Speaker's Slides

COLORANT CHEMISTRY From Prisms to Phthalocyanines

Jeffery H. Banning PhD Principal Scientist 3D SYSTEMS CORP. Wilsonville, Oregon

I. ADDITIVE / SUBTRACTIVE COLORATION:

II. CLASSIFICATION OF COLORANTS:

BASED ON THE ELECTRONIC ORIGIN OF THE COLORANT*:

(A) Acyclic and Cyclic Polyene Chromogens.

(B) Donor-Acceptor Chromogens.

III. INDUSTRIAL EXPERIENCES WITH MODIFYING COLORANTS [Yes, you can do it too!!]

* Griffiths, J.: Colour and Constitution of Organic Molecules. Academic Press 1976

1 Primary Colors for Additive Coloration Primary Colors for Subtractive Coloration Maxwell's arrangement - additive coloration - e.g., phosphors of a color TV Superimposed dyes - subtractive coloration - e.g., artists paint palatte, color printer, etc Kirk-Othmer Encyclopedia of Chemical Technology - 3rd Ed., Vol 6, page 619 Kirk-Othmer Encyclopedia of Chemical Technology - 3rd Ed., Vol 6, page 619

See: "The Fifteen Causes of Color (see table 3 and pp.860-875)" From the chapter on Color (pp. 841-876) Kirk-Othmer Encyclopedia of Chemical Technology Kurt Nasau, Consultant 4th Edition, Volume 6 John Wiley and Sons, Inc. 1993 ISBN 0-471-52674-6 Also: The Causes of Color by Kurt Nassau 1980 SCIENTIFIC AMERICAN, INC p.124 https://www.physics.utoronto.ca/~phy189h1/Causes%20of%20Color%20scientificamerican1080-124.pdf 2 ADDITIVE COLORATION:

SUN

"WHITE LIGHT" (Contains "all" wavelengths of visible light)

3 4 ADDITIVE COLORATION: SUN Red: Longest "WHITE LIGHT" wavelength, (Contains all wavelengths of light) lower energy Yellow

Green A prism can be used to "separate" all of the different wavelengths of "visible" light as Green-Blue shown above. Blue

Violet: Shortest wavelength, highest energy

5 F IL T E R

F IL T E R

6 Examples seen with: phosphors of the “old” cathode ray tube based colored TV set, LEDs, OLEDs or any emissive based display today.

7 ADDITIVE COLORATION:

Three monochromatic radiations are selected so that they are well separated sectors can be combined to make the color in the center (ex. Green, blue and red to make white)

8 ADDITIVE COLORATION:

Two monochromatic radiations from any pair of flanking sectors can be combined to make the color in the between them (ex. Green and red to make yellow )

9 SUBTRACTIVE COLORATION:

"WHITE LIGHT" (Contains all wavelengths of light)

The eye SUN perceives this complex

Greenish-Blue mixture as ORANGE.

F IL T Greenish-Blue light selectively filtered out E R

Most colors that are prevalent throughout our environment arise from what is known as the subtractive color mixing process.

In additive coloration we saw that the mixing of all the wavelengths (of colors) in the visible spectrum give "white light".

However, if one of the components of "white light" (one wavlength, or even a narrow band of wavelengths) is removed, the color registered by the eye is the complementary color of the radiation removed (despite the fact that the light falling on the eye is still a complex mixture of wavelengths).

Example shown above: If sunlight is passed through a filter that removes a band of wavelengths in the region of 485 nm (i.e., Greenish-blue light) the eye will perceive the complementary color of greenish-blue -- i.e., orange (vice verse would be true: if only orange wavelength removed would appear greenish-blue). 10 The eye perceives this complex mixture as BLUE.

11 SUBTRACTIVE COLORATION: The eye perceives this "WHITE LIGHT" complex (Contains all mixture as wavelengths of light) YELLOW.

SUN

) ut o ed er ilt (f d be or bs a y el tiv ec el s ht lig e lu B

lemon Example shown above: When "white light" from a lightbulb or the sun hits the lemon, the pigments in the lemon absorb (filter) light (band of wavelengths) corresponding to the blue region. Hence, the remaining wavelengths of "white light" (less the blue) hit the retina of the eye.

The eye will perceive the complementary color of blue - namely yellow 12 SUBTRACTIVE COLORATION:

The eye "WHITE LIGHT" perceives this (Contains all wavelengths of light) complex mixture as GREEN. SUN

) ut o ed er ilt (f d be or bs a y el tiv ec el s ht ig t l le io v nd a ed R

green pepper

Example shown above: When "white light" from a lightbulb or the sun hits the "green" pepper, the pigments in the pepper absorb (filter) light corresponding to the purple region. But, no wavelength corresponding to purple exists. Instead wavelengths corresponding to red and violet (both flanking the purple region) are absorbed (i.e., effectively filtered) and the remaining wavelengths will hit the retina of the eye.

The eye will perceive the complementary color of red and violet as green. 13 SUBTRACTIVE COLORATION:

"WHITE LIGHT" (Contains all The eye wavelengths of light) perceives this 8-ball as BLACK. SUN

t) ou ed ter fil d ( be or bs a ely tiv lec se is ht lig L AL

8-ball

Example shown above: When "white light" from a lightbulb or the sun hits the "black" 8-ball, the pigments in the ball absorb (filter) light corresponding to all wavelengths (i.e., all light is absorbed). Black is the absence of color (wavelengths) hitting the retina of the eye.

The eye will perceive the absence of any color (light of any wavelength) hitting it as black. 14 SUBTRACTIVE COLORATION:

The eye "WHITE LIGHT" perceives this (Contains all complex wavelengths of light) mixture as WHITE.

SUN

) ed er ilt (f d be or bs a re a ht ig f l o hs gt en el av w o N

White Object (baseball)

Example shown above: When "white light" from a lightbulb or the sun hits the white baseball, no light absorbs (or is filtered). Instead, all of the wavelengths are reflected and will hit the retina of the eye.

The eye will perceive this as white.

