Structure and bonding in an octahedral Li4C2 cluster, the dilithium bis {dihydrido(silylimino)phosphorano}methanide dimer. A combined DFT–AIM analysis

Homo‐ and Heterodimetallic Geminal Dianions Derived from the Bis(phosphinimine) {Ph2P(NSiMe3)}2CH2 and the Alkali Metals Li, Na, and K

“…Recent independent theoretical investigations by Klobukowski, [53] MØzailles [20] and Harder [45] have addressed the electronic structure of bis(phosphinimine)-stabilized geminal dianions (or the closely related bis(thiophosphinoyl) species). [54] Findings of importance are: i) the À2 charge remains largely localized at the central carbanion in the form of two lone pairs, ii) the individual atomic centers are highly charged in the form Si (anion) and PÀN bonds are present, and iv) the PÀC (anion) distances decrease and the remaining bond lengths at phosphorous increase upon deprotonation of the ligand.…”

“…The change in the bond lengths upon deprotonation have been rationalized as a consequence of either substantial negative hyperconjugative contributions between the two lone pairs of the carbanion and the adjacent stabilizing groups, or alternatively through the formation of strong electrostatic interactions on the ligand backbone. [20,45,53,55] Studies thus far have solely focused on dilithiated complexes. Our variously metalated systems provide the opportunity to examine the bonding situation from a unique perspective.…”

A Spirocyclic, Bimetallic, Carbon-Bridged Bis(iminophosphorano)methanediide Complex of Palladium(II): Synthesis, Crystal Structure, Solution Behavior, and DFT Bonding Analysis

“…21 The two four-membered rings subtended from C(10) are not planar; both are folded about the P-Pd axis with one, C(10)-P(2)-N(2)-Pd(2), being more bent (23°) than the other (C(10)-P(1)-N(1)-Pd(1); 11°). Both Pd-allyl groups project to the same side of C (10). Complexes that contain chelating C, N ligands with a carbenic C are relatively rare; other examples are the Ruaminocarbene complexes [RuCp(L)(κ 2 N,N-py-NdC(H)-Ph)][PF 6 ] (L=CH 3 CN, PMe 3 , PPh 3 ), 29 the tris(pyrazolyl)borate ruthenium carbenes, 30 and our recently reported bimetallic Rh/Pd complexes.…”

“…Several years ago, we , and others reported the synthesis and characterization of the structurally unusual dimeric organolithium complex [Li 2 C(Ph 2 PNSiMe 3 ) 2 ] 2 ([Li 2 - 1 ] 2 ), which was easily obtained by double deprotonation of the methylene C atom of the parent ligand, CH 2 (Ph 2 PNSiMe 3 ) 2 (H 2 - 1 ), , using alkyl- or aryllithium reagents. Subsequently we employed both [Li 2 - 1 ] 2 and H 2 - 1 to prepare a number of novel “pincer” carbene complexes of group 4, group 9 and 10 transition metals, − and lanthanides .…”

Geminal dianions stabilized by phosphonium substituents

“…Cavell and co-workers were the first to calculate the charge distribution in the dianionic bis(iminophosphorane)methandiide ligand [41] and concluded that there is a high negative charge of up to −1.79 on the bridging C. Henderson and co-workers showed that the charge in the model system M 4 [C(H 2 P NSiH 3 ) 2 ] 2 is dependent on the interaction between the ligand and the cations: smaller Li + ions localize the charge on C (calculated NPA-charge: −1.809) whereas larger cations like K + are less localizing (calculated NPA charges: −1.688) [32]. The bridging C in Li 2 C(Ph 2 P S) 2 also carries a high negative charge of −1.77 [25].…”