Syntheses and structures of highly hindered N-functionalised alkyl–group 2 metal complexes [M{NC 5 H 4 C(SiMe 3 ) 2 -2} 2 ](M = Mg, Zn, Cd, or Hg)

The complexes [[graphic omitted](SiMe3)2-2}2][M = Mg (1), Zn (2), Cd (3), or Hg (4), accessible either by metallation of NC5H4{CH(SiMe3)2}-2 (RH)[for (1), using MgBunBus], or from LiR(thf)n(thf = tetrahydrofuran)[for (2)–(4), using MCl2], are mononuclear metal(II) alkyls in which the dative metal–nitrogen interactions progressively weaken and C–M–C angles become more open in the sequence (1)→(4)[ , : 2.13 Å, 157°, (1); 2.30 Å, 164°, (2); 2.49 Å, 174°, (3); 2.78 Å, 180°, (4); corresponding mean M–C distances are 2.22; 2.07; 2.27; 2.16 Å].