the solvents for nmr spectroscopy ( eurisotop ) were degassed prior to use and stored over molecular sieve . h and c solution nmr spectra were recorded on a bruker avance 250 ( 250.13  mhz for h , 62.86  mhz for c ) equipped with a 5  mm inverse - broadband probe head and a z - gradient unit . ti(oipr)4 ( 1  cm , 3.45  mmol ) was added to a solution of 291  mm methacrylic acid ( 3.45  mmol ) in 3  cm of water - free isopropanol at 0  c . a white precipitate formed immediately , which was dissolved by adding 1  cm of ch2cl2 . crystals of 1 were obtained from the clear solution at 10  c after 2  days . yield 500  mg ( 43  % ) ; h nmr ( c6d6 , 250  mhz ) :   =  0.941.82 ( m , 42h , chch3 ) , 1.952.29 ( m , 6h , cch3 ) , 4.51 ( br , 2h , och ) , 4.885.33 ( m , 5h , och ) , 5.42 ( br , 2h , c = ch2 ) , 6.47  ppm ( br , 2h , c = ch2 ) ppm ; c nmr ( c6d6 , 62.90  mhz ) :   =  18.22 ( br , cch3 ) , 24.98 ( chch3 ) , 25.37 ( br , chch3 ) , 77.90 ( och ) , methacrylic acid ( 2 : 582  mm , 6.90  mmol ; 4 : 1.75  cm , 20.69  mmol ; 5 : 2.33  cm , 27.58  mmol ) was added to 1  cm of ti(oipr)4 ( 3.45  mmol ) and the solution was stirred for 5  min . crystals were obtained after 26  months at room temperature . 2 : yield 350  mg ( 40  % ) ; h nmr ( cdcl3 , 200  mhz ) :   =  1.001.44 ( m , 48h , chch3 ) , 1.681.96 ( m , 24h , cch3 ) , 3.97 ( m , j  =  6.16  hz , 1h , ch ) , 4.30 ( m , j  =  6.06  hz , 1h , ch ) , 4.584.85 ( m , 4h , ch ) , 4.935.12 ( m , 2h , ch ) , 5.245.56 ( m , 8h , ch2 ) , 5.906.27  ppm ( m , 8h , ch2 ) ppm ; c nmr ( cdcl3 , 50.3  mhz ) :   =  18.17 , 18.26 , 18.48 , 18.58 , 18.64 , 18.74 , 18.81 ( cch3 ) , 24.41 , 24.52 , 24.90 , 25.25 , 25.33 , 25.40 , 25.47 , 77.20 , 78.13 , 78.40 , 78.85 , 80.27 , 81.62 , 81.75 ( chch3 ) , 125.81 , 126.96 , 127.90 ( ch2 ) , 137.45 , 137.61 , 138.12 , 138.55 , 138.75 , 139.19 , 139.29 , 139.40 ( c = ch2 ) , 172.77 , 173.14 , 174.31 , 174.71 , 175.12 , 175.81 ( coo ) ppm . 4 : yield 330  mg ( 39  % ) ; h nmr ( cdcl3 , 250  mhz ) :   =  0.881.11 ( m , 3h , chch3 ) , 1.14 ( d , j  =  6.12  hz , 6h , chch3 ) , 1.171.60 ( m , 15h , chch3 ) , 1.641.96 ( m , 48h , cch3 ) , 3.97 ( m , j  =  6.11  hz , 1h , ch ) , 4.935.04 ( m , 1h , ch ) , 5.205.58 ( m , 16h , ch2 ) , 5.61 ( m , 3h , ch ) , 5.956.31  ppm ( m , 16h , ch2 ) ppm . 5 : yield 80  mg ( 12  % ) ; h nmr ( cdcl3 , 250  mhz ) :   =  1.851.93 ( m , 48h , ch3 ) , 5.295.69 ( m , 16h , ch2 ) , 6.176.22  ppm ( m , 16h , ch2 ) ppm ; c nmr ( cdcl3 , 62.90  mhz ) :   =  17.918.4 ( ch3 ) , 126.0128.3 ( ch2 ) , 136.2138.4 ( c ) , 176.7  ppm ( coo ) . methacrylic acid ( 580  mm , 6.87  mmol ) was added to 1  cm of ti(oipr)4 ( 3.45  mmol ) at room temperature . after 5  min of stirring , the reaction vessel was stored at 4  c . after 6  months , no crystals were obtained ; therefore , the mixture was warmed to room temperature . all measurements were performed at 100  k using mok (   =  71.073  pm ) radiation . data were collected on a bruker axs smart apex ii four - circle diffractometer with -geometry , with  and  scans and different frame widths . the data were corrected for polarization and lorentz effects , and an empirical absorption correction ( sadabs ) was employed . saint plus software ( bruker analytical x - ray instruments , 2007 ) was used to integrate the frames.table  2crystal data and structure refinement details for 1 , 2 , 4 , and 5 

