A comparative study of new platinum methyl complexes cis-(dfmp) 2 Pt(Me) 2 and trans-(dfmp) 2 Pt(Me)X (dfmp ) (C 2 F 5 ) 2 MeP; X ) O 2 CCF 3 , OTf, OSO 2 F) with previously reported acceptor chelate analogues (dfepe)Pt(Me)X (dfepewhich is inert to both H 2 and CO addition, cis-(dfmp) 2 Pt(Me) 2 reacts readily to form (dfmp) 4 Pt and cis-(dfmp)(CO)-Pt(Me) 2 , respectively. Similarly, whereas (dfepe)Pt(Me) 2 is stable up to 180 °C, thermolysis of cis-(dfmp) 2 Pt(Me) 2 in benzene-d 6 at 80 °C leads to ethane reductive elimination and production of (dfmp) 4 Pt. Dissolving cis-(dfmp) 2 Pt(Me) 2 in neat trifluoroacetic, triflic, or fluorosulfonic acid at ambient temperature cleanly produces the corresponding trans-(dfmp) 2 Pt(Me)(X) complexes. Attempted isolation of trans-(dfmp) 2 Pt(Me)(O 2 CCF 3 ) resulted in dfmp loss and reversible formation of the crystallographically characterized dimer, [(dfmp)Pt(Me)(µ-O 2 CCF 3 )] 2 . Monitoring the thermolysis of trans-(dfmp) 2 Pt(Me)(X) complexes by 31 P NMR in their respective neat acids reveals a kinetic protolytic stability that is dependent on the nature of the trans X ligand: whereas trans-(dfmp) 2 Pt(Me)(O 2 CCF 3 ) is less stable than the corresponding (dfepe)Pt(Me)(O 2 CCF 3 ) complex, trans-(dfmp) 2 Pt(Me)-(OTf) and trans-(dfmp) 2 Pt(Me)(OSO 2 F) are significantly more resistant to protolytic cleavage than the chelating analogues. Thermolysis in CF 3 CO 2 D or DOTf resulted in deuteration of the methyl ligand prior to methane loss, indicating the reversible formation of a methane adduct intermediate.

The comparative reactivity properties of previously reported trans-(dfmp) 2 Pt(Me)X (dfmp ) (C 2 F 5 ) 2 -MeP; X ) O 2 CCF 3 , OTf, OSO 2 F) with small molecules are presented. Anionic ligand displacement by CO depends upon X and the corresponding acid solvent. In trifluoroacetic acid, treatment of trans-(dfmp) 2 Pt(Me)(O 2 CCF 3 ) with CO results in loss of dfmp to form the mixed phosphine/carbonyl product (dfmp)(CO)Pt(Me)(O 2 CCF 3 ). However, in triflic and fluorosulfonic acids trans-(dfmp) 2 Pt(Me)(X) compounds react with CO to form trans-(dfmp) 2 Pt(Me)(CO) + (X) -. trans-(dfmp) 2 Pt(Me)(X) systems react with H 2 under both acidic and aprotic conditions to form trans-(dfmp) 2 Pt(H)(X); trans-(dfmp) 2 Pt(H)-(OTf) has been crystallographically characterized. Treatment of trans-(dfmp) 2 Pt(H)(OTf) with CO or dfmp gives trans-(dfmp) 2 Pt(H)(CO) + or (dfmp) 3 Pt(H) + , respectively. In contrast to trans-(dfmp) 2 Pt(Me)-(OTf), which releases methane in HOTf, trans-(dfmp) 2 Pt(Me)(OSO 2 F) in FSO 3 H at 80 °C cleanly produces the reductive elimination product MeOSO 2 F. Carbonylation of trans-[(dfmp) 2 PtMe(CO)] + Xunder 1000 psi CO in turn cleanly produces MeC(O)X at ambient temperatures. The mechanism of reductive elimination from these Pt(II) precursors is discussed.

Nitric oxide's beta-quinol clathrate rapidly and quantitatively releases nitric oxide upon dissolution to give well defined spatiotemporal gradients.

The protolytic stability of (dfepe)PtMe 2 (dfepe = (C 2 F 2 ) 2 PCH 2 CH 2 P(C 2 F 5 ) 2 ) and cis-(dfmp) 2 PtMe 2 (dfmp = (C 2 F 5 ) 2 PMe) and NMR characterization of their corresponding products in SbF 5 −HF superacid solvent mixtures are reported. Dissolution of (dfepe)Pt(Me) 2 in 10 mol % of SbF 5 −HF at −60 °C resulted in the clean protonolysis of a single Pt−Me bond to form the cationic methyl complex (dfepe)Pt(Me) + ; further conversion of (dfepe)Pt(Me) + to (dfepe)Pt 2+ occurred upon warming to −20 °C and followed pseudo-first-order kinetics (k = [1.4( 2)] × 10 −2 min −1 ). In contrast, dissolution of the nonchelating analogue cis-(dfmp) 2 PtMe 2 in 10 mol % of SbF 5 −HF at 20 °C evolved methane and cleanly produced the stable monomethyl complex trans-(dfmp) 2 Pt(Me) + . trans-(dfmp) 2 Pt(Me) + is the most protolytically stable organometallic known: 33% conversion to the cis dicationic product cis-(dfmp) 2 Pt 2+ requires 2 weeks in 10 mol % of SbF 5 −HF at 20 °C, whereas >90% conversion was observed in 30 h in 50 mol % of SbF 5 −HF. Dissolution of cis-(dfmp) 2 Pt(CD 3 ) 2 cleanly generated trans-(dfmp) 2 Pt(CD 3 ) + , which subsequently underwent complete proton incorporation to produce trans-(dfmp) 2 Pt(CH 3 ) + within 1 h at 25 °C. This labeling study supports the reversible formation of the methane complex intermediate trans-(dfmp) 2 Pt(CH 4 ) 2+ under these conditions. Treatment of trans-(dfmp) 2 Pt(Me) + in 10 mol % of SbF 5 −HF at −100 °C with 200 psi of H 2 resulted in the clean formation of the dihydrogen complex trans-(dfmp) 2 Pt(Me)(η 2 -H 2 ) + , which upon warming to −20 °C underwent methane loss and generated the hydride product trans-(dfmp) 2 Pt(H) + . The dihydrogen complex trans-(dfmp) 2 Pt(H)(η 2 -H 2 ) + has not been directly observed but has been implicated in exchange bradening behavior observed for trans-(dfmp) 2 Pt(H) + under H 2 . Treatment of trans-(dfmp) 2 Pt(CD 3 ) + in 10 mol % of SbF 5 −HF at −40 °C with 200 psi of H 2 cleanly produced trans-(dfmp) 2 Pt(CD 3 )(η 2 -H 2 ) + No significant H/D exchange into the Pt−CD 3 group prior to trans-(dfmp) 2 Pt(H) + formation was observed.

The crystal structure of the title compound, (bicyclo[2.2.1]hepta-2,5-diene)dichloroplatinum(II), [PtCl2(C7H8)], has been determined from single-crystal X-ray analysis. The coordination sphere about the Pt atom is pseudo-square planar, with shorter Pt-C distances than in the corresponding dichloro(cyclooctadiene)platinum(II) complex.