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A simplified kinetic model was developed for the rhodium-catalyzed low-pressure hydroformylation using chelating phosphite ligands. This allowed the determination of the relative rate constants for linear and branched aldehyde formation starting with terminal olefins using data from complex product mixtures. Structural data were obtained using X-ray crystallography and served as the basis for molecular modeling of rhodium complexes with such chelating ligands. The interaction of linear and branched alkyl groups with the ligand environment in such complexes was quantified using molecular modeling. The energy differences obtained with molecular modeling were plotted against the energy differences obtained from kinetic experiments and a linear correlation was found. This type of approach, i.e., development of a structure–activity relationship, can be used to quickly and efficiently investigate such catalytic systems.

The compound (μ-H) 2 Os 3 (CO) 9 (μ 3 -Te) has been prepared from Os 3 (CO) 10 -(NCCH 3 ) 2 and H 2 Te, and its structure has been determined by X-ray crystallography.

125 Te and 77 Se NMR spectroscopy of transition metal complexes containing “naked” tellurium or selenium as a bridging ligand allow the nature of differently bound tellurium or selenium ligands to be determined, as well as the detection of neighbouring hydrido ligands by analyzing the 1 H- 125 Te( 77 Se) couplings. A correla-tion of structural features with chemical shifts of these heteronuclei is not possible owing to the dominant paramagnetic term of the chemical shift.

The gold compound Ph3PAu CHPh SO2-t-Bu is obtained from the reaction of (PhCH SO2-t-Bu)−Li+ with Ph3PAuCl. A crystal structure determination shows that gold is coordinated only at the sulfone's benzylic carbon atom. In contrast, α-sulfonyl-lithium compounds show coordination of the metal exclusively at the sulfonyl oxygen atoms.

Selenium acts as a bridging ligand between two iron atoms in the novel complex (μ-Se)(η 5 -C 5 H 5 )Fe(CO) 2 ] 2 ( 1 ), obtained in 60% yield from Na + [(η 5 -C 5 H 5 )Fe(CO) 2 ] and Se 2 Cl 2 . 1 displays nucleophilic reactivity towards protic acids (e.g., HBF 4 ·OEt 2 ) and methyl triflate, CF 3 SO 3 CH 3 , thus giving the protonated and methylated ionic species [(μ-SeR)(η 5 -C 5 H 5 )Fe(CO) 2 2 ] + (R = H: 2a , BF 4 salt; R = CH 3 : 2b , PF 6 salt) in quantitative yields. Rapid deprotonation of 2a occurs in the presence of bases such as diethylamine. Analogous protonation and methylation reactions have been observed with the tellurium complex (μ-Te)[(η 5 -C 5 H 5 )Cr(CO) 3 ] 2 ( 3 ); the ionic compounds [(μ-TeH)(η 5 -C 5 H 5 )Cr(CO) 3 2 ]BF 4 ( 4a ) and [(μ-TeCH 3 ) (η 5 -C 5 H 5 )Cr(CO) 3 2 ]PF 6 ( 4a ), respectively, are obtained. In contrast, the electron-deficient tellurium ligand of the manganese complex (μ 3 -Te)[(η 5 -C 5 H 5 )Mn(CO) 2 ] 3 ( 5 ) is neither attacked by Bronsted acids nor by electrophilic methylating agents (e.g., CF 3 SO 3 CH 3 ) but is rather methylated by methyllithium to give the anionic species [(μ 3 -TeCH 3 )η 5 -C 5 H 5 )Mn(CO) 2 3 ] − that can be isolated pure as the PPN + salt 6 .