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Acta Cryst. (2007). E63, m2452    [ doi:10.1107/S1600536807042547 ]

(2,2'-Biquinoline)tetracarbonylmolybdenum(0)

K. J. Muir, G. P. McQuillan and W. T. A. Harrison

Abstract top

In the title compound, [Mo(C18H12N2)(CO)4], the differences in the Mo-C and C-O bond lengths may be interpreted in terms of a classical back-bonding model of electronic structure. In the crystal structure, an acute C-H...O interaction may help to establish the packing.

Comment top

Although the substitution reactions of Mo(CO)6 with amine bases have been intensively studied for many decades (Cotton & Wilkinson, 1966), the crystal structures of many of the resulting compounds remain to be studied. The structure of the simple compound Mo(CO)4(C10H8N2), (I), (Braga et al., 2007) has just been reported (C10H8N2 = 2,2-bipyridine or bipy).

In the title compound, (II), Mo(CO)4(C18H12N2), 2,2'-biquinoline (biquin) has replaced bipy. A distorted cis-MoN2C4 octahedron results for the metal (Fig. 1, Table 1). The N—Mo—N bite angle for the biquin molecule is 72.31 (6)°. The dihedral angle between the N1/C5/C10—C13 and N2/C14—C17/C22 ring systems of 16.57 (11)° in (II) indicates a significant degree of twisting about the linking C13—C14 bond. The quinoline fused rings are slightly distorted from planarity: the C5—C10 and N1/C5/C10—C13 rings make a dihedral angle of 2.15 (11)°; C17—C22 and N2/C14—C17/C22 are twisted by 3.46 (12)°. Mo1 is close to coplanar with N1/C5/C10—C15 [displacement = −0.030 (1) Å] but substantially displaced, by 0.715 (1) Å, from N2/C14—C17/C22. Otherwise, all the biquin bond lengths and angles may be regarded as normal (Allen et al., 1995). The C2—Mo1—C4 bond angle of 169.31 (9)° indicates that these two carbonyl groups are bent away from the biquin molecule, perhaps for steric reasons.

The four Mo—C bond lengths in (II) fall into two groups of two. The shorter Mo1—C1 and Mo1—C3 bonds are trans to the diquin N atoms and the longer Mo1—C2 and Mo1—C4 bonds are trans to each other. The traditional explanation for this phenomenon assesses the π-acceptor propeties of the ligand trans to the carbon atom in question. If the trans atom has little or no π acceptor properties, then there is a greater tendency for the C atom to accept back bonded metal d electrons, and the Mo—C bond assumes a higher bond order and is shortened. Because the back bonded electrons are accommodated in the antibonding π* orbital of CO, the C—O bond length is expected to be lengthened as the Mo—C bond length decreases. This effect seems to be just visible in the present study, with the mean of C1—O1 and C3—O3 some 0.024Å longer than the mean of C2—O2 and C4—O4.

In the crystal of (II), an acute C—H···O interaction (Table 2) may help to establish the packing. There are also a number of π-π stacking contacts with centroid-centroid separations in the range 3.6623 (13)–3.8227 (13) Å.

Related literature top

For a related structure, see: Braga et al., (2007). For background, see: Cotton & Wilkinson (1966). For reference structural data, see: Allen et al. (1995).

Experimental top

Equimolar quantities of Mo(CO)6 and and 2,2'-biquinoline were refluxed in toluene under an N2 atmosphere for six hours. After cooling, air-stable, dark orange, blocks of (II) were recovered by vacuum filtration and rinsing with light petroleum ether in 78% yield based on Mo(CO)6.

