Octahedral manganese(i) and ruthenium(ii) complexes containing 2-(methylamido)pyridine–borane as a tripod κ³N,H,H-ligand

Abstract

Abstract:The borane adduct of the 2-(methylamido)pyridine anion, [

Metal–CO Bonding in Mononuclear Transition Metal Carbonyl Complexes

“… 51 The arguments of the author are based on real-space partitioning methods, 52 − 57 which had previously been used for analyzing the nature of metal–CO interactions in transition metal complexes. 58 − 61 An earlier study by Pendás and co-workers using the IQA (Interacting Quantum Atoms) method 55 , 56 , 62 showed that the results of the IQA calculations basically support the DCD model concerning the relevance of π-backdonation for the red-shift of the C–O stretching frequencies in carbonyl complexes, but the calculated values of the delocalization indices (DI) suggest a possible multicenter bonding among the ligands in some carbonyl complexes such as [V(CO) 6 ] − , Cr(CO) 6 , and [Fe(CO) 6 ] 2+ . 58 − 60 Since the DI values of the alkaline earth octacarbonyls deviate even stronger from those of classical carbonyl complexes, Van der Maelen concluded that the DCD model is not valid for the M–CO interactions in M(CO) 8 (M = Ca, Sr, Ba).…”

“…Landis and co-workers questioned the method of bonding analysis and suggested that the alkaline earth octacarbonyls are mainly bonded by ionic interactions between M 2+ and [(CO) 8 ] 2– . , Koch and co-workers challenged the interpretation of the red-shift of the CO stretching frequencies of Ca­(CO) 8 in terms of π-backbonding from the d AOs of calcium, because calculations of the complex without d AOs of Ca reproduce the stretching frequencies quite well. − Van der Maelen also disputed the relevance of the d AOs of Ca, Sr, Ba for the M → (CO) 8 π-backdonation and suggests that the red-shift of the CO stretching frequencies is instead due to interligand interactions between the CO ligands . The arguments of the author are based on real-space partitioning methods, − which had previously been used for analyzing the nature of metal–CO interactions in transition metal complexes. − An earlier study by Pendás and co-workers using the IQA (Interacting Quantum Atoms) method ,, showed that the results of the IQA calculations basically support the DCD model concerning the relevance of π-backdonation for the red-shift of the C–O stretching frequencies in carbonyl complexes, but the calculated values of the delocalization indices (DI) suggest a possible multicenter bonding among the ligands in some carbonyl complexes such as [V­(CO) 6 ] − , Cr­(CO) 6 , and [Fe­(CO) 6 ] 2+ . − Since the DI values of the alkaline earth octacarbonyls deviate even stronger from those of classical carbonyl complexes, Van der Maelen concluded that the DCD model is not valid for the M–CO interactions in M­(CO) 8 (M = Ca, Sr, Ba). …”

From a PGeP Pincer-Type Germylene to Metal Complexes Featuring Chelating (Ir) and Tripodal (Ir) PGeP Germyl and Bridging (Mn2) and Chelating (Ru) PGeP Germylene Ligands

“…An XRD study has established that the structure of the only hitherto known pincer-type diphosphane-germylene Ge-(NCH 2 P t Bu 2 ) 2 C 6 H 4 (1) is that previously predicted by DFT methods, 15,17 which indicated that the most stable conformation of the molecule has the lone pairs of both P atoms weakly interacting with empty orbitals mainly located on the Ge atom.…”

“…A subsequent in-depth DFT study on PEP tetrylenes of the type E(NCH 2 P t Bu 2 ) 2 C 6 H 4 (E = C, Si, Ge, Sn) concluded that the most stable conformation of the molecules with E = Ge, Sn has the lone pairs of both P atoms weakly interacting with empty orbitals with a large participation of the Ge atom, resulting in unexpectedly short separations between the E and P atoms, but this is not the case for the lighter tetrylenes (E = C, Si). 17 After many attempts, we have now been able to crystallize germylene 1 and its molecular structure has finally been determined by XRD. Figure 1 confirms that 1 has C 2 symmetry and that the P atoms, which are almost in the plane defined by the atoms of the 2-germabenzimidazol-2-ylidene fragment, are only 3.320(2) Å away from the Ge atom, a distance that is 0.6 Å shorter than the sum of van der Waals radii of these elements.…”

“…18 This structure is similar to that of the tin analogue Sn(NCH 2 P t Bu 2 ) 2 C 6 H 4 , in which the Sn•••P distances are 3.277(1) and 3.313(1) Å (in this case, the molecule is not symmetric). 17 Iridium(I) Derivatives of Germylene 1. The iridium(I) dimer [Ir 2 (μ-Cl) 2 (η 4 -cod) 2 ] (cod = 1,5-cyclooctadiene) reacted readily with germylene 1 (1:2 mole ratio) to give the chloridogermyl complex [Ir{κ 2 Ge,P-GeCl(NCH 2 P t Bu 2 ) 2 C 6 H 4 }-(η 4 -cod)] (2) as the only reaction product (Scheme 2).…”