The pentacoordinate titanium complex [TiCl₂(NMe₂)₂(HNMe₂)]

Amido complexes of titanium are useful reagents in a variety of syntheses and as precursors for chemical vapour deposition of TiN. The title compound, di­chloro­bis­(di­methyl­amido)(di­methyl­amine)­titanium(IV), [TiCl₂(C₂H₆N)₂(C₂H₇N)], crystallizes with one mol­ecule in the asymmetric unit. The neutral complex shows an unusual fivefold coordination of the titanium centre with a distorted trigonal-bipyramidal geometry and the di­methyl­amine mol­ecule occupying an axial position.

S1. Comment

Crystals of dichlorobis(dimethylamido)(dimethylammine)titanium(IV), (I), were obtained as a side product of the synthesis of Ti(NMe₂)₄ from TiCl₄ and LiNMe₂. Sublimation of the residual solid gave crystals of (I) in a low isolated yield. \scheme

S2. Experimental

To a solution of dimethylamine (0.50 l, 2.0 M in THF, 1.0 mol), cooled to 195 K, was added a solution of n-butyllithium (0.63 l, 1.6 M in hexane, 1.0 mol). After stirring for 30 min, the solution was warmed to room temperature and stirred an additional 1 h. After cooling to 195 K, a solution of titanium tetrachloride (0.027 l, 0.25 mol) in hexane (0.10 l) was added slowly to the solution of lithium dimethylamide. The red–brown mixture was warmed to room temperature. Volatiles were removed in vacuo and the main product tetrakis(dimethylamido)titanium(IV) (44 g, 0.20 mol) collected by distillation (343 K at 0.5 Torr; 1 Torr = 133.322 Pa). The solid residue was placed in a large sublimator. Sublimation at room temperature and 0.5 Torr yielded yellow crystals of chlorotris(dimethylamido)titanium(IV) (1.5 g, 0.01 mol). After yellow crystals no longer formed on the cold finger of the sublimator the apparatus was placed in an oil bath held at 323 K whereupon large orange crystals of dichlorobis(dimethylamido)(dimethylamine)titanium(IV) (4.6 g, 0.02 mol) formed. Further sublimation at 353 K afforded a crop of red–brown crystals of dichlorobis(dimethylamido)titanium(IV) (3.7 g, 0.02 mol).

S3. Refinement

Backgrounds were obtained from analysis of the scan profile (Blessing et al., 1974). All H atoms were refined; N—H = 0.74 (2) Å and C—H = 0.87 (2)–1.08 (3) Å.

Computing details

Data collection: CAD-4 Operations Manual (Enraf-Nonius, 1977); cell refinement: CAD-4 Operations Manual; data reduction: PROCESS in MolEN (Fair, 1990); program(s) used to solve structure: Patterson and Fourier (MolEN); program(s) used to refine structure: LSFM in MolEN; software used to prepare material for publication: CIF VAX in MolEN.

(I)

Crystal data

C6H19Cl2N3Ti	F(000) = 528
Mr = 252.04	Dx = 1.32 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 8.3083 (7) Å	Cell parameters from 50 reflections
b = 11.5075 (9) Å	θ = 10–12°
c = 13.360 (2) Å	µ = 1.06 mm^−1
β = 96.034 (9)°	T = 225 K
V = 1270.3 (4) Å^3	Irregular block, orange
Z = 4	0.50 × 0.20 × 0.05 mm

Data collection

Enraf-Nonius CAD-4 diffractometer	Rint = 0.022
θ/2θ scans	θmax = 26.0°, θmin = 2.3°
Absorption correction: ψ scan (North et al., 1968)	h = 0→10
Tmin = 0.799, Tmax = 0.949	k = 0→14
2809 measured reflections	l = −16→16
2486 independent reflections	3 standard reflections every 50 min
1992 reflections with I > 3σ(I)	intensity decay: 0.1%