Refinement top

The hydrogen atoms were geometrically placed (C—H = 0.93 Å) and refined as riding with Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. View of the molecular structure of the title compound showing 50% displacement ellipsoids (arbitrary spheres for the H atoms).
(2,2'-Biquinoline)tetracarbonylmolybdenum(0) top
Crystal data top
[Mo(C18H12N2)(CO)4]Z = 2
Mr = 464.28F000 = 464
Triclinic, P1Dx = 1.690 Mg m−3
Hall symbol: -P 1Mo Kα radiation
λ = 0.71073 Å
a = 7.7365 (4) ÅCell parameters from 4201 reflections
b = 9.8294 (5) Åθ = 2.6–29.8º
c = 12.8060 (6) ŵ = 0.75 mm−1
α = 93.512 (1)ºT = 296 (2) K
β = 94.215 (1)ºBlock, very dark orange
γ = 109.394 (1)º0.42 × 0.18 × 0.12 mm
V = 912.29 (8) Å3
Data collection top
Bruker SMART1000 CCD
diffractometer		5200 independent reflections
Radiation source: fine-focus sealed tube4267 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.021
T = 296(2) Kθmax = 30.0º
ω scansθmin = 2.2º
Absorption correction: multi-scan
(SADABS; Bruker, 1999)		h = −10→10
Tmin = 0.743, Tmax = 0.917k = −13→12
8669 measured reflectionsl = −17→15
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.031H-atom parameters constrained
wR(F2) = 0.079  w = 1/[σ2(Fo2) + (0.0418P)2]
where P = (Fo2 + 2Fc2)/3
S = 0.99(Δ/σ)max = 0.001
5200 reflectionsΔρmax = 0.59 e Å−3
262 parametersΔρmin = −0.66 e Å−3
Primary atom site location: structure-invariant direct methodsExtinction correction: none
Crystal data top
[Mo(C18H12N2)(CO)4]γ = 109.394 (1)º
Mr = 464.28V = 912.29 (8) Å3
Triclinic, P1Z = 2
a = 7.7365 (4) ÅMo Kα
b = 9.8294 (5) ŵ = 0.75 mm−1
c = 12.8060 (6) ÅT = 296 (2) K
α = 93.512 (1)º0.42 × 0.18 × 0.12 mm
β = 94.215 (1)º
Data collection top
Bruker SMART1000 CCD
diffractometer		5200 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 1999)		4267 reflections with I > 2σ(I)
Tmin = 0.743, Tmax = 0.917Rint = 0.021
8669 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.031262 parameters
wR(F2) = 0.079H-atom parameters constrained
S = 0.99Δρmax = 0.59 e Å−3
5200 reflectionsΔρmin = −0.66 e Å−3
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2sigma(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R– factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Mo10.51011 (3)0.182250 (18)0.252976 (16)0.03327 (7)
C10.4418 (3)0.0088 (2)0.1555 (2)0.0449 (6)
C20.7505 (3)0.2330 (3)0.1855 (2)0.0429 (5)
C30.6115 (4)0.0645 (3)0.3394 (2)0.0480 (6)
C40.2617 (4)0.0919 (3)0.3117 (2)0.0497 (6)
O10.4053 (3)−0.0975 (2)0.10119 (19)0.0718 (6)
O20.8801 (3)0.2432 (3)0.14597 (19)0.0728 (6)
O30.6716 (4)−0.0104 (2)0.3855 (2)0.0820 (7)
