Synthesis and crystal and molecular structure of an .eta.-cyclopropene complex of molybdenum

Synthesis, Characterization, and Isomerization of an Iridabenzvalene

“…[10] The PMe 3 analogue of this series (8) was characterized by single-crystal X-ray crystallography. Furthermore, a molybdenum complex (9) with an intramolecular cyclopropene ligand coordinated to the metal center in an h 2 fashion has been reported by Hughes et al [11] H Ph (OC) 2 The structure of 5 was confirmed by a single-crystal X-ray diffraction study (Figure 1). The axis of the olefinic cyclopropene bond in 5 lies in the equatorial plane of the complex, which is typical of a trigonal-bipyramidal d 8 complex.…”

“…The corresponding values for benzvalene (11) are 25.9 AE 0.2 kcal mol À1 and 1.6 AE 0.7 eu, respectively. [17] Figure 2.…”

Isolable Copper(I) η2-Cyclopropene Complexes

“…There are no copper cyclopropene η 2 -complexes for comparisons. However, a search of CSD revealed that structural data are available for a few transition metal η 2 -cyclopropenes complexes (See also Table S3), − ,− and they all show much longer cyclopropene CC bond distances (with an average of 1.448 Å for 14 molecules spanning 1.50(1) Å for a Pt(0) complex (PPh 3 ) 2 Pt­(1,2-Me 2 -cyclopropene) to 1.407 Å for a Mo­(II) adduct, Cp*Mo­(CO) 2 (2,3-Ph 2 -2-cyclopropene-1-carboxylate)) relative to the corresponding bond distance in [(CF 3 ) 2 Bp]­Cu­(Cyp- 2 ), [(CF 3 ) 2 Bp]­Cu­(Cyp- 3 ), and [(CF 3 ) 2 Bp]­Cu­(Cyp- 4 ) of 1.3481(12), 1.3583(18), and 1.3659(11) Å, respectively. This indicates that compared to these early transition metal complexes, the σ/π-interaction between d 10 -copper­(I) and cyclopropenes in [(CF 3 ) 2 Bp]­Cu­(Cyp- 2 ), [(CF 3 ) 2 Bp]­Cu­(Cyp- 3 ), and [(CF 3 ) 2 Bp]­Cu­(Cyp- 4 ) are weaker.…”

“…The room-temperature 13 C­{ 1 H} NMR spectrum of [(CF 3 ) 2 Bp]­Cu­(Cyp- 2 ) in CDCl 3 shows a peak at δ 91.1 ppm corresponding to the carbons of the copper bound olefinic moiety of cyclopropene ligand, which is an upfield shift (Δδ of 15.4 ppm; Δδ = δ free ligand – δ metal complex) compared with the corresponding resonance of the free ligand Cyp- 2 (δ 106.5 ppm, Table S1). The early transition metal η 2 -cyclopropene complexes such as Cp*Mo­(CO) 2 (2,3-Ph 2 -2-cyclopropene-1-carboxylate), [Me 2 Tp]­Nb­( cyclo -C 3 H 4 )­(NC 5 H 5 )­(MeCCMe) and W­(3,3-Ph 2 ‑cyclopropene)­Cl 2 (NPh)­[P­(OMe) 3 ] 2 with stronger metal–cyclopropene bonds display their metal-bound cyclopropene carbon chemical shifts at significantly greater upfield regions: δ 71.91, 58.64 ppm; δ 74.5, 68.4 ppm; and δ 64.8 ppm, respectively. The carbonyl carbon signal of [(CF 3 ) 2 Bp]­Cu­(Cyp- 2 ) also shows a small but noticeable 4 ppm shift relative to that of the free ligand Cyp- 2 .…”

C–H Activation of 3,3-diphenylcyclopropene in the reaction with Os(CO)2(PPh3)3: 3,3-diphenylcyclopropenyl, 2,2-diphenylcyclopropyl, and 3-phenylindenyl complexes of osmium(II)

“…Crystal structures for several of these iridabenzvalene and rhodabenzvalene complexes have been reported [14][15][16][17]. A related structure has been reported for molybdenum(II), where the cyclopropene is tethered to the metal by a carboxylate group [18].…”