R.Harry Cragg

Organoboron compounds: XXII. A 13C NMR study of some dialkylaminophenylboranes☆

The effect of substituents on the free enthalpy of rotation about the boronnitrogen bond for the two series PhBNMe2X and PhBNPri2X (where X = F, Cl, Br, OMe and SEt) have been investigated by VT 13C NMR.

Contributions to group IV organometallic chemistry: VII. The effect of electronegativity on substituent shifts in silicon-29 NMR

Abstract Silicon-29 NMR shifts for silanes of the type Me2−nPhnSiX2 (X = H, Me, Ph, F, Cl, NR2 and OR) indicate that the shifts on replacement of a methyl by a phenyl group are largely determined by the electronegativity and donor ability of X.

Contributions to group IV organometallic chemistry. VIII: Preparation and properties of some organo-1,3,2-dioxasilacycloheptanes and their cyclic dimers

Abstract The preparation and properties of some organo-1,3,2-dioxasilacycloheptanes are reported and their mass spectra, 13C and 29Si NMR spectra are fully discussed.

Contributions to group IV organometallic chemistry

Abstract The preparation and properties of some 2-methylphenyl-4-oxobenzo-1,3,2-dioxasilanes and related compounds are reported and their general mass spectral features and 13 C and 29 Si NMR spectra are fully discussed.

Organoboron compounds XVIII. Chlorodialkylaminophenylboranes

Summary The synthesis and properties of a series of chlorodialkylaminophenylboranes, PhB(NR 2 )Cl, are reported and their 1 H and 13 C NMR spectra discussed.

Contributions to organoboron chemistry : XV. Aminodiphenylboranes

Abstract The synthesis of a series of aminodiphenylboranes is reported together with the results of a detailed study of their 13 C NMR spectra. All compounds exhibited peaks assignable to the carbon atom directly bonded to boron when run under appropriate conditions. The 13 C spectra of primary aminodiphenylboranes provided further evidence for restricted rotation about the B—N bond.

Organoboron compounds XVI. Alkylaminodialkylaminophenylboranes

Abstract The synthesis and properties of a series of alkylaminodialkylaminophenylboranes, PhB(NHR)NR′ 2 , are reported. The 13 C NMR of these compounds indicate restricted rotation about the bond.

Preparation and carbonyl-substitution reactions of hexacarbonyldicobalt-complexed 1,3-dioxa-2-silacyclohept-5-ynes and 1,3,8,10-tetraoxa-2,9-disilacyclotetradeca-5,12-diynes. X-Ray crystal structure of [(Ph3P)(OC)5Co2-{µ-(C2CH2OSiPh2OCH2)2}Co2(CO)5(PPh3)]

Reactions between [Co2(µ-HOCH2C2CH2OH)L1L2(CO)4][L1= L2= CO or L1–L2= bis(diphenyl-phosphino)methane (dppm)] and SiR1(R2)Cl2(R1= R2= Me or Ph; R1= Me, R2= Ph) afford hexacarbonyldicobalt-complexed 1,3-dioxa-2-silacyclohept-5-ynes which undergo carbonyl substitution in the case of L1= L2= CO with PPh3 or dppm. Fast-atom-bombardment (FAB) mass spectral evidence indicates that the 2,2-diphenyl-1,3-dioxa-2-silacyclohept-5-yne complex and its monophosphine-substituted derivative are dimers which is confirmed by the X-ray crystal structure of the latter, [(Ph3P)(OC)5Co2{µ-(C2CH2OSiPh2OCH2)2}Co2(CO)5(PPh3)], in which the phosphine ligands occupy axial positions on opposite sides of the fourteen-membered ring. Only monomers are identified in the mass spectra of the other compounds, but evidence for unseparated higher oligomers as minor products is found in the NMR spectra of the 2,2-dimethyl-1,3-dioxa-2-silacyclohept-5-yne complex and its monophosphine and dppm derivatives.

Organoboron compounds: XXVIII. Novel heterocyclic organoboranes

Abstract The preparations of a number of heterocyclic organoboranes, each containing a tertiary nitrogen atom, are reported, and the interactions of these species with organic isocyanates are discussed.

Contributions to group IV organometallic chemistry: X. Organo-1,3,2-diazasilacycloalkanes

Abstract The preparation and properties of a series of organo-1,3,2-diazasilacycloalkanes are reported and their mass spectra and 1 H, 13 C and 29 Si NMR spectra discussed in detail.