O40.1260 (3)0.0274 (3)0.3410 (2)0.0884 (8)
N10.4173 (2)0.34601 (18)0.16198 (14)0.0305 (4)
N20.6003 (2)0.39737 (18)0.35795 (14)0.0315 (4)
C50.3033 (3)0.3170 (2)0.06860 (17)0.0318 (4)
C60.2348 (3)0.1767 (2)0.0164 (2)0.0446 (6)
H60.26670.10250.04490.054*
C70.1222 (4)0.1478 (3)−0.0754 (2)0.0514 (6)
H70.08090.0546−0.10920.062*
C80.0679 (3)0.2555 (3)−0.1195 (2)0.0487 (6)
H8−0.01170.2335−0.18100.058*
C90.1322 (3)0.3924 (3)−0.0720 (2)0.0434 (5)
H90.09640.4643−0.10150.052*
C100.2526 (3)0.4278 (2)0.02170 (18)0.0339 (4)
C110.3256 (3)0.5690 (2)0.07031 (19)0.0387 (5)
H110.29520.64350.04120.046*
C120.4409 (3)0.5972 (2)0.15997 (18)0.0373 (5)
H120.49210.69130.19160.045*
C130.4835 (3)0.4821 (2)0.20574 (17)0.0310 (4)
C140.5987 (3)0.5123 (2)0.30702 (17)0.0324 (4)
C150.7002 (3)0.6559 (2)0.34873 (19)0.0413 (5)
H150.69940.73300.31030.050*
C160.7981 (3)0.6816 (2)0.4437 (2)0.0436 (5)
H160.86900.77580.46940.052*
C170.7923 (3)0.5647 (2)0.50393 (19)0.0381 (5)
C180.8853 (3)0.5847 (3)0.6060 (2)0.0470 (6)
H180.95560.67740.63520.056*
C190.8721 (4)0.4689 (3)0.6615 (2)0.0536 (7)
H190.93600.48250.72780.064*
C200.7634 (4)0.3295 (3)0.6195 (2)0.0502 (6)
H200.75250.25150.65930.060*
C210.6725 (3)0.3061 (3)0.5205 (2)0.0431 (5)
H210.60020.21270.49400.052*
C220.6881 (3)0.4231 (2)0.45865 (17)0.0340 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mo10.03857 (11)0.02369 (9)0.03904 (12)0.01230 (7)0.00274 (7)0.00546 (7)
O10.0909 (16)0.0349 (10)0.0889 (17)0.0275 (10)−0.0093 (13)−0.0141 (10)
O20.0544 (12)0.0794 (15)0.0858 (17)0.0205 (11)0.0272 (12)0.0045 (12)
O30.114 (2)0.0671 (14)0.0856 (17)0.0568 (14)−0.0014 (14)0.0281 (12)
O40.0646 (14)0.0749 (16)0.110 (2)−0.0026 (12)0.0359 (14)0.0072 (14)
N10.0339 (9)0.0258 (8)0.0329 (10)0.0116 (7)0.0029 (7)0.0040 (7)
N20.0342 (9)0.0300 (8)0.0321 (10)0.0129 (7)0.0029 (7)0.0044 (7)
C10.0468 (13)0.0303 (11)0.0589 (16)0.0156 (10)−0.0004 (11)0.0060 (10)
C20.0457 (13)0.0359 (12)0.0467 (14)0.0141 (10)0.0010 (11)0.0034 (10)
C30.0590 (15)0.0380 (12)0.0519 (16)0.0225 (11)0.0034 (12)0.0086 (11)
C40.0525 (15)0.0379 (13)0.0564 (17)0.0124 (11)0.0068 (12)0.0013 (11)
C50.0333 (10)0.0303 (10)0.0329 (11)0.0114 (8)0.0052 (8)0.0062 (8)
C60.0533 (14)0.0295 (11)0.0479 (14)0.0122 (10)−0.0062 (11)0.0028 (10)
C70.0572 (15)0.0369 (12)0.0520 (16)0.0086 (11)−0.0083 (12)−0.0002 (11)
C80.0447 (13)0.0507 (14)0.0439 (14)0.0094 (11)−0.0076 (11)0.0064 (11)
C90.0433 (12)0.0454 (13)0.0438 (14)0.0180 (10)−0.0010 (10)0.0108 (10)
C100.0343 (10)0.0342 (10)0.0361 (12)0.0142 (8)0.0046 (9)0.0091 (9)
C110.0471 (13)0.0326 (11)0.0425 (13)0.0201 (9)0.0049 (10)0.0106 (9)