15 The eye perceives this lemon as BLACK.

t) ou d re lte fi ( ed rb so ab

ht ig l l al

Example shown above: When "white light" from a lightbulb or the sun is filtered so that only the single wavelength of light corresponding to blue is able to hit the lemon, the pigments in the lemon absorb (filter) light in the blue region. Hence, no remaining wavelengths of visible light are left to hit the retina of the eye (i.e., all wavelengths of visible light are absorbed by the lemon)

The eye will perceive this situation - with no reflected visible light 16 as black SUBTRACTIVE COLORATION:

glass cuvette with yellow "WHITE LIGHT" dye dissolved The eye (Contains all in colorless wavelengths of light) perceives this solvent complex mixture as YELLOW. SUN

The wavelength corresponding to blue light is absorbed by the dye in solution and not "seen" by the eye (detector)

The remaining wavelengths of visible light are transmitted through the dye in solution and "seen" by the eye (detector)

Example shown above: When "white light" from a lightbulb or the sun hits the cuvette containing a dye, the dye in solution absorb (filter) light (band of wavelengths) corresponding to the blue region. Hence, the remaining wavelengths of "white light" (less the blue) hit the retina of the eye.

The eye will perceive the complementary color of blue - namely yellow 17 SUBTRACTIVE COLORATION: (With Cyanine Dye)

"WHITE LIGHT" Xanthene (Contains all wavelengths of light) (Rhodamine B)

H3CH2C CH2CH3 N O N SUN H3CH2C CH2CH3 *

CO2 -

NBMO

The visible absorption band corresponds to the excitation of an electron from the HOMO (which is the NBMO in this case) into one of the LUMO (which is the vacant * orbital) of the chromogen.

The Green radiation matches “exactly” the energy necessary to excite and electron from the HOMO to the LUMO

The eye will perceive the complementary color of green - namely Magenta

Example shown above: When "white light" hits the dye, the dye absorbs light corresponding to the green region.

Hence, the remaining wavelengths of "white light" hit (are transmitted to) the retina of the eye. 18 max

A = log (1/T)

19 SUBTRACTIVE COLORATION: (With Cyanine Dye) - FLUORESCENCE The eye perceives this complex mixture as "WHITE LIGHT" Xanthene MAGENTA (Contains all with an wavelengths of light) (Rhodamine B) ORANGISH fluorescene H3CH2C CH2CH3 N O N SUN H3CH2C CH2CH3 *

CO2 -

NBMO

H3CH2C CH2CH3 N O N H3CH2C CH2CH3

* CO2 -

NBMO

* (LUMO) * (LUMO) heat light

NBMO (HOMO) NBMO (HOMO)

Radiationless transition Fluorescence (occurs when an excited electron drops back to (occurs when an excited electron drops back to its ground its ground state without the emission of light and state - emmitting a photon of light. Usually this emmision of usually involves transfer of heat to solvent) radiation is of a longer wavelength than the radiation that was absorbed) Note: 20 only the lowest vibrational energy levels are shown - the associated vibrational levels are not shown II. CLASSIFICATIONS OF COLORANTS BASED ON THE ELECTRONIC ORIGIN OF THE COLORANT*

** *

(A) Acyclic (& Cyclic) Poly-ene Chromogens (B) Donor-Acceptor Chromogens (C) Cyanine-Typce Chromogens

- There are no donors or acceptors per se'.

- Can be regarded as simply a collection of sp2 or sp-hybridized atoms in which overlap (some to complete) of all the p-orbitals occurs giving a conjugated -electron system containing as many electrons as there are p-orbitals.

- Color is simply due to the fact that conjugation is large.

- Intensities are normally good (extinction coefficients > 20,000) - Show convergence in absorption wavelengths (at about 600 nm)

THREE SUB-CLASSES OF COMPOUNDS CAN FALL INTO THIS CATEGORY: 1. Acyclic polyenes (poly-enes). 2. Non-Benzenoid Alternant Cyclic Systems 3. Polycyclic Benzenoid Compounds.

ALMOST IMPOSSIBLE TO BREAK INTO NIR REGION 21 (unless cyclic aromatic structures are present) *Griffiths, J.: Colour and Constitution of Organic Molecules, Academic Press 1976 (A) Linear Acyclic Poly-ene and light absorption

Ultra-Violet Spectrum Visible Spectrum

227 nm 413 nm max = 227 nm 2 double bonds

o i Note: these are not

r actual absorption

o s bands, but ChemDraw b

A generated peaks max = 275 nm 3 double bonds representing actual literature values

max = 310 nm 4 double bonds 200 250 300 350 400 450 500 550 600

 Wavelength (in nanometers)

max = 341 nm 5 double bonds

max = 380 nm 6 double bonds

max = 396 nm7 double bonds

At about 8 double bonds the system breaks into the visible spectrum (it would appear yellow).

max = 413 nm 8 double bonds

2 max = 600 nm 20 double bonds - At about 20 double bonds the converges on 600 nms (and doesn't increase no matter the additional double bonds). 22 *Griffiths, J.: Colour and Constitution of Organic Molecules, Academic Press 1976 (A) Linear Acyclic Poly-ene and light absorption

11 2 3 4 5 6 7 8 9 10

max = 470 nm 11 conjugated double bonds

Lycopene - the "parent structure" for all of the caretenoids

- Has 11 conjugated double bonds. - Responsible for red color in tomatos

23 (A) Linear Acyclic and Cyclic Poly-ene Chromogens 2) NON-BENZENOID ALTERNANT CYCLIC SYSTEMS (PORPHYRINS)

Porphyrins are highly colored heterocyclic compounds that occur widely in nature.

The parent structure is a macrocycle containing 4 pyrrole units linked by methine bridges called a porphin. N N H Porphyrins are classified as polyene H chromogens as they contain no donor N N or acceptor groups (i.e., they resemble annulenes).

The maximum delocalization of electrons occurs about the [16]-annulene pathway shown to right: N N The system has 18 -electrons (when H 2 of the N atoms provide 2 electrons H N N each) and is therefore isoconjugate with the [16]-annulene dianion which is a (4n+2) system, therefore showing aromatic character (thus explaining in part the stability of the phorphyrins).