 1 

 2 

 4 

 5 
 emp . formulac29h60o11ti2 
 c56h96o28ti6 
 c85.50h123o48.50ti9 
 c64h80o40ti8 

 m 
 r 
 680.571504.732357.941872.48crystal systemmonoclinicmonoclinictriclinicmonoclinicspace group 
 p21/n 

 p21/c 

 p 
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 c2/c 
 a / pm1065.27(5)1155.03(4)1182.0(3)2401.7(2 ) 
 b / pm1819.00(8)1895.81(5)1626.7(3)1662.8(2 ) 
 c / pm1961.76(8)1702.46(5)3060.3(7)2430.8(2 ) 
 /deg909087.652(5)90 /deg100.688(2)105.181(1)88.160(6)90.459(6 ) 
 /deg909072.026(5)90 
 v / pm    10 
 3735.4(3)3597.8(2)5591(2)9707(1 ) 
 z 
 4224 
 d 
 x / g  cm 
 1.211.391.401.28 
 /mm 
 0.4760.7100.6930.699crystal size / mm0.5    0.5    0.50.4    0.25    0.20.2    0.15    0.050.65    0.64    0.33no . 2(i)]20,68510,63861907847 
  
 max / deg44.8933.5020.0226.38 
 r [ f 
 >  2(f ) ] , wr ( f 
 ) , s 
 0.0540 , 0.0960 , 1.1080 . 0361 , 0 . 0605 , 1.0320.0824 , 0.1509 , 1.0870.1195 , 0.2594 , 3.502weighting scheme 

 w  =  1/[ 
 ( f 
 02 )  +  ( 0.0447p )  +  1.7418p ] 
 w  =  1/[ 
 ( f 
 02 )  +  ( 0.0459p )  +  1.6781p ] 
 w  =  1/[ 
 ( f 
 02 )  +  ( 0.1135p )  +  28.5259p ] w  =  1/[ 
 ( f 
 02 )  +  ( 0.0275p )  +  11.5003p] 
 max , min / e10 pm 
 1.08 , 0.520.96 , 0.590.87 , 0.911.45 , 1.00 
 p  =  ( f 
 02 +  2f 
 c2)/3 crystal data and structure refinement details for 1 , 2 , 4 , and 5 
 