C120.0488 (13)0.0270 (10)0.0393 (12)0.0169 (9)0.0035 (10)0.0053 (8)
C130.0358 (10)0.0258 (9)0.0341 (11)0.0138 (8)0.0047 (8)0.0023 (8)
C140.0379 (11)0.0279 (9)0.0333 (11)0.0134 (8)0.0048 (9)0.0032 (8)
C150.0544 (14)0.0278 (10)0.0422 (13)0.0158 (10)0.0019 (11)0.0016 (9)
C160.0487 (13)0.0323 (11)0.0458 (14)0.0112 (10)−0.0007 (11)−0.0045 (10)
C170.0368 (11)0.0427 (12)0.0364 (12)0.0165 (9)0.0029 (9)−0.0013 (9)
C180.0447 (13)0.0547 (15)0.0401 (14)0.0179 (11)−0.0020 (11)−0.0048 (11)
C190.0498 (15)0.0758 (19)0.0369 (14)0.0251 (14)−0.0031 (11)0.0058 (13)
C200.0535 (15)0.0597 (16)0.0415 (14)0.0227 (13)0.0037 (12)0.0157 (12)
C210.0457 (13)0.0445 (13)0.0408 (14)0.0161 (10)0.0054 (10)0.0111 (10)
C220.0337 (10)0.0381 (11)0.0332 (12)0.0155 (9)0.0047 (9)0.0045 (9)
Geometric parameters (Å, °) top
Mo1—C11.946 (3)C9—H90.9300
Mo1—C31.953 (3)C10—C111.399 (3)
Mo1—C22.031 (3)C11—C121.355 (3)
Mo1—C42.051 (3)C11—H110.9300
Mo1—N22.3020 (18)C12—C131.425 (3)
Mo1—N12.3107 (17)C12—H120.9300
C1—O11.158 (3)C13—C141.474 (3)
C2—O21.134 (3)C14—C151.416 (3)
C3—O31.160 (3)C15—C161.347 (3)
C4—O41.136 (3)C15—H150.9300
N1—C131.333 (3)C16—C171.413 (3)
N1—C51.388 (3)C16—H160.9300
N2—C141.342 (3)C17—C181.415 (3)
N2—C221.381 (3)C17—C221.418 (3)
C5—C61.406 (3)C18—C191.357 (4)
C5—C101.425 (3)C18—H180.9300
C6—C71.367 (4)C19—C201.397 (4)
C6—H60.9300C19—H190.9300
C7—C81.397 (4)C20—C211.371 (4)
C7—H70.9300C20—H200.9300
C8—C91.357 (4)C21—C221.414 (3)
C8—H80.9300C21—H210.9300
C9—C101.413 (3)
C1—Mo1—C381.52 (11)C11—C10—C9122.2 (2)
C1—Mo1—C283.18 (10)C11—C10—C5118.3 (2)
C3—Mo1—C285.46 (11)C9—C10—C5119.5 (2)
C1—Mo1—C486.98 (10)C12—C11—C10119.83 (19)
C3—Mo1—C488.99 (11)C12—C11—H11120.1
C2—Mo1—C4169.31 (9)C10—C11—H11120.1
C1—Mo1—N2175.64 (9)C11—C12—C13119.9 (2)
C3—Mo1—N2101.26 (9)C11—C12—H12120.1
C2—Mo1—N293.66 (8)C13—C12—H12120.1
C4—Mo1—N296.38 (8)N1—C13—C12122.3 (2)
C1—Mo1—N1104.72 (8)N1—C13—C14118.33 (17)
C3—Mo1—N1172.97 (9)C12—C13—C14119.36 (18)
C2—Mo1—N192.03 (8)N2—C14—C15122.0 (2)
C4—Mo1—N194.50 (9)N2—C14—C13116.71 (18)
N2—Mo1—N172.31 (6)C15—C14—C13121.33 (19)
C13—N1—C5118.22 (17)C16—C15—C14120.4 (2)
C13—N1—Mo1114.78 (14)C16—C15—H15119.8
C5—N1—Mo1127.00 (13)C14—C15—H15119.8
C14—N2—C22117.79 (18)C15—C16—C17119.6 (2)
C14—N2—Mo1114.41 (14)C15—C16—H16120.2
C22—N2—Mo1126.38 (13)C17—C16—H16120.2
O1—C1—Mo1176.5 (2)C16—C17—C18122.5 (2)
O2—C2—Mo1171.4 (2)C16—C17—C22117.6 (2)
O3—C3—Mo1176.1 (3)C18—C17—C22119.9 (2)
O4—C4—Mo1172.3 (2)C19—C18—C17120.2 (2)
N1—C5—C6120.94 (19)C19—C18—H18119.9
N1—C5—C10121.43 (19)C17—C18—H18119.9
C6—C5—C10117.6 (2)C18—C19—C20120.5 (2)
C7—C6—C5121.1 (2)C18—C19—H19119.8
C7—C6—H6119.5C20—C19—H19119.8