Phthalocyanine (a commercially N valuable pigment) can be described as a t e t r a - a z o - t e t r a - b e n z - porphin. N N H Metal Free Phthalocyanine N N Pigment Blue 16 H N N CI 74100

Steamrollers, Sportscars and Security: Phthalocyanines Through the Ages 24 J of Porphyrins and Phthalocyanines 3 (1999) 468-476 (A) Linear Acyclic and Cyclic Poly-ene Chromogens (C) ACYCLIC AND CYCLIC POLYENE CHROMOGENS - PREPARATION OF COMMERCIAL PHTHALOCYANINE DYES: PROPOSED MECHANISM base (B:) induced cyclotetramerization

CN 4 B: CuCl / ~140oC CN 2 Exotherm to C C C N C N o N Phthalonitrile 260-300 C N N N 1 hour C C C C 2+ N Cu2+ N N Cu N C C C C

N N N N N C N C C C

The metal (Cu+2) acts as a template of sorts N= N N COPPER PHTHALOCYANINE = Pigment Blue 15 N Cu N C.I. 74160 (Greenish Blue) N N N= =

25 II. CLASSIFICATIONS OF COLORANTS BASED ON THE ELECTRONIC ORIGIN OF THE COLORANT*

* * *

(A) Acyclic (& Cyclic) Poly-ene Chromogens (B) Donor-Acceptor Chromogens (C) Cyanine-Type Chromogens

- There are no donors or acceptors per se'. - There are donors or acceptors.

- Can be regarded as simply a - Can still basically be regarded as simply a collection of sp2 or sp-hybridized collection of sp2 or sp-hybridized atoms in which atoms in which overlap (some to overlap (some to complete) of all the p-orbitals complete) of all the p-orbitals occurs occurs giving a conjugated - electron system giving a conjugated -electron system containing as many electrons as there are p- containing as many electrons as there orbitals - but donors and acceptors groups have are p-orbitals. large effect on light absorption.

- Color is simply due to the - Color is simply due to the fact that conjugation fact that conjugation is large. is large and donors and acceptors groups.

- Intensities are normally good - Intensities are normally good (extinction coefficients > 20,000) (extinction coefficients 15,000 –300,000) - Show convergence in absorption - Show convergence in absorption wavelengths (at about 600 nm) wavelengths (can be longer than 600 nm because of donors and acceptors groups)

THREE SUB-CLASSES OF COMPOUNDS CAN MOLECULES CONTAIN 3 PORTIONS: FALL INTO THIS CATEGORY: 1. Donor Portion. 1. Acyclic polyenes (poly-enes). 2. Conjugated Bridge Portion 2. Non-Benzenoid Alternant Cyclic Systems 3. Acceptor Portion. 3. Polycyclic Benzenoid Compounds.

ALMOST IMPOSSIBLE TO BREAK INTO NIR REGION DIFFICULT BUT POSSIBLE TO BREAK INTO NIR 26 (unless cyclic aromatic structures are present) (with lots and strong EWG /EDGS /conjugation/ metallization ) *Griffiths, J.: Colour and Constitution of Organic Molecules, Academic Press 1976 (B) Donor-Acceptor Chromogens

 Represents the largest group of Chromogens.

 The majority of commercial dyes and pigments fall into this class.

 Extinction coefficients range from 15,000 - 300,000.

 Azo dyes, Methine dyes, Azomethine dyes, and Anthraquinone dyes are examples of colorants that fall into this category.

27 (B) Donor-Acceptor Chromogens

An electron withdrawing group(s) - The orbital containing the lone pair electrons An electron donating group(s) - EDG EWG (functional groups that possess (from the EDG) must be aligned with the adjacent (i.e., an atom possessing lone pair electronegative atoms conjugated with p-orbitals of the conjugated (bridge) system, system - e.g., Nitrile, Nitro, Diazo groups). electrons directly linked to a conjugated so that the lone pair electrons may be partly -electron system). Example: delocalized into the --system. Example: Example:

NC CH3 NC CH3 NC CH3 C C N C C N H C C N H NC CH3 H NC CH3 NC CH3

CH NC 3 N NC CH 3 28 SUBTRACTIVE COLORATION: (With Donor-Acceptor Dye) The eye perceives this "WHITE LIGHT" complex (Contains all wavelengths of light) mixture as H C 3 CH3 H3C CH3 YELLOW. N N

SUN

HC HC

C C C C C C

N N N N YELLOW DYE The wavelength corresponding to blue light is absorbed by the dye and not "seen" by the eye (detector) * *

 

% ABSORBANCE

WAVELENGTH (nm) The remaining wavelengths of visible light are transmitted through the dye and "seen" by the eye (detector)

% TRANSMISSION 29 WAVELENGTH (nm) page 21 (B) Donor-Acceptor Chromogens (cont.)

For predictive purposes, rough rules of thumb are as follows:

1) Adding more EDGs to the donor portion or replacing an EDG of a given chromogen with a more efficient donating group will lead to a BATHOCHROMIC shift (the reverse will lead to a HYPSOCHROMIC shift). The actual location (e.g., ortho, meta, or para) of these substituents can have a critical effect on the magnitude of the shift.

A. SOME EDGs IN ORDER OF EFFICIENCY:

-OAc Least Effective -OH -NHAc -OCH3 -SH -NH2 -SCH3 -NHCH3 -N(CH3)2 Most Effective

Griffiths, J.: Colour and Constitution of organic molecules. Academic Press 1976

30 (B) Donor-Acceptor Chromogens (cont.)

For predictive purposes, rough rules of thumb are as follows:

2. RELATIVE EDG STRENGTHS OF N,N'-DIALKYL AMINO GROUPS:

R H3C N N N N H3C H3C H3C CH3 WEAKEST EDG INTERMEDIATE EDG STRONGER EDG (aziridine) (Julolidine) STRONGER EDG (and better lightfastness) (trimethyl tetrahydroquinoline)

3. IONIZED EDGs: The electron donor strength of a particular group can be enhance greatly by imparting a negative charge to the heteroatom. This is normally achieved by deprotonation of the grouping by a base.

