Mononuclear Molybdenum(IV) Complexes with Two Multiply Bonded Chalcogen Ligands in Trans Configuration and Chelating Biphosphine Ligands
dataset
posted on 1997-05-21, 00:00 authored by F. Albert Cotton, Günter SchmidA series of molybdenum(IV) complexes of the type
trans-Mo(Q)(Q‘)(P⌒P)2 has been
prepared where Q and Q‘
are chalcogen ligands (O, S, Se, Te) and P⌒P is either
cis-1,2-bis(diphenylphosphino)ethylene (dppee) or
1,2-bis(diphenylphosphino)ethane (dppe). X-ray
crystallographic studies were carried out to investigate how
the
Mo−Q distance is influenced by the mutually competitive
dπ−pπ interactions between the
px and py orbitals
of
the chalcogen ligands and the dxz and
dyz orbitals of the molybdenum center.
trans-Mo(O)2(dppee)2
(1) has been
prepared by the hydrolysis and deprotonation reaction of
[Mo(O)(Cl)(dppee)2]Cl with NaOH in
methanol. The
compounds where Q represents the heavier chalcogens (S, Se, Te) have
been prepared by the reaction between
trans-Mo(N2)2(P⌒P)2
and a chalcogen source:
trans-Mo(S)2(dppee)2
(2), BzS3Bz (dibenzyl trisulfide);
trans-Mo(Se)2(dppee)2 (3),
elemental Se;
trans-Mo(Te)2(dppee)2
(4), TePEt3 (Et = ethyl);
trans-Mo(S)2(dppe)2
(5),
BzS3Bz;
trans-Mo(Se)2(dppe)2
(6), Se.
trans-Mo(O)(S)(dppee)2
(7) was obtained from the reaction of
MoCl3(THF)3 (THF = tetrahydrofuran), dppee, and NaHS in a
mixture of THF and methanol. The attempted
preparation
of 7 by the reaction of SO2 and
trans-Mo(N2)2(dppee)2
yielded Mo(SO2)2(dppee)2
(8). 1 crystallizes in the
monoclinic space group P21/c (No. 14,
Z = 2) with a = 11.1340(15) Å,
b = 18.435(2) Å, c = 12.515(2) Å,
and
β = 110.999(9)°; 2 crystallizes in the triclinic
space group P1̄ (No. 2, Z = 1) with
a = 10.102(4) Å, b =
10.722(4) Å, c = 12.195(3) Å, α = 100.95(3)°,
β = 95.04(4)°, and γ = 117.81(2)°; 3
crystallizes in the monoclinic
space group P21/c (No. 14,
Z = 2) with a = 11.186(5) Å,
b = 18.005(8) Å, c = 12.761(9) Å,
and β = 110.35(4)°; 4 crystallizes in the triclinic space group
P1̄ (No. 2, Z = 2) with a =
12.681(4) Å, b = 19.280(5) Å, c
=
10.454(3) Å, α = 104.60(2)°, β =
111.61(2)°, and γ = 75.12(2)°; 5
crystallizes in the monoclinic space group
C2/c (No. 15, Z = 8) with
a = 49.515(7) Å, b = 10.9286(12)
Å, c = 18.203(3) Å, and β = 98.306(12)°;
6
crystallizes in the monoclinic space group C2/c
(No. 15, Z = 8) with a = 49.566(9) Å,
b = 10.9765(15) Å,
c = 18.282(3) Å, and β = 98.541(13)°;
7 crystallizes in the triclinic space group
P1̄ (No. 2, Z = 1) with a
=
10.040(1) Å, b = 10.563(1) Å, c =
12.162(2) Å, α = 75.30(1)°, β = 85.93(1)°,
and γ = 63.21(1)°; 8 crystallizes
in the monoclinic space group C2/c (No. 15,
Z = 4) with a = 21.534(6) Å,
b = 12.4271(13) Å, c =
19.550(5)
Å, and β = 118.480(14)°. The UV/vis and the
31P{1H} NMR data for compounds
1−7 are also reported and
discussed.
