Rt. Stibrany et al., Product of a DMF aminalization, bis[bis(3,5-dimethylpyrazol-1-yl)(dimethylamino)methane]copper(II) perchlorate-bis(dichloromethane), INORG CHEM, 38(1), 1999, pp. 132-135
Bis[bis(3,5-dimethylpyrazol-1-yl)(dimethylamino)methane]copper(II) perchlor
ate-bis(dichloromethane), Cu(II)-(1)(2)(ClO4)(2). 2CH(2)Cl(2), 2, is the un
anticipated product of the reaction of tris(3,5-dimethylpyrazol-1-yl)methyl
silane, 3, with Cu(II)(DMF)(4) (ClO4)(2). In the title complex, the Cu(II)(
1)(2) cations exhibit a tetragonal Cu(II)N-6 geometry arising from coordina
tion of four pyrazole N atoms and two tertiary amine Id atoms from two bis(
3,5-dimethylpyrazol-1-yl)(dimethylamino)methane ligands, 1. The tridentate
(N)3 ligands 1 coordinate copper facially with one Cu-N (pyrazole) axial [C
u-N, 2.407(4) Angstrom] and the second equatorial [Cu-N, 1.995(4) Angstrom]
; the cations exhibit crystallographic 2-fold symmetry that relates one lig
and to the other. Cu(II)(1)(2)(ClO4)(2). 2CH(2)Cl(2), CuC28H46-Cl6N10O8. 2C
H(2)Cl(2), 2CH(2)Cl(2), crystallizes in the monoclinic space group C2/c, wi
th a 26.278(5) Angstrom, b = 8.835(2) Angstrom, c = 20.655(4) Angstrom. bet
a = 120.73(3)degrees, Z = 4, and R-F (R-wF(2)) = 0.049 (0.122) for 1979 obs
erved reflections with I > 2 sigma(I). Crystals of 2 an stable in dry air b
ut hydrolyze readily to yield dirnethylformamide and 3,5-dimethylpyrazole.
A mechanism is proposed for the formation of complex 2 by silane-promoted a
minalization tan aminal is the diaza analogue of an acetal) of dimethylform
amide.