Examples: R-O- , R-S- , and R-NH-

31 max = 423 (acetone) O N N Cl H C S N OH Examples of AZO dyes with different EDGs 3 O Cl CH3 (Electron Donating Groups) O N N max = 427 (acetone) CH3 H3C S N N in order of efficiency O Cl CH2CH2-OH O N N max = 446 (acetone) CH2CH2-CN H3C S N O Cl CH2CH2-OH  = 455 (acetone) O N N max CH2CH2-CN H3C S N H C O 3

Cl CH2CH2-OH  = 459 (acetone) O N N max CH2CH2-OH H3C S N O Cl

Cl CH2CH2-OH C O N N max = 460 (acetone)

CH2CH2-OH I H3C S N A. SOME EDGs IN ORDER OF EFFICIENCY: O Cl CH CH M

2 3 O N N  = 467 (acetone) CH2CH2-OH max H3C S N O

-OAc Least Effective R Cl CH CH 2 3 O N N max = 474 (acetone) CH2CH3 -OH H H3C S N

-NHAc Cl C CH2CH3 O N N CH CH -OH max = 475 (acetone) -OCH 2 2 O H3C S N

3 H C O 3

-SH Cl CH CH CH CH H

2 2 2 3 O N N max = 479 (acetone)

CH CH CH CH T H C S N 2 2 2 3 -NH2 3 O

-SCH Cl 3 CH2CH2-OH O N N  = 484 (acetone) max B -NHCH CH2CH2-OH 3 H3C S N O HN -N(CH3)2 Most Effective Cl O CH2CH2-OH  = 485 (acetone) Griffiths, J.: Colour and Constitution of organic molecules. Academic Press 1976 O N N max CH2CH2-OH H3C S N O HN Cl CH3 O H3C CH3 max =485 (acetone) CH O N N 3 CH2CH2OCH2CH2-OH H3C S N O H3C Cl O N N max = 511 (acetone)

H3C S N O O-CH3 Cl CH2CH2-OH O N N max = 527 (acetone) CH CH -OH H C S N 2 2 3 32 O HN Cl CH3 O (B) Donor-Acceptor Chromogens (cont.)

2) Adding more Electron Withdrawing Groups - EWGs to the acceptor portion or replacing an EWG of a given chromogen with a more efficient withdrawing group will lead to a BATHOCHROMIC shift (the reverse will lead to a HYPSOCHROMIC shift). The actual location (e.g., ortho, meta, or para) of these substituents can have a critical effect on the magnitude of the shift.

SOME EWGs IN ORDER OF EFFICIENCY:

- -CO2 M+ Least Effective -NO -CHO

-CONH2 -CO2CH3 -CO2H -CF3 - + -SO3 M -SOCH3 -COCH3 -CN

-SOCF3 -SO2CH3 -NO2 -SO2CF3 Most Effective

Griffiths, J.: Colour and Constitution of Organic Molecules. Academic Press 1976 33 CH2CH3 N N max = 413 (acetone) CH CH Examples of AZO dyes with different EWGs H N 2 3 (Electron Withdrawing Groups) CH2CH3 N N max = 418 (acetone) CH CH in order of efficiency F N 2 3

CH2CH3 O N N  = 422 (acetone) CH CH max HO S N 2 3 O CH2CH3 N N  = 431 (acetone) CH CH max Br N 2 3

SOME EWGs IN ORDER CH2CH3 N N  = 435 (acetone) OF EFFICIENCY: CH CH max Cl N 2 3

- C -CO M+ Least Effective CH2CH3 2 O N N I  = 440 (acetone) CH CH max -NO H N S N 2 3 2 M

-CHO O CH CH O 2 3 -CONH O N N  = 440 (acetone) 2 max R CH2CH3 -CO CH H2N C N 2 3 H

CH2CH3 -CO2H N N C max = 442 (acetone) CH2CH3 -CF3 F C N O

3 - + -SO3 M CH2CH3 H O N N max = 448 (acetone) -SOCH CH CH T 3 HO C N 2 3

-COCH3 CH2CH3

O B -CN N N max = 449 (acetone) CH2CH3 H3CH2CO C N -SOCF3 CH CH -SO CH O 2 3 2 3 N N max = 454 (acetone) CH2CH3 -NO2 H C N -SO CF Most Effective CH2CH3 2 3 O N N max = 456 (acetone) CH2CH3 Griffiths, J.: Colour and Constitution of Organic Molecules. Academic Press 1976 H3C C N

CH2CH3 N N  = 462 (acetone) CH CH max NC N 2 3

CH2CH3 O N N max = 487 (acetone) CH2CH3 F3C S N O CH2CH3  = 490 (acetone) N N max 34 CH2CH3 O2N N (B) Donor-Acceptor Chromogens (cont.)

3) Extending the conjugated bridge of a given chromogen will normally lead to a BATHOCHROMIC shift (the reverse leading to a HYPSOCHROMIC shift)

Longitudinal extension of the conjugated system, in general, is more effective than lateral extension in producing a BATHOCHROMIC shift.

Acceptor Conjugated Donor (EWGs) Bridge (EDGs)

NC CH3 max = 430 nmacetone C C N CV = 276 H NC CH3

NC CH3 C C N  = 452 nm H max acetone CV = 84.6 NC CH3

NC CH3 max = 483 nmacetone C C CH C N CV = 199 35 NC H H CH3 II. CLASSIFICATIONS OF COLORANTS BASED ON THE ELECTRONIC ORIGIN OF THE COLORANT*

* * *

(A) Acyclic (& Cyclic) Poly-ene Chromogens (B) Donor-Acceptor Chromogens (C) Cyanine-Type Chromogens - Sometimes depicted as having 2 donors (although - There are no donors or acceptors per se'. - There are donors or acceptors. there are no donors or acceptors per se') but Odd Alternant hydrocarbon analog possessing NBMO equivalent. - Can be regarded as simply a - Can still basically be regarded as simply a collection of sp2 or sp-hybridized collection of sp2 or sp-hybridized atoms in which - The Cationic molecules with terminal heteroatoms atoms in which overlap (some to overlap (some to complete) of all the p-orbitals (usually N's) can still basically be regarded as simply a complete) of all the p-orbitals occurs occurs giving a conjugated - electron system collection of sp2 or sp-hybridized atoms in which giving a conjugated -electron system containing as many electrons as there are p- overlap is complete. Possess NBMO and hence a low containing as many electrons as there orbitals - but donors and acceptors groups have energy 1st electronic transition (replacement of C’s at are p-orbitals. large effect on light absorption. other positions follow Dewar's rules).