C5—C6—H6119.5C21—C20—C19120.9 (2)
C6—C7—C8121.2 (2)C21—C20—H20119.6
C6—C7—H7119.4C19—C20—H20119.6
C8—C7—H7119.4C20—C21—C22120.4 (2)
C9—C8—C7119.4 (2)C20—C21—H21119.8
C9—C8—H8120.3C22—C21—H21119.8
C7—C8—H8120.3N2—C22—C21119.8 (2)
C8—C9—C10121.1 (2)N2—C22—C17122.11 (19)
C8—C9—H9119.4C21—C22—C17118.1 (2)
C10—C9—H9119.4
C1—Mo1—N1—C13−167.03 (16)C5—N1—C13—C120.1 (3)
C2—Mo1—N1—C13−83.56 (16)Mo1—N1—C13—C12179.76 (16)
C4—Mo1—N1—C13104.91 (16)C5—N1—C13—C14177.65 (18)
N2—Mo1—N1—C139.64 (14)Mo1—N1—C13—C14−2.7 (2)
C1—Mo1—N1—C512.61 (19)C11—C12—C13—N11.7 (3)
C2—Mo1—N1—C596.09 (17)C11—C12—C13—C14−175.8 (2)
C4—Mo1—N1—C5−75.44 (18)C22—N2—C14—C157.0 (3)
N2—Mo1—N1—C5−170.72 (18)Mo1—N2—C14—C15−160.21 (17)
C3—Mo1—N2—C14160.90 (16)C22—N2—C14—C13−172.04 (18)
C2—Mo1—N2—C1474.80 (16)Mo1—N2—C14—C1320.7 (2)
C4—Mo1—N2—C14−108.86 (16)N1—C13—C14—N2−12.3 (3)
N1—Mo1—N2—C14−16.16 (14)C12—C13—C14—N2165.3 (2)
C3—Mo1—N2—C22−5.07 (19)N1—C13—C14—C15168.6 (2)
C2—Mo1—N2—C22−91.17 (18)C12—C13—C14—C15−13.8 (3)
C4—Mo1—N2—C2285.17 (18)N2—C14—C15—C16−2.1 (4)
N1—Mo1—N2—C22177.87 (18)C13—C14—C15—C16176.9 (2)
C13—N1—C5—C6177.5 (2)C14—C15—C16—C17−2.9 (4)
Mo1—N1—C5—C6−2.1 (3)C15—C16—C17—C18−177.2 (2)
C13—N1—C5—C10−2.0 (3)C15—C16—C17—C222.7 (3)
Mo1—N1—C5—C10178.40 (14)C16—C17—C18—C19178.6 (2)
N1—C5—C6—C7179.9 (2)C22—C17—C18—C19−1.2 (4)
C10—C5—C6—C7−0.6 (4)C17—C18—C19—C20−1.6 (4)
C5—C6—C7—C8−1.4 (4)C18—C19—C20—C212.0 (4)
C6—C7—C8—C91.9 (4)C19—C20—C21—C220.4 (4)
C7—C8—C9—C10−0.3 (4)C14—N2—C22—C21171.6 (2)
C8—C9—C10—C11177.8 (2)Mo1—N2—C22—C21−22.9 (3)
C8—C9—C10—C5−1.8 (4)C14—N2—C22—C17−7.2 (3)
N1—C5—C10—C112.1 (3)Mo1—N2—C22—C17158.32 (16)
C6—C5—C10—C11−177.4 (2)C20—C21—C22—N2178.1 (2)
N1—C5—C10—C9−178.3 (2)C20—C21—C22—C17−3.1 (3)
C6—C5—C10—C92.2 (3)C16—C17—C22—N22.5 (3)
C9—C10—C11—C12−179.8 (2)C18—C17—C22—N2−177.7 (2)
C5—C10—C11—C12−0.2 (3)C16—C17—C22—C21−176.4 (2)
C10—C11—C12—C13−1.6 (3)C18—C17—C22—C213.5 (3)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C11—H11···O1i0.932.453.122 (3)129
Symmetry codes: (i) x, y+1, z.
Selected geometric parameters (Å) top
Mo1—C11.946 (3)Mo1—N12.3107 (17)
Mo1—C31.953 (3)C1—O11.158 (3)
Mo1—C22.031 (3)C2—O21.134 (3)
Mo1—C42.051 (3)C3—O31.160 (3)
Mo1—N22.3020 (18)C4—O41.136 (3)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C11—H11···O1i0.932.453.122 (3)129
Symmetry codes: (i) x, y+1, z.
references
References top

Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1995). International Tables for Crystallography, Vol. C, section 9.5, pp. 685–706). Dordrecht: Kluwer Academic Publishers.

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