounds with weak ligands, methods have been developed whereby water is either absent from the start or is removed through a chemical reaction/ In this contribution the preparation of coordination compounds of some divalent metals with nitromethane, ethanol, acetone, diphenyl sulfoxide, and acetonitrile are described. These descriptions are merely examples of simple general methods for the preparation of coordination compounds of Mg, Mn, Fe, Co, Ni, Cu, Zn, and Cd with weak ligands, such as those mentioned above and acetic acid, nitrobenzene, hydrogen cyanide, tetrahydrofurane, dioxane, diglyme (l,l-oxybis[2-methoxyethane]), 1,4,7,10,13,16-hexa-oxacyclooctadecane (18-trown-6), ethyl acetate, and 2,4-pentanedione (acetylacetone in the neutral ketonic form). ... 

Diphenyl sulfoxide (DPSO) is a stronger ligand than ethanol and a weaker ligand than water. It can thus form coordination compounds from hydrates through the intermediate action of a dehydrating agent. - ... 

Well-defined coordination compounds of Pb(CH3)4 are not known. However, from the increase of the NMR coupling constants J( ° Pb, H) In various solvents, solvation of Pb(CH3)4 by one solvent molecule and formation of complexes with trigonal bipyramidal geometry were inferred. The ability of the solvent to solvate Pb(CH3)4 increased along the series CeHi2 < 1,2-dimethoxyethane dioxane hexamethylphosphortriamide < pyridine < tetrahydro-thiophene < triethylamine < THF < triethylphosphine < N,N,N, N -tetramethylethylenedi-amine acetone < dimethylformamide < dimethyl sulfoxide [2]. In another paper 2j(207pb iH) was considered to be independent of solvent donor strength and this is consistent... 

The heavier chalcogens are more prone towards secondary interactions than sulfur. In particular, the chemistry of tellurium has numerous examples of intramolecular coordination in derivatives such as diazenes, Schiff bases, pyridines, amines, and carbonylic compounds. The oxidation state of the chalcogen is also influential sulfur(IV) centres engender stronger interactions than sulfur(II). For example, the thiazocine derivative 15.9 displays a S N distance that is markedly longer than that in the corresponding sulfoxide 15.10 (2.97 A V5. 2.75-2.83 A, respectively). ... 

Entries 8-13 in Table 21.9 illustrate the effect of S-O coordination on the hydrogenation of allyl alcohols. The hydrogenation of (a-hydroxyalkyl)vinyl sul-fones follows the same stereochemical course as the corresponding acrylate via HO coordination (entries 8 and 9). However, the hydrogenation of (a-hydro-xyalkyl)vinyl sulfoxides is directed by S-O coordination, which overrides the HO-participation in the stereochemical course (entries 10-13) [56]. The directing power of S-O may be limited to vinylic examples, as compounds having the S-O and double bond in an allylic relationship failed to reduce under the standard conditions. 

The coordination polymer [Zn(tmbdc)(dmso)2]-2(DMSO) (tmbdc = 2,3,5,6-tetramethyl-l,4-benzenedicarboxylate) has been synthesized by layer diffusion in DMSO (dimethyl sulfoxide) solution. The compound contains ID chain formed by octahedraly coordinated Zn ion chelated by the carboxyl groups of tmbdc. In another recently reported coordination polymer [Zn2(bdc)2(dmso)2]-5(DMSO) (bdc = 1,4-... 

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