- Color is due to the fact that molecules possess - Color is simply due to the fact that conjugation - Color is simply due to the NBMO are isoelectronic with odd alternant anion (and is large and donors and acceptors groups. fact that conjugation is large. conjugation is present)

- Intensities are normally good - Intensities are normally good - Intensities are normally good (extinction coefficients (extinction coefficients > 20,000) (extinction coefficients 15,000 –300,000) 15,000 - 300,000)

- Show convergence in absorption - Show convergence in absorption -A convergent behavior of wavelengths is wavelengths (at about 600 nm) wavelengths (can be longer than 600 nm because not observed. Possess high degree of bond uniformity of donors and acceptors groups)

THREE SUB-CLASSES OF COMPOUNDS CAN MOLECULES CONTAIN 3 PORTIONS: CHROMOGENS POSSESS: FALL INTO THIS CATEGORY: 1. Donor Portion. 1. Non-bonded Molecular Orbital NBMO. 1. Acyclic polyenes (poly-enes). 2. Conjugated Bridge Portion 2. Bond Uniformity 2. Non-Benzenoid Alternant Cyclic Systems 3. Acceptor Portion. 3. Non-Convergent Wavelength Behavior 3. Polycyclic Benzenoid Compounds. FAIRLY "EASY" TO GET IN NIR (with lots Conjugation) ALMOST IMPOSSIBLE TO BREAK INTO NIR REGION DIFFICULT BUT POSSIBLE TO BREAK INTO NIR 36 (unless cyclic aromatic structures are present) (with lots and strong EWG /EDGS /conjugation/ metallization ) *Griffiths, J.: Colour and Constitution of Organic Molecules, Academic Press 1976 DEWAR'S RULE SUMMARY: PUTTING IT ALL TOGETHER!

CH * * 3 (R)2N N(R) (R) N N(R) (R) N * * N(R) 2 2 2 2 N * 2 * * * *  = 491 nm max= 610 nm max= 610 nm max

1st: Trace a continuous path through 2nd: Place the substituent (perturbant) the -portion of the molecule, on/in the appropriate atom starring alternate atoms and go to grid below for prediction:

DEWAR'S RULE SUMMARY:

STARRED ATOM UN-STARRED ATOM

Increase HYPSOCHROMIC BATHOCHROMIC Electronegativity SHIFT SHIFT (or add EWG)

Decrease BATHOCHROMIC HYPSOCHROMIC Electronegativity SHIFT SHIFT (or add EDG) 37 Ultra-Violet Range Visible Range Near Infra-Red Range (UV) (Vis) (NIR)

736 nm 227 nm 275 nm3103 nnmm341 nm380 nm414 nm 519 nm 625 nm

p Note: these are not

o actual absorption

b bands, but ChemDraw A generated peaks representing actual literature values

200 300 400 500 600 700 800 900 Wavelength (in nanometers) Linear Poly-ene Linear Cyanine R N NR2 R

max = 313 nm 2 double bonds max = 227 nm 2 double bonds R N NR2 R

max = 414 nm 3 double bonds max = 275 nm 3 double bonds

R N NR2 R

max = 310 nm 4 double bonds max = 519 nm 4 double bonds R N NR2 R  = 625nm max = 341 nm 5 double bonds max 5 double bonds R N NR2 R

 = 380 nm  = 736 nm max 6 double bonds max 6 double bonds 38 *Griffiths, J.: Colour and Constitution of Organic Molecules, Academic Press 1976 III. INDUSTRIAL EXPERIENCES WITH MODIFYING COLORANTS [Yes, you can do it too!!]

39 Select Aldrich/TCI Chemicals For Making Dyes O2N CN

CN 4-Nitrophthalonitrile Bromamine Acid Sodium Salt CAS Number 1-Amino-4-bromoanthraquinone-2-sulfonic Acid Sodium Salt Linear Formula XXXXXXXX 1-Amino-4-bromo-9,10-dihydro-9,10-dioxo-2-anthracenesulfonic Molecular Weight xxxxx acid sodium salt N0524 TCI

M.F. C14H7BrNNaO5S M.W. 404.17 CAS RN 6258-06-6 A0279 TCI America CN Bromaminic acid sodium salt Sigma Aldrich 3-Diethylaminophenol 2-[4-(Dibutylamino)-2-hydroxybenzoyl]benzoic acid CAS Number: 91-68-9 CAS Number 54574-82-2 Molecular Weight: 165.23 CN Linear Formula [CH3(CH2)3]2NC6H3(OH)COC6H4CO2H 102091 Aldrich Molecular Weight 369.45 Phthalonitrile Mp = 190-193°C(lit.) CAS Number Aldrich 402400 Linear Formula XXXXXXXX [THIS IS DHB Molecular Weight xxxxx [I HAVE MAX/GRIFF PREP FOR THIS]] QUINIZARIN P0404 TCI CAS Number 81-64-1

Linear Formula C14H8O4 Molecular Weight 240.21 D0243 TCI AMERICA

N,N-Dibutyl-3-aminophenol Squaric Acid CAS 43141-69-1 1-Cyclobutene-3,4-dione-1,2-diol Linear Formula C14H23NO 3,4-Dihydroxy-3-cyclobutene-1,2-dione Molecular Weight 221.34 CAS Number 2892-51-5 D2138 TCI N,N-Dimethylaniline Linear Formula C4H2O4 CAS 121-69-7 LEUCOQUINIZARIN Molecular Weight 114.06 Linear Formula C H N CAS Number 476-60-8 8 11 D1399 TCI AMERICA Molecular Weight 121.18 Linear Formula C H O 14 10 4 D0665 TCI Molecular Weight 242.23 T0116 TCI AMERICA