Refinement

Refinement on F	0 restraints
Least-squares matrix: full	All H-atom parameters refined
R[F^2 > 2σ(F^2)] = 0.030	w = 4Fo^2/[σ^2(Fo^2) + 0.0009Fo^4]
wR(F^2) = 0.040	(Δ/σ)max = 0.001
S = 1.29	Δρmax = 0.22 e Å^−3
1992 reflections	Δρmin = −0.34 e Å^−3
185 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Ti	0.72390 (4)	0.22524 (3)	0.75747 (3)	0.02432 (8)
Cl(1)	0.67764 (7)	0.36681 (5)	0.88297 (4)	0.0388 (1)
Cl(2)	0.84887 (9)	0.37154 (5)	0.67102 (5)	0.0524 (2)
N(1)	0.8142 (2)	0.1192 (2)	0.8518 (1)	0.0353 (5)
N(2)	0.5096 (2)	0.1895 (2)	0.7165 (2)	0.0387 (5)
N(3)	0.8074 (2)	0.1143 (2)	0.6337 (1)	0.0295 (4)
C(1)	0.7508 (4)	0.0191 (2)	0.8996 (2)	0.0569 (8)
C(2)	0.9718 (3)	0.1557 (2)	0.8990 (2)	0.0451 (6)
C(3)	0.4305 (3)	0.2019 (2)	0.6145 (2)	0.0538 (7)
C(4)	0.3962 (3)	0.1603 (3)	0.7884 (2)	0.0575 (8)
C(5)	0.7412 (3)	−0.0047 (2)	0.6315 (2)	0.0431 (6)
C(6)	0.9850 (3)	0.1073 (2)	0.6348 (2)	0.0440 (6)
H(1)	0.832 (4)	−0.048 (3)	0.897 (2)	0.11 (1)*
H(2)	0.652 (3)	0.002 (2)	0.866 (2)	0.049 (7)*
H(3)	0.721 (3)	0.039 (3)	0.971 (2)	0.09 (1)*
H(4)	0.957 (3)	0.182 (2)	0.967 (2)	0.060 (8)*
H(5)	1.053 (3)	0.100 (3)	0.894 (2)	0.070 (9)*
H(6)	1.012 (3)	0.222 (2)	0.867 (2)	0.041 (7)*
H(7)	0.351 (3)	0.259 (2)	0.609 (2)	0.069 (9)*
H(8)	0.384 (3)	0.128 (3)	0.584 (2)	0.08 (1)*
H(9)	0.509 (3)	0.223 (3)	0.567 (2)	0.072 (9)*
H(10)	0.459 (3)	0.161 (2)	0.863 (2)	0.066 (9)*
H(11)	0.320 (4)	0.224 (3)	0.787 (3)	0.11 (1)*
H(12)	0.349 (3)	0.085 (3)	0.773 (2)	0.09 (1)*
H(13)	0.619 (3)	−0.005 (2)	0.626 (2)	0.060 (8)*
H(14)	0.782 (3)	−0.040 (2)	0.685 (2)	0.059 (8)*
H(15)	0.765 (3)	−0.049 (3)	0.568 (2)	0.09 (1)*
H(16)	1.009 (3)	0.063 (2)	0.574 (2)	0.050 (7)*
H(17)	1.028 (3)	0.062 (2)	0.699 (2)	0.061 (8)*
H(18)	1.039 (3)	0.192 (3)	0.628 (2)	0.08 (1)*
H(19)	0.774 (2)	0.146 (2)	0.588 (2)	0.030 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ti	0.0263 (2)	0.0219 (2)	0.0245 (2)	−0.0017 (1)	0.0016 (1)	−0.0000 (1)
Cl(1)	0.0483 (3)	0.0347 (3)	0.0334 (3)	0.0077 (2)	0.0044 (2)	−0.0072 (2)
Cl(2)	0.0846 (4)	0.0319 (3)	0.0446 (3)	−0.0193 (3)	0.0255 (3)	−0.0016 (2)
N(1)	0.048 (1)	0.0289 (9)	0.0292 (9)	0.0082 (8)	0.0039 (8)	0.0009 (8)
N(2)	0.0292 (8)	0.036 (1)	0.050 (1)	−0.0014 (8)	0.0028 (8)	−0.0113 (9)
N(3)	0.0298 (8)	0.0323 (9)	0.0259 (8)	0.0008 (7)	0.0003 (7)	0.0001 (7)
C(1)	0.081 (2)	0.044 (1)	0.046 (1)	0.000 (1)	0.009 (1)	0.013 (1)
C(2)	0.050 (1)	0.048 (1)	0.036 (1)	0.017 (1)	−0.002 (1)	−0.003 (1)
C(3)	0.041 (1)	0.054 (2)	0.062 (2)	0.009 (1)	−0.014 (1)	−0.008 (1)
C(4)	0.039 (1)	0.060 (2)	0.077 (2)	−0.010 (1)	0.017 (1)	−0.006 (2)
C(5)	0.052 (1)	0.030 (1)	0.047 (1)	−0.005 (1)	0.004 (1)	−0.010 (1)
C(6)	0.035 (1)	0.056 (1)	0.042 (1)	0.005 (1)	0.007 (1)	−0.008 (1)

