1,3-Bis(N,N,N′,N′-tetramethylguanidino)propane: synthesis, characterization and bonding properties of the first bidentate, peralkylated guanidine ligand †

Abstract

The first bidentate, peralkylated guanidine based ligand has been synthesized and its complexation chemistry examined by the preparation of three representative coordination compounds. The novel chelate ligand 1,3-bis(N,N,NЈ,NЈ-tetramethylguanidino)propane (btmgp, 1) has been synthesized by the reaction of N,N,NЈ,NЈtetramethylguanidine (TMG) with 1,3-dibromopropane and subsequent deprotonation of the resulting guanidinium salt with sodium ethoxide. The bifunctional N-donor compound was treated with copper() iodide, copper() chloride and iron() iodide in a 1 : 1 molar ratio to yield the corresponding electroneutral complexes [CuI(btmgp)] 2, [CuCl 2 (btmgp)] 3 and [FeI 2 (btmgp)] 4. The structures of the dihydrochloride of 1 (1b) and of the complexes 2-4 have been determined by X-ray crystallography. A comparison of the molecular structures (2-4) shows that, in each case, btmgp acts as a bidentate ligand which is able to stabilize not only trigonal-planar (2), but also (distorted) square-planar (3) and tetrahedral coordination environments (4).

Mono‐ and Diprotonation of the Superbasic Bisguanidine 1,2‐Bis(N,N,N′,N′‐tetramethylguanidino)benzene (btmgb) and PtII and PtIV Complexes of Chelating Bisguanidines and Guanidinates

“…Keywords: chelates · guanidinates · guanidines · platinum · structure elucidation transition metal complexes include the CuI, CuCl 2 , and FeI 2 complexes of btmgp. [8] Owing to their strong basicity, complexes with guanidine ligands should have interesting properties. Hence with the tripodal tren (tris(2-aminoethyl)amine) derivative tris(tetramethylguanidino)tren ((tmg) 3 tren), the cationic Cu complex [(tmg) 3 …”

“…Table 7. Selected bond lengths [pm] and angles [8] of 6 as obtained by Xray diffraction studies(see Figure 6 for atom numbering). …”

“…[4,5] The application of these molecules as ligands in molecular complexes of transition metals, however, is still very underdeveloped. Bridged bisguanidine molecules which have been synthesized [6] include 1,2-bis(N,N,N',N'-tetramethylguanidino)ethane [7] (btmge), 1,3-bis(N,N,N',N'-tetramethylguanidino)propane [8] (btmgp), 1,2-bis(N,N,N',N'-tetramethylguanidino)benzene [9] (btmgb), 1,8-bis(N,N,N',N'-tetramethylguanidino)naphthalene [1] (btmgn), and 2,2'-bis(N,N,N',N'-tetramethylguanidino)biphenyl (btmgbp) [10] . Rare examples of structurally characterized …”

The Flexible Coordination Modes of Guanidine Ligands in Zn Alkyl and Halide Complexes: Chances for Catalysis

“…Recently, a Cu I complex of a tripodal, superbasic and sterically encumbered tris-(tetramethylguandino)tren (TMG3tren) ligand, which forms the first 1:1 Cu/O 2 complex featuring an end-on-coordinated superoxo (O 2 -) unit and its chemistry were reported. [5,6] Other Cu and also Fe complexes of chelating guanidines were synthesized by Henkel, Tamm et al [7,8] Group 10 (Ni, Pd and Pt) and Zn, Mg and Al complexes of chelating guanidines and their application in some catalytic reactions were studied by our group. [9] Bis(imines) are known to be excellent ligands in late-transition metal complexes that can be applied as catalysts in olefin polymerization.…”

Successive Ligand and Metal Oxidation: Redox Reactions Involving Binuclear CuI Complexes of Chelating Guanidine Ligands

“…[9,10] Harmjanz, Henkel et al showed that 1,3-bis(tetramethylguanidino)propane can be used as a bidentate ligand in a number of complexes including Cu I and Cu II . [11] In addition, Tamm et al reported on the synthesis and reactivity of some Cu I complexes that feature bisguanidine ligands. [12] Reactions of some of these complexes with O 2 were analyzed, and the complexes were successfully applied as catalysts for the polymerization of styrene.…”