Synthesis and crystal structure of an octahedral nickel(II) complex derived from pentaerythrityl tetraamine

Abstract

A. MCAULEY, S. SUBRAMANIAN, and T. W. WHITCOMBE. Can. J. Chem. 67, 1650 (1989). The Ni(I1) complex, ~i ( H t a m )~~+ (tam = pentaerythrityl tetraamine), has been prepared under controlled conditions. In this ion, three of the four amino groups of each ligand are coordinated to yield an octahedral structure which shows tetragonal and trigonal distortion. The fourth amino group is protonated in each case and binds strongly to the counter ion so4*-. The crystal structure (triclinic, P i , a = 8.913(3), b = 9.775(2), c = 7.505(3), a = 102.61(4)", P = 106.28(4)", y = 96.40(3)") has been refined, converging to final values ofR = 0.0347 and R,,, = 0.0386. The three dimensional nature of the hydrogen bonding in the crystal structure has been described. Differences in Ni-N bond lengths are observed. A transient nickel(II1) species is generated chemically or electrochemically. The esr spectrum is consistent with a low spin d7 centre and is axial in nature.Key words: nickel, pentaerythrityl tetraamine, hydrogen bonding, oxidation.A. MCAULEY, S. SUBRAMANIAN et T. W. WHITCOMBE. Can. J. Chem. 67, 1650 (1989). Optrant dans des conditions contr61ies, on a pripari le complexe de Ni(II), N i ( H t a~n )~~+ (tam = pentatrythrityl tttraamine). Dans cet ion, trois des quatre groupements amints de chacun des ligands sont coordonnis pour donner une structure octaedrique qui prtsente une distorsion tttragonale et trigonale. Dans chaque cas, le quatritme-groupement amini est protone et il se lie fortement au contre-ion ~0 4~' .On a affini la structure cristalline (triclinique, PI, a = 8,913(3), b = 9,775(2) et c = 7,505(3) A, a = 102,61(4), P = 106,28(4) et y = 96,40(3)") jusqu'i des valeurs finales de R = 0,0347 et R,,. = 0,0386. On decrit la nature tridimensionnelle des liaisons hydrogenes dans la structure cristalline. On a observt des differences dans les longueurs des liaisons Ni-N. I1 y a gkniration chimique ou Clectrochimique d'une espece transitoire de Ni(II1). Le spectre rpe est en accord avec un centre d7 de faible spin et de nature exiale.

Pentaerythrityltetramine Scaffolds for Solid-Phase Combinatorial Chemistry1

“…The first large-scale synthesis of pentaerythrityltetramine [tetrakis(aminomethyl)methane, TAM] was based on displacement of the bromo substituents from pentaerythrityl tetrabromide with p -toluenesulfonamide ion and subsequent hydrolysis of the sulfonamide groups with sulfuric acid . The more recent syntheses include treatment of pentaerythrityl tetrachloride with excess of supercritical ammonia and reduction of the explosive tetra azide analogue. − The conversion of commercially available 2,2-bis(bromomethyl)propane-1,3-diol ( 14 ) to 2,2-bis(azidomethyl)propane-1,3-diol and further to 2,2-bis(hydroxymethyl)propane-1,3-diamine ( 15 ), described by Bitha et al, , appeared, however, a more appropriate method to obtain the desired branching units 1 and 2 . The amino groups of 15 were Boc-protected ( 16 ) and the hydroxy groups mesylated ( 17 ).…”

Pentaerythrityltetramine

“…Pentaerythrityltetramine , has been suggested as a precipitant for nitric acid and as a starting material for several products. Although at least three laboratory procedures ,, for preparing it are available, the tetramine has never been available as a high-volume, staple item. There is a need for a preparative procedure suitable for large-scale manufacture.…”