SYNTHESIS OF CYCLOPENTADIENYL-(1,4-DIISOPROPYL-1,3-DIAZABUTADIENE)(L)RUTHENIUM TRIFLUOROMETHANESULFONATE (L = ALKENE, ALKYNE, CO, PYRIDINE, PPH3) - X-RAY STRUCTURE OF [(ETA-5-C5H5)RU(IPR-DAB)(ETA-2-PROPENE)][CF3SO3]

Reaction of CpRuCl(iPr-DAB) (1) with AgOTf (AgCF3SO3) in THF and subsequent addition of L (L = ethene (a), propene (b), cis-2-butene (c), dimethyl maleate (d), dimethyl fumarate (e), fumaronitrile (f), acetylene (i), dimethyl acetylenedicarboxylate (DMAC) (j), CO (1), pyridine (m), triphenylphosphine (n)) led to the ionic complexes [CpRu(iPr-DAB)(L)][OTf] 2a-f,i,j,l-n, respectively. For trans-2-butene (g) and 2-methylpropene (h), no coordination complex was formed. Addition of methyl propiolate (HC=CC(O)OCH3, k) to [CpRu(iPr-DAB)][OTf] resulted in [CpRu(iPr-DAB)(eta-HC=CC(O)OCH3)][OTf] (2k) and 21 in a 4:1 ratio. An X-ray structure determination on 2b was carried out. Crystal data for 2b: triclinic, space group P1BAR with a = 9.0649(6) angstrom, b = 9.6151(6) angstrom, c = 13.0099(6) angstrom, alpha = 94.322(6)-degrees, beta = 104.258(8)-degrees, gamma = 98.977(6)-degrees, Z = 2, final R = 0.033. Surprisingly, the structure shows the propene eta2-coordinated to the metal center with the methyl group pointing toward the cyclopentadienyl ring. Nucleophilic attack of OCH3- on [CpRu(iPr-DAB)(eta2-dimethyl maleate)][OTf] (2d) at 20-degrees-C led to two diastereomers of CpRu(iPr-DAB)CH(C(O)OCH3)-CH(OCH3)(C(O)OCH3) (3) in a 97:3 ratio. Reaction of [CpRu(iPr-DAB)(eta2-DMAC)][OTf] (2j) with -OCH3 at 20-degrees-C yielded CpRu(iPr-DAB)OCH3 (6), whereas reaction at -40-degrees-C gave 6 (30%) and CpRu(iPr-DAB)C(C(O)OCH3)=C(OCH3)(C(O)OCH3) (4; 70%). Reaction of 2d with NH2iPr and NHiPr2 as the nucleophiles yielded the substitution products [CpRu(iPr-DAB)(NH2iPr)][OTf] (2p) and [CpRu(iPr-DAB)(NHiPr2)][OTf] (2q), respectively. Complex 2j reacted with NH2iPr to form 2p, whereas 2j was inert to substitution with NHiPr2.