4-Phenylazo-1-naphthylamine Naphthyl Red 4-Dimethylaminobenzaldehyde 1,8-Naphthalenediamine Solvent Yellow 4 PHTHALIC ANHYDRIDE CAS Number 479-27-6 CAS Number 131-22-6 CAS 100-10-7 CAS Number 85-44-9 Linear Formula C9H11NO Linear Formula C10H10N2 Linear Formula C16H13N3 Linear Formula C8H4O3 Molecular Weight 158.20 Molecular Weight 247.30 Molecular Weight 149.19 Molecular Weight 148.12 D0102 TCI AMERICA P0584 TCI AMERICA D1495 TCI 40 P1614 TCI AMERICA III. SYNTHETIC STRATEGIES FOR TAILOR MAKING DYES:

VARIOUS CLASSES OF CYAN (& BLUE & GREEN) CHROMOPHORES THAT ARE NC COMMERCIALLY AVAILABLE and/or SYNTHETICALLY ACCESSIBLE CN

CH2CH2CH2CH2CH2CH3 C SO3Na O N H S H N CH2CH2CH2CH2CH2CH3 O O H3C NaO3S SO3Na N Cl Cl H METHINE N N N O Disperse Blue 354 INDIGOID DYE CI 48480 NaO S N Cu 3 N SO3Na Acid Blue 74 (Blue) N N CI 73015 N N N N Cl Cl (Greenish Blue) N Cu N H3CH2C CH2CH3 Cl Cl N N N N N CH2 CH2 NaO3S SO3Na SO3Na

O NH-CH CH CH CH SO3 - COPPER PHTHALOCYANINE 2 2 2 3 C.I. Acid Blue 249 Cl Cl C.I. 74220 (Greenish Blue) COPPER PHTHALOCYANINE TRIPHENYLMETHANE C.I. Pigment Green 37 C.I. Acid Blue 9 O NH-CH2CH2CH2CH3 C.I. 74255 C.I. 42090 (Bluish Green) ANTHRAQUINONE (Bright Greenish Blue) Solvent Blue 35 CI 61554 (Greenish Blue) O NH H3C 2 O CH ANTHRAQUINONE 3 O NH-CH CI Acid Blue 62 3 NO2 N-CH CH CH -O-CH CH3 CI 62045 2 2 2 3 N N (Bright Reddish Blue) O N N CH2CH3 O 2 O NH2 H3CH2C H N N N O CN CH3 O HN ANTHRAQUINONE SO3Na H3CH2C O Disperse Blue 60 MONO AZO DYES CI 61104 R INDOPHENOL Disperse Blue 338 CH3 (Bright Greenish Blue) Solvent Blue 22 CI 11405 ANTHRAQUINONE CI 49705 (Greenish Blue) Acid Blue 27 (Blue) CI 61530 (R = H) (Greenish Blue)

(NOTE: portions in red show potential sites for modification 41 BROMAMINE ACID

ANTHRAQUINONE CI Acid Blue 62 CI 62045 (Bright Reddish Blue)

NaOH/H2O CuSO4

Bromamine Acid Sodium Salt 1-Amino-4-bromoanthraquinone-2-sulfonic Acid Sodium Salt 1-Amino-4-bromo-9,10-dihydro-9,10-dioxo-2- anthracenesulfonic acid sodium salt ANTHRAQUINONE CI Acid Blue 62 M.F. C14H7BrNNaO5S M.W. 404.17 CI 62045 CAS RN 6258-06-6 (Bright Reddish Blue) A0279 TCI America Bromaminic acid sodium salt Sigma Aldrich

42 NH2 Polyethylene Imine [PEI] HN Ratio of the 3 types of amines BROMAMINE ACID H H o o o N N N 1 amines 2 amines 3 amines H2N N N NH2 1 2 1 H

NH2 n

Na2CO3 /CuSO4 Water/reflux

O NH2 O NH2 SO3Na O NH2 SO3Na SO3Na n = 3 O NH O HN NH O HN NH HN O O H H H H SO Na N N N H H 3 H2N N N N N N N H H N N N N N H N N N NH H 2 NaO3S H O HN O HN O O O HN

SO3Na SO3Na O NH2 SO3Na O NH2 O NH2 43 CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 O Si O Si O Si O Si O Si O Si O Si O Si O Si O Si O BROMAMINE ACID n CH3 CH3 CH3 CH3 CH3 CH2 CH3 CH3 CH3 CH3

CH2

NH2

Na2CO3 /CuSO4 THF/Water/reflux Bromamine Acid

CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 O Si O Si O Si O Si O Si O Si O Si O Si O Si O Si O n CH3 CH3 CH3 CH3 CH3 CH2 CH3 CH3 CH3 CH3

CH2

CH2 HN O

SO3Na 44 138 USP 8841472 9-23-2014 Xerox - Colored Polysiloxanes O NH2 QUINIZARIN/LEUCOQUINIZARIN

ANTHRAQUINONE Solvent Blue 35 CI 61554 (Greenish Blue)

LEUCO-QUINIZARIN QUINIZARIN (reduced [H] form) (oxidized [OX] form)

45 QUINIZARIN / LEUCOQUINIZARIN LEUCO-QUINIZARIN QUINIZARIN (reduced [H] form) (oxidized [OX] form)

LEUCO-QUINIZARIN (reduced [H] form)

This condensation actually takes place in a stepwise fashion (i.e., first the MONO-imine forms primarily in the 1 position then in the 4 position) followed by oxidation

BIS-IMINE

QUINIZARIN (oxidized [OX] form)

KETO FORM ENOL FORM

46 USP 6437155 & USP 6447591 Anthraquinone Colorants for Inks TRIPHENYL METHANES

TRIPHENYLMETHANE C.I. Acid Blue 9 C.I. 42090 (Bright Greenish Blue)

1. H O/H SO Oleum 2 2 4 (fuming sulfuric acid) Reflux 2. Neutralize 3. Filter 4. [OX]

47 TRIPHENYL METHANES

1. H2O/H2SO4 1. Ethanol/heat Reflux 2. oxidize 2. Neutralize A- 3. Filter

[-H2O]

Leuco [H] form Adjust pH to ~10 With 40% NaOH

A-

Add “Acid” -H2O [Water is a great LG] Carbinol form

130 USP8303671 11-6-2012 basic dye and acid dye providing an internal salt composition 48 126 USP7997712 8-16-2011 Xerox TPM-Acid Dye Internal Salt TRIPHENYL METHANES

