Inorganic Chemistry, Vol.41, No.1, 19-27, 2002
Syntheses and solid state structures of tris(pyrazolyl) methane complexes of sodium, potassium, calcium, and strontium: Comparison of structures with analogous complexes of lead(II)
The reaction of NaI with 2 equiv of HC(pz)(3) or HC(3,5-Me(2)pz)(3) (pz = pyrazolyl ring) leads to the formation of {[HC(pz)(3)](2)Na}(I) (1) and {[HC(3,5-Me(2)pz)(3)](2)Na}(I) (2), respectively. Both compounds have trigonally distorted octahedral arrangements about the sodium. A similar reaction of KPF6 with HC(3,5-Me(2)pz)(3) results in the formation of {[HC(3,5-Me(2)pz)(3)](2)K}(PF6) (3), a complex also shown crystallographically to have a trigonally distorted octahedral arrangement about the potassium, which is an unusually low coordination number for this large metal ion. The complex {[HC(pz)(3)](2)Sr}(BF4)(2) (4) forms in the reaction of Sr(acac)(2) (acac = acetylacetonate) with HBF4.Et2O followed by 2 equiv of HC(pz)(3). The structure is highly distorted, showing k(3) bonding of both tris(pyrazolyl)methane ligands and, in addition, interactions with the metal from three fluorine atoms from the BF4- counterions. The symmetrical structure of 1 and the nine-coordinate structure of 4 are both very different from the distorted, six-coordinate structure {[HC(pz)(3)](2)Pb}(BF4)(2), indicating that for this compound the lone pair on lead(II) is influencing the structure. The reaction of M(acac)(2) (M = Sr, Ca) with H{B[3,5-(CF3)(2)C6H3](4)} followed by 2 equiv of HC(pz)(3) produces {[HC(pz)(3)](2)(Hacac)Sr}{B[3,5-(CF3)(2)C6H3](4)}(2) (5) (when the reaction is done in CH2Cl2), {[HC(pz)(3)](2)(Me2CO)(2)Sr} {B[3,5-(CF3)(2)C6H3](4)}(2) (6) (when the reaction is done in acetone), and {[HC(pz)(3)](2)(Hacac)Ca}{B[3,5-(CF3)(2)C6H3](4)}(2) (7), respectively. The structures of all three complexes show a distorted eight-coordinate arrangement of the ligands about the metal. Crystal data: 1 is orthorhombic, Pnma, a = 16.931 (1), b = 22.368(3), c = 7.937-(2) Angstrom, alpha = 90, beta = 90, gamma = 90degrees, Z = 4; 2 is trigonal, R (3) over bar, a = 10.7483(8), b = 10.7483(8), c = 35.395(4) Angstrom, alpha = 90, beta = 90, gamma = 120degrees, Z = 3; 3 is monoclinic, P2(1)/c, a = 9.144(4), b = 13.377(6), c = 15.988(7) Angstrom, alpha = 90, beta = 92.291(10), gamma = 90degrees, Z = 2; 4 is hexagonal, P6(5), a = 9.42530(10), b = 9.42530(10), c = 55.3713(5) Angstrom, alpha = 90, beta = 90, gamma = 120degrees, Z = 6; 5 is monoclinic, P2/n, a = 14.1601(3), b = 13.1756(3), c = 27.1826(6) Angstrom, alpha = 90, beta = 90.1744(7), gamma = 90degrees, Z = 2; 6 is monoclinic, P2/n, a = 14.2709(7), b = 13.2646(7), c = 27.4189(13) Angstrom, alpha = 90, beta = 90.3850(10), gamma = 90degrees, Z = 2; 7 is monoclinic, P2/n, a = 14.2388(2), b = 13.1919-(2), c = 26.7879(3) Angstrom, alpha = 90, beta = 90.0650(8), gamma = 90degrees, Z = 2.