 p  =  ( f 
 02 +  2f 
 c2)/3 the structures were solved by the patterson method ( shelxs97 ) . refinement was performed by the full - matrix least - squares method based on f ( shelxl97 ) with anisotropic thermal parameters for all non - hydrogen atoms . three oipr groups in 1 are disordered and were refined with around 80  % occupancy of the carbon atoms marked as  a  ( e.g. c12a ) . one molecule of 2-propanol and two of methacrylic acid were found in the asymmetric unit of 4 , of which the 2-propanol was refined with 50  % occupancy . the electron density in the void opened by the ring of 5 could not be refined and was removed using the squeeze function in platon . ccdc-1024252 ( 1 ) , -1024253 ( 2 ) , -1024254 ( 4 ) , and -1024255 ( 5 ) contain the supplementary crystallographic data for this paper . these data can be obtained free of charge from the cambridge crystallographic data center via www.ccdc.cam.ac.uk/data_request/cif . ti(oipr)4 ( 1  cm , 3.45  mmol ) was added to a solution of 291  mm methacrylic acid ( 3.45  mmol ) in 3  cm of water - free isopropanol at 0  c . a white precipitate formed immediately , which was dissolved by adding 1  cm of ch2cl2 . crystals of 1 were obtained from the clear solution at 10  c after 2  days . yield 500  mg ( 43  % ) ; h nmr ( c6d6 , 250  mhz ) :   =  0.941.82 ( m , 42h , chch3 ) , 1.952.29 ( m , 6h , cch3 ) , 4.51 ( br , 2h , och ) , 4.885.33 ( m , 5h , och ) , 5.42 ( br , 2h , c = ch2 ) , 6.47  ppm ( br , 2h , c = ch2 ) ppm ; c nmr ( c6d6 , 62.90  mhz ) :   =  18.22 ( br , cch3 ) , 24.98 ( chch3 ) , 25.37 ( br , chch3 ) , 77.90 ( och ) , 72.379.36 ( br , och ) , 125.1126.8 ( br , cch2 ) ppm . methacrylic acid ( 2 : 582  mm , 6.90  mmol ; 4 : 1.75  cm , 20.69  mmol ; 5 : 2.33  cm , 27.58  mmol ) was added to 1  cm of ti(oipr)4 ( 3.45  mmol ) and the solution was stirred for 5  min . crystals were obtained after 26  months at room temperature . 2 : yield 350  mg ( 40  % ) ; h nmr ( cdcl3 , 200  mhz ) :   =  1.001.44 ( m , 48h , chch3 ) , 1.681.96 ( m , 24h , cch3 ) , 3.97 ( m , j  =  6.16  hz , 1h , ch ) , 4.30 ( m , j  =  6.06  hz , 1h , ch ) , 4.584.85 ( m , 4h , ch ) , 4.935.12 ( m , 2h , ch ) , 5.245.56 ( m , 8h , ch2 ) , 5.906.27  ppm ( m , 8h , ch2 ) ppm ; c nmr ( cdcl3 , 50.3  mhz ) :   =  18.17 , 18.26 , 18.48 , 18.58 , 18.64 , 18.74 , 18.81 ( cch3 ) , 24.41 , 24.52 , 24.90 , 25.25 , 25.33 , 25.40 , 25.47 , 77.20 , 78.13 , 78.40 , 78.85 , 80.27 , 81.62 , 81.75 ( chch3 ) , 125.81 , 126.96 , 127.90 ( ch2 ) , 137.45 , 137.61 , 138.12 , 138.55 , 138.75 , 139.19 , 139.29 , 139.40 ( c = ch2 ) , 172.77 , 173.14 , 174.31 , 174.71 , 175.12 , 175.81 ( coo ) ppm . 4 : yield 330  mg ( 39  % ) ; h nmr ( cdcl3 , 250  mhz ) :   =  0.881.11 ( m , 3h , chch3 ) , 1.14 ( d , j  =  6.12  hz , 6h , chch3 ) , 1.171.60 ( m , 15h , chch3 ) , 1.641.96 ( m , 48h , cch3 ) , 3.97 ( m , j  =  6.11  hz , 1h , ch ) , 4.935.04 ( m , 1h , ch ) , 5.205.58 ( m , 16h , ch2 ) , 5.61 ( m , 3h , ch ) , 5.956.31  ppm ( m , 16h , ch2 ) ppm . 5 : yield 80  mg ( 12  % ) ; h nmr ( cdcl3 , 250  mhz ) :   =  1.851.93 ( m , 48h , ch3 ) , 5.295.69 ( m , 16h , ch2 ) , 6.176.22  ppm ( m , 16h , ch2 ) ppm ; c nmr ( cdcl3 , 62.90  mhz ) :   =  17.918.4 ( ch3 ) , 126.0128.3 ( ch2 ) , 136.2138.4 ( c ) , 176.7  ppm ( coo ) . methacrylic acid ( 580  mm , 6.87  mmol ) was added to 1  cm of ti(oipr)4 ( 3.45  mmol ) at room temperature . after 5  min of stirring , after 6  months , no crystals were obtained ; therefore , the mixture was warmed to room temperature . all measurements were performed at 100  k using mok (   =  71.073  pm ) radiation . data were collected on a bruker axs smart apex ii four - circle diffractometer with -geometry , with  and  scans and different frame widths . the data were corrected for polarization and lorentz effects , and an empirical absorption correction ( sadabs ) was employed . the cell dimensions were refined with all unique reflections ( table  2 ) . saint plus software ( bruker analytical x - ray instruments , 2007 ) was used to integrate the frames.table  2crystal data and structure refinement details for 1 , 2 , 4 , and 5 