HA -1 HSO4

H2SO4

-H2O

HA -H2O

-H2O

-H2O 130 USP8303671 11-6-2012 basic dye and acid dye providing an internal salt composition 49 126 USP7997712 8-16-2011 Xerox TPM-Acid Dye Internal Salt PHTHALOCYANINES

COPPER PHTHALOCYANINE C.I. Acid Blue 249 C.I. 74220 (Greenish Blue)

CuCl / 14OoC CN 2 Exotherm to 260- 300oC / 1 hour CN N N N N Phthalonitrile N PURIFICATION: N N Cu N N Cu N 1. Oleum O OR -Dissolve in conc H2SO4 (fuming sulfuric acid) N N N -ppt w/hot water 2. Neutralize N N N O CuCl2 / -xs- UREA -Wash with NH4OH (NH3)nMoO4/NH4Cl O 200oC / 3 hour 90 - 100% Yield Phthalic (UREA PROCESS) Anhydride

50 PHTHALOCYANINES

Thiol functionalized PDMS

DMF/K2CO3/HEAT

CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 O Si O Si O Si O Si O Si O Si O Si O Si O Si O Si O n CH3 CH3 CH3 CH3 CH3 CH2 CH3 CH3 CH3 CH3

CH2

CH2 S

51 138 USP 8841472 9-23-2014 Xerox - Colored Polysiloxanes NC CN CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 O Si O Si O Si O Si O Si O Si O Si O Si O Si O Si O n PHTHALOCYANINES CH3 CH3 CH3 CH3 CH3 CH2 CH3 CH3 CH3 CH3

CH2

CH2 S

NC CN [actually ~8+ moles are used instead of the 3 moles CN necessary to make the desired dye to ensure no crosslinking can take place. As a result some 8 phthalocyanine pigment is produced which is not CN soluble and will either precipitate out or can be filtered out to yield the PDMS-dye]

138 USP 8841472 9-23-2014 Xerox - Colored Polysiloxanes

Copper phthalocyanine PDMS/Copper Pigment Phthalocyanine dye [Precipitate] 52 Which is filtered out III. SYNTHETIC STRATEGIES FOR TAILOR MAKING DYES:

H3C R' CH3 VARIOUS CLASSES OF YELLOW CHROMOPHORES THAT ARE COMMERCIALLY AVAILABLE and/or SYNTHETICALLY ACCESSIBLE R CH CH NH O-CH3 N - X CH3

H3C CN H3C POLYMETHINE CH2CH3 Basic Yellow 13 NO2 CI 48056 N O N O (R , R' = H) Cl N N NC CH2CH2-O-C

H O CH2CH3 CN METHINE Disperse Yellow 9O Cl AZO PYRIDONE CI 48OO7 O Disperse Yellow 211 CI 12755 N

H3CH2C R' N O O Br CH CH CH 2 3 OH 3 COUMERIN DYES O R N N Disperse Yellow 232 R CI 55165 N CH3 N R' MONO AZO DYES H O Solvent Yellow 2 CI 11020 QUINOLINE DYES (Butter Yellow) Disperse Yellow 64 NO2 (R , R' = H) CI 47023 H O (R , R' = H) Cl N CH3 N

NH CH3 O NO2 R CO Na 2 H H N SO3Na O2N N N Cl N N HANSA-TYPE YELLOWS O AZO PYRAZOLONES Pigment Yellow 98 NITRODIPHENYL AMINE DYES NaO3S Acid Yellow 23 CI 11727 Disperse Yellow 14 CI 19140 CI 10340 53 (R = H) (NOTE: portions in red show potential sites for modification METHINE & AZOMETHINES

METHINE Disperse Yellow 9O CI 48OO7

Active Methylene

Knoevenagel condensation 1. Ethanol/reflux

NH4OAc [cat] Aldehyde 2. Cool/ppt filter

54 (B) Donor-Acceptor Chromogens: METHINE & AZOMETHINES METHINEs & AZOMETHINES

H3CO O max = 371 nm max = 386 nm max = 392 nm max = 386 nm max = 424 nm max = 440 nm HO C-H CV = 129.9 CV = 98.4 CV = 51 CV = 94.0

O H3C  = 422 nm  = 430 nm  = 448 nm  = 456 nm  = 466 nm  = 493 nm  = 519 nm N C-H max max max max max max max H3C CV = 55 CV = 276 CV = CV = 219.6 CV = 141 CV = 237 CV = 217.4

O H CH C 3 2  = 429 nm  = 458 nm  = 462 nm  = 470nm  = 511 nm  = 525 nm max max = 436 nm max max max max max N C-H CV = 85 CV = 89.2 CV = 217.3 CV = 140 CV = 200 CV = 143 H3CH2C CV = 263

O H CH C 3 2  = 440 nm  = 476 nm max = 470 nm  = 516 nm  = 544 nm max max = 446 nm max max max N C-H CV = 62  = 490 nmMeOH CV = 200 CV = 165.7 CV = 244 max H3CH2C CV = 141 MeOH CH3

O H3C max = 452 nm max = 552 nm N C-H CV = CV = 85 MeOH EthOH H3C

 = 520 nm O max = 442 nm max = 483 nm max = 483 nm max = 486 nm max max = 548 CV = 76 max = 456 nm CV = 103 CV = 195 max=522 nmEthOH CV = 222 N C-H CV = 226 CV = 254 EthOH

O H3C max = 483 nm max = 514 nm max = 484 nm max = 576 nm max =591 nm N CH=CH-C-H CV = 167 CV = 195 H3C CV = 199

H3CH2C max = 495 nm max = 513 nm max = 427nm max = 521 nm N N=O CV = 220 CV = 99 H3CH2C

NOTE: All spectral measurements performed in acetone unless otherwise stated 55 CV =  /MW METHINE & AZOMETHINES

56 III. SYNTHETIC STRATEGIES FOR TAILOR MAKING DYES:

VARIOUS CLASSES OF RED & MAGENTA CHROMOPHORES THAT ARE COMMERCIALLY AVAILABLE and/or SYNTHETICALLY ACCESSIBLE R O2N S N CH2CH2-CN N N N

