US EPA

1146354 

Journal Article 

Direct detection of methylphenylgermylene and 1,2-dimethyl-1,2-diphenyldigermene - Kinetic studies of their reactivities in solution 

Leigh, WJ; Dumbrava, IG; Lollmahomed, F 

2006 

Yes 

Canadian Journal of Chemistry
ISSN: 0008-4042
EISSN: 1480-3291 

CANADIAN SCIENCE PUBLISHING 

OTTAWA 

84 

7 

934-948 

English 

10.1139/V06-107 

WOS:000240546000002 

Photolysis of 1,3,4-trimethyl-1-phenylgermacyclopent-3-ene (5) in hydrocarbon solvents containing isoprene, methanol, or acetic acid affords 2,3-dimethyl-1,3-butadiene (DMB) and the expected trapping products of methylphenylgermylene (GeMePh) in chemical yields exceeding 90%. The germylene has been detected in hexane solution by laser flash photolysis as a short-lived species (τ ∼ 2 μs) exhibiting a UV-vis absorption spectrum centered at λmax = 490 nm. It decays with second-order kinetics and a rate constant close to the diffusion-controlled limit, with the concomitant growth of a second longer-lived transient (λmax = 420 nm) that is assigned to a mixture of (E)- and (Z)-1,2-dimethyl-1,2-diphenyldigermene (4). Absolute rate constants have been determined for the reactions of the germylene with primary and tertiary amines (n-BuNH2 and Et 3N, respectively), acetic acid (AcOH), a terminal alkyne and alkene, isoprene, DMB, CCl4, and the group 14 hydrides Et3SiH and Bu3SnH. GeMePh is slightly more reactive than GePh2 towards all the reagents studied in this work; both are significantly less reactive than GeMe2 toward the same substrates. Absolute rate constants for the reactions of 4 have also been measured or assigned upper limits in every case and are compared to previously reported values for tetraphenyl- and tetramethyl-digermene with the same reagents. © 2006 NRC Canada. 

germylene; digermene; kinetics; laser flash photolysis; germirane; germirene; vinylgermirane; complex; UV-vis spectrum; insertion; addition