 1 

 2 

 4 

 5 
 emp . c56h96o28ti6 
 c85.50h123o48.50ti9 
 c64h80o40ti8 

 m 
 r 
 680.571504.732357.941872.48crystal systemmonoclinicmonoclinictriclinicmonoclinicspace group 
 p21/n 

 p21/c 

 p 
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				 \begin{document}$$ \overline{1 } $ $ \end{document}1 

 c2/c 
 a / pm1065.27(5)1155.03(4)1182.0(3)2401.7(2 ) 
 b / pm1819.00(8)1895.81(5)1626.7(3)1662.8(2 ) 
 c / pm1961.76(8)1702.46(5)3060.3(7)2430.8(2 ) 
 /deg909087.652(5)90 
 /deg100.688(2)105.181(1)88.160(6)90.459(6 ) 
 /deg909072.026(5)90 v / pm    10 
 3735.4(3)3597.8(2)5591(2)9707(1 ) 
 z 
 4224 
 d 
 x / g  cm 
 1.211.391.401.28 
 /mm 
 0.4760.7100.6930.699crystal size / mm0.5    0.5    0.50.4    0.25    0.20.2    0.15    0.050.65    0.64    0.33no . msd . refl.244,599103,239108,9329827obs . 2(i)]20,68510,63861907847 
  
 max / deg44.8933.5020.0226.38 
 r [ f 
 >  2(f ) ] , wr ( f 
 ) , s 
 0.0540 , 0.0960 , 1.1080 . 0361 , 0 . 0605 , 1.0320.0824 , 0.1509 , 1.0870.1195 , 0.2594 , 3.502weighting scheme 

 w  =  1/[ 
 ( f 
 02 )  +  ( 0.0447p )  +  1.7418p ] 
 w  =  1/[ 
 ( f 
 02 )  +  ( 0.0459p )  +  1.6781p ] 
 w  =  1/[ 
 ( f 
 02 )  +  ( 0.1135p )  +  28.5259p ] 
 w  =  1/[ 
 ( f 
 02 )  +  ( 0.0275p )  +  11.5003p] 
 max , min / e10 pm 
 1.08 , 0.520.96 , 0.590.87 , 0.911.45 , 1.00 
 p  =  ( f 
 02 +  2f 
 c2)/3 crystal data and structure refinement details for 1 , 2 , 4 , and 5 
 
 p  =  ( f 
 02 +  2f 
 c2)/3 the structures were solved by the patterson method ( shelxs97 ) . refinement was performed by the full - matrix least - squares method based on f ( shelxl97 ) with anisotropic thermal parameters for all non - hydrogen atoms . three oipr groups in 1 are disordered and were refined with around 80  % occupancy of the carbon atoms marked as  a  ( e.g. c12a ) . one molecule of 2-propanol and two of methacrylic acid were found in the asymmetric unit of 4 , of which the 2-propanol was refined with 50  % occupancy . the electron density in the void opened by the ring of 5 could not be refined and was removed using the squeeze function in platon . ccdc-1024252 ( 1 ) , -1024253 ( 2 ) , -1024254 ( 4 ) , and -1024255 ( 5 ) contain the supplementary crystallographic data for this paper . these data can be obtained free of charge from the cambridge crystallographic data center via www.ccdc.cam.ac.uk/data_request/cif .
abstractwhen ti(oipr)4 was reacted with increasing proportions of methacrylic acid ( mcoh ) , the compounds ti2(oipr)6(omc)2(iproh ) , ti6o4(oipr)8(omc)8 , ti9o8(oipr)4(omc)16 , and ti8o8(omc)16 were obtained in sequence . 
 this allowed conclusions on the relative ratio of substitution and hydrolysis reactions , the latter being due to ester formation between the acid and cleaved alcohol . 
 this ratio is also influenced by the reaction temperature , since ti4o2(oipr)6(omc)6 was formed instead of ti6o4(oipr)8(omc)8 at lower temperature with the same precursor ratio.graphical abstract