Geometric parameters (Å, º)

Ti—Cl(1)	2.3976 (7)	C(2)—H(4)	0.98 (3)
Ti—Cl(2)	2.3449 (8)	C(2)—H(5)	0.94 (3)
Ti—N(1)	1.855 (2)	C(2)—H(6)	0.95 (2)
Ti—N(2)	1.853 (2)	C(3)—H(7)	0.92 (3)
Ti—N(3)	2.255 (2)	C(3)—H(8)	1.00 (3)
N(1)—C(1)	1.443 (3)	C(3)—H(9)	0.99 (3)
N(1)—C(2)	1.455 (3)	C(4)—H(10)	1.08 (3)
N(2)—C(3)	1.456 (3)	C(4)—H(11)	0.96 (4)
N(2)—C(4)	1.454 (4)	C(4)—H(12)	0.96 (3)
N(3)—C(5)	1.474 (3)	C(5)—H(13)	1.01 (2)
N(3)—C(6)	1.476 (3)	C(5)—H(14)	0.87 (2)
N(3)—H(19)	0.74 (2)	C(5)—H(15)	1.02 (3)
C(1)—H(1)	1.03 (3)	C(6)—H(16)	1.00 (2)
C(1)—H(2)	0.92 (2)	C(6)—H(17)	1.03 (2)
C(1)—H(3)	1.04 (3)	C(6)—H(18)	1.08 (3)
Cl(1)—Ti—Cl(2)	88.20 (2)	N(1)—C(2)—H(5)	113 (2)
Cl(1)—Ti—N(1)	93.14 (6)	N(1)—C(2)—H(6)	112 (1)
Cl(1)—Ti—N(2)	97.90 (7)	H(4)—C(2)—H(5)	116 (2)
Cl(1)—Ti—N(3)	169.01 (5)	H(4)—C(2)—H(6)	105 (2)
Cl(2)—Ti—N(1)	129.69 (6)	H(5)—C(2)—H(6)	103 (2)
Cl(2)—Ti—N(2)	118.38 (7)	N(2)—C(3)—H(7)	113 (2)
Cl(2)—Ti—N(3)	81.91 (5)	N(2)—C(3)—H(8)	114 (2)
N(1)—Ti—N(2)	111.22 (9)	N(2)—C(3)—H(9)	112 (2)
N(1)—Ti—N(3)	89.55 (7)	H(7)—C(3)—H(8)	109 (2)
N(2)—Ti—N(3)	91.03 (8)	H(7)—C(3)—H(9)	106 (2)
Ti—N(1)—C(1)	133.3 (2)	H(8)—C(3)—H(9)	102 (2)
Ti—N(1)—C(2)	112.7 (1)	N(2)—C(4)—H(10)	109 (1)
C(1)—N(1)—C(2)	113.1 (2)	N(2)—C(4)—H(11)	106 (2)
Ti—N(2)—C(3)	125.4 (2)	N(2)—C(4)—H(12)	110 (2)
Ti—N(2)—C(4)	121.7 (2)	H(10)—C(4)—H(11)	105 (2)
C(3)—N(2)—C(4)	112.4 (2)	H(10)—C(4)—H(12)	110 (2)
Ti—N(3)—C(5)	113.4 (1)	H(11)—C(4)—H(12)	115 (3)
Ti—N(3)—C(6)	114.1 (1)	N(3)—C(5)—H(13)	112 (2)
Ti—N(3)—H(19)	102 (2)	N(3)—C(5)—H(14)	108 (2)
C(5)—N(3)—C(6)	108.7 (2)	N(3)—C(5)—H(15)	112 (2)
C(5)—N(3)—H(19)	110 (2)	H(13)—C(5)—H(14)	111 (2)
C(6)—N(3)—H(19)	109 (2)	H(13)—C(5)—H(15)	103 (2)
N(1)—C(1)—H(1)	108 (2)	H(14)—C(5)—H(15)	111 (2)
N(1)—C(1)—H(2)	107 (2)	N(3)—C(6)—H(16)	108 (1)
N(1)—C(1)—H(3)	111 (2)	N(3)—C(6)—H(17)	107 (1)
H(1)—C(1)—H(2)	112 (2)	N(3)—C(6)—H(18)	112 (1)
H(1)—C(1)—H(3)	115 (2)	H(16)—C(6)—H(17)	110 (2)
H(2)—C(1)—H(3)	102 (2)	H(16)—C(6)—H(18)	106 (2)
N(1)—C(2)—H(4)	107 (1)	H(17)—C(6)—H(18)	115 (2)