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The reduction of 3,6-di-tert-butyl-o-benzoquinone with tin amalgam gives the different tin catecholate complexes. The use of polar solvents for this reaction leads to the formation of Cat2Sn · L2 species (where Cat—dianion of 3,6-di-tert-butylcatechol, L = Et2O, THF, Py). The reaction carried out in toluene produces the mixture of dicatecholate tin(IV) and catecholate tin(II) derivatives. The complex Cat2Sn · (Et2O)2 was shown to be a good starting reagent for the preparation of different tin(IV) catecholate complexes of the type Cat2Sn · L′ (L′ = 1,2-dimethoxyethane, 1,4-di-tert-butyldiazadiene-1,3, o-phenantrolyne, α,α′-dipyridyl) using ligand exchange reactions. Compounds Cat2Sn · (Et2O)2, Cat2Sn · (THF)2, Cat2Sn · (ButNCHCHNBut), and (CatSn)3 have been crystallographically characterized. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:481–490, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20271

New catecholate Sb(V) complexes triphenyl(3,6-di-tert-butylcatecholato)antimony(V) Ph3Sb(3,6-DBCat) (1) and triphenyl(perchloroxanthrenecatecholato)antimony(V) Ph3Sb(OXCatCl) (2) were synthesized by the oxidative addition reaction of corresponding o-quinones (3,6-di-tert-butyl-o-benzoquinone and perchloroxanthrenequinone-2,3) with triphenylantimony. Catecholates 1 and 2 can alternatively be synthesized by reacting the appropriate thallium catecholate with triphenylantimony dichloride. The oxidative addition reaction of an equimolar ratio of 4,4′-di-(3-methyl-6-tert-butyl-o-benzoquinone) and triphenylantimony yielded 4-(2-methyl-5-tert-butyl-cyclohexadien-1,5-dion-3,4-yl)-(3-methyl-6-tert-butyl-catecholato)triphenylantimony(V) Ph3Sb(Cat-Q) (3); in the case of a 1:2 molar ratio, complex 4,4′-di-[(3-methyl-6-tert-butyl-catecholato)triphenylantimony(V)] Ph3Sb(Cat-Cat)SbPh3 (4) resulted. Complexes 1–4 were characterized by IR- and 1H NMR spectroscopy. Molecular structures of 1, 2 and 4 were determined by X-ray crystallography to be a distorted tetragonal-pyramidal.

3,6-Di- tert -butyl- o -benzosemiquinone is very convenient for the investigation of the interaction between organometallic R 2 M and carbonyl compounds. The reaction of organometallic compounds R 2 M with o-quinone, where R = Ph, Me, Et, Pr, 1 Pr or t Bu and M ≡ Zn, Cd, and Al, proceeds in two ways: (1) the single-electron oxidation of the organometallic compound by o -quinone, resulting in derivatives of alkyl(phenyl)oxyphenols; (2) the polar 1,2 and 1,4 addition of organometallic molecules to o -quinone as to conjugated ketone, which produces hydroxycyclohexadienones after hydrolysis. The relationship between these two is defined by the nature of the organometallic compound. The products of polar addition are rearranged easily in different ways, finally resulting in new o-quinones: 3-(R)-6- tert -butyl- o -benzoquinones and 3,6-di- tert -butyl-4-(R)- o -benzoquinones where R ≡ alkyl.

The reaction between salts of transition metal sandwich cations and β-diketones (HCh) has been investigated using allyl, cyclopentadienyl and arene derivatives of Fe, Pd, Cr, Ti as sandwich components, and with acetylacetone (HA), dibenzoylmethane (HD), thenoyltrifluoroacetone (HT), ferrocenoyltrifluoroacetone (Ho) as chelating components. The sequence of bond stabilities in bis-aromatic iron complexes has been established as Ch-Fe > Cp-Fe > Arene-Fe whilst in allyl complexes the corresponding sequence has been shown to be Ch-Fe > All-Fe > CO-Fe. Disproportionation products of mixed sandwich chelate complexes containing one hydrocarbon ligand have been isolated. The corresponding influence of hydrocarbon ligands and of the chelate in mixed complexes as indicated by IR and electronic spectra are discussed as are the possible changes in bond character which occur in these complexes.