The Reactivity of 1,3,2-Diheterophospholans Containing a Tricoordinate Phosphorus Atom

Abstract

I present high-resolution column density maps of two molecular clouds (MCs) having strikingly different star formation rates. To better understand the unusual, massive G216-2.5, an MC with no massive star formation, the distribution of its molecular gas is compared to that of the Rosette MC. Far-infrared data from Herschel are used to derive N(H 2 ) maps of each cloud and are combined with I CO data to determine the CO-to-H 2 ratio, X CO . In addition, the probability distribution functions (PDFs) and cumulative mass fractions of the clouds are compared. For G216-2.5, á ñ =Ń (H ) 7.8 10 2 20 cm −2 and á ñ =X 2.2 10 CO 20 cm −2 (K km s −1 ) −1 ; for the Rosette, á ñ =Ń (H ) 1.8 10 2 21 cm −2 and á ñ =X 2.8 10 CO 20 cm −2 (K km s −1 ) −1 . The PDFs of both clouds are lognormal for extinctions below ∼2 mag and both show departures from log-normality at high extinctions. Although it is the less-massive cloud, the Rosette has a higher fraction of its mass in the form of dense gas and contains  M 1389 of gas above the so-called extinction threshold for star formation, = A 7.3 V mag. The G216-2.5 cloud has  M 874of dense gas above this threshold.

Reactions of 1,3,2‐Diselenaphospholanes with Lewis Acids: Borane and (Pentamethylcyclopentadienyl)rhodium and ‐iridium Dichloride

“…The basicity of three‐coordinate phosphorus in phospholanes appears to be markedly lower than in corresponding six‐membered rings or noncyclic derivatives, as has been noted for complexation of 1,3,2‐dioxaphospholanes with H + , BH 3 , BF 3 ,1 and metals 1,2. This was attributed to the electronegativity of oxygen as well as to the ring strain in the five‐membered heterocycles 3,4.…”

Novel 1,3-dichalcogeno-2-phospholanes with an annelated 1,2-dicarba-closo-dodecaborane(12) Unit

“…Again this is in contrast to A or B (E = O; Fig. 1) which dimerize very slowly or not at all (Dutasta, 1980;Pudovik, 1983). Figure 2 shows the molecular structure of the dimer 10c, as determined by Xray analysis.…”

[4,4',6,6'-Tetramethyl-(2,2'-isobutylidenedi-o-phenylene)] (2,6,7-Trioxa-1-phosphabicyclo[2.2.2]oct-4-ylmethyl) Phosphite, C25H32P2O6

“…Because of their ability to decompose peroxides, certain phosphites have a widespread application in protecting polymers during processing and storage (Ivanov & Zheltukhin, 1970). The reactivity of organic phosphites is largely modified when incorporated into a cyclic structure (Pudovik, Ovchinnikov, Cherkasov & Pudovik, 1983). In our efforts to design more effective antioxidants, we have developed a one-pot synthesis of the heterocyclic diphosphite (3).…”