Tetrahedral nickel nitrosyl complexes with tripodal [N3] and [Se3] donor ancillary ligands: structural and computational evidence that a linear nitrosyl is a trivalent ligand

Abstract

Linear nickel nitrosyl compounds supported by tridentate nitrogen and selenium ligands, namely the tris(3,5-dimethylpyrazolyl)hydroborato and tris(2-seleno-1-mesitylimidazolyl)hydroborato complexes, [TpMe2]NiNO and [TseMes]NiNO, have been synthesized and structurally characterized by X-ray diffraction. Computational studies demonstrate that the linear nitrosyl ligand behaves as a trivalent X3 ligand such that the Ni-N interaction has multiple bond character.

Metal–Ligand Electron Transfer in 4d and 5d Group 9 Transition Metal Complexes with Pyridine, Diimine Ligands

“…[28,31,32,33] While IR and 15 N NMR spectroscopic data are helpful to distinguish between the linear and bent binding modes of the NO ligand, the assignment of its formal charge, for example NO + /NO -/NO 3-, is not unambiguously possible. [28] Problems with the assignment of formal oxidation states in metal nitrosyl complexes can be circumvented in an elegant way using the Enemark and Feltham {MNO} n notation.…”

“…[28,31,33,34,35] Currently, charges of +1, -1, and -3 for the linear and -1 and -3 for the bent M-NO binding modes are considered. [32] Note that, for the sake of argument, the triply negatively charged ligand has not been included in the previous discussion. The electronic situation (MϵN + -O -) would nevertheless be identical to the N 3-ligand (entries 9 and 10 in Table 1).…”

“…Unfortunately, the 15 N NMR spectroscopic data provide only little information with regard to the electron count within the NO moiety (NO + /NO -, NO 3-). [28,32,31] These data can be summed up as follows: (1) Two electrons are transferred from the d xz orbital to ligand-centered orbitals. Based on the long bond length of the exocyclic C-C bond of the pyridine unit in combination with the Mulliken population analysis, we suggest that these electrons are exclusively transferred to the PDI ligand, rendering it doubly reduced, PDI 2-.…”

Synthetic Bioinorganic Chemistry: Scorpionates Turn 50

“…Given the popularity of Tm R ligands since their inception 20 years ago, it was only a matter of time until their oxygen and selenium analogues would emerge. Predictably, Parkin and coworkers have already reported the syntheses and initial reactivity studies of the tris(oxoimidazolyl)borate (To R ) [162] and tris (selenoimidazolyl)borate (Tse R ) [163][164][165] ligand systems ( Fig. 13) in 2006 and 2011, respectively.…”

The Stability of Mercaptobenzothiazole Based Soft Scorpionate Complexes

“…A schematic representation of the developments in scorpionate chemistry. From left to right: hydrotris(pyrazolyl)borate (Tp) (far left) [1,2]; the soft scorpionates hydrotris(methimazolyl)borate (Tm R ; R = Me, Ph, t Bu, etc)(centre left, top) [4,5] and hydrotris(mercaptobenzothiazolyl)borate (Tbz)(centre left, below) [9]; selenium and oxygen donor systems (centre right) [6,14,15]; and the poly(alkylthioalkyl)borates (right) [3,16]. The tetrakis(thioalky)borate anion (top right) was the first alternative soft donor system to be reported [3].…”