Correlation of nuclear magnetic resonance coupling constants with transition metal–ligand bond lengths in tertiary phosphine complexes

Novel 1,2‐Dicarba‐closo‐dodecaborane(12) Derivatives of Selenium

“…The molecular structures of 4 and 7 were determined by X-ray analysis. The solution-state structures of the new compounds are supported by multinuclear NMR data ( 1 H, 11 B, 13 C, 29 Si, 31 (6) and unreacted carborane 1, thus indicating the preferred conversion of 1 into 2, followed by double insertion of selenium into the C-Li bonds to give 3. In context with the chemistry of heterosubstituted tropylium derivatives we have attempted to prepare a 1,2-bis(tropyliumseleno)-1,2-dicarba-closo-docecaborane (12) by cleavage of the Se-Si bonds.…”

“…[1a,20] However, careful setting of the experimental conditions enables the measurement of these signals readily, and further information is provided by observation of 77 Se satellite signals, as shown in the case of 5 ( Figure 1 [21] ). 29 Si NMR spectra helped us to monitor the reaction of 5 with tropylium bromide (Scheme 1), and they also established the formation of the monosubstituted species 6 as a side product (Figure 2). The presence of the 77 Se satellite signals corresponding to 1 J77 Se, 29 Si indicates the presence of an Si-Se bond; the magnitude of 1 J77 Se, 29 Si is similar in 5 and 6 and also to data reported for other silylselanes.…”

An acetone complex of platinum

“…The Pt-O distance of 2.168 (5) A is longer than either the literature value of 2.00 A for Pt-OR 2 bonds (Shustorovich, Porai-Koshits & Buslaev, 1975) or 1.991 (8)A for a bis(acac)Pt H complex (Onuma, Horioka, Inoue & Shibata, 1980). It is probably longer than the Pt-O distance of 2.144 (9) A found in a Pt n complex with an ether ligand trans to a phosphine ligand (Clark, McBride, Payne & Wong, 1979), where the extremely large 1Jpt_ P coupling constant of 4529.9 Hz for the Pt-P bond trans to the ethereal O atom established the ether group as a ligand with a very weak trans influence (Appleton & Bennett, 1978;Mather, Pidcock & Rapsey, 1973).…”

13C Nuclear Magnetic Resonance Studies of Organometallic Compounds. V. Di- and Trimethylplatinum(IV) Derivatives

“…In contrast, the ratios of 'Jptc for the Pt(IV):Pt(II) complexes considered here fall in the range 1.02-1.14. This may be rationalized by the scheme described by Pidcock and co-workers (20,21). I n Pt(IV) us.…”

“…It has been noted (20) that the ratios of lJplp for Pt(IV):Pt(II) analogs are commonly in the range 0.564.68, close to 0.67, the ratio of the s-characters in six and four bond hybrids respectively. In contrast, the ratios of 'Jptc for the Pt(IV):Pt(II) complexes considered here fall in the range 1.02-1.14.…”