Reactions of Organic Isocyanates and tert-Butyl isocyanide with Manganese(II) Alkyls and Trimesitylchromium

Article abstract of DOI:10.1039/DT9920000019

The dialkylmanganese compounds t)2>4 and 2 react with organic isocyanates to give chelating amido products that can be verfied by hydrolysis to the amides.For Me3SiNCO the products of reaction with t)2>4 with 2 and 4 equivalents have been shown by X-ray crystallography to be, respectively, Mn3(CH2Bu^t)2<μ-OC(CH2Bu^T)N(SiMe3)>2(μ-CH2Bu^t)2 and Mn4(CH2Bu^t)2(μ₃-NCO)2<μ-OC(CH2Bu^t)N(SiMe3)>4.In the triangular, and quite unsymmetrical, trinuclear species each manganese has a distorted four-co-ordinate geometry.Two manganese atoms are chelated by the amide ligands (Mn-O 2.208, 2.276 Angstroem; Mn-N 2.149, 2.184 Angstroem) the oxygen of which then bridge to a neighbouring metal atom.Two of the manganese atoms carry one terminal alkyl (Mn-C 2.122 and 2.154 Angstroem) and one edgeof the Mn3 triangle is bridged by one symmetrical (Mn-C 2.309 and 2.311 Angstroem) and one unsymmetrical (Mn-C 2.184 and 2.646 Angstroem) bridging alkyl.The tetranuclear species is centrosymmetric.One of the unique Mn atoms carries a terminal alkyl (Mn-C 2.092 Angstroem) and is further co-ordinated by two bridging amide oxygens (Mn-O 2.070 and 2.073 Angstroem) and one triply bridging cyanate nitrogen (Mn-N 2.282 Angstroem).The other independent manganese is chelated by two amides with Mn-O 2.308 and ngstroem, Mn-N 2.146 and 2.176 Angstroem, and its six-co-ordination is completed by bonds to both triply bridging cyanate groups with Mn-N 2.298 and 2.138 Angstroem.The reaction of Cr(mes)3(thf) (mes = 2,4,6-Me3C6H2, thf = tetrahydrofuran) with BuNCO gives Crt>3.Similar interactions using Bu^tNC lead to MntCH2C=NBu^t>2(PMe3) and Cr<(mes)C=NBu^t>3.

Full text of DOI:10.1039/DT9920000019

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