Synthesis and structural characterisation of some novel lithium and sodium N,N′-di(para-tolyl)formamidinate complexes

Abstract

Treatment of N, NЈ-di(para-tolyl)formamidine (p-tolylformH) (1) with LiBu n in THF, DME or hexane/TMEDA leads to deprotonation of the amidine affording [Li 2 (p-tolylform) 2 (THF) 3 ]ؒ2THF (2), [Li(DME) 3 ][Li 2 (p-tolylform) 3 ] (3) and [{Li 2 (p-tolylform) 2 (TMEDA)} ∞ ] (4) respectively. Similar treatment of 1 with NaH or [Na{N(SiMe 3 ) 2 }] in THF or DME yields trinuclear [Na 3 (p-tolylform) 3 (THF) 4 ] (5) and dinuclear [{Na(p-tolylform)(DME)} 2 ] ( 6). All complexes were characterised by spectroscopy (NMR and IR) and X-ray crystallography. These show p-tolylform to be a versatile ligand for alkali metals, exhibiting a wide variety of binding modes, viz. µ-η 1 :η 1 in 2 and 3 (i.e. bridging mode), µ-η 2 :η 1 in 4 and 6 (i.e. bridging and chelating) and µ-η 2 :η 2 (i.e. bridging and double chelating) and µ 3 -η 2 :η 1 :η 1 (i.e. chelating and bridging between three metal centres) in 5. DALTON

Synthesis, structures, and properties of lantern-type dinuclear ruthenium(II,III) complexes cis-[Ru2{3,5-(CF3)2-pf}2(O2CMe)2Cl] and [Ru2{3,5-(CF3)2-pf}3(O2CMe)Cl], 3,5-(CF3)2-pf−=N,N′-bis[3,5-bis(trifluoromethyl)phenyl]formamidinate anion

“…S1. As previously reported for the other formamidines, the C-N bond lengths are different (C(1)-N(1) = 1.286(2) Å and C(2)-N(1) = 1.4199(19) Å) in the N-CH-N skeleton between two phenyl rings [18][19][20][21][22]. The former C-N bond length corresponds to the C@N (imine) double bond and the latter C-N bond length corresponds to the C-N (amine) single bond.…”

“…There are disorders at fluorine atoms for H{3,5-(CF 3 ) 2 -pf} and 4(acetone)ÁC 6 H 14 , hence their positions were divided to two positions (F(4), F(5), F(6), and F (7)) for H{3,5-(CF 3 ) 2 -pf} (see Fig. S1) and F(16), F(17), F (20), F(31) and F(32) for 4(acetone)ÁC 6 H 14 (see Fig. 2).…”

Potassium C–F Interactions and the Structural Consequences in N,N′-Bis(2,6-difluorophenyl)formamidinate Complexes

“…This further led to partial, or complete, exclusion of bound donor molecules (e.g., Et2O, thf), by the formation of either binuclear, or for potassium, polymeric constructs (e.g., [Na(FForm)(Et2O)]2 or [K(FForm)]∞) [19]. This contrasts the group one complexes of the non-fluorinated N,N′-di(aryl)formamidinate ligands [21][22][23], which readily retain coordinating solvent. Since then, we have expanded the use of fluorinated formamidinate ligands to f-block chemistry [9,16,17,[24][25][26][27][28], in a variety of different contexts [5].…”

“…Initial extension of the coordination of the DFForm ligand in 1 shows that the nitrogen atoms are further bridging to an adjacent potassium ion in a μ-(N,N′):(N,N′) manner ( Figure 1C, also Figure 2A). Such formamidinate bridging is known for other s-and f-block complexes [16,22,31]. This bridging is mirrored by a symmetry equivalent DFForm ligand, generating a potassium nitrogen based cube of volume: 6.78 Å 3 ( Figure 1C).…”

Synthesis of O,O Ethane Bridged Bis-copper(II) Macrocycles. Selective Enzyme Model for Catecholase Activity

“…The 13 C carbon signals appear in the same range in the dinuclear complex along with a new signal at 68-70 p.p.m. due to O-CH 2 -CH 2 -O which further authenticate the formation of the CH 2 -CH 2 -bridged dinuclear Ni(II) complex [41]. …”