A comparative study of the structure and bonding in heavier pnictinidene complexes [(ArE)M(CO)_n] (E = As, Sb and Bi; M = Cr, Mo, W and Fe)

Abstract

N,C,N-Chelated pnictinidenes ArE [where E = As (1), Sb (2) or Bi (3); Ar = CH-2,6-(CH[double bond, length as m-dash]Nt-Bu)] were used as ligands for the coordination of transition metal carbonyls. Thus, the reaction of 1-3 with [M(CO)THF] (where M = Cr, W) or [Mo(CO)(MeN)] gave complexes [(ArE)M(CO)] [where E = As and M = Cr (1a), Mo (1b), W (1c); E = Sb and M = Cr (2a), Mo (2b), W (2c); E = Bi and M = Cr (3a), Mo (3b), W (3c)]. Analogously, the treatment of 1-3 with [Fe(CO)] resulted in the formation of the complexes [(ArE)Fe(CO)] [where E = As (1d), Sb (2d) or Bi (3d)]. All compounds were characterized by H andC NMR spectroscopy, Raman, IR and UV-Vis spectroscopy. The molecular structures of the majority of the compounds (except 1b and 1c) were also determined by the single-crystal X-ray diffraction analysis. Furthermore, the structure and bonding of the title compounds have also been thoroughly investigated using a computational approach.

Structure and Reactivity of 1,8-Bis(naphthalenediyl)dipnictanes

“…Assuming an ideal C4v symmetry of the M(CO)5 fragment in 4 -6, three carbonyl absorptions corresponding to two A1 and one E vibrational modes should be observed. In addition, the IR forbidden B1 fundamental stretching is often observed as weak band in the IR spectra of such Cr(CO)5 complexes as a result of the perturbation of the ideal C4v symmetry as was reported for pnictinidene complexes (ArE)Cr(CO)5 (E = As, Sb, Bi), [82] H3SbCr(CO)5, [83] Ph3ECr(CO)5 (E = As, Sb, Bi) [84] and other complexes of the general type LCr(CO)5. [85][86][87] However, IR spectra of crystalline 4 -6 are rather broad and contain more than the expected number of bands in the expected region of 1860-2060 cm −1 (Figures S9, S13, S16).…”

Recent developments in the chemistry of non-trigonal pnictogen pincer compounds: from bonding to catalysis

“…50,56,57,63 Recent reports of the coordination chemistry of such Pn(I) species to transition metal carbonyl species indicate that the occupied p-orbital at the pnictogen center is capable of acting as a 2e À donor ligand due to its observed metal coordination geometry, perpendicular to the molecular-plane. 21,51,57,[63][64][65][66][67][68] A recent review covers this topic comprehensively for phosphorus-based compounds, 31 however we would like to address new reports which make use of this unusual electronic conguration beyond traditional L-type ligand coordination. 1 was derivatized by 2-pyridyl substituents to provide a conned pocket for transition metal complexation.…”

(N),C,N‐Coordinated Heavier Group 13–15 Compounds: Synthesis, Structure and Applications

“…The initial examination of coordination abilities have been performed on Group 6 metals and iron carbonyls. In obtained 1 : 1 complexes, N,C,N ‐chelated pnictinidenes Ar N=C=N E (E=As, Sb, Bi) exclusively act as 2 e σ ‐donors via the p‐type lone pair as revealed by a DFT study (Scheme ). This fact is reflected in the perpendicular coordination of the ligand that differs significantly form classical trivalent counterparts R 3 E. The utilization of Mn and Co carbonyl complexes allowed isolation of structurally different compounds, albeit the coordination mode of the ligand via p ‐type orbital remained the same (Scheme ) …”