Syntheses and Spectroscopic and Structural Characterization of Silver(I) Complexes Containing Tertiary Phosphines and Hydrotris(pyrazol-1-yl)-, Hydrotris(4-bromopyrazol-1-yl)-, Hydrotris(3,5-dimethypyrazol-1-yl)-, and Hydrotris(3-methyl-2-thioxo-1-imidazolyl)borates

(Trialkyl- and (triarylphosphine)silver(I)
derivatives containing anionic
tris(1H-pyrazol-1-yl)borates were
prepared
from AgX (X = CF3SO3 or
NO3), PR3 (R = phenyl, benzyl, cyclohexyl,
2,4,6-trimethylphenyl, or o-, m-,
and
p-tolyl) or PMePh2, and
M[HB(pz)3] [M = K or Na; pzH = pyrazole in
general; in detail, pyrazole (PzH), 3,5-dimethylpyrazole (3,5-Me2PzH), or 4-bromopyrazole
(4-BrPzH)] and characterized through analytical and
spectral
(IR; 1H, 13C, and 31P NMR)
measurements. These air stable, light-sensitive complexes are not
electrolytes in
CH2Cl2 and acetone. In these solvents
they decompose even with strict exclusion of oxygen and light.
The
solid-state structures show that the silver atom adopts a distorted
tetrahedral geometry. Crystal data with Mo Kα
(λ = 0.710 70 Å) at 293 K: 
[HB(Pz)3]Ag(PPh3),
C54H50Ag2B2N12P2,
a = 15.082(2) Å, b = 19.728(2) Å,
c =
9.432(1) Å, α = 94.8(1)°, β = 107.4(1)°,
γ = 87.8(1)°, triclinic, P1̄, Z
= 2;
[HB(Pz)3]Ag[P(o-tolyl)3],
C30H31AgBN6P, a = 14.461(2) Å, b =
14.461(2) Å, c = 30.473(2) Å, α = 90°,
β = 90°, γ = 120°, trigonal, R3̄,
Z =
6; [HB(Pz)3]AgP(Bz)3,
C30H31AgBN6P, a =
12.183(2) Å, b = 18.596(2) Å, c =
13.804(2) Å, β = 100.8(1)°,
monoclinic, P21/n, Z =
4;
[HB(3,5-Me2Pz)3]Ag[P(p-tolyl)3],
C36H41AgBN6P, a =
34.839(3) Å, b = 10.375(2) Å,
c = 10.203(2) Å, β = 90.8(1)°,
monoclinic, P21/n, Z = 4. Crystal data
with Cu Kα (λ = 1.5418 Å):  [HB(4-BrPz)3]AgPPh3,
C27H22AgBBr3N6P2,
a = 10.306(2) Å, b = 11.425(2) Å,
c = 13.571(2) Å, α = 90.3(1)°, β
=
107.0(1)°, γ = 91.4(1)°, triclinic,
P1̄, Z = 2. The anionic soft
S3-donor
hydrotris(3-methyl-2-thioxo-1-imidazolyl)borate (Tm) was synthesized as its potassium salt from the
corresponding imidazole and KBH4 in high
yield.
The potassium complex KTm was used as ligand transfer agent in the
preparation of the silver(I) derivatives
[(Tm)Ag]n and
(Tm)Ag(PPh3). The S-donor
1-methylimidazolyl-2-thione (Hmimt) reacts with
[HB(3,5-Me2Pz)3]Ag(PPh3), yielding the
derivative
[HB(3,5-Me2Pz)3](Hmimt)AgPPh3
in which the
[HB(3,5-Me2Pz)3]-
acts
likely as bidentate N2-donor.