Structural Studies of Bis-Catecholate, Bis-Dithiocatecholate, and Tetraalkoxy Diborane(4) Compounds

X-ray structures are described for the bis-catecholate, bis-dithiocatecholate, and tetraalkoxy diborane(4) compounds
B2(1,2-O2C6H4)2 (1), B2(1,2-O2-4-ButC6H3)2 (2), B2(1,2-O2-3,5-But2C6H2)2 (3), B2(1,2-S2C6H4)2 (4), B2(1,2-S2-4-MeC6H3)2 (5), and B2(OCH2CMe2CH2O)2 (6). All the compounds adopt structures in the solid-state in which
the B2O4 or B2S4 units are planar or very nearly so. In compounds 2 and 3, the dihedral angles between the two
BO2C2 planes are 17.3 and 31.8° respectively whereas in 1, 4 and 5 these angles are exactly 0°. In 6, a 3-fold
disorder precluded our obtaining accurate positions for the two boron atoms, yet a dihedral angle of 0° is required
by the 3̄ site symmetry. The structure of the bis(Lewis base) adduct of B2Cl4, [B2Cl4(NHMe2)2] (7), is also
described and structures of the salt [NH2Me2][B(1,2-O2C6H4)2] (8) and the NMe2-bridged dimer [{BCl2(μ-NMe2)}2]
(9) are available in the Supporting Information. Compound 1 crystallized in the monoclinic space group P21/c
with a = 4.746(1) Å, b = 16.427(3) Å, c = 7.053(2) Å, β = 98.59(2)°, and Z = 2. Crystals of 2 were monoclinic,
space group P21/c with a = 6.847(1) Å, b = 18.871(5) Å, c = 15.270(2) Å, β = 93.16(2)°, and Z = 4. Crystals
of 3 were triclinic, space group P1̄ with a = 9.478(4) Å, b = 10.355(4) Å, c = 15.082(7) Å, α = 105.71(3)°, β
= 100.31(4)°, γ = 94.58(3)°, and Z = 2. Crystals of 4 were monoclinic, space group P21/c with a = 15.364(3)
Å, b = 4.0502(4) Å, c = 21.532(3) Å, β = 99.320(7)°, and Z = 4. Crystals of 5 were monoclinic, space group
P21/c with a = 6.0458(9) Å, b = 7.5319(11) Å, c = 16.552(2) Å, β = 96.291(3)° and Z = 2. Compound 6
crystallized in the rhombohedral space group R3̄m with a = 8.876(2) Å, c = 13.821(3) Å and Z = 3. Crystals
of 7 were monoclinic, space group P21/c with a = 11.831(3) Å, b = 19.458(5) Å, c = 14.823(5) Å, β = 96.63(4)°, and Z = 12.