H3CH2C CH2CH3 O CH2CH2-OCOCH3 N O N MONO AZO DYES H CH C CH2CH3 R 3 2 HN NH Disperse Red 177 NC CH3 CI 11122 (Bright Bluish Pink) N CO2 - O

NC CH3

CN METHINE Magenta XANTHENE R Org. Syn. Col. Vol. 4 p.953 C.I. Solvent Red 49 DPP (Diketopyrrolopyrrole) O (R = H) C.I. 45170:1 H H C N O (Bright Bluish Red) C.I. Pigment Red 255 (R=H) 3 (Rhodamine B) C.I. 561050 NH-CH3 (BrightYellowish Red) N CH3 H O O NH 2 QUINACRIDONE O R C.I. Pigment Red 122 O HN C.I. 73915 SO3Na (Bright Bluish Red) ANTHRAPYRIDONE O OH ANTHRAQUINONE Acid Red 80 CH3 Disperse Red 60 (R=H) CH3 CI 68215 CI 60756 Br (Bright Bluish Red) (Bluish Red) O HN Ba2+ Br SO - H C R' 3 3 CH 3 H O CO2 - R CH CH 2 3 H C N R CH CH N 3 N CH -CH O OH N - Cl 2 3 CH3 ANTHRAQUINONE POLYMETHINE Solvent Red 172 Basic Violet 16 LITHOL RUBINE CI 607280 CI 48013 C.I. Pigment Red 57:2 Magenta (Bright Bluish Red) C.I. 15850:2 - Ba Salt (R , R' = H) (Bluish Red) (NOTE: portions in red show potential sites for modification 57 H CH C CH CH 3 2 2 3 RHODAMINES N O N CH2CH3 H3CH2C

CO2 -

XANTHENE C.I. Solvent Red 49 C.I. 45170:1 (Bright Bluish Red) (Rhodamine B) RHODAMINES

59 III. SYNTHETIC STRATEGIES FOR TAILOR MAKING DYES: OH HO O VARIOUS CLASSES OF BLACK CHROMOPHORES THAT ARE OH R COMMERCIALLY AVAILABLE and/or SYNTHETICALLY ACCESSIBLE R NaO2C NH2 R H HO N H O O2N NH2 O N N N HO R N N O N N Natural Black 1 DISAZO DYE HO S NaO3S SO3Na CI 75290 (w/ Hydrazone) 3 R (R=H) Direct Black 51 CI 27720 DISAZO DYE (R=H) (w/ Hydrazone) NH Acid Black 1 CH3 CI 20470 N N N CH (R=H) R N NH 3 R N N N N N N N N N N H H H H X DISAZO DYE X X Solvent Black 3 DIAZINE DYE CI 26150 Pigment Black 1 (R=H) (Aniline Black) CI 50440 (R=H)

R N X

R N N NO N N N 2 X N Cl OH O O +3 Cr O C MONO AZO DYES DIAZINE/AZO DYE O Solvent Black 35 (R=H) Basic Black 2 CARBON BLACK N CI 12198 CI 11825 Pigment Black 7 O2N N (is the chromium salt (R=H) CI 77266 of CI 121945 & 121965) R

(NOTE: portions in red show potential sites for modification 60 DISAZO BLACK NH CH3

CH R N NH 3 N N N

DISAZO DYE Solvent Black 3 CI 26150 (R=H)

2,3-dihydro-2,2- Toluene dimethylperimidine Reflux adduct Dean-Star Trap

[-H2O] acetone 1,8-diaminonaphthalene

HONO

Solvent Black 3 61 DIAZO DYES [PYRIMIDINE INTERMEDIATE]

2,3-dihydro-2,2- Toluene dimethylperimidine Reflux adduct Dean-Star Trap

[-H2O] acetone 1,8-diaminonaphthalene

Toluene 2,3-dihydro-2,2- Reflux distearylperimidine Dean-Star Trap adduct

[-H2O] stearone

2,3-dihydro-2,2- Toluene methyl, hydroxyethyl Reflux perimidine adduct Dean-Star Trap [-H O] 2-Hydroxyethyl Methyl Ketone 2

HONO Solvent Black 3

HONO

140 USP 8884012 11-11-2014 Xerox - Dye Compound and Method of Making the Compound [waxy pyrimidine intermediate for SK3 and Squarine based NIR dyes] 147 USP 9193869 11-24-15 Xerox Dye compounds, method of making the compounds and ink composition employing the compounds [DSSK, Squaric IR dye, etc.] 149 USP 9309410 4-12-16 Xerox COLORANT COMPOUNDS [IR absorb and SK3 dyes] 155 USP 9738811 8-22-17 Xerox Phase Change Inks Containing Wax-Soluble Near IR Dyes [Squaric acid NIR Dye] 65 140 USP 8884012 11-11-2014 Xerox - Dye Compound and Method of Making the Compound [waxy pyrimidine intermediate for SK3 and Squarine based NIR dyes] 147 USP 9193869 11-24-15 Xerox Dye compounds, method of making the compounds and ink composition employing the compounds [DSSK, Squaric IR dye, etc.] 149 USP 9309410 4-12-16 Xerox COLORANT COMPOUNDS [IR absorb and SK3 dyes] 155 USP 9738811 8-22-17 Xerox Phase Change Inks Containing Wax-Soluble Near IR Dyes [Squaric acid NIR Dye] 66 R X METALLIZED AZO DYE

N NO2 N O O +3 Cr O MONO AZO DYES O Solvent Black 35 (R=H) N CI 12198

O2N N (is the chromium salt of CI 121945 & 121965) R

Can be a 1o 2o or 3o amine

67 Preparation of Derivatives of Metallized Dyes

M3+ M3+

Free acid form of metal complexed dye

Can be a 1o 2o or 3o amine

Free acid form of metal complexed dye 68 Special Thanks to

• Sarah Patty, Jian Yao, Alex Kugel, Tim Andrews, Virginia Espina, Michael Harpole, Ruben Magni, Amanda Haymond, Marcus Peterson, James Hart, Jim O’Connell, Lori Lancaster, Max Weaver, John Griffiths, James Esplin, Keith Grosse and Arnold Ariss, Marty Jones, the entire Ink R&D group (XOG), former colleagues at XRCC, current colleagues at 3DSystems